https://issues.dlang.org/show_bug.cgi?id=14464
Issue ID: 14464 Summary: coverage merge doesn't work Product: D Version: D2 Hardware: All OS: All Status: NEW Severity: normal Priority: P1 Component: druntime Assignee: nob...@puremagic.com Reporter: c...@dawg.eu Using dmd_coverSetMerge(true) to combine the coverage results of multiple runs produces garbage numbers, because the code in rt.cover that parses the existing .lst files is broken [¹]. Enabling merge only works if .lst files already exist, otherwise coverage generation is silently skipped. Merging coverage reports should be the default, similar to gcov and dmd's -prof, as overwriting existing data is rarely useful. [¹]: https://github.com/D-Programming-Language/druntime/blob/111892fa6ac6bb2005f4f13b4c6bad98399f65b1/src/rt/cover.d#L174 --