ILVerify: soft comparison ignoring IL byte offset drift#19553
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Add offset-tolerant fallback to ILVerify baseline comparison so that changes which only shift IL byte offsets no longer fail CI.
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Description
Implements soft comparison for ILVerify baseline checks, as discussed in #18090.
IL byte offsets (
[offset 0x...]) in ILVerify output shift whenever code above the error site changes, even though the verification error itself is semantically identical. This causes spurious CI failures on unrelated PRs.Changes
tests/ILVerify/ilverify.ps1: AddedRemove-IlverifyOffsetsfunction and a two-level comparison: exact match is tried first; if it fails, a soft comparison (ignoring IL offsets and trailing whitespace) is used as a fallback. Soft match = success with a warning to update baselines. Also cleaned up a misleading comment on the$ignore_errorsvariable.tests/ILVerify/ilverify.Tests.ps1: New Pester test file — 17 tests coveringNormalize-IlverifyOutputLine,Remove-IlverifyOffsets, and end-to-end soft comparison scenarios.DEVGUIDE.md: Documented the soft comparison behavior and the/run ilverifyPR comment command..github/skills/ilverify-failure/SKILL.md: Added section on offset-only differences.What this does NOT change
The full pseudocode in #18090 also proposed making "baseline does not exist" a success. This PR intentionally leaves that behavior unchanged to keep the scope minimal and the risk low — it can be addressed separately if desired.
Fixes #18090
Checklist
🤖 This PR was researched and implemented with assistance from Claude Code.