docs: Add tx/rpc AGENTS.md files and symlink convention

Documents the amendment workflow (features.macro) under src/libxrpl/tx
and the API-CHANGELOG.md requirement under src/xrpld/rpc. Also makes
it an explicit rule in CONTRIBUTING.md that any new AGENTS.md gets a
CLAUDE.md symlink alongside it.

.cspell.config.yaml

@@ -256,8 +256,6 @@ words:
   - replayer
   - repodata
   - repomd
-  - repost
-  - reposts
   - rerandomize
   - rerandomization
   - rerandomized
@@ -305,7 +303,6 @@ words:
   - sponsees
   - SRPMS
   - sslws
-  - stackful
   - statsd
   - STATSDCOLLECTOR
   - stissue

.github/actions/cargo-cache/action.yml

@@ -0,0 +1,38 @@
+name: Use cargo artifacts cache
+description: >
+  Cache the cargo build artifacts with rust-cache. Never caches ~/.cargo/bin:
+  when saving the cache, rust-cache deletes all binaries that were already
+  present there, which on persistent self-hosted runners wipes the tools
+  installed by prepare-runner. Harmless on ephemeral runners, but kept
+  consistent everywhere.
+
+inputs:
+  workspaces:
+    description: "Workspaces to cache, as 'workspace -> target' lines."
+    required: false
+    default: crates
+  key:
+    description: "Additional part of the cache key."
+    required: false
+    default: ""
+  cache-directories:
+    description: "Additional non-workspace directories to cache."
+    required: false
+    default: ""
+  save-if:
+    description: "Condition for saving the cache after the job."
+    required: false
+    default: "true"
+
+runs:
+  using: composite
+
+  steps:
+    - name: Use cargo artifacts cache
+      uses: Swatinem/rust-cache@6323deb102c322ba6fcbdcafc7e3dddab59af2b6 # v2.9.2
+      with:
+        cache-bin: "false"
+        cache-directories: ${{ inputs.cache-directories }}
+        key: ${{ inputs.key }}
+        save-if: ${{ inputs.save-if }}
+        workspaces: ${{ inputs.workspaces }}

.github/dependabot.yml

@@ -4,6 +4,7 @@ updates:
     directories:
       - /
       - .github/actions/build-deps/
+      - .github/actions/cargo-cache/
       - .github/actions/release-info/
       - .github/actions/set-compiler-env/
       - .github/actions/setup-conan/

.github/workflows/build-nix-images.yml

@@ -58,7 +58,7 @@ jobs:
             base_image: debian:bookworm
           - name: rhel
             base_image: registry.access.redhat.com/ubi9/ubi:latest
-    uses: XRPLF/actions/.github/workflows/build-multiarch-image.yml@9e7e4e80af9e684c116b38369add8eea64451f32
+    uses: XRPLF/actions/.github/workflows/build-multiarch-image.yml@65d5a0bd72be4ecea95cff0673a6e0672ab5243a
     with:
       image_name: xrpld/nix-${{ matrix.distro.name }}
       dockerfile: nix/docker/Dockerfile

.github/workflows/build-packaging-images.yml

@@ -39,7 +39,7 @@ jobs:
           # AlmaLinux rather than UBI9, which does not ship rpm-sign.
           - name: rhel
             base_image: almalinux:9
-    uses: XRPLF/actions/.github/workflows/build-multiarch-image.yml@9e7e4e80af9e684c116b38369add8eea64451f32
+    uses: XRPLF/actions/.github/workflows/build-multiarch-image.yml@65d5a0bd72be4ecea95cff0673a6e0672ab5243a
     with:
       image_name: xrpld/packaging-${{ matrix.distro.name }}
       dockerfile: package/Dockerfile

.github/workflows/build-pre-commit-image.yml

@@ -30,7 +30,7 @@ jobs:
     permissions:
       contents: read
       packages: write
-    uses: XRPLF/actions/.github/workflows/build-multiarch-image.yml@9e7e4e80af9e684c116b38369add8eea64451f32
+    uses: XRPLF/actions/.github/workflows/build-multiarch-image.yml@65d5a0bd72be4ecea95cff0673a6e0672ab5243a
     with:
       image_name: xrpld/pre-commit
       dockerfile: bin/pre-commit/Dockerfile

.github/workflows/check-tools.yml

@@ -79,7 +79,7 @@ jobs:
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
 
       - name: Prepare runner
-        uses: XRPLF/actions/prepare-runner@51af40f99ea91a08c3528ddf16d98132dcc7e63c
+        uses: XRPLF/actions/prepare-runner@7bf7ceca5932114abdd0d43493c3c30c5a654e13
         with:
           enable_ccache: false
 

.github/workflows/pre-commit.yml

@@ -14,7 +14,7 @@ on:
 jobs:
   # Call the workflow in the XRPLF/actions repo that runs the pre-commit hooks.
   run-hooks:
-    uses: XRPLF/actions/.github/workflows/pre-commit.yml@3ba08d6ddf114092891d48491fc2e26c3ba15552
+    uses: XRPLF/actions/.github/workflows/pre-commit.yml@f1952595d212e86169935135efc66294b4574131
     with:
       runs_on: ubuntu-latest
       container: '{ "image": "ghcr.io/xrplf/xrpld/pre-commit:sha-f56b79f" }'

.github/workflows/publish-docs.yml

@@ -47,7 +47,7 @@ jobs:
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
 
       - name: Prepare runner
-        uses: XRPLF/actions/prepare-runner@51af40f99ea91a08c3528ddf16d98132dcc7e63c
+        uses: XRPLF/actions/prepare-runner@7bf7ceca5932114abdd0d43493c3c30c5a654e13
         with:
           enable_ccache: false
 

.github/workflows/reusable-build-test-config.yml

@@ -129,7 +129,7 @@ jobs:
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
 
       - name: Prepare runner
-        uses: XRPLF/actions/prepare-runner@51af40f99ea91a08c3528ddf16d98132dcc7e63c
+        uses: XRPLF/actions/prepare-runner@7bf7ceca5932114abdd0d43493c3c30c5a654e13
         with:
           enable_ccache: ${{ inputs.ccache_enabled }}
 
@@ -163,7 +163,7 @@ jobs:
           compiler: ${{ inputs.compiler }}
 
       - name: Use cargo artifacts cache
-        uses: Swatinem/rust-cache@6323deb102c322ba6fcbdcafc7e3dddab59af2b6 # v2.9.2
+        uses: ./.github/actions/cargo-cache
         with:
           cache-directories: ${{ env.BUILD_DIR }}/corrosion
           key: ${{ inputs.config_name }}

.github/workflows/reusable-clang-tidy.yml

@@ -27,7 +27,7 @@ jobs:
   determine-files:
     permissions:
       contents: read
-    uses: XRPLF/actions/.github/workflows/determine-tidy-files.yml@d041ac9f1fa9f07a4ba335eb4c1c82233fb3fef6
+    uses: XRPLF/actions/.github/workflows/determine-tidy-files.yml@70145243b905dc3e040a61d39c00e178cfb96f71
 
   run-clang-tidy:
     name: Run clang tidy
@@ -43,7 +43,7 @@ jobs:
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
 
       - name: Prepare runner
-        uses: XRPLF/actions/prepare-runner@51af40f99ea91a08c3528ddf16d98132dcc7e63c
+        uses: XRPLF/actions/prepare-runner@7bf7ceca5932114abdd0d43493c3c30c5a654e13
         with:
           enable_ccache: false
 
@@ -60,7 +60,7 @@ jobs:
           compiler: ${{ env.COMPILER }}
 
       - name: Use cargo artifacts cache
-        uses: Swatinem/rust-cache@6323deb102c322ba6fcbdcafc7e3dddab59af2b6 # v2.9.2
+        uses: ./.github/actions/cargo-cache
         with:
           cache-directories: ${{ env.BUILD_DIR }}/corrosion
           save-if: ${{ github.ref == 'refs/heads/develop' || startsWith(github.ref, 'refs/heads/release') }}

.github/workflows/reusable-rust.yml

@@ -33,9 +33,7 @@ jobs:
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
 
       - name: Use cargo artifacts cache
-        uses: Swatinem/rust-cache@6323deb102c322ba6fcbdcafc7e3dddab59af2b6 # v2.9.2
-        with:
-          workspaces: crates
+        uses: ./.github/actions/cargo-cache
 
       - name: Run clippy
         run: cargo clippy --workspace --all-targets --all-features --locked -- -D warnings
@@ -48,9 +46,7 @@ jobs:
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
 
       - name: Use cargo artifacts cache
-        uses: Swatinem/rust-cache@6323deb102c322ba6fcbdcafc7e3dddab59af2b6 # v2.9.2
-        with:
-          workspaces: crates
+        uses: ./.github/actions/cargo-cache
 
       - name: Generate coverage report
         run: cargo llvm-cov nextest --workspace --all-features --locked --no-tests=warn --lcov --output-path lcov.info
@@ -76,9 +72,7 @@ jobs:
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
 
       - name: Use cargo artifacts cache
-        uses: Swatinem/rust-cache@6323deb102c322ba6fcbdcafc7e3dddab59af2b6 # v2.9.2
-        with:
-          workspaces: crates
+        uses: ./.github/actions/cargo-cache
 
       - name: Build documentation
         env:

.github/workflows/upload-conan-deps.yml

@@ -68,7 +68,7 @@ jobs:
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
 
       - name: Prepare runner
-        uses: XRPLF/actions/prepare-runner@c00c22ada3bd6bcda48fcb0d62fbbab49fec8a0f
+        uses: XRPLF/actions/prepare-runner@7bf7ceca5932114abdd0d43493c3c30c5a654e13
         with:
           enable_ccache: false
 

.gitignore

@@ -72,11 +72,19 @@ DerivedData
 /.zed/
 
 # AI tools.
+# Shared/committable AI agent config (AGENTS.md, CLAUDE.md, GEMINI.md, .claude/settings.json,
+# tool-specific rules files, etc.) should be checked in — see CONTRIBUTING.md. Only the
+# personal/local variants below are ignored.
 /.agent
 /.agents
 /.augment
-/.claude
-/CLAUDE.md
+/.claude/settings.local.json
+AGENTS.local.md
+CLAUDE.local.md
+GEMINI.local.md
+.aider.chat.history.md
+.aider.input.history
+.aider.tags.cache.v3
 
 # Python
 __pycache__

AGENTS.md

@@ -0,0 +1,73 @@
+# AGENTS.md
+
+This file provides guidance to AI coding agents (Claude Code, and other AGENTS.md-compatible tools) when working with code in this repository. `CLAUDE.md` is a symlink to this file.
+
+For personal, untracked notes to an AI agent (not meant to be shared with other contributors), use `AGENTS.local.md` / `CLAUDE.local.md` instead — see [CONTRIBUTING.md](./CONTRIBUTING.md).
+
+## Build
+
+Preferred: use the Nix devshell, which sets up the compiler, Conan, ccache, and (optionally) Rust automatically.
+
+```bash
+nix develop # default shell (clang on macOS, gcc on Linux); also .#gcc, .#clang, .#gcc-plain, .#clang-plain, .#apple-clang
+```
+
+Manual build (also what the devshell does under the hood):
+
+```bash
+./conan/init.sh         # one-time Conan profile/remote setup (auto-run inside nix develop)
+mkdir .build && cd .build
+conan install .. --output-folder . --build missing --settings build_type=Release
+cmake -DCMAKE_TOOLCHAIN_FILE:FILEPATH=build/generators/conan_toolchain.cmake -DCMAKE_BUILD_TYPE=Release -Dxrpld=ON -Dtests=ON ..
+cmake --build . --parallel <N>
+```
+
+Key CMake options: `-Dxrpld=ON` (build the server binary, not just `libxrpl`), `-Dtests=ON`, `-Drust=ON` (builds `crates/`, requires cargo/rustc — off by default but always on in CI), `-Dunity=ON`, `-Dcoverage=ON`, `-Dwerr=ON`. `-Dverify_headers` is on by default; `cmake --build . --target verify-headers` compiles every header standalone.
+
+Protocol codegen (from `.macro` files) must be regenerated and committed when changed:
+
+```bash
+cmake --build . --target setup_code_gen
+cmake --build . --target code_gen
+```
+
+Rust crate tests (independent of the CMake build): `cargo test --manifest-path crates/Cargo.toml --workspace` (CI uses `cargo nextest`).
+
+## Testing
+
+Unit tests are a custom framework built into the `xrpld` binary itself (not Boost.Test/GTest/Catch). Build first (e.g. `cmake --build .build -j10`), then run from the build directory:
+
+```bash
+.build/xrpld --unittest --unittest-jobs <N>     # run all suites; N = ~half of available cores
+.build/xrpld --unittest xrpl.app.Credentials    # run one suite by name
+```
+
+(Multi-config generators produce the binary under e.g. `.build/Release/xrpld`.) A suite's `--unittest` name is built from the arguments to its `BEAST_DEFINE_TESTSUITE`/`BEAST_DEFINE_TESTSUITE_PRIO` macro (usually at the bottom of the test file), in reverse order and joined with `.`: `BEAST_DEFINE_TESTSUITE(Credentials, app, xrpl)` → `xrpl.app.Credentials`. `--unittest` also matches by prefix unless there's an exact name match, in which case only that exact suite runs. `--unittest-arg` does nothing — don't use it. Tests that run offline in under a minute should be automatic `--unittest` suites under `src/test/`; anything else is a manual/integration test. `tests/` (top-level, separate from `src/test/`) holds integration tests exercised against `libxrpl`/`xrpld`.
+
+## Lint/Format
+
+```bash
+pip install pre-commit && pre-commit install
+pre-commit run --all-files
+pre-commit run clang-format --all-files # single hook
+TIDY=1 pre-commit run clang-tidy        # clang-tidy is opt-in (needs local clang-tidy + generated headers)
+```
+
+Manual clang-tidy: build the `tidy_prerequisites` target first, then `run-clang-tidy -p build -allow-no-checks src tests` (add `-fix -format` to auto-fix).
+
+## Architecture
+
+- `include/xrpl/` + `src/libxrpl/` — the core protocol library: ledger, shamap, consensus, crypto, json, resource, nodestore, rdb, peerfinder, and `tx/` (transaction application: `Transactor.cpp`, `applySteps.cpp`, invariants, payment paths). `tx/transactors/` has one file per transaction type, grouped by subsystem: `escrow/`, `vault/`, `lending/`, `sponsor/`, `nft/`, `token/` (MPT), `payment_channel/`, `permissioned_domain/`, `dex/`, `oracle/`, `did/`, `credentials/`, `bridge/`, `check/`, `delegate/`, `account/`, `system/`. Any change to transaction-processing behavior must be gated behind an Amendment.
+- `src/xrpld/` — the server application built on top of `libxrpl`: `app`, `core`, `overlay` (P2P networking), `peerfinder`, `perflog`, `rpc`, `shamap`. `main` builds an `ApplicationImp` implementing `Application`; most components hold a reference to it (`app_`), giving broad cross-component access — expect to trace call chains through `Application&`.
+- `src/test/` — unit tests mirroring the subsystems above, plus `jtx/` (the transaction-building test DSL — e.g. `jtx/escrow.h`, `jtx/vault.h`, `jtx/sponsor.h`, `jtx/permissioned_dex.h`) and `unit_test/` (the custom test framework itself, derived from Beast).
+- `src/tests/` — a second, separate tree of integration-style tests for `libxrpl`.
+- `crates/` — a Rust workspace (only built with `-Dxrpld -Drust=ON`) bridged into C++ via `cxxbridge`/the `cxx` crate; currently just a `hello_world` interop scaffold. Requires the Rust toolchain pinned in `rust-toolchain.toml` (the Nix devshell provides it automatically).
+
+## Code Style (see `docs/CodingStyle.md` and `CONTRIBUTING.md` for full detail)
+
+- New file placement is strict: `libxrpl` headers → `include/xrpl`; `libxrpl` sources → `src/libxrpl`; other non-test server code → `src/xrpld`; tests → `src/test`; benchmarks → `src/benchmarks`.
+- Header includes must stay levelized (checked by `.github/scripts/levelization`).
+- Allman braces, tabs-as-4-spaces (no literal tabs), 80-char lines, east `const`, no naked `new`/`delete`, `*`/`&` bound to the type not the variable (`SomeObject* myObject`), never declare multiple pointers/refs in one statement.
+- Class member order: private members first, then the six special members in order (dtor, default ctor, copy ctor, copy assign, move ctor, move assign).
+- Use `XRPL_ASSERT`/`UNREACHABLE` instead of raw `assert`/`assert(false)` outside constexpr functions and unit tests; each needs a unique name of the form `scope::function : short description` (used for Antithesis instrumentation).
+- Commits: imperative subject line ≤50 chars (72 hard limit), capitalized, no trailing period; each commit should build and pass tests on its own; prefer squashing to one logical commit per PR.

CLAUDE.md

@@ -0,0 +1 @@
+AGENTS.md

CONTRIBUTING.md

@@ -59,6 +59,12 @@ to an existing XLS. Neither change will be released (in an amendment's
 case, marked as `Supported::yes`) until the corresponding XLS's status
 is `Final`.
 
+## AI coding agents
+
+[`AGENTS.md`](./AGENTS.md) (and its `CLAUDE.md` symlink, for Claude Code) holds shared, checked-in guidance for AI coding agents working in this repository — build/test/lint commands and architecture notes. Additional `AGENTS.md` files may exist in subdirectories to give agents context specific to that part of the codebase; whenever you add one, also add a `CLAUDE.md` symlink pointing to it (`ln -s AGENTS.md CLAUDE.md`) so Claude Code picks it up too.
+
+If you want to give an agent personal instructions that shouldn't be shared with other contributors (e.g. your own workflow preferences), put them in `AGENTS.local.md` or `CLAUDE.local.md` instead — those are gitignored. Likewise, `.claude/settings.local.json` is for personal, untracked Claude Code settings, while `.claude/settings.json` is shared.
+
 ## Before making a pull request
 
 (Or marking a draft pull request as ready.)

cmake/XrplCompiler.cmake

@@ -120,7 +120,10 @@ if(MSVC)
             _SILENCE_ALL_CXX17_DEPRECATION_WARNINGS
             $<$<AND:$<COMPILE_LANGUAGE:CXX>,$<CONFIG:Debug>>:_CRTDBG_MAP_ALLOC>
     )
-    target_link_libraries(common INTERFACE -errorreport:none -machine:X64)
+    target_link_libraries(
+        common
+        INTERFACE -errorreport:none -machine:X64 -ignore:4099
+    )
 else()
     target_compile_options(
         common

crates/Cargo.lock

@@ -57,9 +57,9 @@ dependencies = [
 
 [[package]]
 name = "cxx"
-version = "1.0.198"
+version = "1.0.199"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6fe442a792c7c736eea18b32a7f8a3b63cf8aafabda6760042dc2fdeda456291"
+checksum = "824894a4a85dca76d4c95c2b9098c036f5a29f627b30c12780774f6654e60974"
 dependencies = [
  "cc",
  "cxx-build",
@@ -72,9 +72,9 @@ dependencies = [
 
 [[package]]
 name = "cxx-build"
-version = "1.0.198"
+version = "1.0.199"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e3184a94384c663718698311a78a51ac00c484c10b4eeac06fb0a068c5f64fa2"
+checksum = "f1ae0b651ea5b0000b19513aef5a03f194d7e3486f2d9258b658da8677fe9036"
 dependencies = [
  "cc",
  "codespan-reporting",
@@ -87,9 +87,9 @@ dependencies = [
 
 [[package]]
 name = "cxxbridge-cmd"
-version = "1.0.198"
+version = "1.0.199"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0148d8fd1199329ddf1d157a5e134e51ceff37c6a7ddd38615c399d81cb05d8d"
+checksum = "fb05f91d3fb8435d9bab6ac5ce6ac1868be774325fb7fb2a91be39393b21388e"
 dependencies = [
  "clap",
  "codespan-reporting",
@@ -101,15 +101,15 @@ dependencies = [
 
 [[package]]
 name = "cxxbridge-flags"
-version = "1.0.198"
+version = "1.0.199"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "52850339faed2eaadd24e286dc1d8268cc6f8a7bd9524d713adc9099566b4c89"
+checksum = "bf293202e0e3e98495785745389e8d0755b217e66f19194a5c695c25e03282ef"
 
 [[package]]
 name = "cxxbridge-macro"
-version = "1.0.198"
+version = "1.0.199"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2c77c856545d886c9bd5215409ebb63b925e262135248b50c79e5a5f194ee47c"
+checksum = "ca001d746947c7249ed9d332a10f7a59daedbafeb0ec68c5c18a7db7a93f6ccc"
 dependencies = [
  "indexmap",
  "proc-macro2",

docs/install.md

@@ -65,7 +65,7 @@ wherever it appears in the repository configuration.
 4.  Add the repository, using the channel you picked in [Release channels](#release-channels):
 
     ```bash
-    echo "deb [signed-by=/etc/apt/keyrings/xrplf.asc] https://packages.xrplf.org/repository/deb-stable focal main" | \
+    echo "deb [signed-by=/etc/apt/keyrings/xrplf.asc] https://packages.xrplf.org/repository/deb-stable any main" | \
         sudo tee /etc/apt/sources.list.d/xrplf.list
     ```
 
@@ -98,13 +98,13 @@ wherever it appears in the repository configuration.
     enabled=1
     baseurl=https://packages.xrplf.org/repository/rpm-stable/
     gpgcheck=1
-    repo_gpgcheck=0
+    repo_gpgcheck=1
     gpgkey=https://packages.xrplf.org/xrplf.asc
     REPOFILE
     ```
 
     `gpgcheck=1` verifies each package against the key above.
-    `repo_gpgcheck` is off because the repository metadata is generated by the server and is not signed.
+    `repo_gpgcheck=1` verifies the repository metadata, which the server signs with the same key.
 
 3.  Install the `xrpld` package:
 

include/xrpl/core/CoroTask.h

@@ -1,713 +0,0 @@
-#pragma once
-
-#include <xrpl/beast/utility/instrumentation.h>
-
-#include <coroutine>
-#include <exception>
-#include <type_traits>
-#include <utility>
-#include <variant>
-
-namespace xrpl {
-
-template <typename T = void>
-class CoroTask;
-
-/**
- * CoroTask<void> -- coroutine return type for void-returning coroutines.
- *
- * Class / Dependency Diagram
- * ==========================
- *
- *   CoroTask<void>
- *   +-----------------------------------------------+
- *   | - handle_ : Handle (coroutine_handle<promise>) |
- *   +-----------------------------------------------+
- *   | + handle(), done()                             |
- *   | + await_ready/suspend/resume  (Awaiter iface)  |
- *   +-----------------------------------------------+
- *            |  owns
- *            v
- *   promise_type
- *   +-----------------------------------------------+
- *   | - exception_    : std::exception_ptr           |
- *   | - continuation_ : std::coroutine_handle<>      |
- *   +-----------------------------------------------+
- *   | + get_return_object() -> CoroTask              |
- *   | + initial_suspend()   -> suspend_always (lazy) |
- *   | + final_suspend()     -> FinalAwaiter          |
- *   | + return_void()                                |
- *   | + unhandled_exception()                        |
- *   +-----------------------------------------------+
- *            |  returns at final_suspend
- *            v
- *   FinalAwaiter
- *   +-----------------------------------------------+
- *   | await_suspend(h):                              |
- *   |   if continuation_ set -> symmetric transfer   |
- *   |   else                 -> noop_coroutine        |
- *   +-----------------------------------------------+
- *
- * Design Notes
- * ------------
- * - Lazy start: initial_suspend returns suspend_always, so the coroutine
- *   body does not execute until the handle is explicitly resumed.
- * - Symmetric transfer: await_suspend returns a coroutine_handle instead
- *   of void/bool, allowing the scheduler to jump directly to the next
- *   coroutine without growing the call stack.
- * - Continuation chaining: when one CoroTask is co_await-ed inside
- *   another, the caller's handle is stored as continuation_ so
- *   FinalAwaiter can resume it when this task finishes.
- * - Move-only: the handle is exclusively owned; copy is deleted.
- *
- * Usage Examples
- * ==============
- *
- * 1. Basic void coroutine (the most common case in xrpld):
- *
- *      CoroTask<void> doWork(std::shared_ptr<CoroTaskRunner> runner) {
- *          // do something
- *          co_await runner->suspend();   // yield control
- *          // resumed later via runner->post() or runner->resume()
- *          co_return;
- *      }
- *
- * 2. co_await-ing one CoroTask<void> from another (chaining):
- *
- *      CoroTask<void> inner() {
- *          // ...
- *          co_return;
- *      }
- *      CoroTask<void> outer() {
- *          co_await inner();   // continuation_ links outer -> inner
- *          co_return;          // FinalAwaiter resumes outer
- *      }
- *
- * 3. Exceptions propagate through co_await:
- *
- *      CoroTask<void> failing() {
- *          throw std::runtime_error("oops");
- *          co_return;
- *      }
- *      CoroTask<void> caller() {
- *          try { co_await failing(); }
- *          catch (std::runtime_error const&) { // caught here }
- *      }
- *
- * Caveats / Pitfalls
- * ==================
- *
- * BUG-RISK: Dangling references in coroutine parameters.
- *   Coroutine parameters are copied into the frame, but references
- *   are NOT -- they are stored as-is. If the referent goes out of scope
- *   before the coroutine finishes, you get use-after-free.
- *
- *      // BROKEN -- local dies before coroutine runs:
- *      CoroTask<void> bad(int& ref) { co_return; }
- *      void launch() {
- *          int local = 42;
- *          auto task = bad(local);  // frame stores &local
- *      }  // local destroyed; frame holds dangling ref
- *
- *      // FIX -- pass by value, or ensure lifetime via shared_ptr.
- *
- * BUG-RISK: GCC 14 corrupts reference captures in coroutine lambdas.
- *   When a lambda that returns CoroTask captures by reference ([&]),
- *   GCC 14 may generate a corrupted coroutine frame. Always capture
- *   by explicit pointer-to-value instead:
- *
- *      // BROKEN on GCC 14:
- *      jq.postCoroTask(t, n, [&](auto) -> CoroTask<void> { ... });
- *
- *      // FIX -- capture pointers explicitly:
- *      jq.postCoroTask(t, n, [ptr = &val](auto) -> CoroTask<void> { ... });
- *
- * BUG-RISK: Resuming a destroyed or completed CoroTask.
- *   Calling handle().resume() after the coroutine has already run to
- *   completion (done() == true) is undefined behavior. The CoroTaskRunner
- *   guards against this with an XRPL_ASSERT, but standalone usage of
- *   CoroTask must check done() before resuming.
- *
- * BUG-RISK: Moving a CoroTask that is being awaited.
- *   If task A is co_await-ed by task B (so A.continuation_ == B), moving
- *   or destroying A will invalidate the continuation link. Never move
- *   or reassign a CoroTask while it is mid-execution or being awaited.
- *
- * LIMITATION: CoroTask is fire-and-forget for the top-level owner.
- *   There is no built-in notification when the coroutine finishes.
- *   The caller must use external synchronization (e.g. CoroTaskRunner::join
- *   or a gate/condition_variable) to know when it is done.
- *
- * LIMITATION: No cancellation token.
- *   There is no way to cancel a suspended CoroTask from outside. The
- *   coroutine body must cooperatively check a flag (e.g. jq_.isStopping())
- *   after each co_await and co_return early if needed.
- *
- * LIMITATION: Stackless -- cannot suspend from nested non-coroutine calls.
- *   If a coroutine calls a regular function that wants to "yield", it
- *   cannot. Only the immediate coroutine body can use co_await.
- *   This is acceptable for xrpld because all yield() sites are shallow.
- */
-template <>
-class CoroTask<void>
-{
-public:
-    // The C++ coroutine protocol mandates these names (promise_type,
-    // initial_suspend, await_ready, ...) and instance-callable awaiter
-    // methods, which conflict with the project naming/static conventions.
-    // NOLINTBEGIN(readability-identifier-naming, readability-convert-member-functions-to-static)
-    struct promise_type;
-    using Handle = std::coroutine_handle<promise_type>;
-
-    /**
-     * Coroutine promise. Compiler uses this to manage coroutine state.
-     * Stores the exception (if any) and the continuation handle for
-     * symmetric transfer back to the awaiting coroutine.
-     */
-    struct promise_type
-    {
-        // Captured exception from the coroutine body, rethrown in
-        // await_resume() when this task is co_await-ed by a caller.
-        std::exception_ptr exception_;
-
-        // Handle to the coroutine that is co_await-ing this task.
-        // Set by await_suspend(). FinalAwaiter uses it for symmetric
-        // transfer back to the caller. Null if this is a top-level task.
-        std::coroutine_handle<> continuation_;
-
-        /**
-         * Create the CoroTask return object.
-         * Called by the compiler at coroutine creation.
-         */
-        CoroTask
-        get_return_object()
-        {
-            return CoroTask{Handle::from_promise(*this)};
-        }
-
-        /**
-         * Lazy start. The coroutine body does not execute until the
-         * handle is explicitly resumed (e.g. by CoroTaskRunner::resume).
-         */
-        std::suspend_always
-        initial_suspend() noexcept
-        {
-            return {};
-        }
-
-        /**
-         * Awaiter returned by final_suspend(). Uses symmetric transfer:
-         * if a continuation exists, transfers control directly to it
-         * (tail-call, no stack growth). Otherwise returns noop_coroutine
-         * so the coroutine frame stays alive for the owner to destroy.
-         */
-        struct FinalAwaiter
-        {
-            /**
-             * Always false. We need await_suspend to run for
-             * symmetric transfer.
-             */
-            bool
-            await_ready() noexcept
-            {
-                return false;
-            }
-
-            /**
-             * Symmetric transfer: returns the continuation handle so
-             * the compiler emits a tail-call instead of a nested resume.
-             * If no continuation is set, returns noop_coroutine to
-             * suspend at final_suspend without destroying the frame.
-             *
-             * @param h Handle to this completing coroutine
-             *
-             * @return Continuation handle, or noop_coroutine
-             */
-            std::coroutine_handle<>
-            await_suspend(Handle h) noexcept
-            {
-                if (auto cont = h.promise().continuation_)
-                    return cont;
-                return std::noop_coroutine();
-            }
-
-            void
-            await_resume() noexcept
-            {
-            }
-        };
-
-        /**
-         * Returns FinalAwaiter for symmetric transfer at coroutine end.
-         */
-        FinalAwaiter
-        final_suspend() noexcept
-        {
-            return {};
-        }
-
-        /**
-         * Called by the compiler for `co_return;` (void coroutine).
-         */
-        void
-        return_void()
-        {
-        }
-
-        /**
-         * Called by the compiler when an exception escapes the coroutine
-         * body. Captures it for later rethrowing in await_resume().
-         */
-        void
-        unhandled_exception()
-        {
-            exception_ = std::current_exception();
-        }
-    };
-    // NOLINTEND(readability-identifier-naming, readability-convert-member-functions-to-static)
-
-    /**
-     * Default constructor. Creates an empty (null handle) task.
-     */
-    CoroTask() = default;
-
-    /**
-     * Takes ownership of a compiler-generated coroutine handle.
-     *
-     * @param h Coroutine handle to own
-     */
-    explicit CoroTask(Handle h) : handle_(h)
-    {
-    }
-
-    /**
-     * Destroys the coroutine frame if this task owns one.
-     */
-    ~CoroTask()
-    {
-        if (handle_)
-            handle_.destroy();
-    }
-
-    /**
-     * Move constructor. Transfers handle ownership, leaves other empty.
-     */
-    CoroTask(CoroTask&& other) noexcept : handle_(std::exchange(other.handle_, {}))
-    {
-    }
-
-    /**
-     * Move assignment. Destroys current frame (if any), takes other's.
-     */
-    CoroTask&
-    operator=(CoroTask&& other) noexcept
-    {
-        if (this != &other)
-        {
-            if (handle_)
-                handle_.destroy();
-            handle_ = std::exchange(other.handle_, {});
-        }
-        return *this;
-    }
-
-    CoroTask(CoroTask const&) = delete;
-    CoroTask&
-    operator=(CoroTask const&) = delete;
-
-    /**
-     * @return The underlying coroutine_handle
-     */
-    [[nodiscard]] Handle
-    handle() const
-    {
-        return handle_;
-    }
-
-    /**
-     * @return true if the coroutine has run to completion (or thrown)
-     */
-    [[nodiscard]] bool
-    done() const
-    {
-        return handle_ && handle_.done();
-    }
-
-    // -- Awaiter interface: allows `co_await someCoroTask;` --
-
-    /**
-     * Always false. This task is lazy, so co_await always suspends
-     * the caller to set up the continuation link.
-     */
-    // NOLINTBEGIN(readability-identifier-naming, readability-convert-member-functions-to-static)
-    [[nodiscard]] bool
-    await_ready() const noexcept
-    {
-        return false;
-    }
-
-    /**
-     * Stores the caller's handle as our continuation, then returns
-     * our handle for symmetric transfer (caller suspends, we resume).
-     *
-     * @param caller Handle of the coroutine doing co_await on us
-     *
-     * @return Our handle for symmetric transfer
-     */
-    std::coroutine_handle<>
-    await_suspend(std::coroutine_handle<> caller) noexcept
-    {
-        XRPL_ASSERT(handle_, "xrpl::CoroTask<void>::await_suspend : handle is valid");
-        handle_.promise().continuation_ = caller;
-        return handle_;  // Symmetric transfer
-    }
-
-    /**
-     * Called in the awaiting coroutine's context after this task
-     * completes. Rethrows any exception captured by
-     * unhandled_exception().
-     */
-    void
-    await_resume()
-    {
-        XRPL_ASSERT(handle_, "xrpl::CoroTask<void>::await_resume : handle is valid");
-        if (auto& ep = handle_.promise().exception_)
-            std::rethrow_exception(ep);
-    }
-    // NOLINTEND(readability-identifier-naming, readability-convert-member-functions-to-static)
-
-private:
-    // Exclusively-owned coroutine handle. Null after move or default
-    // construction. Destroyed in the destructor.
-    Handle handle_;
-};
-
-/**
- * CoroTask<T> -- coroutine return type for value-returning coroutines.
- *
- * Class / Dependency Diagram
- * ==========================
- *
- *   CoroTask<T>
- *   +-----------------------------------------------+
- *   | - handle_ : Handle (coroutine_handle<promise>) |
- *   +-----------------------------------------------+
- *   | + handle(), done()                             |
- *   | + await_ready/suspend/resume  (Awaiter iface)  |
- *   +-----------------------------------------------+
- *            |  owns
- *            v
- *   promise_type
- *   +-----------------------------------------------+
- *   | - result_       : variant<monostate, T,        |
- *   |                           exception_ptr>       |
- *   | - continuation_ : std::coroutine_handle<>      |
- *   +-----------------------------------------------+
- *   | + get_return_object() -> CoroTask              |
- *   | + initial_suspend()   -> suspend_always (lazy) |
- *   | + final_suspend()     -> FinalAwaiter          |
- *   | + return_value(T)     -> stores in result_[1]  |
- *   | + unhandled_exception -> stores in result_[2]  |
- *   +-----------------------------------------------+
- *            |  returns at final_suspend
- *            v
- *   FinalAwaiter  (same symmetric-transfer pattern as CoroTask<void>)
- *
- * Value Extraction
- * ----------------
- * await_resume() inspects the variant:
- *   - index 2 (exception_ptr) -> rethrow
- *   - index 1 (T)             -> return value via move
- *
- * Usage Examples
- * ==============
- *
- * 1. Simple value return:
- *
- *      CoroTask<int> computeAnswer() { co_return 42; }
- *
- *      CoroTask<void> caller() {
- *          int v = co_await computeAnswer();  // v == 42
- *      }
- *
- * 2. Chaining value-returning coroutines:
- *
- *      CoroTask<int> add(int a, int b) { co_return a + b; }
- *      CoroTask<int> doubleSum(int a, int b) {
- *          int s = co_await add(a, b);
- *          co_return s * 2;
- *      }
- *
- * 3. Exception propagation from inner to outer:
- *
- *      CoroTask<int> failing() {
- *          throw std::runtime_error("bad");
- *          co_return 0;  // never reached
- *      }
- *      CoroTask<void> caller() {
- *          try {
- *              int v = co_await failing();  // throws here
- *          } catch (std::runtime_error const& e) {
- *              // e.what() == "bad"
- *          }
- *      }
- *
- * Caveats / Pitfalls (in addition to CoroTask<void> caveats above)
- * ================================================================
- *
- * BUG-RISK: await_resume() moves the value out of the variant.
- *   Calling co_await on the same CoroTask<T> instance twice is undefined
- *   behavior -- the second call will see a moved-from T. CoroTask is
- *   single-shot: one co_return, one co_await.
- *
- * BUG-RISK: T must be move-constructible.
- *   return_value(T) takes by value and moves into the variant.
- *   Types that are not movable cannot be used as T.
- *
- * LIMITATION: No co_yield support.
- *   CoroTask<T> only supports a single co_return. It does not implement
- *   yield_value(), so using co_yield inside a CoroTask<T> coroutine is a
- *   compile error. For streaming values, a different return type
- *   (e.g. Generator<T>) would be needed.
- *
- * LIMITATION: Result is only accessible via co_await.
- *   There is no .get() or .result() method. The value can only be
- *   extracted by co_await-ing the CoroTask<T> from inside another
- *   coroutine. For extracting results in non-coroutine code, pass a
- *   pointer to the caller and write through it (as the tests do).
- */
-template <typename T>
-class CoroTask
-{
-    static_assert(
-        std::is_move_constructible_v<T>,
-        "CoroTask<T> requires T to be move-constructible");
-
-public:
-    // The C++ coroutine protocol mandates these names (promise_type,
-    // initial_suspend, await_ready, ...) and instance-callable awaiter
-    // methods, which conflict with the project naming/static conventions.
-    // NOLINTBEGIN(readability-identifier-naming, readability-convert-member-functions-to-static)
-    struct promise_type;
-    using Handle = std::coroutine_handle<promise_type>;
-
-    /**
-     * Coroutine promise for value-returning coroutines.
-     * Stores the result as a variant: monostate (not yet set),
-     * T (co_return value), or exception_ptr (unhandled exception).
-     */
-    struct promise_type
-    {
-        // Tri-state result:
-        //   index 0 (monostate) -- coroutine has not yet completed
-        //   index 1 (T)         -- co_return value stored here
-        //   index 2 (exception) -- unhandled exception captured here
-        std::variant<std::monostate, T, std::exception_ptr> result_;
-
-        // Handle to the coroutine co_await-ing this task. Used by
-        // FinalAwaiter for symmetric transfer. Null for top-level tasks.
-        std::coroutine_handle<> continuation_;
-
-        /**
-         * Create the CoroTask return object.
-         * Called by the compiler at coroutine creation.
-         */
-        CoroTask
-        get_return_object()
-        {
-            return CoroTask{Handle::from_promise(*this)};
-        }
-
-        /**
-         * Lazy start. Coroutine body does not run until explicitly resumed.
-         */
-        std::suspend_always
-        initial_suspend() noexcept
-        {
-            return {};
-        }
-
-        /**
-         * Symmetric-transfer awaiter at coroutine completion.
-         * Same pattern as CoroTask<void>::FinalAwaiter.
-         */
-        struct FinalAwaiter
-        {
-            bool
-            await_ready() noexcept
-            {
-                return false;
-            }
-
-            /**
-             * Returns continuation for symmetric transfer, or
-             * noop_coroutine if this is a top-level task.
-             *
-             * @param h Handle to this completing coroutine
-             *
-             * @return Continuation handle, or noop_coroutine
-             */
-            std::coroutine_handle<>
-            await_suspend(Handle h) noexcept
-            {
-                if (auto cont = h.promise().continuation_)
-                    return cont;
-                return std::noop_coroutine();
-            }
-
-            void
-            await_resume() noexcept
-            {
-            }
-        };
-
-        FinalAwaiter
-        final_suspend() noexcept
-        {
-            return {};
-        }
-
-        /**
-         * Called by the compiler for `co_return value;`.
-         * Moves the value into result_ at index 1.
-         *
-         * @param value The value to store
-         */
-        void
-        return_value(T value)
-        {
-            result_.template emplace<1>(std::move(value));
-        }
-
-        /**
-         * Captures unhandled exceptions at index 2 of result_.
-         * Rethrown later in await_resume().
-         */
-        void
-        unhandled_exception()
-        {
-            result_.template emplace<2>(std::current_exception());
-        }
-    };
-    // NOLINTEND(readability-identifier-naming, readability-convert-member-functions-to-static)
-
-    /**
-     * Default constructor. Creates an empty (null handle) task.
-     */
-    CoroTask() = default;
-
-    /**
-     * Takes ownership of a compiler-generated coroutine handle.
-     *
-     * @param h Coroutine handle to own
-     */
-    explicit CoroTask(Handle h) : handle_(h)
-    {
-    }
-
-    /**
-     * Destroys the coroutine frame if this task owns one.
-     */
-    ~CoroTask()
-    {
-        if (handle_)
-            handle_.destroy();
-    }
-
-    /**
-     * Move constructor. Transfers handle ownership, leaves other empty.
-     */
-    CoroTask(CoroTask&& other) noexcept : handle_(std::exchange(other.handle_, {}))
-    {
-    }
-
-    /**
-     * Move assignment. Destroys current frame (if any), takes other's.
-     */
-    CoroTask&
-    operator=(CoroTask&& other) noexcept
-    {
-        if (this != &other)
-        {
-            if (handle_)
-                handle_.destroy();
-            handle_ = std::exchange(other.handle_, {});
-        }
-        return *this;
-    }
-
-    CoroTask(CoroTask const&) = delete;
-    CoroTask&
-    operator=(CoroTask const&) = delete;
-
-    /**
-     * @return The underlying coroutine_handle
-     */
-    [[nodiscard]] Handle
-    handle() const
-    {
-        return handle_;
-    }
-
-    /**
-     * @return true if the coroutine has run to completion (or thrown)
-     */
-    [[nodiscard]] bool
-    done() const
-    {
-        return handle_ && handle_.done();
-    }
-
-    // -- Awaiter interface: allows `T val = co_await someCoroTask;` --
-
-    /**
-     * Always false. co_await always suspends to set up continuation.
-     */
-    // NOLINTBEGIN(readability-identifier-naming, readability-convert-member-functions-to-static)
-    [[nodiscard]] bool
-    await_ready() const noexcept
-    {
-        return false;
-    }
-
-    /**
-     * Stores caller as continuation, returns our handle for
-     * symmetric transfer.
-     *
-     * @param caller Handle of the coroutine doing co_await on us
-     *
-     * @return Our handle for symmetric transfer
-     */
-    std::coroutine_handle<>
-    await_suspend(std::coroutine_handle<> caller) noexcept
-    {
-        XRPL_ASSERT(handle_, "xrpl::CoroTask<T>::await_suspend : handle is valid");
-        handle_.promise().continuation_ = caller;
-        return handle_;
-    }
-
-    /**
-     * Extracts the result: rethrows if exception, otherwise moves
-     * the T value out of the variant. Single-shot: calling twice
-     * on the same task is undefined (moved-from T).
-     *
-     * @return The co_return-ed value
-     */
-    T
-    await_resume()
-    {
-        XRPL_ASSERT(handle_, "xrpl::CoroTask<T>::await_resume : handle is valid");
-        auto& result = handle_.promise().result_;
-        if (auto* ep = std::get_if<2>(&result))
-            std::rethrow_exception(*ep);
-        return std::get<1>(std::move(result));
-    }
-    // NOLINTEND(readability-identifier-naming, readability-convert-member-functions-to-static)
-
-private:
-    // Exclusively-owned coroutine handle. Null after move or default
-    // construction. Destroyed in the destructor.
-    Handle handle_;
-};
-
-}  // namespace xrpl

include/xrpl/core/CoroTaskRunner.ipp

@@ -1,448 +0,0 @@
-#pragma once
-
-/**
- * @file CoroTaskRunner.ipp
- *
- * CoroTaskRunner inline implementation.
- *
- * This file contains the business logic for managing C++20 coroutines
- * on the JobQueue. It is included at the bottom of JobQueue.h.
- *
- * Data Flow: suspend / post / resume cycle
- * =========================================
- *
- *         coroutine body                 CoroTaskRunner              JobQueue
- *         --------------                 --------------              --------
- *              |
- *    co_await runner->suspend()
- *              |
- *              +--- await_suspend ------> onSuspend()
- *              |                            ++nSuspend_ ------------> nSuspend_
- *              |                          [coroutine is now suspended]
- *              |
- *              .    (externally or by yieldAndPost())
- *              .
- *              +--- (caller calls) -----> post()
- *              |                            ++runCount_
- *              |                            addJob(resume) ----------> job enqueued
- *              |                                                        |
- *              |                                                      [worker picks up]
- *              |                                                        |
- *              +--- <----- resume() <-----------------------------------+
- *              |             --nSuspend_ ------> nSuspend_
- *              |             swap in LocalValues (lvs_)
- *              |             task_.handle().resume()
- *              |                |
- *              |    [coroutine body continues here]
- *              |                |
- *              |             swap out LocalValues
- *              |             --runCount_
- *              |             cv_.notify_all()
- *              v
- *
- * Thread Safety
- * =============
- * - mutex_     : guards task_.handle().resume() so that post()-before-suspend
- *                races cannot resume the coroutine while it is still running.
- *                (See the race condition discussion in JobQueue.h)
- * - mutexRun_ : guards runCount_ counter; used by join() to wait until
- *                all in-flight resume operations complete.
- * - jq_.mutex_: guards nSuspend_ increments/decrements.
- *
- * Common Mistakes When Modifying This File
- * =========================================
- *
- * 1. Changing lock ordering.
- *    resume() acquires locks sequentially (never held simultaneously):
- *    jq_.mutex_ (released immediately), then mutex_ (held across resume),
- *    then mutexRun_ (released after decrement). post() acquires only
- *    mutexRun_. Any new code path must follow the same order.
- *
- * 2. Removing the shared_from_this() capture in post().
- *    The lambda passed to addJob captures [this, sp = shared_from_this()].
- *    If you remove sp, 'this' can be destroyed before the job runs,
- *    causing use-after-free. The sp capture is load-bearing.
- *
- * 3. Forgetting to decrement nSuspend_ on a new code path.
- *    Every ++nSuspend_ must have a matching --nSuspend_. If you add a new
- *    suspension path (e.g. a new awaiter) and forget to decrement on resume
- *    or on failure, JobQueue::stop() will hang.
- *
- * 4. Calling task_.handle().resume() without holding mutex_.
- *    This allows a race where the coroutine runs on two threads
- *    simultaneously. Always hold mutex_ around resume().
- *
- * 5. Swapping LocalValues outside of the mutex_ critical section.
- *    The swap-in and swap-out of LocalValues must bracket the resume()
- *    call. If you move the swap-out before the lock_guard(mutex_) is
- *    released, you break LocalValue isolation for any code that runs
- *    after the coroutine suspends but before the lock is dropped.
- */
-
-namespace xrpl {
-
-/**
- * Construct a CoroTaskRunner. Sets runCount_ to 0; does not
- * create the coroutine. Call init() afterwards.
- *
- * @param jq   The JobQueue this coroutine will run on
- * @param type Job type for scheduling priority
- * @param name Human-readable name for logging
- */
-inline JobQueue::CoroTaskRunner::CoroTaskRunner(
-    CreateT,
-    JobQueue& jq,
-    JobType type,
-    std::string name)
-    : jq_(jq), type_(type), name_(std::move(name))
-{
-}
-
-/**
- * Initialize with a coroutine-returning callable.
- * Stores the callable on the heap (FuncStore) so it outlives the
- * coroutine frame. Coroutine frames store a reference to the
- * callable's implicit object parameter (the lambda). If the callable
- * is a temporary, that reference dangles after the caller returns.
- * Keeping the callable alive here ensures the coroutine's captures
- * remain valid.
- *
- * @param f Callable: CoroTask<void>(shared_ptr<CoroTaskRunner>)
- */
-template <class F>
-void
-JobQueue::CoroTaskRunner::init(F&& f)
-{
-    using Fn = std::decay_t<F>;
-    auto store = std::make_unique<FuncStore<Fn>>(std::forward<F>(f));
-    task_ = store->func(shared_from_this());
-    storedFunc_ = std::move(store);
-}
-
-/**
- * Destructor. Waits for any in-flight resume() to complete, then
- * asserts (debug) that the coroutine has finished or
- * expectEarlyExit() was called.
- *
- * The join() call is necessary because with async dispatch the
- * coroutine runs on a worker thread. The gate signal (which wakes
- * the test thread) can arrive before resume() has set finished_.
- * join() synchronizes via mutexRun_, establishing a happens-before
- * edge: finished_ = true -> unlock(mutexRun_) in resume() ->
- * lock(mutexRun_) in join() -> read finished_.
- */
-inline JobQueue::CoroTaskRunner::~CoroTaskRunner()
-{
-#ifndef NDEBUG
-    join();
-    XRPL_ASSERT(finished_, "xrpl::JobQueue::CoroTaskRunner::~CoroTaskRunner : is finished");
-#endif
-}
-
-/**
- * Increment the JobQueue's suspended-coroutine count (nSuspend_).
- */
-inline void
-JobQueue::CoroTaskRunner::onSuspend()
-{
-    std::scoped_lock const lock(jq_.mutex_);
-    ++jq_.nSuspend_;
-}
-
-/**
- * Decrement nSuspend_ without resuming.
- */
-inline void
-JobQueue::CoroTaskRunner::onUndoSuspend()
-{
-    std::scoped_lock const lock(jq_.mutex_);
-    --jq_.nSuspend_;
-}
-
-/**
- * Return a SuspendAwaiter whose await_suspend() increments nSuspend_
- * before the coroutine actually suspends. The caller must later call
- * post() or resume() to continue execution.
- *
- * @return Awaiter for use with `co_await runner->suspend()`
- */
-inline auto
-JobQueue::CoroTaskRunner::suspend()
-{
-    /**
-     * Custom awaiter for suspend(). Always suspends (await_ready
-     * returns false) and increments nSuspend_ in await_suspend().
-     */
-    // The C++ coroutine protocol mandates these awaiter names and
-    // instance-callable methods, which conflict with the project
-    // naming/static conventions.
-    // NOLINTBEGIN(readability-identifier-naming, readability-convert-member-functions-to-static)
-    struct SuspendAwaiter
-    {
-        CoroTaskRunner& runner_;  // The runner that owns this coroutine.
-
-        /**
-         * Always returns false so the coroutine suspends.
-         */
-        [[nodiscard]] bool
-        await_ready() const noexcept
-        {
-            return false;
-        }
-
-        /**
-         * Called when the coroutine suspends. Increments nSuspend_
-         * so the JobQueue knows a coroutine is waiting.
-         */
-        void
-        await_suspend(std::coroutine_handle<>) const
-        {
-            runner_.onSuspend();
-        }
-
-        void
-        await_resume() const noexcept
-        {
-        }
-    };
-    // NOLINTEND(readability-identifier-naming, readability-convert-member-functions-to-static)
-    return SuspendAwaiter{*this};
-}
-
-/**
- * Suspend and immediately repost on the JobQueue. Equivalent to
- * `co_await JobQueueAwaiter{runner}` but uses an inline struct
- * to work around a GCC-12 codegen bug (see declaration in JobQueue.h).
- *
- * If the JobQueue is stopping (post fails), the suspend count is
- * undone and the coroutine continues immediately via symmetric
- * transfer back to its own handle.
- *
- * @return An inline YieldPostAwaiter
- */
-inline auto
-JobQueue::CoroTaskRunner::yieldAndPost()
-{
-    // The C++ coroutine protocol mandates these awaiter names and
-    // instance-callable methods, which conflict with the project
-    // naming/static conventions.
-    // NOLINTBEGIN(readability-identifier-naming, readability-convert-member-functions-to-static)
-    struct YieldPostAwaiter
-    {
-        CoroTaskRunner& runner_;
-
-        [[nodiscard]] bool
-        await_ready() const noexcept
-        {
-            return false;
-        }
-
-        /**
-         * Returns a coroutine_handle<> (symmetric transfer) rather than
-         * void + h.resume(). Two reasons:
-         *
-         *  1. h.resume() runs the coroutine nested inside this frame. A
-         *     coroutine that yields in a loop against a stopping JobQueue
-         *     fails post() every iteration, so the stack grows without
-         *     bound. Symmetric transfer is a tail call and does not nest.
-         *
-         *  2. After h.resume() returns, the coroutine may have completed
-         *     and destroyed its frame -- the frame this awaiter lives in.
-         *     Returning from await_suspend would then touch freed memory.
-         *
-         * A bool return would also avoid nesting, but GCC-12 miscompiles
-         * bool-returning await_suspend (see JobQueueAwaiter.h).
-         *
-         * @return noop_coroutine() to stay suspended (job posted);
-         *         the caller's handle to continue now (JQ stopping)
-         */
-        std::coroutine_handle<>
-        await_suspend(std::coroutine_handle<> h)
-        {
-            runner_.onSuspend();
-            if (!runner_.post())
-            {
-                runner_.onUndoSuspend();
-                return h;
-            }
-            return std::noop_coroutine();
-        }
-
-        void
-        await_resume() const noexcept
-        {
-        }
-    };
-    // NOLINTEND(readability-identifier-naming, readability-convert-member-functions-to-static)
-    return YieldPostAwaiter{*this};
-}
-
-/**
- * Schedule coroutine resumption as a job on the JobQueue.
- * A shared_ptr capture (sp) prevents this CoroTaskRunner from being
- * destroyed while the job is queued but not yet executed.
- *
- * @return false if the JobQueue rejected the job (shutting down)
- */
-inline bool
-JobQueue::CoroTaskRunner::post()
-{
-    {
-        std::scoped_lock const lk(mutexRun_);
-        ++runCount_;
-    }
-
-    // sp prevents 'this' from being destroyed while the job is pending
-    if (jq_.addJob(type_, name_, [this, sp = shared_from_this()]() { resume(); }))
-    {
-        return true;
-    }
-
-    // The coroutine will not run. Undo the runCount_ increment.
-    std::scoped_lock const lk(mutexRun_);
-    --runCount_;
-    cv_.notify_all();
-    return false;
-}
-
-/**
- * Resume the coroutine on the current thread.
- *
- * Steps:
- *   1. Decrement nSuspend_ (under jq_.mutex_)
- *   2. Swap in this coroutine's LocalValues for thread-local isolation
- *   3. Resume the coroutine handle (under mutex_)
- *   4. Swap out LocalValues, restoring the thread's previous state
- *   5. Decrement runCount_ and notify join() waiters
- *
- * @pre post() must have been called before resume(). Direct calls
- *      without a prior post() will corrupt runCount_ and break join().
- * Note: runCount_ is NOT incremented here — post() already did that.
- * This ensures join() stays blocked for the entire post->resume lifetime.
- */
-inline void
-JobQueue::CoroTaskRunner::resume()
-{
-    {
-        std::scoped_lock const lock(jq_.mutex_);
-        --jq_.nSuspend_;
-    }
-    auto saved = detail::getLocalValues().release();
-    detail::getLocalValues().reset(&lvs_);
-    std::scoped_lock const lock(mutex_);
-    XRPL_ASSERT(
-        task_.handle() && !task_.done(),
-        "xrpl::JobQueue::CoroTaskRunner::resume : task handle is valid and not done");
-    if (task_.handle() && !task_.done())
-    {
-        task_.handle().resume();
-    }
-    else
-    {
-        // A resume() with no coroutine to run (e.g. a duplicate external
-        // post() after completion). Resuming a null or finished handle is
-        // undefined behavior, so skip it -- this matches the old
-        // Coro::resume() `if (coro_)` guard. The bookkeeping below still
-        // runs to balance the ++runCount_ done by the post() that
-        // scheduled this call.
-        JLOG(jq_.journal_.warn())
-            << "CoroTaskRunner::resume called for coroutine '" << name_
-            << "' with no runnable coroutine (duplicate post or already completed)";
-    }
-    detail::getLocalValues().release();
-    detail::getLocalValues().reset(saved);
-    if (task_.done())
-    {
-        finished_ = true;
-        // An exception that escapes a top-level coroutine body is captured
-        // by promise_type::unhandled_exception() but has no awaiter to
-        // rethrow it, so it would vanish with the frame. Surface it in the
-        // log. (The old Boost path propagated it out of resume() instead.)
-        if (auto const& ep = task_.handle().promise().exception_)
-        {
-            try
-            {
-                std::rethrow_exception(ep);
-            }
-            catch (std::exception const& e)
-            {
-                JLOG(jq_.journal_.error())
-                    << "Unhandled exception in coroutine '" << name_ << "': " << e.what();
-            }
-            catch (...)
-            {
-                JLOG(jq_.journal_.error())
-                    << "Unhandled non-standard exception in coroutine '" << name_ << "'";
-            }
-        }
-        // Break the shared_ptr cycle: frame -> shared_ptr<runner> -> this.
-        // Use std::move (not task_ = {}) so task_.handle_ is null BEFORE the
-        // frame is destroyed. operator= would destroy the frame while handle_
-        // still holds the old value -- a re-entrancy hazard on GCC-12 if
-        // frame destruction triggers runner cleanup.
-        [[maybe_unused]] auto completed = std::move(task_);
-    }
-    std::scoped_lock const lk(mutexRun_);
-    --runCount_;
-    cv_.notify_all();
-}
-
-/**
- * @return true if the coroutine has not yet run to completion
- */
-inline bool
-JobQueue::CoroTaskRunner::runnable() const
-{
-    // After normal completion, task_ is reset to break the shared_ptr cycle
-    // (handle_ becomes null). A null handle means the coroutine is done.
-    return task_.handle() && !task_.done();
-}
-
-/**
- * Handle early termination when the coroutine never ran (e.g. JobQueue
- * is stopping). Decrements nSuspend_ and destroys the coroutine frame
- * to break the shared_ptr cycle: frame -> lambda -> runner -> frame.
- */
-inline void
-JobQueue::CoroTaskRunner::expectEarlyExit()
-{
-    if (!finished_)
-    {
-        std::scoped_lock const lock(jq_.mutex_);
-        --jq_.nSuspend_;
-        finished_ = true;
-    }
-    // Break the shared_ptr cycle: frame -> shared_ptr<runner> -> this.
-    // The coroutine is at initial_suspend and never ran user code, so
-    // destroying it is safe. Use std::move (not task_ = {}) so
-    // task_.handle_ is null before the frame is destroyed.
-    {
-        [[maybe_unused]] auto completed = std::move(task_);
-    }
-    storedFunc_.reset();
-}
-
-/**
- * Block until all pending/active resume operations complete.
- * Uses cv_ + mutexRun_ to wait until runCount_ reaches 0 or
- * finished_ becomes true. The finished_ check handles the case
- * where resume() is called directly (without post()), which
- * decrements runCount_ below zero. In that scenario runCount_
- * never returns to 0, but finished_ becoming true guarantees
- * the coroutine is done and no more resumes will occur.
- *
- * Note: when join() returns via the finished_ disjunct, the final
- * resume() call may still be executing its post-completion
- * bookkeeping (the --runCount_ / notify after finished_ is set).
- * That is safe -- the coroutine body has fully completed and the
- * runner is kept alive by the resume job's shared_ptr -- but
- * callers must not assume resume() itself has returned.
- */
-inline void
-JobQueue::CoroTaskRunner::join()
-{
-    std::unique_lock<std::mutex> lk(mutexRun_);
-    cv_.wait(lk, [this]() { return runCount_ == 0 || finished_; });
-}
-
-}  // namespace xrpl

include/xrpl/core/JobQueue.h

@@ -2,7 +2,6 @@
 
 #include <xrpl/basics/LocalValue.h>
 #include <xrpl/core/ClosureCounter.h>
-#include <xrpl/core/CoroTask.h>
 #include <xrpl/core/JobTypeData.h>
 #include <xrpl/core/detail/Workers.h>
 #include <xrpl/json/json_value.h>
@@ -153,420 +152,6 @@ public:
         join();
     };
 
-    /**
-     * C++20 coroutine lifecycle manager. Replaces Coro for new code.
-     *
-     *  Class / Inheritance / Dependency Diagram
-     *  =========================================
-     *
-     *  std::enable_shared_from_this<CoroTaskRunner>
-     *            ^
-     *            | (public inheritance)
-     *            |
-     *  CoroTaskRunner
-     *  +---------------------------------------------------+
-     *  | - lvs_         : detail::LocalValues               |
-     *  | - jq_          : JobQueue&                         |
-     *  | - type_        : JobType                           |
-     *  | - name_        : std::string                       |
-     *  | - runCount_    : int         (in-flight resumes)    |
-     *  | - mutex_       : std::mutex      (coroutine guard) |
-     *  | - mutexRun_    : std::mutex      (join guard)      |
-     *  | - cv_          : condition_variable                 |
-     *  | - task_        : CoroTask<void>                    |
-     *  | - storedFunc_  : unique_ptr<FuncBase> (type-erased)|
-     *  +---------------------------------------------------+
-     *  | + init(F&&)         : set up coroutine callable    |
-     *  | + onSuspend()       : ++jq_.nSuspend_              |
-     *  | + onUndoSuspend()   : --jq_.nSuspend_              |
-     *  | + suspend()         : returns SuspendAwaiter       |
-     *  | + post()            : schedule resume on JobQueue  |
-     *  | + resume()          : resume coroutine on caller   |
-     *  | + runnable()        : !task_.done()                |
-     *  | + expectEarlyExit() : teardown for failed post     |
-     *  | + join()            : block until not running       |
-     *  +---------------------------------------------------+
-     *          |                          |
-     *          | owns                     | references
-     *          v                          v
-     *    CoroTask<void>             JobQueue
-     *    (coroutine frame)          (thread pool + nSuspend_)
-     *
-     *    FuncBase / FuncStore<F>    (type-erased heap storage
-     *                                for the coroutine lambda)
-     *
-     *  Coroutine Lifecycle (Control Flow)
-     *  ===================================
-     *
-     *  Caller thread              JobQueue worker thread
-     *  -------------              ----------------------
-     *  postCoroTask(f)
-     *    |
-     *    +-- reserve a jobCounter_ slot (reject if JQ shutting down)
-     *    +-- ++nSuspend_  (lazy start counts as suspended)
-     *    +-- make_shared<CoroTaskRunner>
-     *    +-- init(f)
-     *    |     +-- store lambda on heap (FuncStore)
-     *    |     +-- task_ = f(shared_from_this())
-     *    |           [coroutine created, suspended at initial_suspend]
-     *    +-- post()
-     *    |     +-- ++runCount_
-     *    |     +-- addJob(type_, [resume]{})
-     *    |                                    resume()
-     *    |                                      |
-     *    |                                      +-- --nSuspend_
-     *    |                                      +-- swap in LocalValues
-     *    |                                      +-- task_.handle().resume()
-     *    |                                      |     [coroutine body runs]
-     *    |                                      |     ...
-     *    |                                      |     co_await suspend()
-     *    |                                      |       +-- ++nSuspend_
-     *    |                                      |       [coroutine suspends]
-     *    |                                      +-- swap out LocalValues
-     *    |                                      +-- --runCount_
-     *    |                                      +-- cv_.notify_all()
-     *    |
-     *  post()  <-- called externally or by yieldAndPost()
-     *    +-- ++runCount_
-     *    +-- addJob(type_, [resume]{})
-     *                                         resume()
-     *                                           |
-     *                                           +-- [coroutine body continues]
-     *                                           +-- co_return
-     *                                           +-- --runCount_
-     *                                           +-- cv_.notify_all()
-     *  join()
-     *    +-- cv_.wait([]{runCount_ == 0})
-     *    +-- [done]
-     *
-     *  Usage Examples
-     *  ==============
-     *
-     *  1. Fire-and-forget coroutine (most common pattern):
-     *
-     *      jq.postCoroTask(JtClient, "MyWork",
-     *          [](auto runner) -> CoroTask<void> {
-     *              doSomeWork();
-     *              co_await runner->suspend();  // yield to other jobs
-     *              doMoreWork();
-     *              co_return;
-     *          });
-     *
-     *  2. Manually controlling suspend / resume (external trigger):
-     *
-     *      auto runner = jq.postCoroTask(JtClient, "ExtTrigger",
-     *          [&result](auto runner) -> CoroTask<void> {
-     *              startAsyncOperation(callback);
-     *              co_await runner->suspend();
-     *              // callback called runner->post() to get here
-     *              result = collectResult();
-     *              co_return;
-     *          });
-     *      // ... later, from the callback:
-     *      runner->post();   // reschedule the coroutine on the JobQueue
-     *
-     *  3. Using yieldAndPost() for automatic suspend + repost:
-     *
-     *      jq.postCoroTask(JtClient, "AutoRepost",
-     *          [](auto runner) -> CoroTask<void> {
-     *              step1();
-     *              co_await runner->yieldAndPost();  // yield + auto-repost
-     *              step2();
-     *              co_await runner->yieldAndPost();
-     *              step3();
-     *              co_return;
-     *          });
-     *
-     *  4. Checking shutdown after co_await (cooperative cancellation):
-     *
-     *      jq.postCoroTask(JtClient, "Cancellable",
-     *          [&jq](auto runner) -> CoroTask<void> {
-     *              while (moreWork()) {
-     *                  co_await runner->yieldAndPost();
-     *                  if (jq.isStopping())
-     *                      co_return;  // bail out cleanly
-     *                  processNextItem();
-     *              }
-     *              co_return;
-     *          });
-     *
-     *  Caveats / Pitfalls
-     *  ==================
-     *
-     *  BUG-RISK: Calling suspend() without a matching post()/resume().
-     *    After co_await runner->suspend(), the coroutine is parked and
-     *    nSuspend_ is incremented.  If nothing ever calls post() or
-     *    resume(), the coroutine is leaked and JobQueue::stop() will
-     *    hang forever waiting for nSuspend_ to reach zero.
-     *
-     *  BUG-RISK: Calling post() on an already-running coroutine.
-     *    post() schedules a resume() job.  If the coroutine has not
-     *    actually suspended yet (no co_await executed), the resume job
-     *    will try to call handle().resume() while the coroutine is still
-     *    running on another thread.  This is UB.  The mutex_ prevents
-     *    data corruption but the logic is wrong — always co_await
-     *    suspend() before calling post().  (The test incorrect_order()
-     *    shows this works only because mutex_ serializes the calls.)
-     *
-     *  BUG-RISK: Dropping the shared_ptr<CoroTaskRunner> before join().
-     *    The CoroTaskRunner destructor asserts that finished_ is true
-     *    (the coroutine completed). If you let the last shared_ptr die
-     *    while the coroutine is still running or suspended, you get an
-     *    assertion failure in debug and UB in release.  Always call
-     *    join() or expectEarlyExit() first.
-     *
-     *  BUG-RISK: Lambda captures outliving the coroutine frame.
-     *    The lambda passed to postCoroTask is heap-allocated (FuncStore)
-     *    to prevent dangling.  But objects captured by pointer still need
-     *    their own lifetime management.  If you capture a raw pointer to
-     *    a stack variable, and the stack frame exits before the coroutine
-     *    finishes, the pointer dangles.  Use shared_ptr or ensure the
-     *    pointed-to object outlives the coroutine.
-     *
-     *  BUG-RISK: Forgetting co_return in a void coroutine.
-     *    If the coroutine body falls off the end without co_return,
-     *    the compiler may silently treat it as co_return (per standard),
-     *    but some compilers warn.  Always write explicit co_return.
-     *
-     *  LIMITATION: CoroTaskRunner only supports CoroTask<void>.
-     *    The task_ member is CoroTask<void>.  To return values from
-     *    the top-level coroutine, write through a captured pointer
-     *    (as the tests demonstrate), or co_await inner CoroTask<T>
-     *    coroutines that return values.
-     *
-     *  LIMITATION: One coroutine per CoroTaskRunner.
-     *    init() must be called exactly once.  You cannot reuse a
-     *    CoroTaskRunner to run a second coroutine.  Create a new one
-     *    via postCoroTask() instead.
-     *
-     *  LIMITATION: No timeout on join().
-     *    join() blocks indefinitely.  If the coroutine is suspended
-     *    and never posted, join() will deadlock.  Use timed waits
-     *    on the gate pattern (condition_variable + wait_for) in tests.
-     */
-    class CoroTaskRunner : public std::enable_shared_from_this<CoroTaskRunner>
-    {
-    private:
-        // Per-coroutine thread-local storage. Swapped in before resume()
-        // and swapped out after, so each coroutine sees its own LocalValue
-        // state regardless of which worker thread executes it.
-        detail::LocalValues lvs_;
-
-        // Back-reference to the owning JobQueue. Used to post jobs,
-        // increment/decrement nSuspend_, and acquire jq_.mutex_.
-        JobQueue& jq_;
-
-        // Job type passed to addJob() when posting this coroutine.
-        JobType type_;
-
-        // Human-readable name for this coroutine job (for logging).
-        std::string name_;
-
-        // Number of in-flight resume operations (pending + active).
-        // Incremented by post(), decremented when resume() finishes.
-        // Guarded by mutexRun_. join() blocks until this reaches 0.
-        //
-        // A counter (not a bool) is needed because post() can be called
-        // from within the coroutine body (e.g. via yieldAndPost()),
-        // enqueuing a second resume while the first is still running.
-        // A bool would be clobbered: R2.post() sets true, then R1's
-        // cleanup sets false — losing the fact that R2 is still pending.
-        int runCount_ = 0;
-
-        // Serializes all coroutine resume() calls, preventing concurrent
-        // execution of the coroutine body on multiple threads. Handles the
-        // race where post() enqueues a resume before the coroutine has
-        // actually suspended (post-before-suspend pattern).
-        std::mutex mutex_;
-
-        // Guards runCount_. Used with cv_ for join() to wait
-        // until all pending/active resume operations complete.
-        std::mutex mutexRun_;
-
-        // Notified when runCount_ reaches zero, allowing
-        // join() waiters to wake up.
-        std::condition_variable cv_;
-
-        // The coroutine handle wrapper. Owns the coroutine frame.
-        // Set by init(). Reset to empty in resume() upon coroutine
-        // completion (to break the shared_ptr cycle) or in
-        // expectEarlyExit() on early termination.
-        CoroTask<void> task_;
-
-        /**
-         * Type-erased base for heap-stored callables.
-         * Prevents the coroutine lambda from being destroyed before
-         * the coroutine frame is done with it.
-         *
-         * @see FuncStore
-         */
-        struct FuncBase
-        {
-            virtual ~FuncBase() = default;
-        };
-
-        /**
-         * Concrete type-erased storage for a callable of type F.
-         * The coroutine frame stores a reference to the lambda's implicit
-         * object parameter. If the lambda is a temporary, that reference
-         * dangles after the call returns. FuncStore keeps it alive on
-         * the heap for the lifetime of the CoroTaskRunner.
-         */
-        template <class F>
-        struct FuncStore : FuncBase
-        {
-            F func;  // The stored callable (coroutine lambda).
-            explicit FuncStore(F&& f) : func(std::move(f))
-            {
-            }
-        };
-
-        // Heap-allocated callable storage. Set by init(), ensures the
-        // lambda outlives the coroutine frame that references it.
-        std::unique_ptr<FuncBase> storedFunc_;
-
-        // True once the coroutine has completed or expectEarlyExit() was
-        // called. Asserted in the destructor (debug) to catch leaked
-        // runners. Available in all builds to guard expectEarlyExit()
-        // against double-decrementing nSuspend_.
-        bool finished_ = false;
-
-    public:
-        /**
-         * Tag type for private construction. Prevents external code
-         * from constructing CoroTaskRunner directly. Use postCoroTask().
-         */
-        struct CreateT
-        {
-            explicit CreateT() = default;
-        };
-
-        /**
-         * Construct a CoroTaskRunner. Private by convention (CreateT tag).
-         *
-         * @param jq   The JobQueue this coroutine will run on
-         * @param type Job type for scheduling priority
-         * @param name Human-readable name for logging
-         */
-        CoroTaskRunner(CreateT, JobQueue&, JobType, std::string);
-
-        CoroTaskRunner(CoroTaskRunner const&) = delete;
-        CoroTaskRunner&
-        operator=(CoroTaskRunner const&) = delete;
-
-        /**
-         * Destructor. Asserts (debug) that the coroutine has finished
-         * or expectEarlyExit() was called.
-         */
-        ~CoroTaskRunner();
-
-        /**
-         * Initialize with a coroutine-returning callable.
-         * Must be called exactly once, after the object is managed by
-         * shared_ptr (because init uses shared_from_this internally).
-         * This is handled automatically by postCoroTask().
-         *
-         * @param f Callable: CoroTask<void>(shared_ptr<CoroTaskRunner>)
-         */
-        template <class F>
-        void
-        init(F&& f);
-
-        /**
-         * Increment the JobQueue's suspended-coroutine count (nSuspend_).
-         * Called when the coroutine is about to suspend. Every call
-         * must be balanced by a corresponding decrement (via resume()
-         * or onUndoSuspend()), or JobQueue::stop() will hang.
-         */
-        void
-        onSuspend();
-
-        /**
-         * Decrement nSuspend_ without resuming.
-         * Used to undo onSuspend() when a scheduled post() fails
-         * (e.g. JobQueue is stopping).
-         */
-        void
-        onUndoSuspend();
-
-        /**
-         * Suspend the coroutine.
-         * The awaiter's await_suspend() increments nSuspend_ before the
-         * coroutine actually suspends. The caller must later call post()
-         * or resume() to continue execution.
-         *
-         * @return An awaiter for use with `co_await runner->suspend()`
-         */
-        auto
-        suspend();
-
-        /**
-         * Suspend the coroutine and immediately repost it on the
-         * JobQueue. Combines suspend() + post() atomically inside
-         * await_suspend, so there is no window where an external
-         * event could race between the two.
-         *
-         * Equivalent to JobQueueAwaiter but defined as an inline
-         * awaiter returned from a member function. This avoids a
-         * GCC-12 coroutine codegen bug where an external awaiter
-         * struct (JobQueueAwaiter) used at multiple co_await points
-         * corrupts the coroutine state machine's resume index,
-         * causing the coroutine to hang on the third resumption.
-         *
-         * @return An awaiter for use with `co_await runner->yieldAndPost()`
-         */
-        auto
-        yieldAndPost();
-
-        /**
-         * Schedule coroutine resumption as a job on the JobQueue.
-         * Captures shared_from_this() to prevent this runner from being
-         * destroyed while the job is queued.
-         *
-         * @return true if the job was accepted; false if the JobQueue
-         *         is stopping (caller must handle cleanup)
-         */
-        bool
-        post();
-
-        /**
-         * Resume the coroutine on the current thread.
-         * Decrements nSuspend_, swaps in LocalValues, resumes the
-         * coroutine handle, swaps out LocalValues, and notifies join()
-         * waiters. Lock ordering (sequential, non-overlapping):
-         * jq_.mutex_ -> mutex_ -> mutexRun_.
-         *
-         * @pre post() must have been called before resume(). Direct
-         *      calls without a prior post() will corrupt runCount_
-         *      and break join().
-         */
-        void
-        resume();
-
-        /**
-         * @return true if the coroutine has not yet run to completion
-         */
-        bool
-        runnable() const;
-
-        /**
-         * Handle early termination when the coroutine never ran.
-         * Decrements nSuspend_ and destroys the coroutine frame to
-         * break the shared_ptr cycle (frame -> lambda -> runner -> frame).
-         * Called by postCoroTask() when post() fails.
-         */
-        void
-        expectEarlyExit();
-
-        /**
-         * Block until all pending/active resume operations complete.
-         * Uses cv_ + mutexRun_ to wait until runCount_ reaches 0.
-         * Warning: deadlocks if the coroutine is suspended and never posted.
-         */
-        void
-        join();
-    };
-
     using JobFunction = std::function<void()>;
 
     JobQueue(
@@ -612,20 +197,6 @@ public:
     std::shared_ptr<Coro>
     postCoro(JobType t, std::string const& name, F&& f);
 
-    /**
-     * Creates a C++20 coroutine and adds a job to the queue to run it.
-     *
-     * @param t The type of job.
-     * @param name Name of the job.
-     * @param f Callable with signature
-     * CoroTask<void>(std::shared_ptr<CoroTaskRunner>).
-     *
-     * @return shared_ptr to posted CoroTaskRunner. nullptr if not successful.
-     */
-    template <class F>
-    std::shared_ptr<CoroTaskRunner>
-    postCoroTask(JobType t, std::string const& name, F&& f);
-
     /**
      * Jobs waiting at this priority.
      */
@@ -848,8 +419,7 @@ private:
 
 }  // namespace xrpl
 
-#include <xrpl/core/Coro.ipp>            // IWYU pragma: keep
-#include <xrpl/core/CoroTaskRunner.ipp>  // IWYU pragma: keep
+#include <xrpl/core/Coro.ipp>  // IWYU pragma: keep
 
 namespace xrpl {
 
@@ -872,82 +442,4 @@ JobQueue::postCoro(JobType t, std::string const& name, F&& f)
     return coro;
 }
 
-// postCoroTask — entry point for launching a C++20 coroutine on the JobQueue.
-//
-// Control Flow
-// ============
-//
-//   postCoroTask(t, name, f)
-//     |
-//     +-- 1. Reserve a jobCounter_ slot — reject if JQ shutting down
-//     |
-//     +-- 2. ++nSuspend_   (mirrors Boost Coro ctor's implicit yield)
-//     |        The coroutine is "suspended" from the JobQueue's perspective
-//     |        even though it hasn't run yet — this keeps the JQ shutdown
-//     |        logic correct (it waits for nSuspend_ to reach 0).
-//     |
-//     +-- 3. Create CoroTaskRunner (shared_ptr, ref-counted)
-//     |
-//     +-- 4. runner->init(f)
-//     |        +-- Heap-allocate the lambda (FuncStore) to prevent
-//     |        |   dangling captures in the coroutine frame
-//     |        +-- task_ = f(shared_from_this())
-//     |              [coroutine created but NOT started — lazy initial_suspend]
-//     |
-//     +-- 5. runner->post()
-//     |        +-- addJob(type_, [resume]{})   → resume on worker thread
-//     |        +-- failure (JQ stopping):
-//     |              +-- runner->expectEarlyExit()
-//     |              |     --nSuspend_, destroy coroutine frame
-//     |              +-- return nullptr
-//     |
-//     +-- 6. Release the jobCounter_ slot (on return)
-//
-// Why reserve a jobCounter_ slot?
-// ===============================
-// JobQueue::stop() joins jobCounter_ before it acquires mutex_ and asserts
-// nSuspend_ == 0.  Without a reservation, stop() could run to completion in
-// the window between the ++nSuspend_ in step 2 and the balancing post() or
-// expectEarlyExit() in step 5, tripping that assert.  Holding a slot blocks
-// stop()'s join() for the whole function, closing the window.  wrap() also
-// returns nullopt once the counter is joined, so it doubles as the shutdown
-// check — a plain stopping_ read cannot do this, because the read and the
-// ++nSuspend_ are not a single atomic step.
-//
-// Why async post() instead of synchronous resume()?
-// ==================================================
-// The initial dispatch MUST use async post() so the coroutine body runs on
-// a JobQueue worker thread, not the caller's thread.  resume() swaps the
-// caller's thread-local LocalValues with the coroutine's private copy.
-// If the coroutine mutates LocalValues (e.g. thread_specific_storage test),
-// those mutations bleed back into the caller's thread-local state after the
-// swap-out, corrupting subsequent tests that share the same thread pool.
-// Async post() avoids this by running the coroutine on a worker thread whose
-// LocalValues are managed by the thread pool, not by the caller.
-//
-template <class F>
-std::shared_ptr<JobQueue::CoroTaskRunner>
-JobQueue::postCoroTask(JobType t, std::string const& name, F&& f)
-{
-    // Held until this function returns. Null once jobCounter_ is joined,
-    // which is how a shutting-down JobQueue rejects new coroutines.
-    auto const shutdownGuard = jobCounter_.wrap([]() {});
-    if (!shutdownGuard)
-        return nullptr;
-
-    {
-        std::scoped_lock const lock(mutex_);
-        ++nSuspend_;
-    }
-
-    auto runner = std::make_shared<CoroTaskRunner>(CoroTaskRunner::CreateT{}, *this, t, name);
-    runner->init(std::forward<F>(f));
-    if (!runner->post())
-    {
-        runner->expectEarlyExit();
-        runner.reset();
-    }
-    return runner;
-}
-
 }  // namespace xrpl

include/xrpl/core/JobQueueAwaiter.h

@@ -1,212 +0,0 @@
-#pragma once
-
-#include <xrpl/beast/utility/instrumentation.h>
-#include <xrpl/core/JobQueue.h>
-
-#include <coroutine>
-#include <memory>
-
-namespace xrpl {
-
-/**
- * Awaiter that suspends and immediately reschedules on the JobQueue.
- * Equivalent to calling yield() followed by post() in the old Coro API.
- *
- * Usage:
- *     co_await JobQueueAwaiter{runner};
- *
- * What it waits for: The coroutine is re-queued as a job and resumes
- * when a worker thread picks it up.
- *
- * Which thread resumes: A JobQueue worker thread.
- *
- * What await_resume() returns: void.
- *
- * Dependency Diagram
- * ==================
- *
- *   JobQueueAwaiter
- *   +----------------------------------------------+
- *   | + runner : shared_ptr<CoroTaskRunner>         |
- *   +----------------------------------------------+
- *   | + await_ready()   -> false (always suspend)   |
- *   | + await_suspend() -> bool (suspend or cancel) |
- *   | + await_resume()  -> void                     |
- *   +----------------------------------------------+
- *          |                         |
- *          | uses                    | uses
- *          v                         v
- *   CoroTaskRunner              JobQueue
- *   .onSuspend()                (via runner->post() -> addJob)
- *   .onUndoSuspend()
- *   .post()
- *
- * Control Flow (await_suspend)
- * ============================
- *
- *   co_await JobQueueAwaiter{runner}
- *     |
- *     +-- await_ready() -> false
- *     +-- await_suspend(handle)
- *           |
- *           +-- runner->onSuspend()     // ++nSuspend_
- *           +-- runner->post()          // addJob to JobQueue
- *           |     |
- *           |     +-- success? return noop_coroutine()
- *           |     |     // coroutine stays suspended;
- *           |     |     // worker thread will call resume()
- *           |     +-- failure? (JQ stopping)
- *           |           +-- runner->onUndoSuspend()  // --nSuspend_
- *           |           +-- return handle  // symmetric transfer back
- *           |                              // coroutine continues immediately
- *           |                              // so it can clean up and co_return
- *
- * DEPRECATED — prefer `co_await runner->yieldAndPost()`
- * =====================================================
- *
- * GCC-12 has a coroutine codegen bug where using this external awaiter
- * struct at multiple co_await points in the same coroutine corrupts the
- * state machine's resume index. After the second co_await, the third
- * resumption enters handle().resume() but never reaches await_resume()
- * or any subsequent user code — the coroutine hangs indefinitely.
- *
- * The fix is `co_await runner->yieldAndPost()`, which defines the
- * awaiter as an inline struct inside a CoroTaskRunner member function.
- * GCC-12 handles inline awaiters correctly at multiple co_await points.
- *
- * This struct is retained for single-use scenarios and documentation
- * purposes. For any code that may use co_await in a loop or at
- * multiple points, always use `runner->yieldAndPost()`.
- *
- * Usage Examples
- * ==============
- *
- * 1. Yield and auto-repost (preferred — works on all compilers):
- *
- *     CoroTask<void> handler(auto runner) {
- *         doPartA();
- *         co_await runner->yieldAndPost();   // yield + repost
- *         doPartB();                         // runs on a worker thread
- *         co_return;
- *     }
- *
- * 2. Multiple yield points in a loop:
- *
- *     CoroTask<void> batchProcessor(auto runner) {
- *         for (auto& item : items) {
- *             process(item);
- *             co_await runner->yieldAndPost();  // let other jobs run
- *         }
- *         co_return;
- *     }
- *
- * 3. Graceful shutdown — checking after resume:
- *
- *     CoroTask<void> longTask(auto runner, JobQueue& jq) {
- *         while (hasWork()) {
- *             co_await runner->yieldAndPost();
- *             // If JQ is stopping, await_suspend resumes the coroutine
- *             // immediately without re-queuing. Always check
- *             // isStopping() to decide whether to proceed:
- *             if (jq.isStopping())
- *                 co_return;
- *             doNextChunk();
- *         }
- *         co_return;
- *     }
- *
- * Caveats / Pitfalls
- * ==================
- *
- * BUG-RISK: Using a stale or null runner.
- *   The runner shared_ptr must be valid and point to the CoroTaskRunner
- *   that owns the coroutine currently executing. Passing a runner from
- *   a different coroutine, or a default-constructed shared_ptr, is UB.
- *
- * BUG-RISK: Assuming resume happens on the same thread.
- *   After co_await, the coroutine resumes on whatever worker thread
- *   picks up the job. Do not rely on thread-local state unless it is
- *   managed through LocalValue (which CoroTaskRunner automatically
- *   swaps in/out).
- *
- * BUG-RISK: Ignoring the shutdown path.
- *   When the JobQueue is stopping, post() fails and await_suspend()
- *   resumes the coroutine immediately (symmetric transfer back to h).
- *   The coroutine body continues on the same thread. If your code
- *   after co_await assumes it was re-queued and is running on a worker
- *   thread, that assumption breaks during shutdown. Always handle the
- *   "JQ is stopping" case, either by checking jq.isStopping() or by
- *   letting the coroutine fall through to co_return naturally.
- *
- * DIFFERENCE from runner->suspend() + runner->post():
- *   Both JobQueueAwaiter and yieldAndPost() combine suspend + post
- *   in one atomic operation. With the manual suspend()/post() pattern,
- *   there is a window between the two calls where an external event
- *   could race. The atomic awaiters remove that window — onSuspend()
- *   and post() happen within the same await_suspend() call while the
- *   coroutine is guaranteed to be suspended. Use yieldAndPost() unless
- *   you need an external party to decide *when* to call post().
- */
-struct JobQueueAwaiter
-{
-    // The CoroTaskRunner that owns the currently executing coroutine.
-    std::shared_ptr<JobQueue::CoroTaskRunner> runner;
-
-    /**
-     * Always returns false so the coroutine suspends.
-     */
-    // The C++ coroutine protocol mandates these awaiter names and
-    // instance-callable methods, which conflict with the project
-    // naming/static conventions.
-    // NOLINTBEGIN(readability-identifier-naming, readability-convert-member-functions-to-static)
-    [[nodiscard]] bool
-    await_ready() const noexcept
-    {
-        return false;
-    }
-
-    /**
-     * Increment nSuspend (equivalent to yield()) and schedule resume
-     * on the JobQueue (equivalent to post()). If the JobQueue is
-     * stopping, undoes the suspend count and transfers back to the
-     * coroutine so it can clean up and co_return.
-     *
-     * Returns a coroutine_handle<> (symmetric transfer) instead of
-     * bool to work around a GCC-12 codegen bug where bool-returning
-     * await_suspend leaves the coroutine in an invalid state —
-     * neither properly suspended nor resumed — causing a hang.
-     *
-     * WARNING: GCC-12 has an additional codegen bug where using this
-     * external awaiter struct at multiple co_await points in the same
-     * coroutine corrupts the state machine's resume index, causing the
-     * coroutine to hang on the third resumption. Prefer
-     * `co_await runner->yieldAndPost()` which uses an inline awaiter
-     * that GCC-12 handles correctly.
-     *
-     * @return noop_coroutine() to stay suspended (job posted);
-     *         the caller's handle to resume immediately (JQ stopping)
-     */
-    std::coroutine_handle<>
-    await_suspend(std::coroutine_handle<> h)
-    {
-        XRPL_ASSERT(runner, "xrpl::JobQueueAwaiter::await_suspend : runner is valid");
-        runner->onSuspend();
-        if (!runner->post())
-        {
-            // JobQueue is stopping. Undo the suspend count and
-            // transfer back to the coroutine so it can clean up
-            // and co_return.
-            runner->onUndoSuspend();
-            return h;
-        }
-        return std::noop_coroutine();
-    }
-
-    void
-    await_resume() const noexcept
-    {
-    }
-    // NOLINTEND(readability-identifier-naming, readability-convert-member-functions-to-static)
-};
-
-}  // namespace xrpl

package/README.md

@@ -126,15 +126,15 @@ release defaults to 1 and is overridable with `-Dpkg_release=N`.
 
 Packages are published to the XRPLF repositories on Sonatype Nexus at
 `https://packages.xrplf.org`. The `release-info` action decides the channel from
-the event, and `publish_pkg.sh` maps that channel to a repository pair:
+the event, and `publish_pkg.sh` maps that channel to its repositories:
 
-| Event                    | Version           | Channel        | DEB repository     | RPM repository     |
-| ------------------------ | ----------------- | -------------- | ------------------ | ------------------ |
-| tag                      | `X.Y.Z`           | `stable`       | `deb-stable`       | `rpm-stable`       |
-| tag                      | `X.Y.Z-rcN`       | `unstable`     | `deb-unstable`     | `rpm-unstable`     |
-| tag                      | `X.Y.Z-bN`        | `experimental` | `deb-experimental` | `rpm-experimental` |
-| push to `develop`        | `xrpld --version` | `develop`      | `deb-develop`      | `rpm-develop`      |
-| tag, non-public codebase | _any_             | `private`      | `deb-private`      | `rpm-private`      |
+| Event                    | Version           | Channel        | DEB repository     | RPM upload repository     |
+| ------------------------ | ----------------- | -------------- | ------------------ | ------------------------- |
+| tag                      | `X.Y.Z`           | `stable`       | `deb-stable`       | `rpm-stable-hosted`       |
+| tag                      | `X.Y.Z-rcN`       | `unstable`     | `deb-unstable`     | `rpm-unstable-hosted`     |
+| tag                      | `X.Y.Z-bN`        | `experimental` | `deb-experimental` | `rpm-experimental-hosted` |
+| push to `develop`        | `xrpld --version` | `develop`      | `deb-develop`      | `rpm-develop-hosted`      |
+| tag, non-public codebase | _any_             | `private`      | `deb-private`      | `rpm-private-hosted`      |
 
 Only a tag names a channel — do not extend that to `develop`, where
 `BuildInfo.cpp`'s `versionString` moves through `-bN`, `-rcN` and even the final
@@ -155,12 +155,15 @@ Conan remote.
 
 Nexus owns the repository metadata; nothing here indexes anything. Worth knowing:
 
-- Each apt-hosted repository needs a distribution and a PGP signing keypair
-  configured in Nexus, which rejects one created without a keypair. Nexus signs
-  the apt metadata with it, never the packages.
-- Hosted yum repositories cannot be signed by Nexus at all, so `sign_rpm.sh`
-  signs the RPMs before they are uploaded, and rpm clients verify with
-  `gpgcheck=1` rather than `repo_gpgcheck=1`.
+- Each apt-hosted repository needs a distribution (ours use `any`) and a PGP
+  signing keypair configured in Nexus, which rejects one created without a
+  keypair. Nexus signs the apt metadata with it, never the packages.
+- Hosted yum repositories cannot be signed by Nexus, so each `rpm-<channel>-hosted`
+  repository sits behind a `rpm-<channel>` yum group repository whose metadata
+  Nexus signs. Uploads go to the hosted repository; clients point at the group
+  and verify the metadata with `repo_gpgcheck=1`. Nexus never signs the RPMs
+  themselves, so `sign_rpm.sh` signs them before they are uploaded, and clients
+  verify them with `gpgcheck=1`.
 - yum metadata is rebuilt asynchronously, so a successful publish is not
   immediately installable.
 - Each job uploads only what it built, and uploads are not transactional, so a

package/publish_pkg.sh

@@ -7,10 +7,13 @@ set -euo pipefail
 # Usage: publish_pkg.sh <channel> [package-dir]
 #
 #   channel      release channel, selecting the 'deb-<channel>' and
-#                'rpm-<channel>' repository pair
+#                'rpm-<channel>-hosted' repositories
 #   package-dir  searched recursively for *.deb, *.ddeb and *.rpm ('build' by
 #                default)
 #
+# RPMs are uploaded to the hosted repository, but yum clients install from the
+# 'rpm-<channel>' group repository in front of it, which serves signed metadata.
+#
 # NEXUS_USERNAME and NEXUS_PASSWORD are required. NEXUS_URL overrides the target
 # instance, and DRY_RUN=1 lists the uploads without performing them.
 
@@ -24,7 +27,7 @@ if [[ -z "${channel}" ]]; then
 fi
 
 deb_repo="deb-${channel}"
-rpm_repo="rpm-${channel}"
+rpm_repo="rpm-${channel}-hosted"
 
 if [[ -z "${DRY_RUN:-}" ]]; then
     : "${NEXUS_USERNAME:?is required}" "${NEXUS_PASSWORD:?is required}"

package/sign_rpm.sh

@@ -1,9 +1,10 @@
 #!/usr/bin/env bash
 set -euo pipefail
 
-# Sign the RPMs built by build_pkg.sh. Nexus cannot sign hosted yum metadata, so
-# the packages carry the signature themselves and rpm clients verify them with
-# gpgcheck=1.
+# Sign the RPMs built by build_pkg.sh. Nexus signs the yum repository metadata
+# (via the 'rpm-<channel>' group repository), but never the packages themselves,
+# so they carry their own signature. Clients verify the packages with gpgcheck=1
+# and the metadata with repo_gpgcheck=1.
 #
 # Usage: sign_rpm.sh [package-dir]
 #
@@ -12,8 +13,9 @@ set -euo pipefail
 # PKG_SIGNING_KEY must hold an armoured PGP private key. It has no flag, to keep
 # the key out of the process list.
 #
-# There is no DEB equivalent: apt trusts the repository metadata, which Nexus
-# signs, rather than the packages themselves.
+# The DEBs are deliberately not signed: embedded DEB signatures exist (debsigs),
+# but apt does not verify them by default and trusts the repository metadata,
+# which Nexus signs, instead.
 
 pkg_dir="${1:-build}"
 

src/libxrpl/tx/AGENTS.md

@@ -0,0 +1,5 @@
+# AGENTS.md — tx
+
+See the repo-level [AGENTS.md](../../../AGENTS.md) for general build/test/style guidance. `CLAUDE.md` in this directory is a symlink to this file.
+
+Any change to transaction-processing behavior must be gated behind an amendment. New amendments (and fixes, i.e. `fix*` amendments) are added to [`include/xrpl/protocol/detail/features.macro`](../../../include/xrpl/protocol/detail/features.macro), as an `XRPL_FEATURE(...)` or `XRPL_FIX(...)` entry added to the top of the list (the list is kept in reverse chronological order).

src/libxrpl/tx/CLAUDE.md

@@ -0,0 +1 @@
+AGENTS.md

src/test/app/PathMPT_test.cpp

@@ -19,7 +19,6 @@
 
 #include <xrpl/basics/base_uint.h>
 #include <xrpl/beast/unit_test/suite.h>
-#include <xrpl/core/CoroTask.h>
 #include <xrpl/core/Job.h>
 #include <xrpl/core/JobQueue.h>
 #include <xrpl/json/json_value.h>
@@ -124,6 +123,7 @@ public:
              .ledgerMaster = app.getLedgerMaster(),
              .consumer = c,
              .role = Role::USER,
+             .coro = {},
              .infoSub = {},
              .apiVersion = rpc::kApiVersionIfUnspecified},
             {},
@@ -135,28 +135,22 @@ public:
         numSrc.reserve(rpc::tuning::kMaxSrcCur);
         for (std::uint8_t i = 0; i < rpc::tuning::kMaxSrcCur; ++i)
             numSrc.push_back(makeMptID(i, bob));
-        // Safe capture: the test blocks on g.waitFor() until the coroutine
-        // completes, so the captured locals outlive the coroutine.
-        // NOLINTNEXTLINE(cppcoreguidelines-avoid-capturing-lambda-coroutines)
-        app.getJobQueue().postCoroTask(JtClient, "RPC-Client", [&](auto) -> CoroTask<void> {
+        app.getJobQueue().postCoro(JtClient, "RPC-Client", [&](auto const& coro) {
             context.params = xrpl::test::detail::rpf(alice, bob, usd, numSrc);
+            context.coro = coro;
             rpc::doCommand(context, result);
             g.signal();
-            co_return;
         });
         BEAST_EXPECT(g.waitFor(5s));
         BEAST_EXPECT(!result.isMember(jss::error));
 
         // Test more than rpc::tuning::max_src_cur source currencies.
         numSrc.push_back(makeMptID(rpc::tuning::kMaxSrcCur, bob));
-        // Safe capture: the test blocks on g.waitFor() until the coroutine
-        // completes, so the captured locals outlive the coroutine.
-        // NOLINTNEXTLINE(cppcoreguidelines-avoid-capturing-lambda-coroutines)
-        app.getJobQueue().postCoroTask(JtClient, "RPC-Client", [&](auto) -> CoroTask<void> {
+        app.getJobQueue().postCoro(JtClient, "RPC-Client", [&](auto const& coro) {
             context.params = xrpl::test::detail::rpf(alice, bob, usd, numSrc);
+            context.coro = coro;
             rpc::doCommand(context, result);
             g.signal();
-            co_return;
         });
         BEAST_EXPECT(g.waitFor(5s));
         BEAST_EXPECT(result.isMember(jss::error));
@@ -168,28 +162,22 @@ public:
             auto curm = MPTTester({.env = env, .issuer = alice, .holders = {bob}});
             numSrc.push_back(curm.issuanceID());
         }
-        // Safe capture: the test blocks on g.waitFor() until the coroutine
-        // completes, so the captured locals outlive the coroutine.
-        // NOLINTNEXTLINE(cppcoreguidelines-avoid-capturing-lambda-coroutines)
-        app.getJobQueue().postCoroTask(JtClient, "RPC-Client", [&](auto) -> CoroTask<void> {
+        app.getJobQueue().postCoro(JtClient, "RPC-Client", [&](auto const& coro) {
             context.params = xrpl::test::detail::rpf(alice, bob, usd, {});
+            context.coro = coro;
             rpc::doCommand(context, result);
             g.signal();
-            co_return;
         });
         BEAST_EXPECT(g.waitFor(5s));
         BEAST_EXPECT(!result.isMember(jss::error));
 
         // Test more than rpc::tuning::max_auto_src_cur source currencies.
         auto curm = MPTTester({.env = env, .issuer = alice, .holders = {bob}});
-        // Safe capture: the test blocks on g.waitFor() until the coroutine
-        // completes, so the captured locals outlive the coroutine.
-        // NOLINTNEXTLINE(cppcoreguidelines-avoid-capturing-lambda-coroutines)
-        app.getJobQueue().postCoroTask(JtClient, "RPC-Client", [&](auto) -> CoroTask<void> {
+        app.getJobQueue().postCoro(JtClient, "RPC-Client", [&](auto const& coro) {
             context.params = xrpl::test::detail::rpf(alice, bob, usd, {});
+            context.coro = coro;
             rpc::doCommand(context, result);
             g.signal();
-            co_return;
         });
         BEAST_EXPECT(g.waitFor(5s));
         BEAST_EXPECT(result.isMember(jss::error));

src/test/app/Path_test.cpp

@@ -26,7 +26,6 @@
 
 #include <xrpl/basics/base_uint.h>
 #include <xrpl/beast/unit_test/suite.h>
-#include <xrpl/core/CoroTask.h>
 #include <xrpl/core/Job.h>
 #include <xrpl/core/JobQueue.h>
 #include <xrpl/json/json_reader.h>
@@ -164,6 +163,7 @@ public:
              .ledgerMaster = app.getLedgerMaster(),
              .consumer = c,
              .role = Role::USER,
+             .coro = {},
              .infoSub = {},
              .apiVersion = rpc::kApiVersionIfUnspecified},
             {},
@@ -188,14 +188,11 @@ public:
 
         json::Value result;
         Gate g;
-        // Safe capture: the test blocks on g.waitFor() until the coroutine
-        // completes, so the captured locals outlive the coroutine.
-        // NOLINTNEXTLINE(cppcoreguidelines-avoid-capturing-lambda-coroutines)
-        app.getJobQueue().postCoroTask(JtClient, "RPC-Client", [&](auto) -> CoroTask<void> {
+        app.getJobQueue().postCoro(JtClient, "RPC-Client", [&](auto const& coro) {
             context.params = std::move(params);
+            context.coro = coro;
             rpc::doCommand(context, result);
             g.signal();
-            co_return;
         });
 
         using namespace std::chrono_literals;
@@ -277,6 +274,7 @@ public:
              .ledgerMaster = app.getLedgerMaster(),
              .consumer = c,
              .role = Role::USER,
+             .coro = {},
              .infoSub = {},
              .apiVersion = rpc::kApiVersionIfUnspecified},
             {},
@@ -284,27 +282,21 @@ public:
         json::Value result;
         Gate g;
         // Test rpc::tuning::max_src_cur source currencies.
-        // Safe capture: the test blocks on g.waitFor() until the coroutine
-        // completes, so the captured locals outlive the coroutine.
-        // NOLINTNEXTLINE(cppcoreguidelines-avoid-capturing-lambda-coroutines)
-        app.getJobQueue().postCoroTask(JtClient, "RPC-Client", [&](auto) -> CoroTask<void> {
+        app.getJobQueue().postCoro(JtClient, "RPC-Client", [&](auto const& coro) {
             context.params = rpf(Account("alice"), Account("bob"), rpc::tuning::kMaxSrcCur);
+            context.coro = coro;
             rpc::doCommand(context, result);
             g.signal();
-            co_return;
         });
         BEAST_EXPECT(g.waitFor(5s));
         BEAST_EXPECT(!result.isMember(jss::error));
 
         // Test more than rpc::tuning::max_src_cur source currencies.
-        // Safe capture: the test blocks on g.waitFor() until the coroutine
-        // completes, so the captured locals outlive the coroutine.
-        // NOLINTNEXTLINE(cppcoreguidelines-avoid-capturing-lambda-coroutines)
-        app.getJobQueue().postCoroTask(JtClient, "RPC-Client", [&](auto) -> CoroTask<void> {
+        app.getJobQueue().postCoro(JtClient, "RPC-Client", [&](auto const& coro) {
             context.params = rpf(Account("alice"), Account("bob"), rpc::tuning::kMaxSrcCur + 1);
+            context.coro = coro;
             rpc::doCommand(context, result);
             g.signal();
-            co_return;
         });
         BEAST_EXPECT(g.waitFor(5s));
         BEAST_EXPECT(result.isMember(jss::error));
@@ -312,28 +304,22 @@ public:
         // Test rpc::tuning::max_auto_src_cur source currencies.
         for (auto i = 0; i < (rpc::tuning::kMaxAutoSrcCur - 1); ++i)
             env.trust(Account("alice")[std::to_string(i + 100)](100), "bob");
-        // Safe capture: the test blocks on g.waitFor() until the coroutine
-        // completes, so the captured locals outlive the coroutine.
-        // NOLINTNEXTLINE(cppcoreguidelines-avoid-capturing-lambda-coroutines)
-        app.getJobQueue().postCoroTask(JtClient, "RPC-Client", [&](auto) -> CoroTask<void> {
+        app.getJobQueue().postCoro(JtClient, "RPC-Client", [&](auto const& coro) {
             context.params = rpf(Account("alice"), Account("bob"), 0);
+            context.coro = coro;
             rpc::doCommand(context, result);
             g.signal();
-            co_return;
         });
         BEAST_EXPECT(g.waitFor(5s));
         BEAST_EXPECT(!result.isMember(jss::error));
 
         // Test more than rpc::tuning::max_auto_src_cur source currencies.
         env.trust(Account("alice")["AUD"](100), "bob");
-        // Safe capture: the test blocks on g.waitFor() until the coroutine
-        // completes, so the captured locals outlive the coroutine.
-        // NOLINTNEXTLINE(cppcoreguidelines-avoid-capturing-lambda-coroutines)
-        app.getJobQueue().postCoroTask(JtClient, "RPC-Client", [&](auto) -> CoroTask<void> {
+        app.getJobQueue().postCoro(JtClient, "RPC-Client", [&](auto const& coro) {
             context.params = rpf(Account("alice"), Account("bob"), 0);
+            context.coro = coro;
             rpc::doCommand(context, result);
             g.signal();
-            co_return;
         });
         BEAST_EXPECT(g.waitFor(5s));
         BEAST_EXPECT(result.isMember(jss::error));

src/test/app/PayChan_test.cpp

@@ -24,9 +24,7 @@
 #include <xrpl/basics/strHex.h>
 #include <xrpl/beast/unit_test/suite.h>
 #include <xrpl/beast/utility/Zero.h>
-#include <xrpl/core/CoroTask.h>
 #include <xrpl/core/Job.h>
-#include <xrpl/core/JobQueue.h>
 #include <xrpl/core/ServiceRegistry.h>
 #include <xrpl/json/json_value.h>
 #include <xrpl/json/to_string.h>
@@ -1640,6 +1638,7 @@ struct PayChan_test : public beast::unit_test::Suite
              .ledgerMaster = app.getLedgerMaster(),
              .consumer = c,
              .role = Role::USER,
+             .coro = {},
              .infoSub = {},
              .apiVersion = rpc::kApiVersionIfUnspecified},
             {},
@@ -1655,13 +1654,10 @@ struct PayChan_test : public beast::unit_test::Suite
         BEAST_EXPECT(context.loadType == resource::kFeeReferenceRpc);
         json::Value result;
         Gate g;
-        // Safe capture: the test blocks on g.waitFor() until the coroutine
-        // completes, so the captured locals outlive the coroutine.
-        // NOLINTNEXTLINE(cppcoreguidelines-avoid-capturing-lambda-coroutines)
-        app.getJobQueue().postCoroTask(JtClient, "RPC-Client", [&](auto) -> CoroTask<void> {
+        app.getJobQueue().postCoro(JtClient, "RPC-Client", [&](auto const& coro) {
+            context.coro = coro;
             result = doChannelVerify(context);
             g.signal();
-            co_return;
         });
 
         using namespace std::chrono_literals;
@@ -1709,6 +1705,7 @@ struct PayChan_test : public beast::unit_test::Suite
              .ledgerMaster = app.getLedgerMaster(),
              .consumer = c,
              .role = Role::ADMIN,  // channel_authorize requires ADMIN or canSign()
+             .coro = {},
              .infoSub = {},
              .apiVersion = rpc::kApiVersionIfUnspecified},
             {},
@@ -1723,13 +1720,10 @@ struct PayChan_test : public beast::unit_test::Suite
         BEAST_EXPECT(context.loadType == resource::kFeeReferenceRpc);
         json::Value result;
         Gate g;
-        // Safe capture: the test blocks on g.waitFor() until the coroutine
-        // completes, so the captured locals outlive the coroutine.
-        // NOLINTNEXTLINE(cppcoreguidelines-avoid-capturing-lambda-coroutines)
-        app.getJobQueue().postCoroTask(JtClient, "RPC-Client", [&](auto) -> CoroTask<void> {
+        app.getJobQueue().postCoro(JtClient, "RPC-Client", [&](auto const& coro) {
+            context.coro = coro;
             result = doChannelAuthorize(context);
             g.signal();
-            co_return;
         });
 
         using namespace std::chrono_literals;

src/test/core/CoroTask_test.cpp

@@ -1,581 +0,0 @@
-#include <test/jtx/Env.h>
-#include <test/jtx/envconfig.h>
-
-#include <xrpld/core/Config.h>
-
-#include <xrpl/basics/LocalValue.h>
-#include <xrpl/beast/unit_test/suite.h>
-#include <xrpl/core/CoroTask.h>
-#include <xrpl/core/Job.h>
-#include <xrpl/core/JobQueue.h>
-#include <xrpl/core/JobQueueAwaiter.h>
-
-#include <array>
-#include <chrono>
-#include <condition_variable>
-#include <memory>
-#include <mutex>
-#include <stdexcept>
-#include <string>
-#include <vector>
-
-// Tests intentionally capture state in coroutine lambdas; lifetimes are
-// controlled by Gate synchronization and join() before scope exit.
-// NOLINTBEGIN(cppcoreguidelines-avoid-capturing-lambda-coroutines)
-
-namespace xrpl::test {
-
-/**
- * Test suite for the C++20 coroutine primitives: CoroTask, CoroTaskRunner,
- * and JobQueueAwaiter.
- *
- * Dependency Diagram
- * ==================
- *
- *   CoroTask_test
- *   +-------------------------------------------------+
- *   | + Gate (inner class) : condition_variable helper |
- *   +-------------------------------------------------+
- *          |  uses
- *          v
- *   jtx::Env  -->  JobQueue::postCoroTask()
- *                       |
- *                       +-- CoroTaskRunner (suspend / post / resume)
- *                       +-- CoroTask<void> / CoroTask<T>
- *                       +-- JobQueueAwaiter
- *
- * Test Coverage Matrix
- * ====================
- *
- *   Test                      | Primitives exercised
- *   --------------------------+----------------------------------------------
- *   testVoidCompletion        | CoroTask<void> basic lifecycle
- *   testCorrectOrder          | suspend() -> join() -> post() -> complete
- *   testIncorrectOrder        | post() before suspend() (race-safe path)
- *   testJobQueueAwaiter       | JobQueueAwaiter + yieldAndPost suspend/repost
- *   testThreadSpecificStorage | LocalValue isolation across coroutines
- *   testExceptionPropagation  | CoroTask<void> exception via co_await
- *   testMultipleYields        | N sequential suspend/resume cycles
- *   testValueReturn           | CoroTask<T> co_return value
- *   testValueException        | CoroTask<T> exception via co_await
- *   testValueChaining         | nested CoroTask<T> -> CoroTask<T>
- *   testShutdownRejection     | postCoroTask returns nullptr when stopping
- */
-class CoroTask_test : public beast::unit_test::Suite
-{
-public:
-    /**
-     * Simple one-shot gate for synchronizing between test thread
-     * and coroutine worker threads. signal() sets the flag;
-     * waitFor() blocks until signaled or timeout.
-     */
-    class Gate
-    {
-    private:
-        std::condition_variable cv_;
-        std::mutex mutex_;
-        bool signaled_ = false;
-
-    public:
-        /**
-         * Block until signaled or timeout expires.
-         *
-         * @param relTime Maximum duration to wait
-         *
-         * @return true if signaled before timeout
-         */
-        template <class Rep, class Period>
-        bool
-        waitFor(std::chrono::duration<Rep, Period> const& relTime)
-        {
-            std::unique_lock<std::mutex> lk(mutex_);
-            auto b = cv_.wait_for(lk, relTime, [this] { return signaled_; });
-            signaled_ = false;
-            return b;
-        }
-
-        /**
-         * Signal the gate, waking any waiting thread.
-         */
-        void
-        signal()
-        {
-            std::scoped_lock const lk(mutex_);
-            signaled_ = true;
-            cv_.notify_all();
-        }
-    };
-
-    // NOTE: All coroutine lambdas passed to postCoroTask use explicit
-    // pointer-by-value captures instead of [&] to work around a GCC 14
-    // bug where reference captures in coroutine lambdas are corrupted
-    // in the coroutine frame.
-
-    /**
-     * CoroTask<void> runs to completion and runner becomes non-runnable.
-     */
-    void
-    testVoidCompletion()
-    {
-        using namespace std::chrono_literals;
-        using namespace jtx;
-
-        testcase("void completion");
-
-        Env env(*this, envconfig([](std::unique_ptr<Config> cfg) {
-            cfg->forceMultiThread = true;
-            return cfg;
-        }));
-
-        Gate g;
-        auto runner = env.app().getJobQueue().postCoroTask(
-            JtClient, "CoroTaskTest", [gp = &g](auto) -> CoroTask<void> {
-                gp->signal();
-                co_return;
-            });
-        BEAST_EXPECT(runner);
-        if (!BEAST_EXPECT(g.waitFor(5s)))
-            return;
-        runner->join();
-        BEAST_EXPECT(!runner->runnable());
-    }
-
-    /**
-     * Correct order: suspend, join, post, complete.
-     * Mirrors existing Coroutine_test::correct_order.
-     */
-    void
-    testCorrectOrder()
-    {
-        using namespace std::chrono_literals;
-        using namespace jtx;
-
-        testcase("correct order");
-
-        Env env(*this, envconfig([](std::unique_ptr<Config> cfg) {
-            cfg->forceMultiThread = true;
-            return cfg;
-        }));
-
-        Gate g1, g2;
-        auto runner = env.app().getJobQueue().postCoroTask(
-            JtClient, "CoroTaskTest", [g1p = &g1, g2p = &g2](auto runner) -> CoroTask<void> {
-                g1p->signal();
-                co_await runner->suspend();
-                g2p->signal();
-                co_return;
-            });
-        BEAST_EXPECT(runner);
-        if (!BEAST_EXPECT(g1.waitFor(5s)))
-            return;
-        runner->join();
-        runner->post();
-        if (!BEAST_EXPECT(g2.waitFor(5s)))
-            return;
-        runner->join();
-    }
-
-    /**
-     * Incorrect order: post() before suspend(). Verifies the
-     * race-safe path. Mirrors Coroutine_test::incorrect_order.
-     */
-    void
-    testIncorrectOrder()
-    {
-        using namespace std::chrono_literals;
-        using namespace jtx;
-
-        testcase("incorrect order");
-
-        Env env(*this, envconfig([](std::unique_ptr<Config> cfg) {
-            cfg->forceMultiThread = true;
-            return cfg;
-        }));
-
-        Gate g;
-        env.app().getJobQueue().postCoroTask(
-            JtClient, "CoroTaskTest", [gp = &g](auto runner) -> CoroTask<void> {
-                runner->post();
-                co_await runner->suspend();
-                gp->signal();
-                co_return;
-            });
-        BEAST_EXPECT(g.waitFor(5s));
-    }
-
-    /**
-     * Suspend + auto-repost across multiple yield points, using the
-     * external JobQueueAwaiter struct for the first suspension and the
-     * inline yieldAndPost() awaiter for the second. JobQueueAwaiter is
-     * used at only one co_await point per coroutine (see the GCC-12
-     * multi-use warning in JobQueueAwaiter.h).
-     */
-    void
-    testJobQueueAwaiter()
-    {
-        using namespace std::chrono_literals;
-        using namespace jtx;
-
-        testcase("JobQueueAwaiter");
-
-        Env env(*this, envconfig([](std::unique_ptr<Config> cfg) {
-            cfg->forceMultiThread = true;
-            return cfg;
-        }));
-
-        Gate g;
-        std::vector<int> steps;
-        auto runner = env.app().getJobQueue().postCoroTask(
-            JtClient, "CoroTaskTest", [sp = &steps, gp = &g](auto runner) -> CoroTask<void> {
-                sp->push_back(1);
-                co_await JobQueueAwaiter{runner};
-                sp->push_back(2);
-                co_await runner->yieldAndPost();
-                sp->push_back(3);
-                gp->signal();
-                co_return;
-            });
-        BEAST_EXPECT(runner);
-        if (!BEAST_EXPECT(g.waitFor(5s)))
-            return;
-        runner->join();
-        BEAST_EXPECT(steps == std::vector<int>({1, 2, 3}));
-    }
-
-    /**
-     * Per-coroutine LocalValue isolation. Each coroutine sees its own
-     * copy of thread-local state. Mirrors Coroutine_test::thread_specific_storage.
-     */
-    void
-    testThreadSpecificStorage()
-    {
-        using namespace std::chrono_literals;
-        using namespace jtx;
-
-        testcase("thread specific storage");
-        Env env(*this);
-
-        auto& jq = env.app().getJobQueue();
-
-        static constexpr int kN = 4;
-        std::array<std::shared_ptr<JobQueue::CoroTaskRunner>, kN> a;
-
-        LocalValue<int> lv(-1);
-        BEAST_EXPECT(*lv == -1);
-
-        Gate g;
-        jq.addJob(JtClient, "LocalValTest", [&]() {
-            this->BEAST_EXPECT(*lv == -1);
-            *lv = -2;
-            this->BEAST_EXPECT(*lv == -2);
-            g.signal();
-        });
-        if (!BEAST_EXPECT(g.waitFor(5s)))
-            return;
-        BEAST_EXPECT(*lv == -1);
-
-        for (int i = 0; i < kN; ++i)
-        {
-            jq.postCoroTask(
-                JtClient,
-                "CoroTaskTest",
-                [this, ap = &a, gp = &g, lvp = &lv, id = i](auto runner) -> CoroTask<void> {
-                    (*ap)[id] = runner;
-                    gp->signal();
-                    co_await runner->suspend();
-
-                    this->BEAST_EXPECT(**lvp == -1);
-                    **lvp = id;
-                    this->BEAST_EXPECT(**lvp == id);
-                    gp->signal();
-                    co_await runner->suspend();
-
-                    this->BEAST_EXPECT(**lvp == id);
-                    co_return;
-                });
-            if (!BEAST_EXPECT(g.waitFor(5s)))
-                return;
-            a[i]->join();
-        }
-        for (auto const& r : a)
-        {
-            r->post();
-            if (!BEAST_EXPECT(g.waitFor(5s)))
-                return;
-            r->join();
-        }
-        for (auto const& r : a)
-        {
-            r->post();
-            r->join();
-        }
-
-        jq.addJob(JtClient, "LocalValTest", [&]() {
-            this->BEAST_EXPECT(*lv == -2);
-            g.signal();
-        });
-        if (!BEAST_EXPECT(g.waitFor(5s)))
-            return;
-        BEAST_EXPECT(*lv == -1);
-    }
-
-    /**
-     * An exception thrown in an awaited CoroTask<void> is rethrown into
-     * the awaiting coroutine by await_resume(), with the original
-     * message intact. (An exception escaping the top-level body has no
-     * awaiter to rethrow it; it is captured by unhandled_exception()
-     * and logged by CoroTaskRunner::resume().)
-     */
-    void
-    testExceptionPropagation()
-    {
-        using namespace std::chrono_literals;
-        using namespace jtx;
-
-        testcase("exception propagation");
-
-        Env env(*this, envconfig([](std::unique_ptr<Config> cfg) {
-            cfg->forceMultiThread = true;
-            return cfg;
-        }));
-
-        Gate g;
-        std::string what;
-        auto runner = env.app().getJobQueue().postCoroTask(
-            JtClient, "CoroTaskTest", [wp = &what, gp = &g](auto) -> CoroTask<void> {
-                auto inner = []() -> CoroTask<void> {
-                    throw std::runtime_error("test exception");
-                    co_return;
-                };
-                try
-                {
-                    co_await inner();
-                }
-                catch (std::runtime_error const& e)
-                {
-                    *wp = e.what();
-                }
-                gp->signal();
-                co_return;
-            });
-        BEAST_EXPECT(runner);
-        if (!BEAST_EXPECT(g.waitFor(5s)))
-            return;
-        runner->join();
-        BEAST_EXPECT(what == "test exception");
-        BEAST_EXPECT(!runner->runnable());
-    }
-
-    /**
-     * Multiple sequential suspend/resume cycles via co_await.
-     */
-    void
-    testMultipleYields()
-    {
-        using namespace std::chrono_literals;
-        using namespace jtx;
-
-        testcase("multiple yields");
-
-        Env env(*this, envconfig([](std::unique_ptr<Config> cfg) {
-            cfg->forceMultiThread = true;
-            return cfg;
-        }));
-
-        Gate g;
-        int counter = 0;
-        auto runner = env.app().getJobQueue().postCoroTask(
-            JtClient, "CoroTaskTest", [cp = &counter, gp = &g](auto runner) -> CoroTask<void> {
-                ++(*cp);
-                gp->signal();
-                co_await runner->suspend();
-                ++(*cp);
-                gp->signal();
-                co_await runner->suspend();
-                ++(*cp);
-                gp->signal();
-                co_return;
-            });
-        BEAST_EXPECT(runner);
-
-        if (!BEAST_EXPECT(g.waitFor(5s)))
-            return;
-        BEAST_EXPECT(counter == 1);
-        runner->join();
-
-        runner->post();
-        if (!BEAST_EXPECT(g.waitFor(5s)))
-            return;
-        BEAST_EXPECT(counter == 2);
-        runner->join();
-
-        runner->post();
-        if (!BEAST_EXPECT(g.waitFor(5s)))
-            return;
-        BEAST_EXPECT(counter == 3);
-        runner->join();
-        BEAST_EXPECT(!runner->runnable());
-    }
-
-    /**
-     * CoroTask<T> returns a value via co_return. Outer coroutine
-     * extracts it with co_await.
-     */
-    void
-    testValueReturn()
-    {
-        using namespace std::chrono_literals;
-        using namespace jtx;
-
-        testcase("value return");
-
-        Env env(*this, envconfig([](std::unique_ptr<Config> cfg) {
-            cfg->forceMultiThread = true;
-            return cfg;
-        }));
-
-        Gate g;
-        int result = 0;
-        auto runner = env.app().getJobQueue().postCoroTask(
-            JtClient, "CoroTaskTest", [rp = &result, gp = &g](auto) -> CoroTask<void> {
-                auto inner = []() -> CoroTask<int> { co_return 42; };
-                *rp = co_await inner();
-                gp->signal();
-                co_return;
-            });
-        BEAST_EXPECT(runner);
-        if (!BEAST_EXPECT(g.waitFor(5s)))
-            return;
-        runner->join();
-        BEAST_EXPECT(result == 42);
-        BEAST_EXPECT(!runner->runnable());
-    }
-
-    /**
-     * CoroTask<T> propagates exceptions from inner coroutines.
-     * Outer coroutine catches via try/catch around co_await.
-     */
-    void
-    testValueException()
-    {
-        using namespace std::chrono_literals;
-        using namespace jtx;
-
-        testcase("value exception");
-
-        Env env(*this, envconfig([](std::unique_ptr<Config> cfg) {
-            cfg->forceMultiThread = true;
-            return cfg;
-        }));
-
-        Gate g;
-        std::string what;
-        auto runner = env.app().getJobQueue().postCoroTask(
-            JtClient, "CoroTaskTest", [wp = &what, gp = &g](auto) -> CoroTask<void> {
-                auto inner = []() -> CoroTask<int> {
-                    throw std::runtime_error("inner error");
-                    co_return 0;
-                };
-                try
-                {
-                    co_await inner();
-                }
-                catch (std::runtime_error const& e)
-                {
-                    *wp = e.what();
-                }
-                gp->signal();
-                co_return;
-            });
-        BEAST_EXPECT(runner);
-        if (!BEAST_EXPECT(g.waitFor(5s)))
-            return;
-        runner->join();
-        BEAST_EXPECT(what == "inner error");
-        BEAST_EXPECT(!runner->runnable());
-    }
-
-    /**
-     * CoroTask<T> chaining. Nested value-returning coroutines
-     * compose via co_await.
-     */
-    void
-    testValueChaining()
-    {
-        using namespace std::chrono_literals;
-        using namespace jtx;
-
-        testcase("value chaining");
-
-        Env env(*this, envconfig([](std::unique_ptr<Config> cfg) {
-            cfg->forceMultiThread = true;
-            return cfg;
-        }));
-
-        Gate g;
-        int result = 0;
-        auto runner = env.app().getJobQueue().postCoroTask(
-            JtClient, "CoroTaskTest", [rp = &result, gp = &g](auto) -> CoroTask<void> {
-                auto add = [](int a, int b) -> CoroTask<int> { co_return a + b; };
-                auto mul = [add](int a, int b) -> CoroTask<int> {
-                    int const sum = co_await add(a, b);
-                    co_return sum * 2;
-                };
-                *rp = co_await mul(3, 4);
-                gp->signal();
-                co_return;
-            });
-        BEAST_EXPECT(runner);
-        if (!BEAST_EXPECT(g.waitFor(5s)))
-            return;
-        runner->join();
-        BEAST_EXPECT(result == 14);  // (3 + 4) * 2
-        BEAST_EXPECT(!runner->runnable());
-    }
-
-    /**
-     * postCoroTask returns nullptr when JobQueue is stopping.
-     */
-    void
-    testShutdownRejection()
-    {
-        using namespace std::chrono_literals;
-        using namespace jtx;
-
-        testcase("shutdown rejection");
-
-        Env env(*this, envconfig([](std::unique_ptr<Config> cfg) {
-            cfg->forceMultiThread = true;
-            return cfg;
-        }));
-
-        // Stop the JobQueue
-        env.app().getJobQueue().stop();
-
-        auto runner = env.app().getJobQueue().postCoroTask(
-            JtClient, "CoroTaskTest", [](auto) -> CoroTask<void> { co_return; });
-        BEAST_EXPECT(!runner);
-    }
-
-    void
-    run() override
-    {
-        testVoidCompletion();
-        testCorrectOrder();
-        testIncorrectOrder();
-        testJobQueueAwaiter();
-        testThreadSpecificStorage();
-        testExceptionPropagation();
-        testMultipleYields();
-        testValueReturn();
-        testValueException();
-        testValueChaining();
-        testShutdownRejection();
-    }
-};
-
-BEAST_DEFINE_TESTSUITE(CoroTask, core, xrpl);
-
-}  // namespace xrpl::test
-
-// NOLINTEND(cppcoreguidelines-avoid-capturing-lambda-coroutines)

src/test/core/Coroutine_test.cpp

@@ -6,7 +6,6 @@
 
 #include <xrpl/basics/LocalValue.h>
 #include <xrpl/beast/unit_test/suite.h>
-#include <xrpl/core/CoroTask.h>
 #include <xrpl/core/Job.h>
 #include <xrpl/core/JobQueue.h>
 
@@ -50,11 +49,6 @@ public:
         }
     };
 
-    // NOTE: All coroutine lambdas passed to postCoroTask use explicit
-    // pointer-by-value captures instead of [&] to work around a GCC 14
-    // bug where reference captures in coroutine lambdas are corrupted
-    // in the coroutine frame.
-
     void
     correctOrder()
     {
@@ -69,22 +63,14 @@ public:
         }));
 
         Gate g1, g2;
-        std::shared_ptr<JobQueue::CoroTaskRunner> c;
-        env.app().getJobQueue().postCoroTask(
-            JtClient,
-            "CoroTest",
-            // Safe capture: the test blocks on the Gates until the coroutine
-            // completes, so the captured pointers outlive the coroutine.
-            // NOLINTNEXTLINE(cppcoreguidelines-avoid-capturing-lambda-coroutines)
-            [cp = &c, g1p = &g1, g2p = &g2](auto runner) -> CoroTask<void> {
-                *cp = runner;
-                g1p->signal();
-                co_await runner->suspend();
-                g2p->signal();
-                co_return;
-            });
-        if (!BEAST_EXPECT(g1.waitFor(5s)))
-            return;
+        std::shared_ptr<JobQueue::Coro> c;
+        env.app().getJobQueue().postCoro(JtClient, "CoroTest", [&](auto const& cr) {
+            c = cr;
+            g1.signal();
+            c->yield();
+            g2.signal();
+        });
+        BEAST_EXPECT(g1.waitFor(5s));
         c->join();
         c->post();
         BEAST_EXPECT(g2.waitFor(5s));
@@ -104,22 +90,11 @@ public:
         }));
 
         Gate g;
-        env.app().getJobQueue().postCoroTask(
-            JtClient,
-            "CoroTest",
-            // Safe capture: the test blocks on the Gate until the coroutine
-            // completes, so the captured pointer outlives the coroutine.
-            // NOLINTNEXTLINE(cppcoreguidelines-avoid-capturing-lambda-coroutines)
-            [gp = &g](auto runner) -> CoroTask<void> {
-                // Schedule a resume before suspending.  The posted job
-                // cannot actually call resume() until the current resume()
-                // releases CoroTaskRunner::mutex_, which only happens after
-                // the coroutine suspends at co_await.
-                runner->post();
-                co_await runner->suspend();
-                gp->signal();
-                co_return;
-            });
+        env.app().getJobQueue().postCoro(JtClient, "CoroTest", [&](auto const& c) {
+            c->post();
+            c->yield();
+            g.signal();
+        });
         BEAST_EXPECT(g.waitFor(5s));
     }
 
@@ -135,7 +110,7 @@ public:
         auto& jq = env.app().getJobQueue();
 
         static int const kN = 4;
-        std::array<std::shared_ptr<JobQueue::CoroTaskRunner>, kN> a;
+        std::array<std::shared_ptr<JobQueue::Coro>, kN> a;
 
         LocalValue<int> lv(-1);
         BEAST_EXPECT(*lv == -1);
@@ -152,36 +127,26 @@ public:
 
         for (int i = 0; i < kN; ++i)
         {
-            jq.postCoroTask(
-                JtClient,
-                "CoroTest",
-                // Safe capture: the test drives every coroutine to completion
-                // via the Gate/post()/join() sequences below, so the captured
-                // pointers outlive the coroutines.
-                // NOLINTNEXTLINE(cppcoreguidelines-avoid-capturing-lambda-coroutines)
-                [this, ap = &a, gp = &g, lvp = &lv, id = i](auto runner) -> CoroTask<void> {
-                    (*ap)[id] = runner;
-                    gp->signal();
-                    co_await runner->suspend();
+            jq.postCoro(JtClient, "CoroTest", [&, id = i](auto const& c) {
+                a[id] = c;
+                g.signal();
+                c->yield();
 
-                    this->BEAST_EXPECT(**lvp == -1);
-                    **lvp = id;
-                    this->BEAST_EXPECT(**lvp == id);
-                    gp->signal();
-                    co_await runner->suspend();
+                this->BEAST_EXPECT(*lv == -1);
+                *lv = id;
+                this->BEAST_EXPECT(*lv == id);
+                g.signal();
+                c->yield();
 
-                    this->BEAST_EXPECT(**lvp == id);
-                    co_return;
-                });
-            if (!BEAST_EXPECT(g.waitFor(5s)))
-                return;
+                this->BEAST_EXPECT(*lv == id);
+            });
+            BEAST_EXPECT(g.waitFor(5s));
             a[i]->join();
         }
         for (auto const& c : a)
         {
             c->post();
-            if (!BEAST_EXPECT(g.waitFor(5s)))
-                return;
+            BEAST_EXPECT(g.waitFor(5s));
             c->join();
         }
         for (auto const& c : a)

src/test/core/JobQueue_test.cpp

@@ -1,11 +1,11 @@
 #include <test/jtx/Env.h>
 
 #include <xrpl/beast/unit_test/suite.h>
-#include <xrpl/core/CoroTask.h>
 #include <xrpl/core/Job.h>
 #include <xrpl/core/JobQueue.h>
 
 #include <atomic>
+#include <memory>
 
 namespace xrpl::test {
 
@@ -46,114 +46,87 @@ class JobQueue_test : public beast::unit_test::Suite
         }
     }
 
-    // NOTE: All coroutine lambdas passed to postCoroTask use explicit
-    // pointer-by-value captures instead of [&] to work around a GCC 14
-    // bug where reference captures in coroutine lambdas are corrupted
-    // in the coroutine frame.
-
     void
-    testPostCoroTask()
+    testPostCoro()
     {
         jtx::Env env{*this};
 
         JobQueue& jQueue = env.app().getJobQueue();
         {
-            // Test repeated post()s until the coroutine completes.
+            // Test repeated post()s until the Coro completes.
             std::atomic<int> yieldCount{0};
-            auto const runner = jQueue.postCoroTask(
+            auto const coro = jQueue.postCoro(
                 JtClient,
                 "PostCoroTest1",
-                // Safe capture: the test blocks below until the coroutine
-                // completes, so the captured pointer outlives the coroutine.
-                // NOLINTNEXTLINE(cppcoreguidelines-avoid-capturing-lambda-coroutines)
-                [ycp = &yieldCount](auto runner) -> CoroTask<void> {
-                    while (++(*ycp) < 4)
-                        co_await runner->suspend();
-                    co_return;
+                [&yieldCount](std::shared_ptr<JobQueue::Coro> const& coroCopy) {
+                    while (++yieldCount < 4)
+                        coroCopy->yield();
                 });
-            BEAST_EXPECT(runner != nullptr);
+            BEAST_EXPECT(coro != nullptr);
 
             // Wait for the Job to run and yield.
             while (yieldCount == 0)
                 ;
 
-            // Now re-post until the CoroTaskRunner says it is done.
+            // Now re-post until the Coro says it is done.
             int old = yieldCount;
-            while (runner->runnable())
+            while (coro->runnable())
             {
-                BEAST_EXPECT(runner->post());
+                BEAST_EXPECT(coro->post());
                 while (old == yieldCount)
                 {
                 }
-                runner->join();
+                coro->join();
                 BEAST_EXPECT(++old == yieldCount);
             }
             BEAST_EXPECT(yieldCount == 4);
         }
         {
-            // Test repeated post()+join()s until the coroutine completes.
+            // Test repeated resume()s until the Coro completes.
             int yieldCount{0};
-            auto const runner = jQueue.postCoroTask(
+            auto const coro = jQueue.postCoro(
                 JtClient,
                 "PostCoroTest2",
-                // Safe capture: the test blocks below until the coroutine
-                // completes, so the captured pointer outlives the coroutine.
-                // NOLINTNEXTLINE(cppcoreguidelines-avoid-capturing-lambda-coroutines)
-                [ycp = &yieldCount](auto runner) -> CoroTask<void> {
-                    while (++(*ycp) < 4)
-                        co_await runner->suspend();
-                    co_return;
+                [&yieldCount](std::shared_ptr<JobQueue::Coro> const& coroCopy) {
+                    while (++yieldCount < 4)
+                        coroCopy->yield();
                 });
-            if (!runner)
+            if (!coro)
             {
-                // There's no good reason we should not get a runner, but we
+                // There's no good reason we should not get a Coro, but we
                 // can't continue without one.
                 BEAST_EXPECT(false);
                 return;
             }
 
             // Wait for the Job to run and yield.
-            runner->join();
+            coro->join();
 
-            // Now post()+join() until the CoroTaskRunner says it is done.
-            // resume() requires a prior post() (see the precondition on
-            // CoroTaskRunner::resume()), so the posted job performs the
-            // resume and join() blocks until it completes. yieldCount is
-            // deliberately not atomic: the mutexRun_ handoff inside join()
-            // must provide the happens-before edge that makes the
-            // increment visible to this thread.
+            // Now resume until the Coro says it is done.
             int old = yieldCount;
-            while (runner->runnable())
+            while (coro->runnable())
             {
-                BEAST_EXPECT(runner->post());
-                runner->join();
+                coro->resume();  // Resume runs synchronously on this thread.
                 BEAST_EXPECT(++old == yieldCount);
             }
             BEAST_EXPECT(yieldCount == 4);
         }
         {
             // If the JobQueue is stopped, we should no
-            // longer be able to post a coroutine (and calling postCoroTask()
-            // should return nullptr).
+            // longer be able to add a Coro (and calling postCoro() should
+            // return false).
             using namespace std::chrono_literals;
             jQueue.stop();
 
-            // The coroutine should never run, so having it access this
+            // The Coro should never run, so having the Coro access this
             // unprotected variable on the stack should be completely safe.
             // Not recommended for the faint of heart...
             bool unprotected = false;
-            auto const runner = jQueue.postCoroTask(
-                JtClient,
-                "PostCoroTest3",
-                // Safe capture: the JobQueue is stopped, so the coroutine is
-                // never started and the captured pointer is never dereferenced.
-                // NOLINTNEXTLINE(cppcoreguidelines-avoid-capturing-lambda-coroutines)
-                [up = &unprotected](auto) -> CoroTask<void> {
-                    *up = true;
-                    co_return;
+            auto const coro = jQueue.postCoro(
+                JtClient, "PostCoroTest3", [&unprotected](std::shared_ptr<JobQueue::Coro> const&) {
+                    unprotected = false;
                 });
-            BEAST_EXPECT(runner == nullptr);
-            BEAST_EXPECT(unprotected == false);
+            BEAST_EXPECT(coro == nullptr);
         }
     }
 
@@ -162,7 +135,7 @@ public:
     run() override
     {
         testAddJob();
-        testPostCoroTask();
+        testPostCoro();
     }
 };
 

src/test/jtx/impl/TestHelpers.cpp

@@ -23,9 +23,7 @@
 #include <xrpl/basics/strHex.h>
 #include <xrpl/beast/unit_test/suite.h>
 #include <xrpl/beast/utility/instrumentation.h>
-#include <xrpl/core/CoroTask.h>
 #include <xrpl/core/Job.h>
-#include <xrpl/core/JobQueue.h>
 #include <xrpl/core/ServiceRegistry.h>
 #include <xrpl/json/json_value.h>
 #include <xrpl/json/to_string.h>
@@ -225,6 +223,7 @@ findPathsRequest(
          .ledgerMaster = app.getLedgerMaster(),
          .consumer = c,
          .role = Role::USER,
+         .coro = {},
          .infoSub = {},
          .apiVersion = rpc::kApiVersionIfUnspecified},
         {},
@@ -251,14 +250,11 @@ findPathsRequest(
 
     json::Value result;
     Gate g;
-    // Safe capture: the caller blocks on g.waitFor() until the coroutine
-    // completes, so the captured locals outlive the coroutine.
-    // NOLINTNEXTLINE(cppcoreguidelines-avoid-capturing-lambda-coroutines)
-    app.getJobQueue().postCoroTask(JtClient, "RPC-Client", [&](auto) -> CoroTask<void> {
+    app.getJobQueue().postCoro(JtClient, "RPC-Client", [&](auto const& coro) {
         context.params = std::move(params);
+        context.coro = coro;
         rpc::doCommand(context, result);
         g.signal();
-        co_return;
     });
 
     using namespace std::chrono_literals;

src/xrpld/app/main/Application.cpp

@@ -1483,6 +1483,7 @@ ApplicationImp::setup(boost::program_options::variables_map const& cmdline)
              .ledgerMaster = getLedgerMaster(),
              .consumer = c,
              .role = Role::ADMIN,
+             .coro = {},
              .infoSub = {},
              .apiVersion = rpc::kApiMaximumSupportedVersion},
             jvCommand};

src/xrpld/app/main/GRPCServer.cpp

@@ -17,7 +17,6 @@
 #include <xrpl/beast/utility/instrumentation.h>
 #include <xrpl/config/BasicConfig.h>
 #include <xrpl/config/Constants.h>
-#include <xrpl/core/CoroTask.h>
 #include <xrpl/core/Job.h>
 #include <xrpl/core/JobQueue.h>
 #include <xrpl/protocol/ErrorCodes.h>
@@ -148,19 +147,13 @@ GRPCServerImpl::CallData<Request, Response>::process()
     // ensures that finished is always true when this CallData object
     // is returned as a tag in handleRpcs(), after sending the response
     finished_ = true;
-    auto runner = app_.getJobQueue().postCoroTask(
-        JobType::JtRpc,
-        "gRPC-Client",
-        // Safe capture: postCoroTask heap-allocates the lambda (FuncStore)
-        // and thisShared keeps the CallData alive until the coroutine ends.
-        // NOLINTNEXTLINE(cppcoreguidelines-avoid-capturing-lambda-coroutines)
-        [thisShared](auto) -> CoroTask<void> {
-            thisShared->processRequest();
-            co_return;
+    auto coro = app_.getJobQueue().postCoro(
+        JobType::JtRpc, "gRPC-Client", [thisShared](std::shared_ptr<JobQueue::Coro> coro) {
+            thisShared->process(coro);
         });
 
-    // If runner is null, then the JobQueue has already been shutdown
-    if (!runner)
+    // If coro is null, then the JobQueue has already been shutdown
+    if (!coro)
     {
         grpc::Status const status{grpc::StatusCode::INTERNAL, "Job Queue is already stopped"};
         responder_.FinishWithError(status, this);
@@ -169,7 +162,7 @@ GRPCServerImpl::CallData<Request, Response>::process()
 
 template <class Request, class Response>
 void
-GRPCServerImpl::CallData<Request, Response>::processRequest()
+GRPCServerImpl::CallData<Request, Response>::process(std::shared_ptr<JobQueue::Coro> coro)
 {
     try
     {
@@ -211,6 +204,7 @@ GRPCServerImpl::CallData<Request, Response>::processRequest()
                  app_.getLedgerMaster(),
                  usage,
                  role,
+                 coro,
                  InfoSub::pointer(),
                  kApiVersion},
                 request_};

src/xrpld/app/main/GRPCServer.h

@@ -6,6 +6,7 @@
 #include <xrpld/rpc/detail/Handler.h>
 
 #include <xrpl/beast/utility/Journal.h>
+#include <xrpl/core/JobQueue.h>
 #include <xrpl/proto/org/xrpl/rpc/v1/xrp_ledger.grpc.pb.h>
 #include <xrpl/resource/Charge.h>
 #include <xrpl/resource/Consumer.h>
@@ -227,12 +228,9 @@ private:
         clone() override;
 
     private:
-        /**
-         * Process the gRPC request. Called inside the CoroTask lambda
-         * posted to the JobQueue by process().
-         */
+        // process the request. Called inside the coroutine passed to JobQueue
         void
-        processRequest();
+        process(std::shared_ptr<JobQueue::Coro> coro);
 
         // return load type of this RPC
         resource::Charge

src/xrpld/rpc/AGENTS.md

@@ -0,0 +1,5 @@
+# AGENTS.md — rpc
+
+See the repo-level [AGENTS.md](../../../AGENTS.md) for general build/test/style guidance. `CLAUDE.md` in this directory is a symlink to this file.
+
+Any change to a public RPC method's behavior (new/changed/removed fields, parameters, or error conditions) needs a corresponding entry in [`API-CHANGELOG.md`](../../../API-CHANGELOG.md), under the `## Unreleased` section (`### Additions`, `### Deprecations`, etc. as appropriate).

src/xrpld/rpc/CLAUDE.md

@@ -0,0 +1 @@
+AGENTS.md

src/xrpld/rpc/Context.h

@@ -3,11 +3,13 @@
 #include <xrpld/rpc/Role.h>
 
 #include <xrpl/beast/utility/Journal.h>
+#include <xrpl/core/JobQueue.h>
 #include <xrpl/json/json_value.h>
 #include <xrpl/resource/Charge.h>
 #include <xrpl/resource/Consumer.h>
 #include <xrpl/server/InfoSub.h>
 
+#include <memory>
 #include <string_view>
 
 namespace xrpl {
@@ -30,6 +32,7 @@ struct Context
     LedgerMaster& ledgerMaster;
     resource::Consumer& consumer;
     Role role;
+    std::shared_ptr<JobQueue::Coro> coro;
     InfoSub::pointer infoSub;
     unsigned int apiVersion;
 };

src/xrpld/rpc/ServerHandler.h

@@ -184,10 +184,13 @@ public:
 
 private:
     json::Value
-    processSession(std::shared_ptr<WSSession> const& session, json::Value const& jv);
+    processSession(
+        std::shared_ptr<WSSession> const& session,
+        std::shared_ptr<JobQueue::Coro> const& coro,
+        json::Value const& jv);
 
     void
-    processSession(std::shared_ptr<Session> const&);
+    processSession(std::shared_ptr<Session> const&, std::shared_ptr<JobQueue::Coro> coro);
 
     void
     processRequest(
@@ -195,6 +198,7 @@ private:
         std::string const& request,
         beast::ip::Endpoint const& remoteIPAddress,
         Output const&,
+        std::shared_ptr<JobQueue::Coro> coro,
         std::string_view forwardedFor,
         std::string_view user);
 

src/xrpld/rpc/detail/PathRequestManager.cpp

@@ -6,7 +6,6 @@
 #include <xrpld/rpc/detail/PathRequest.h>
 
 #include <xrpl/basics/Log.h>
-#include <xrpl/basics/scope.h>
 #include <xrpl/core/Job.h>
 #include <xrpl/core/JobQueue.h>
 #include <xrpl/json/json_value.h>
@@ -138,12 +137,9 @@ PathRequestManager::updateAll(std::shared_ptr<ReadView const> const& inLedger)
                     }
                     else if (request->hasCompletion())
                     {
-                        // One-shot request with completion function. Fire the
-                        // completion even if doUpdate throws, so the RPC
-                        // handler blocked in doRipplePathFind is released
-                        // immediately instead of waiting out its timeout.
-                        ScopeExit const complete{[&request] { request->updateComplete(); }};
+                        // One-shot request with completion function
                         request->doUpdate(cache, false);
+                        request->updateComplete();
                         ++processed;
                     }
                 }

src/xrpld/rpc/detail/ServerHandler.cpp

@@ -17,7 +17,6 @@
 #include <xrpl/beast/rfc2616.h>
 #include <xrpl/beast/utility/Journal.h>
 #include <xrpl/config/Constants.h>
-#include <xrpl/core/CoroTask.h>
 #include <xrpl/core/Job.h>
 #include <xrpl/core/JobQueue.h>
 #include <xrpl/json/Output.h>
@@ -318,23 +317,9 @@ ServerHandler::onRequest(Session& session)
     }
 
     std::shared_ptr<Session> const detachedSession = session.detach();
-    auto const postResult = jobQueue_.postCoroTask(
-        JtClientRpc,
-        "RPC-Client",
-        // Safe capture: postCoroTask heap-allocates the lambda (FuncStore),
-        // detachedSession is captured by value, and this (the ServerHandler)
-        // outlives the JobQueue jobs.
-        // NOLINTNEXTLINE(cppcoreguidelines-avoid-capturing-lambda-coroutines)
-        [this, detachedSession](auto) -> CoroTask<void> {
-            try
-            {
-                processSession(detachedSession);
-            }
-            catch (std::exception const& e)
-            {
-                JLOG(journal_.error()) << "RPC-Client coroutine exception: " << e.what();
-            }
-            co_return;
+    auto const postResult = jobQueue_.postCoro(
+        JtClientRpc, "RPC-Client", [this, detachedSession](std::shared_ptr<JobQueue::Coro> coro) {
+            processSession(detachedSession, coro);
         });
     if (postResult == nullptr)
     {
@@ -370,30 +355,17 @@ ServerHandler::onWSMessage(
 
     JLOG(journal_.trace()) << "Websocket received '" << jv << "'";
 
-    auto const postResult = jobQueue_.postCoroTask(
+    auto const postResult = jobQueue_.postCoro(
         JtClientWebsocket,
         "WS-Client",
-        // Safe capture: postCoroTask heap-allocates the lambda (FuncStore),
-        // session and jv are captured by value, and this (the ServerHandler)
-        // outlives the JobQueue jobs.
-        // NOLINTNEXTLINE(cppcoreguidelines-avoid-capturing-lambda-coroutines)
-        [this, session, jv = std::move(jv)](auto) -> CoroTask<void> {
-            try
-            {
-                auto const jr = this->processSession(session, jv);
-                auto const s = to_string(jr);
-                auto const n = s.length();
-                boost::beast::multi_buffer sb(n);
-                sb.commit(
-                    boost::asio::buffer_copy(sb.prepare(n), boost::asio::buffer(s.c_str(), n)));
-                session->send(std::make_shared<StreambufWSMsg<decltype(sb)>>(std::move(sb)));
-                session->complete();
-            }
-            catch (std::exception const& e)
-            {
-                JLOG(journal_.error()) << "WS-Client coroutine exception: " << e.what();
-            }
-            co_return;
+        [this, session, jv = std::move(jv)](std::shared_ptr<JobQueue::Coro> const& coro) {
+            auto const jr = this->processSession(session, coro, jv);
+            auto const s = to_string(jr);
+            auto const n = s.length();
+            boost::beast::multi_buffer sb(n);
+            sb.commit(boost::asio::buffer_copy(sb.prepare(n), boost::asio::buffer(s.c_str(), n)));
+            session->send(std::make_shared<StreambufWSMsg<decltype(sb)>>(std::move(sb)));
+            session->complete();
         });
     if (postResult == nullptr)
     {
@@ -438,7 +410,10 @@ logDuration(json::Value const& request, T const& duration, beast::Journal& journ
 }
 
 json::Value
-ServerHandler::processSession(std::shared_ptr<WSSession> const& session, json::Value const& jv)
+ServerHandler::processSession(
+    std::shared_ptr<WSSession> const& session,
+    std::shared_ptr<JobQueue::Coro> const& coro,
+    json::Value const& jv)
 {
     auto is = std::static_pointer_cast<WSInfoSub>(session->appDefined);
     if (is->getConsumer().disconnect(journal_))
@@ -505,6 +480,7 @@ ServerHandler::processSession(std::shared_ptr<WSSession> const& session, json::V
                  .ledgerMaster = app_.getLedgerMaster(),
                  .consumer = is->getConsumer(),
                  .role = role,
+                 .coro = coro,
                  .infoSub = is,
                  .apiVersion = apiVersion},
                 jv,
@@ -575,14 +551,18 @@ ServerHandler::processSession(std::shared_ptr<WSSession> const& session, json::V
     return jr;
 }
 
+// Run as a coroutine.
 void
-ServerHandler::processSession(std::shared_ptr<Session> const& session)
+ServerHandler::processSession(
+    std::shared_ptr<Session> const& session,
+    std::shared_ptr<JobQueue::Coro> coro)
 {
     processRequest(
         session->port(),
         buffersToString(session->request().body().data()),
         session->remoteAddress().atPort(0),
         makeOutput(*session),
+        coro,
         forwardedFor(session->request()),
         [&] -> std::string_view {
             auto const iter = session->request().find("X-User");
@@ -623,6 +603,7 @@ ServerHandler::processRequest(
     std::string const& request,
     beast::ip::Endpoint const& remoteIPAddress,
     Output const& output,
+    std::shared_ptr<JobQueue::Coro> coro,
     std::string_view forwardedFor,
     std::string_view user)
 {
@@ -882,6 +863,7 @@ ServerHandler::processRequest(
              .ledgerMaster = app_.getLedgerMaster(),
              .consumer = usage,
              .role = role,
+             .coro = coro,
              .infoSub = InfoSub::pointer(),
              .apiVersion = apiVersion},
             params,

src/xrpld/rpc/detail/Tuning.h

@@ -65,12 +65,6 @@ static constexpr int kDefaultAutoFillFeeMultiplier = 10;
 static constexpr int kDefaultAutoFillFeeDivisor = 1;
 static constexpr int kMaxPathfindsInProgress = 2;
 static constexpr int kMaxPathfindJobCount = 50;
-
-/**
- * How long a blocking ripple_path_find call waits for the path-finding
- * continuation before giving up and returning an internal error.
- */
-constexpr auto kPathfindCompletionTimeout = std::chrono::seconds{30};
 static constexpr int kMaxJobQueueClients = 500;
 constexpr auto kMaxValidatedLedgerAge = std::chrono::minutes{2};
 static constexpr int kMaxRequestSize = 1000000;

src/xrpld/rpc/handlers/orderbook/RipplePathFind.cpp

@@ -7,15 +7,14 @@
 #include <xrpld/rpc/detail/RPCLedgerHelpers.h>
 #include <xrpld/rpc/detail/Tuning.h>
 
+#include <xrpl/core/JobQueue.h>
 #include <xrpl/json/json_value.h>
 #include <xrpl/protocol/ErrorCodes.h>
 #include <xrpl/protocol/RPCErr.h>
 #include <xrpl/protocol/jss.h>
 #include <xrpl/resource/Fees.h>
 
-#include <condition_variable>
 #include <memory>
-#include <mutex>
 #include <utility>
 
 namespace xrpl {
@@ -48,62 +47,98 @@ doRipplePathFind(rpc::JsonContext& context)
         PathRequest::pointer request;
         lpLedger = context.ledgerMaster.getClosedLedger();
 
-        // The wait below parks this JobQueue worker thread until the
-        // path-finding continuation fires. The continuation is fired by a
-        // JtUpdatePf job, which itself needs a free worker to run. Bound
-        // the number of concurrently parked workers (LegacyPathFind admits
-        // at most kMaxPathfindsInProgress non-admin requests) so that
-        // concurrent ripple_path_find calls cannot occupy every worker and
-        // stall the whole JobQueue. The guard must stay in scope until the
-        // wait completes. (The old Boost.Coroutine implementation did not
-        // need this: it suspended and released the worker instead of
-        // blocking it.)
-        rpc::LegacyPathFind const lpf(isUnlimited(context.role), context.app);
-        if (!lpf.isOk())
-            return rpcError(RpcTooBusy);
-
-        // makeLegacyPathRequest enqueues a path-finding job that runs
-        // asynchronously.  We block this thread with a condition_variable
-        // until the path-finding continuation signals completion.
-        // If makeLegacyPathRequest cannot schedule the job (e.g. during
-        // shutdown), it returns an empty request and we skip the wait.
-        // Replaces the old Coro yield/resume pattern with synchronous
-        // blocking, eliminating shutdown race conditions.
+        // It doesn't look like there's much odd happening here, but you should
+        // be aware this code runs in a JobQueue::Coro, which is a coroutine.
+        // And we may be flipping around between threads.  Here's an overview:
         //
-        // The state is shared with the continuation so that it stays alive
-        // even if we stop waiting before the continuation runs.
-        struct PathDone
-        {
-            std::mutex mtx;
-            std::condition_variable cv;
-            bool done = false;
-        };
-        auto const state = std::make_shared<PathDone>();
-
+        // 1. We're running doRipplePathFind() due to a call to
+        //    ripple_path_find.  doRipplePathFind() is currently running
+        //    inside of a JobQueue::Coro using a JobQueue thread.
+        //
+        // 2. doRipplePathFind's call to makeLegacyPathRequest() enqueues the
+        //    path-finding request.  That request will (probably) run at some
+        //    indeterminate future time on a (probably different) JobQueue
+        //    thread.
+        //
+        // 3. As a continuation from that path-finding JobQueue thread, the
+        //    coroutine we're currently running in (!) is posted to the
+        //    JobQueue.  Because it is a continuation, that post won't
+        //    happen until the path-finding request completes.
+        //
+        // 4. Once the continuation is enqueued, and we have reason to think
+        //    the path-finding job is likely to run, then the coroutine we're
+        //    running in yield()s.  That means it surrenders its thread in
+        //    the JobQueue.  The coroutine is suspended, but ready to run,
+        //    because it is kept resident by a shared_ptr in the
+        //    path-finding continuation.
+        //
+        // 5. If all goes well then path-finding runs on a JobQueue thread
+        //    and executes its continuation.  The continuation posts this
+        //    same coroutine (!) to the JobQueue.
+        //
+        // 6. When the JobQueue calls this coroutine, this coroutine resumes
+        //    from the line below the coro->yield() and returns the
+        //    path-finding result.
+        //
+        // With so many moving parts, what could go wrong?
+        //
+        // Just in terms of the JobQueue refusing to add jobs at shutdown
+        // there are two specific things that can go wrong.
+        //
+        // 1. The path-finding Job queued by makeLegacyPathRequest() might be
+        //    rejected (because we're shutting down).
+        //
+        //    Fortunately this problem can be addressed by looking at the
+        //    return value of makeLegacyPathRequest().  If
+        //    makeLegacyPathRequest() cannot get a thread to run the path-find
+        //    on, then it returns an empty request.
+        //
+        // 2. The path-finding job might run, but the Coro::post() might be
+        //    rejected by the JobQueue (because we're shutting down).
+        //
+        //    We handle this case by resuming (not posting) the Coro.
+        //    By resuming the Coro, we allow the Coro to run to completion
+        //    on the current thread instead of requiring that it run on a
+        //    new thread from the JobQueue.
+        //
+        // Both of these failure modes are hard to recreate in a unit test
+        // because they are so dependent on inter-thread timing.  However
+        // the failure modes can be observed by synchronously (inside the
+        // xrpld source code) shutting down the application.  The code to
+        // do so looks like this:
+        //
+        //   context.app.signalStop();
+        //   while (! context.app.getJobQueue().jobCounter().joined()) { }
+        //
+        // The first line starts the process of shutting down the app.
+        // The second line waits until no more jobs can be added to the
+        // JobQueue before letting the thread continue.
+        //
+        // May 2017
         jvResult = context.app.getPathRequestManager().makeLegacyPathRequest(
             request,
-            [state]() {
+            [&context]() {
+                // Copying the shared_ptr keeps the coroutine alive up
+                // through the return.  Otherwise the storage under the
+                // captured reference could evaporate when we return from
+                // coroCopy->resume().  This is not strictly necessary, but
+                // will make maintenance easier.
+                std::shared_ptr<JobQueue::Coro> const coroCopy{context.coro};
+                if (!coroCopy->post())
                 {
-                    std::scoped_lock const lk(state->mtx);
-                    state->done = true;
+                    // The post() failed, so we won't get a thread to let
+                    // the Coro finish.  We'll call Coro::resume() so the
+                    // Coro can finish on our thread.  Otherwise the
+                    // application will hang on shutdown.
+                    coroCopy->resume();
                 }
-                state->cv.notify_one();
             },
             context.consumer,
             lpLedger,
             context.params);
         if (request)
         {
-            std::unique_lock lk(state->mtx);
-            if (!state->cv.wait_for(
-                    lk, rpc::tuning::kPathfindCompletionTimeout, [&state] { return state->done; }))
-            {
-                // Path-finding continuation never fired (e.g. shutdown
-                // race or unexpected failure). Return an internal error
-                // rather than blocking the RPC thread indefinitely.
-                return rpcError(RpcInternal);
-            }
-            lk.unlock();
+            context.coro->yield();
             jvResult = request->doStatus(context.params);
         }