RFR: 8258477: Pre-submit testing using GitHub Actions should merge changes from target branch

[Robin Westberg]

Hi Thomas,

> On 16 Dec 2020, at 14:54, Thomas Stüfe <thomas.stuefe at gmail.com> wrote:
> 
> Hi Robin,
> 
> does this mean tests won't run on branches which cannot be merged with the
> assumed target branch?

No, if there’s a problem with doing the merge the tests will simply continue without doing it, and just use the commit in the pull request as-is.

Best regards,
Robin
 
> 
> Thanks, Thomas
> 
> 
> On Wed, Dec 16, 2020 at 11:55 AM Robin Westberg <rwestberg at openjdk.java.net>
> wrote:
> 
>> Normally when running GitHub Actions on a pull request, what is checked
>> out is the merge of the pull request with the latest changes on the target
>> branch. This ensure that what is tested is as close as possible to what
>> will actually be the result of integrating said pull request.
>> 
>> In our use of GitHub Actions, we don't run directly on pull requests but
>> instead allow contributors to run them in their own personal forks. In that
>> context, there is no notion of a target branch. However, we can infer the
>> target project and branch by encoding this in the workflow file. This
>> allows us to perform the same merge manually, and achieve the same
>> behaviour.
>> 
>> The change also adds an option to disable this automated merge when
>> launching the workflow manually, which could be useful when investigating
>> unexpected test failures.
>> 
>> Note that downstream projects picking up this change will have to adapt
>> the workflow file to keep using these actions for pre-submit testing. This
>> has been a common request from downstream projects, but could also be done
>> in a separate change (or not at all).
>> 
>> -------------
>> 
>> Commit messages:
>> - Allow opting out of automated merge on manual runs
>> - Initial implementation
>> 
>> Changes: https://git.openjdk.java.net/jdk/pull/1801/files
>> Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1801&range=00
>>  Issue: https://bugs.openjdk.java.net/browse/JDK-8258477
>>  Stats: 117 lines in 1 file changed: 116 ins; 0 del; 1 mod
>>  Patch: https://git.openjdk.java.net/jdk/pull/1801.diff
>>  Fetch: git fetch https://git.openjdk.java.net/jdk
>> pull/1801/head:pull/1801
>> 
>> PR: https://git.openjdk.java.net/jdk/pull/1801
>>