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Compare buffer lengths in SMT buffer equality - #1204
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PEq on buffers was encoded as array equality only, so buffers differing only in length (e.g. all-zero revert data of 31 vs 32 bytes) compared equal and the equivalence checker missed the difference. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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Description
PEqon buffers was encoded in SMT as array equality only, ignoring length. Buffers that differ only in length then compared equal:revert(4, 32)vsmstore(31, byte(0, iszero(calldataload(0)))); revert(32, 31)was reported equivalent, although one reverts with 32 zero bytes and the other with 31. Found byeq-fuzz-cex-replays.The encoding now also asserts that the buffer lengths are equal. This matches
peqon concrete buffers and the keccak injectivity assumptions. Return data was affected the same way; both cases have regression tests.Checklist