1742652 - Fix drop of code coverage on 25 October 2021

Status: RESOLVED FIXED

(Testing :: Code Coverage, defect)

Description

[Marco Castelluccio [:marco]]

We went from around 65% to around 60%.

First bad is 6c01444e17210e96f5fb322c7b55a2e9f87ec0b0
Last good is 5a0ebbb0210fda2defe5a44a5b75f6f2488fe3c6

Drilling down to platform coverage, we can see it was Windows coverage which dropped.

In that range, there is https://hg.mozilla.org/mozilla-central/rev/04330041da3f and https://hg.mozilla.org/mozilla-central/rev/8f78ed673519de2dd9d88ef0e6ee7466eeeee667 who might be the cause of this.

Comment 1

[Marco Castelluccio [:marco]]

The problem is the sccache disabling.

We use z:/build/build/src/ (https://searchfox.org/mozilla-central/rev/aa8c75b83f636948f708986173965c84cae8c25f/testing/mozharness/mozharness/mozilla/testing/codecoverage.py#130) as the prefix to remove from paths, but without sccache the paths are different (they are like Z:/task_163772669043488/build/src/js/src/vm/CodeCoverage.cpp).

Comment 2

[Marco Castelluccio [:marco]]

In a test task, I'd need to know the topsrcdir from the build.
I saw it is available in the target.mozinfo.json artifact from the build task. Is there an easy way to access this info from testing/mozharness/mozharness/mozilla/testing/codecoverage.py?
Do you see any other solution for me to know the topsrcdir in a test task?

Comment 3

[BugBot [:suhaib / :marco/ :calixte]]

Set release status flags based on info from the regressing bug 1712751

Comment 4

[Geoff Brown [:gbrown]]

mozinfo.find_and_update_from_json() tries to find a build environment with a mozinfo.json, but it's not very sophisticated -- I suspect that won't help in codecoverage.py. Similarly, the build system (and mach?) knows where topsrcdir is, but that's probably not of help in codecoverage.py

Hopefully :aryx's idea is helpful: https://searchfox.org/mozilla-central/rev/aa8c75b83f636948f708986173965c84cae8c25f/taskcluster/ci/perftest/linux.yml#11-16

I don't have a better suggestion.

Comment 5

[Joel Maher ( :jmaher ) (UTC -8)]

could we add build_topsrcdir to mozinfo.json ?

We have access to topsrcdir here:
https://searchfox.org/mozilla-central/source/python/mozbuild/mozbuild/config_status.py#149

and would need to find a clean way to get add it in the write_mozinfo() function here:
https://searchfox.org/mozilla-central/source/python/mozbuild/mozbuild/mozinfo.py#147

Comment 6

[Andrew Halberstadt [:ahal]]

Yeah sounds like Sebastian's suggestion of using a fetch (from comment 4) is the right approach. If you specify this config (ideally only in code coverage tasks), it would be available at $MOZ_FETCHES_DIR/target.mozinfo.json which the mozharness script could then access.

Comment 7

[Marco Castelluccio [:marco]]

Sorry forgot to cancel the needinfos, but yeah, Sebastian suggestion seems to be working well (I added the fetch to the test transform for ccov tasks).

Comment 8

[Marco Castelluccio [:marco]]

Attachment: Bug 1742652 - Use topsrcdir from build task mozinfo.json instead of hardcoding the path for the gcov prefix. r=#releng-reviewers

Comment 10

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/5b9c29148e81
Use topsrcdir from build task mozinfo.json instead of hardcoding the path for the gcov prefix. r=releng-reviewers,jmaher DONTBUILD

Comment 11

[Alexandru Michis [:malexandru]]

https://hg.mozilla.org/mozilla-central/rev/5b9c29148e81