Nicholas Dudfield 1ce1079dda feat: structural-anchor FBC short-circuit in null mode ...

Re-enable FullBelowCache in null-nodestore mode. Previously disabled via
useFullBelowCache() returning false, forcing sync to walk every branch.
That was a workaround for the stale-claim problem where an FBC entry
could outlive the canonical node it vouches for, leading to
SHAMapMissingNode on later reads.

At the two FBC short-circuit sites (SHAMap::addKnownNode and
gmn_ProcessNodes), null mode now:

- validates the claim via TreeNodeCache::fetch (returns non-null iff the
  canonical node is held alive anywhere in the system), and
- anchors the canonical into THIS SHAMap via canonicalizeChild, so
  retention is structural and independent of whichever ledger originally
  anchored the claim.

Disk-backed mode is byte-identical to before (gated on isRWDBNullMode()).

With the anchor rule in place, the post-sync wiring walks in
InboundLedger::init() and done() are redundant; drop both and call
setFullyWired() directly in null mode.

Adds projected-source markers at key points for the design doc at
.ai-docs/null-nodestore-backend.md.j2 (not tracked).

2026-04-14 13:42:16 +07:00

..

xrpl

feat: structural-anchor FBC short-circuit in null mode

2026-04-14 13:42:16 +07:00