When a sync pass's transparent (t-address) scan failed, the backend
mishandled it three ways: the retry computed its start height as the
block height minus the batch size, an unsigned subtraction that wrapped
to a huge value for low heights; the block range left un-scanned was
not remembered, so a transient failure left a permanent hole in the
transparent history that nothing ever revisited; and the block times
needed to date the transactions in that range were discarded.
- The owed range and the block times seen so far are now kept and folded
into the next pass, which resumes from the lower of its own first block
and any owed range.
- The scan start never subtracts, so it can no longer underflow.
- A t-address scan owed by an earlier failed pass is paid on the next
sync even when no new block is pending.
Behaviour change: a transparent scan that fails is retried in-process on
the next sync rather than being lost. The owed range lives only in
memory and is never written to the wallet file, so the file format is
unchanged and remains interchangeable with other builds. The debt is
lost if the process exits or the server is switched before a retry
completes; Re-download blocks (rescan) recovers it, as today.
Tests: library tests on the extracted t-scan seam cover a failed pass
keeping its range and block times, a later success clearing the debt,
and the scan start never exceeding the pass start across the batch-size
boundary (the old formula wrapped there).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
DanSandClaude Opus 4.8
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