1201072 - |mach try| Add mode that runs minimum set of full chunks for specified paths

Status: NEW

(Developer Infrastructure :: Try, defect)

Description

[Andrew Halberstadt [:ahal]]

Currently when running |mach try -p linux path/to/test|, the specified tests will run in a single chunk. Sometimes this is what you want, the job will complete a lot faster. But sometimes this isn't what you want, the tests aren't running in the exact same configuration as they are in automation, so there may be interactions between tests that aren't being tested.

It would be really cool if there were a mode that would figure out the minimum number of chunks needed to run every specified test exactly as it gets run in automation. E.g:

    |mach try -p linux --exact path/to/test|

This likely depends on the chunk-finder work that vaibhav is doing in bug 999450.

A big hurdle will be that --total-chunks is still defined in buildbot-configs. Our options are:

1. somehow extract it out of there
2. maintain a copy
3. only support taskcluster jobs

Comment 1

[Jonathan Griffin (:jgriffin)]

We could also potentially get the number of chunks out of ActiveData or Treeherder, but I'm not sure we'd want that dependency.

Comment 2

[Andrew Halberstadt [:ahal]]

This bug will be largely impacted by both bug 1262834 and bug 1262165. We should at least hold off on anything here until we have a better idea on what will come out of those two.