Fix --coverage executing tests for uncovered mutants - #45
Merged
Conversation
runExecJob ran mutateExec before the coverage check, so uncovered mutants paid a full test run and were then discarded. Classify coverage first and skip exec for uncovered lines. Covered-MSI is unchanged.
# Conflicts: # CHANGELOG.md
Contributor
Author
|
Retriggering checks after GitHub Actions outage left runs stuck in queued. |
This was referenced Aug 26, 2026
Merged
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Summary
--coverageclassified mutants as NOT COVERED only after runninggo test(or--exec). Uncovered mutants paid the full suite cost, then were discarded. Covered-MSI was already correct; the waste was execution.Root cause
runExecJobdid this:mutateExec(overlay +go test)coverProfile.IsCoveredThe line number and coverage profile were already on the job before exec.
Fix
Check coverage first. Skip exec for uncovered mutants. Covered-MSI semantics are unchanged.
Test
TestEngineCoverageSkipsExecForUncoveredMutantsuses a covered + uncovered fixture and a counting--exec. Exec count must equal scored mutants, not include not-covered.go test ./internal/engine/ -run TestEngineCoverageSkipsExecForUncoveredMutants -count=1