Print a warning and continue if no results could be fetched in rebaseline_from_try_jobs.py.

Print a warning and continue if no results could be fetched in rebaseline_from_try_jobs.py.

For example, if there's a network issue or results are at some point
not archived in the expected place, a warning can be printed here
instead of exiting with a AttributeError (NoneType has no method...).

BUG=474273
Committed: https://crrev.com/ff2f0894c080a39ed790ff2468095af2fac9e85c
Cr-Commit-Position: refs/heads/master@{#403034}

[qyearsley, 2016-06-29 17:42:23]

Description was changed from

==========
Remove "master." when getting master name in rietveld.py.

This is a follow-up fix to http://crrev.com/2072943002; after that CL,
webkit-patch rebaseline-from-try-jobs would get master names from
Rietveld but the master names included the "master." prefix. This CL
makes it so that that prefix is removed if present. If that prefix is
not present, this is unexpected, so a warning is logged, but it may be OK,
so it just tries to use the master name as-is.

BUG=474273
==========

to

==========
Print a warning and continue if no results could be fetched in
rebaseline_from_try_jobs.py.

This is a follow-up fix to http://crrev.com/2072943002; after that CL,
webkit-patch rebaseline-from-try-jobs would get master names from
Rietveld but the master names included the "master." prefix. This CL
makes it so that that prefix is removed if present. If that prefix is
not present, this is unexpected, so a warning is logged, but it may be OK,
so it just tries to use the master name as-is.

BUG=474273
==========

[qyearsley, 2016-06-29 17:44:04]

Description was changed from

==========
Print a warning and continue if no results could be fetched in
rebaseline_from_try_jobs.py.

This is a follow-up fix to http://crrev.com/2072943002; after that CL,
webkit-patch rebaseline-from-try-jobs would get master names from
Rietveld but the master names included the "master." prefix. This CL
makes it so that that prefix is removed if present. If that prefix is
not present, this is unexpected, so a warning is logged, but it may be OK,
so it just tries to use the master name as-is.

BUG=474273
==========

to

==========
Print a warning and continue if no results could be fetched in
rebaseline_from_try_jobs.py.

For example, if there's a network issue or results are at some point not
archived in the expected place, a warning can be printed here instead of exiting
with a AttributeError (NoneType has no method...).

BUG=474273
==========

[qyearsley, 2016-06-29 17:44:15]

Description was changed from

==========
Print a warning and continue if no results could be fetched in
rebaseline_from_try_jobs.py.

For example, if there's a network issue or results are at some point not
archived in the expected place, a warning can be printed here instead of exiting
with a AttributeError (NoneType has no method...).

BUG=474273
==========

to

==========
Print a warning and continue if no results could be fetched in
rebaseline_from_try_jobs.py.

For example, if there's a network issue or results are at some point
not archived in the expected place, a warning can be printed here
instead of exiting with a AttributeError (NoneType has no method...).

BUG=474273
==========

[qyearsley, 2016-06-29 18:01:00]

qyearsley@chromium.org changed reviewers:
+ dpranke@chromium.org, wkorman@chromium.org

[wkorman, 2016-06-29 18:30:17]

lgtm

https://codereview.chromium.org/2102963003/diff/20001/third_party/WebKit/Tool...
File
third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/rebaseline_from_try_jobs.py
(right):

https://codereview.chromium.org/2102963003/diff/20001/third_party/WebKit/Tool...
third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/rebaseline_from_try_jobs.py:49:
if layout_test_results is None:
Is this preferred to:

if not layout_test_results:

I feel like I see the 'not' more often, but am fine with either.

[qyearsley, 2016-06-29 21:08:45]

On 2016/06/29 at 18:30:17, wkorman wrote:
> lgtm
> 
>
https://codereview.chromium.org/2102963003/diff/20001/third_party/WebKit/Tool...
> File
third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/rebaseline_from_try_jobs.py
(right):
> 
>
https://codereview.chromium.org/2102963003/diff/20001/third_party/WebKit/Tool...
>
third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/rebaseline_from_try_jobs.py:49:
if layout_test_results is None:
> Is this preferred to:
> 
> if not layout_test_results:
> 
> I feel like I see the 'not' more often, but am fine with either.

If layout_test_results is something else bizarre, like an empty string, or empty
list, or False, then the if branch won't be taken and
layout_test_results.unexpected_mismatch_results will raise an AttributeError.

So, I think `if layout_test_results is not None` is a little more explicit
because it shows that I expect it to maybe be None (and this means a failure to
request results). I think that comparing specifically to None is a little like
catching specific exceptions -- if something bizarre and totally unexpected
happens, then it probably shouldn't be caught by an "except" block that you
intended only for catching a specific type of exception.

Anyway, that's my opinion; there's more about this in
https://google.github.io/styleguide/pyguide.html?showone=True/False_evaluatio...,
and the Google Style guide suggests using implicit false (if not x) in most
cases.

[qyearsley, 2016-06-29 21:37:14]

The CQ bit was checked by qyearsley@chromium.org

[commit-bot: I haz the power, 2016-06-29 21:39:28]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-06-30 00:35:26]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-06-30 00:35:40]

CQ bit was unchecked.

[commit-bot: I haz the power, 2016-06-30 00:37:59]

Description was changed from

==========
Print a warning and continue if no results could be fetched in
rebaseline_from_try_jobs.py.

For example, if there's a network issue or results are at some point
not archived in the expected place, a warning can be printed here
instead of exiting with a AttributeError (NoneType has no method...).

BUG=474273
==========

to

==========
Print a warning and continue if no results could be fetched in
rebaseline_from_try_jobs.py.

For example, if there's a network issue or results are at some point
not archived in the expected place, a warning can be printed here
instead of exiting with a AttributeError (NoneType has no method...).

BUG=474273

Committed: https://crrev.com/ff2f0894c080a39ed790ff2468095af2fac9e85c
Cr-Commit-Position: refs/heads/master@{#403034}
==========

[commit-bot: I haz the power, 2016-06-30 00:38:00]

Patchset 2 (id:??) landed as
https://crrev.com/ff2f0894c080a39ed790ff2468095af2fac9e85c
Cr-Commit-Position: refs/heads/master@{#403034}