Wasmtime GitHub notifications bot (Dec 08 2025 at 15:39): Wasmtime GitHub notifications bot (Dec 08 2025 at 15:39):alexcrichton opened PR #12140 from alexcrichton:fix-fuzz to bytecodealliance:main:
This commit fixes a longstanding bug in the implementation of
#[derive(Lift)]which was found by the component_api fuzzer recently. Specifically when an enum or variant had exactly 256 cases the comparison of the discriminant for being out-of-bounds was done in the n-bit space of the discriminant rather than a bit-space that can hold the entire discriminant. The fix here is to compare with au32instead of au8to ensure that if there are 256 variants it actually compares against 256 instead of 0 by accident.<!--
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Wasmtime GitHub notifications bot (Dec 08 2025 at 15:39):alexcrichton requested pchickey for a review on PR #12140.
Wasmtime GitHub notifications bot (Dec 08 2025 at 15:39):alexcrichton requested wasmtime-core-reviewers for a review on PR #12140.
Wasmtime GitHub notifications bot (Dec 08 2025 at 15:39):alexcrichton commented on PR #12140:
I'll note test-wise I opted against adding a test here because it'd be a very large test with 256 wit cases, 256 wat cases, 256 rust cases, etc, so I figured we could lean on the fuzzers here instead.
Wasmtime GitHub notifications bot (Dec 08 2025 at 17:29):pchickey submitted PR review.
Wasmtime GitHub notifications bot (Dec 08 2025 at 17:53):alexcrichton merged PR #12140.
Last updated: Dec 13 2025 at 19:03 UTC