We already don't set GCOV_RESULTS_DIR for baseline tests a few lines before, but if we don't clean the env, a baseline test that comes after a non-baseline test will use the same GCOV_RESULTS_DIR (and, by having a non-empty GCOV_RESULTS_DIR, it will reset/dump the counters).

Comment on attachment 8989171 [details] [diff] [review] Patch Review of attachment 8989171 [details] [diff] [review]: ----------------------------------------------------------------- I trust this is ok ::: testing/mozharness/scripts/desktop_unittest.py @@ +909,5 @@ > per_test_args[-1] > ) > if 'GCOV_RESULTS_DIR' in env: > shutil.rmtree(gcov_dir) > + del env['GCOV_RESULTS_DIR'] I thought this was always deleted in add_per_test_coverage_report. I remember asking about this specifically in my review last week and saw that it was after you mentioned it.

(In reply to Joel Maher ( :jmaher ) (UTC-4) from comment #2) > Comment on attachment 8989171 [details] [diff] [review] > Patch > > Review of attachment 8989171 [details] [diff] [review]: > ----------------------------------------------------------------- > > I trust this is ok > > ::: testing/mozharness/scripts/desktop_unittest.py > @@ +909,5 @@ > > per_test_args[-1] > > ) > > if 'GCOV_RESULTS_DIR' in env: > > shutil.rmtree(gcov_dir) > > + del env['GCOV_RESULTS_DIR'] > > I thought this was always deleted in add_per_test_coverage_report. I > remember asking about this specifically in my review last week and saw that > it was after you mentioned it. That was about the directory (https://bugzilla.mozilla.org/show_bug.cgi?id=1471769#c7) itself, which is removed by add_per_test_coverage_report, but the env variable isn't :(

Pushed by mcastelluccio@mozilla.com: https://hg.mozilla.org/integration/mozilla-inbound/rev/1ef50d759e7d Don't reset/dump counters for baseline tests. r=jmaher