Merge branch 'develop' into ximinez/directory

* XRPLF/develop:
  fix: Inner batch transactions never have valid signatures (6069)
  chore: Change `/Zi` to `/Z7` for ccache, remove debug symbols in CI (6198)
  VaultClawback: Burn shares of an empty vault (6120)
  fix: Truncate thread name to 15 chars on Linux (5758)
  docs: Fix minor spelling issues in comments (6194)

include/xrpl/protocol/detail/features.macro

@@ -16,6 +16,7 @@
 // Add new amendments to the top of this list.
 // Keep it sorted in reverse chronological order.
 
+XRPL_FEATURE(DefragDirectories,          Supported::no,  VoteBehavior::DefaultNo)
 XRPL_FIX    (BatchInnerSigs,             Supported::yes, VoteBehavior::DefaultNo)
 XRPL_FEATURE(LendingProtocol,            Supported::yes, VoteBehavior::DefaultNo)
 XRPL_FEATURE(PermissionDelegationV1_1,   Supported::no,  VoteBehavior::DefaultNo)

src/libxrpl/ledger/ApplyView.cpp

@@ -10,6 +10,14 @@ namespace xrpl {
 
 namespace directory {
 
+struct Gap
+{
+    uint64_t const page;
+    SLE::pointer node;
+    uint64_t const nextPage;
+    SLE::pointer next;
+};
+
 std::uint64_t
 createRoot(
     ApplyView& view,
@@ -112,7 +120,9 @@ insertPage(
         return std::nullopt;
     if (!view.rules().enabled(fixDirectoryLimit) &&
         page >= dirNodeMaxPages)  // Old pages limit
+    {
         return std::nullopt;
+    }
 
     // We are about to create a new node; we'll link it to
     // the chain first:
@@ -134,13 +144,8 @@ insertPage(
     // it's the default.
     if (page != 1)
         node->setFieldU64(sfIndexPrevious, page - 1);
-    XRPL_ASSERT_PARTS(
-        !nextPage, "xrpl::directory::insertPage", "nextPage has default value");
-    /* Reserved for future use when directory pages may be inserted in
-     * between two other pages instead of only at the end of the chain.
     if (nextPage)
         node->setFieldU64(sfIndexNext, nextPage);
-    */
     describe(node);
     view.insert(node);
 
@@ -156,7 +161,7 @@ ApplyView::dirAdd(
     uint256 const& key,
     std::function<void(std::shared_ptr<SLE> const&)> const& describe)
 {
-    auto root = peek(directory);
+    auto const root = peek(directory);
 
     if (!root)
     {
@@ -167,6 +172,44 @@ ApplyView::dirAdd(
     auto [page, node, indexes] =
         directory::findPreviousPage(*this, directory, root);
 
+    if (rules().enabled(featureDefragDirectories))
+    {
+        // If there are more nodes than just the root, and there's no space in
+        // the last one, walk backwards to find one with space, or to find one
+        // missing.
+        std::optional<directory::Gap> gapPages;
+        while (page && indexes.size() >= dirNodeMaxEntries)
+        {
+            // Find a page with space, or a gap in pages.
+            auto [prevPage, prevNode, prevIndexes] =
+                directory::findPreviousPage(*this, directory, node);
+            if (!gapPages && prevPage != page - 1)
+                gapPages.emplace(prevPage, prevNode, page, node);
+            page = prevPage;
+            node = prevNode;
+            indexes = prevIndexes;
+        }
+        // We looped through all the pages back to the root.
+        if (!page)
+        {
+            // If we found a gap, use it.
+            if (gapPages)
+            {
+                return directory::insertPage(
+                    *this,
+                    gapPages->page,
+                    gapPages->node,
+                    gapPages->nextPage,
+                    gapPages->next,
+                    key,
+                    directory,
+                    describe);
+            }
+            std::tie(page, node, indexes) =
+                directory::findPreviousPage(*this, directory, root);
+        }
+    }
+
     // If there's space, we use it:
     if (indexes.size() < dirNodeMaxEntries)
     {

src/xrpld/app/misc/detail/ValidatorSite.cpp

@@ -129,12 +129,7 @@ ValidatorSite::load(
     {
         try
         {
-            // This is not super efficient, but it doesn't happen often.
-            bool found = std::ranges::any_of(sites_, [&uri](auto const& site) {
-                return site.loadedResource->uri == uri;
-            });
-            if (!found)
-                sites_.emplace_back(uri);
+            sites_.emplace_back(uri);
         }
         catch (std::exception const& e)
         {
@@ -196,17 +191,6 @@ ValidatorSite::setTimer(
     std::lock_guard<std::mutex> const& site_lock,
     std::lock_guard<std::mutex> const& state_lock)
 {
-    if (!sites_.empty() &&  //
-        std::ranges::all_of(sites_, [](auto const& site) {
-            return site.lastRefreshStatus.has_value();
-        }))
-    {
-        // If all of the sites have been handled at least once (including
-        // errors and timeouts), call missingSite, which will load the cache
-        // files for any lists that are still unavailable.
-        missingSite(site_lock);
-    }
-
     auto next = std::min_element(
         sites_.begin(), sites_.end(), [](Site const& a, Site const& b) {
             return a.nextRefresh < b.nextRefresh;
@@ -319,16 +303,13 @@ ValidatorSite::onRequestTimeout(std::size_t siteIdx, error_code const& ec)
         // processes a network error. Usually, this function runs first,
         // but on extremely rare occasions, the response handler can run
         // first, which will leave activeResource empty.
-        auto& site = sites_[siteIdx];
+        auto const& site = sites_[siteIdx];
         if (site.activeResource)
             JLOG(j_.warn()) << "Request for " << site.activeResource->uri
                             << " took too long";
         else
             JLOG(j_.error()) << "Request took too long, but a response has "
                                 "already been processed";
-        if (!site.lastRefreshStatus)
-            site.lastRefreshStatus.emplace(Site::Status{
-                clock_type::now(), ListDisposition::invalid, "timeout"});
     }
 
     std::lock_guard lock_state{state_mutex_};