RFR: 1658: Minimize race window when updating PR body

[Zhao Song]

On Tue, 8 Nov 2022 23:18:56 GMT, Magnus Ihse Bursie <ihse at openjdk.org> wrote:

>> Currently, when the pr bot tries to update the PR body, users are also likely to update the PR body at the same time. Therefore, users' updates are likely to be overwritten by bot.  
>> 
>> This is a race between the bot and user and the race window is a little big right now.
>> 
>> To reduce the race window, in this patch, when PR bot is trying to update PR body, it will check whether the PR body has been modified by user. And if the PR bot has been modified, PR bot would not overwrite it.
>
> forge/src/test/java/org/openjdk/skara/forge/github/GitHubRestApiTests.java line 159:
> 
>> 157:         var testPr = testRepo.pullRequest("99");
>> 158: 
>> 159:         String latestBody = testPr.latestBody();
> 
> This looks a bit fragile, but maybe that's a price we have to pay for the manual tests.
> 
> However, I think you should also add an automatic test, that verifies that an updated body makes the bot skip the update that time around, but not otherwise. I think it will be possible to define such a setup without having to resort to race-prone logic.

Thank you for the review and suggestion! 

I will try to add an automatic test, but I need to change some logic related with body in TestPullRequest.

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PR: https://git.openjdk.org/skara/pull/1416