Note: In the comments for https://codereview.chromium.org/2547153002:
 I said that it would be easy to remove this dependency if webkit-patch rebaseline-cl was changed to only support CLs associated with local branches.
 wkorman@ said that we could perhaps do a small survey to see how many people would be affected by that change.

 Issue 692607  has been merged into this issue.

What would it take to rewrite this Tools/Scripts/webkitpy/common/net/rietveld.py for gerrit? How is it becoming easier when requiring the branch being local only?

For the upcoming FreeType rebaseline, using rietveld seems slow and difficult. Gerrit might work much better.

Great question, I didn't fully investigate. In general, the two pieces of information that I think we want to fetch when preparing to rebaseline are (as noted in the original post): the try job status, and the list of changed files.

The public documentation (https://gerrit-review.googlesource.com/Documentation/rest-api-changes.html) doesn't mention try job status, but that information is probably accessible via the API.

The reason why this becomes easier when requiring the branch to be local only is that `git cl try-results` can then be used to get try results, and the rebaseline tool wouldn't have to talk directly to either Rietveld or Gerrit.

I'll start working on this and continue to update this bug until it's resolved.

Thanks, sounds great.

Gerrit does not provide an API for try job results. The display of try job results in Gerrit is via a plugin, which itself relies on the Buildbucket API to get the necessary data. (This is the same API that the CQ itself uses.)

Here's the code in the plugin which constructs the buildbucket query and reads the result:
https://chromium.googlesource.com/infra/gerrit-plugins/buildbucket/+/master/src/main/resources/static/cr-buildbucket-view.js#143

Thanks agable@, that makes sense.

So, besides using on `git cl try-results`, the other way to get try job results would involve making requests to the buildbucket API. I suspect that using git cl try-results is probably going to be easier; the only downside is that it means that rebaseline-cl would just work with local branches.

Now uploaded CL to use git cl try-results to get results: https://codereview.chromium.org/2692423005

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e0b4961639a9d8781023e68392847f6fe37f19d9

commit e0b4961639a9d8781023e68392847f6fe37f19d9
Author: qyearsley <qyearsley@chromium.org>
Date: Sun Feb 19 23:46:59 2017

rebaseline-cl: Get latest try jobs using git-cl when no --issue given.

This CL moves filter_latest_builds() into webkitpy.common.net.buildbot,
and adds a method latest_try_jobs to the GitCL class, which behaves like
the latest_try_jobs method currently on the Rietveld class.

The purpose of this change is to make it easier to drop dependency
on Rietveld.

BUG= 671684 

Review-Url: https://codereview.chromium.org/2692423005
Cr-Commit-Position: refs/heads/master@{#451531}

[modify] https://crrev.com/e0b4961639a9d8781023e68392847f6fe37f19d9/third_party/WebKit/Tools/Scripts/webkitpy/common/net/buildbot.py
[modify] https://crrev.com/e0b4961639a9d8781023e68392847f6fe37f19d9/third_party/WebKit/Tools/Scripts/webkitpy/common/net/buildbot_unittest.py
[modify] https://crrev.com/e0b4961639a9d8781023e68392847f6fe37f19d9/third_party/WebKit/Tools/Scripts/webkitpy/common/net/git_cl.py
[modify] https://crrev.com/e0b4961639a9d8781023e68392847f6fe37f19d9/third_party/WebKit/Tools/Scripts/webkitpy/common/net/git_cl_unittest.py
[modify] https://crrev.com/e0b4961639a9d8781023e68392847f6fe37f19d9/third_party/WebKit/Tools/Scripts/webkitpy/common/net/rietveld.py
[modify] https://crrev.com/e0b4961639a9d8781023e68392847f6fe37f19d9/third_party/WebKit/Tools/Scripts/webkitpy/common/net/rietveld_unittest.py
[modify] https://crrev.com/e0b4961639a9d8781023e68392847f6fe37f19d9/third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/rebaseline_cl.py
[modify] https://crrev.com/e0b4961639a9d8781023e68392847f6fe37f19d9/third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/rebaseline_cl_unittest.py

Update: next proposed change: https://codereview.chromium.org/2700283002

Meanwhile, in theory, using Gerrit should work now as long as you don't use the --issue or --only-changed-tests flags.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/2f99ba4adc9c23b0e611985304dd3a9c52235ed9

commit 2f99ba4adc9c23b0e611985304dd3a9c52235ed9
Author: qyearsley <qyearsley@chromium.org>
Date: Wed Feb 22 18:31:36 2017

rebaseline-cl: Only support local branches, drop Rietveld support.

This continues on from http://crrev.com/2692423005, and also changes
rebaseline-cl so that:

 - Git.changed_files is used instead of Rietveld.changed_files
 - The --issue flag is removed

BUG= 671684 

Review-Url: https://codereview.chromium.org/2700283002
Cr-Commit-Position: refs/heads/master@{#452142}

[modify] https://crrev.com/2f99ba4adc9c23b0e611985304dd3a9c52235ed9/third_party/WebKit/Tools/Scripts/webkitpy/common/checkout/git.py
[modify] https://crrev.com/2f99ba4adc9c23b0e611985304dd3a9c52235ed9/third_party/WebKit/Tools/Scripts/webkitpy/common/checkout/git_mock.py
[modify] https://crrev.com/2f99ba4adc9c23b0e611985304dd3a9c52235ed9/third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/rebaseline_cl.py
[modify] https://crrev.com/2f99ba4adc9c23b0e611985304dd3a9c52235ed9/third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/rebaseline_cl_unittest.py

I believe that rebaseline-cl should now not depend on Rietveld; https://chromium-review.googlesource.com/c/444189/ is the first real test-case.

More work needs to be done for w3c-test-autoroller to stop depending on Rietveld though ( bug 693792 ).