1452891 - Auto-suggest Try configuration in Lando, based on code coverage information

Status: NEW

(Conduit :: Lando, enhancement, P3)

Description

[Jan Keromnes [:janx]]

Once Lando allows triggering Try builds (like MozReview does today [0]), it would be nice to leverage code coverage information to automatically suggest a convenient, minimally covering Try syntax for the list of files actually modified by the patch queue (instead of counting on developers to know the relevant try jobs for their patches, or running all tests with `-b do -p all -u all -t none`).

See also bug 1429463 for the similar `./mach try coverage` feature.

Note: This could be prototyped as a WebExtension on top of MozReview first.

[0] http://mozilla-version-control-tools.readthedocs.io/en/latest/mozreview/autoland.html

Comment 1

[Andrew Halberstadt [:ahal]]

The premise of this bug is still valid, but I'll point out that we are in the process of (slowly) deprecating try syntax. Instead, it would be better to focus on generating a 'try_task_config.json' file as described here:
https://firefox-source-docs.mozilla.org/taskcluster/taskcluster/try.html#try-task-config

This is a file that you can commit to the root of mozilla-central that taskcluster will use to select tasks. It's what |mach try fuzzy| uses, what |mach try coverage| will use and hopefully also what |mach try syntax| will use in the future.

This may require some changes on Lando's end first though.

Comment 2

[Jan Keromnes [:janx]]

> Instead, it would be better to focus on generating a 'try_task_config.json' file

Good idea, thanks! I've updated the bug title to be more generic (s/syntax/configuration/).

> This may require some changes on Lando's end first though.

From what I understand, Lando isn't able to submit Try builds yet, but there is a plan to make it use Autoland for that (please correct me if I'm wrong). So I guess any switching from try syntax to a committed configuration file should be done in Autoland.

Comment 3

[Mark Côté [:mcote]]

Yes, Lando will support try soon after its first release.

Just to clarify terminology, though, "Autoland" is a vague term which we try not to use on its own.  Lando uses part of MozReview's Autoland system, the "transplant service", which is a fairly dumb app that just commits and pushes to a destination branch.  Lando itself is a rewrite of the other half of MozReview-Autoland: the UI and security system.