pebble-release-2.1: rowblk: fix IsLowerBound to account for synthetic suffix#6082
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RaduBerinde merged 1 commit intoMay 27, 2026
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May 27, 2026
`Iter.firstUserKey` has the synthetic prefix prepended but the on-disk suffix is preserved; suffix replacement is only applied per-returned key via `maybeReplaceSuffix`. Comparing `firstUserKey` directly against the probe could return true even though the iterator's actual first key (after synthetic suffix replacement) sorts strictly less than the probe, violating the `blockiter.Data.IsLowerBound` contract. When a synthetic suffix is in effect, only compare the prefix portion of `firstUserKey` and require it to be strictly greater than the probe. The contract permits false negatives, so this conservative comparison is sound and avoids reasoning about the unknown suffix. Adds `TestIsLowerBoundRandomized` which cross-checks `IsLowerBound` against `First()` across random blocks and transform combinations, and documents the transform state of `firstUserKey`.
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Iter.firstUserKeyhas the synthetic prefix prepended but the on-disk suffix is preserved; suffix replacement is only applied per-returned key viamaybeReplaceSuffix. ComparingfirstUserKeydirectly against the probe could return true even though the iterator's actual first key (after synthetic suffix replacement) sorts strictly less than the probe, violating theblockiter.Data.IsLowerBoundcontract.When a synthetic suffix is in effect, only compare the prefix portion of
firstUserKeyand require it to be strictly greater than the probe. The contract permits false negatives, so this conservative comparison is sound and avoids reasoning about the unknown suffix.Adds
TestIsLowerBoundRandomizedwhich cross-checksIsLowerBoundagainstFirst()across random blocks and transform combinations, and documents the transform state offirstUserKey.