L-05 Ensure finality violation is detected even in cases of empty fin…#431
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dhaidashenko wants to merge 3 commits intofix/PLEX-2781-L-03-document-findBlockAfterLCA-behaviorfrom
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Problem
findBlockAfterLCA Can Miss Finality Violations in Sparse Finalized Gaps
The SelectNewestBlock function skips over unstored empty blocks to find the nearest stored ancestor. If the earliest reorged block is before the finalized block, and they both lie inside such an unstored empty-block gap, findBlockAfterLCA can jump below the violated finalized region to an older stored canonical ancestor.
Since that older ancestor's hash matches the parent hash of its RPC child, the function returns immediately. The finality violation check runs only on the mismatch branch, so it is never reached for the skipped finalized gap itself. As a result, a reorg affecting any unstored finalized block at or below latestFinalizedBlockNumber can be handled as a normal rewind instead of raising ErrFinalityViolated.
Fix
Always persist the latest finalized block, even if it's empty.