Ryan VanderMeulen [:RyanVM] Reporter
	Description • 9 years ago

The change to in-tree mozharness broke the ability to build older revisions on Try, which makes it more difficult to bisect bugs found in older releases, especially since the mozregression tool doesn't have archived inbound builds going back that far.

Per our IRC discussion yesterday, it sounds like the archiver can be updated to test for the existence of testing/mozharness/scripts and fall back to using mozharness.json otherwise to allow older revisions to hopefully build on Try again.

	Ryan VanderMeulen [:RyanVM] Reporter
	Comment 1 • 9 years ago

This actively blocks us being able to narrow down older regressions on Try (and inbound archives don't go back far enough to compensate). Is there anything we can do to move this forward?

	Michael Shal [:mshal]
	Comment 2 • 9 years ago

jlund, what would be involved here?

	Jordan Lund (:jlund)
	Comment 3 • 9 years ago

ryanvm is going to run a try job based on a rev that doesn't have mh in tree. There are a few points where the archiver client will exit or raise an exception so having a log will help show what is the final exception.

I suspect it will be at this point: https://dxr.mozilla.org/build-central/source/tools/buildfarm/utils/archiver_client.py?case=true&from=archiver_client.py#105

But what we could do is, if this fails, try to either:

1) checkout mozharness based on the presence of mozharness.json
2) checkout/clone latest hg.m.o/build/mozharness

(1) would be better as it would be based on a more accurate rev that the try job expects. However it would require a lot more work than a simple hg.m.o/build/mozharness clone. The more work would basically be calling this script with the right args from within archiver_client.py instead of a clone: https://dxr.mozilla.org/build-central/source/tools/buildfarm/utils/repository_manifest.py?case=true&from=buildfarm%2Futils%2Frepository_manifest.py

(2) might not be so bad as it is months old and I assume Ryan only cares about the actual build and it completing rather than the mozharness logic around the build.

I am at a work week this week trying to get release promotion out the door so I won't have time to look at this myself but would be happy to help someone who was willing to try my above suggestion.

	Jordan Lund (:jlund)
	Comment 4 • 9 years ago

> I suspect it will be at this point:
> https://dxr.mozilla.org/build-central/source/tools/buildfarm/utils/
> archiver_client.py?case=true&from=archiver_client.py#105
> 

based on ryan's log[1], I was a little off. We would need to plug in the mozharness checkout at this line[2]

[1] https://treeherder.mozilla.org/logviewer.html#?job_id=13875746&repo=try
[2] https://dxr.mozilla.org/build-central/source/tools/buildfarm/utils/archiver_client.py?case=true&from=archiver_client.py#101