1431: The method TestPullRequest#diff sometimes returns wrong information

[lgxbslgx]

Hi all,

The method TestPullRequest#diff always passes the head hash of the target branch to the method Repository#diff as the base hash. But it may be wrong when the target branch was submitted some new commits after creating the pull request. TestPullRequest#diff should find the last common hash of the source and target branch as the base hash.

This patch fixes the bug and adds the test case. I don't know whether it is good to place the test case at the class CSRBotTests, but the method CSRBotTests#testBackportCsr indeed contains the situation of this bug.

Thanks for taking the time to review.

Best Regards,
-- Guoxiong

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Progress

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Issue

• SKARA-1431: The method TestPullRequest#diff sometimes returns wrong information

Reviewers

• Magnus Ihse Bursie (@magicus - Reviewer)
• Erik Joelsson (@erikj79 - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/skara pull/1360/head:pull/1360
$ git checkout pull/1360

Update a local copy of the PR:
$ git checkout pull/1360
$ git pull https://git.openjdk.org/skara pull/1360/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 1360

View PR using the GUI difftool:
$ git pr show -t 1360

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/skara/pull/1360.diff

[bridgekeeper]

👋 Welcome back gli! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[mlbridge]

Webrevs

• 01: Full - Incremental (52a4d4f8)
• 00: Full (19b5f654)

[magicus]

So if the common commit is more than 40 commits away, return "no diff"? :-)

This is only used in testing, right? If so, this you could get away with it, but I think a comment describing the limitations would be needed.

[erikj79]

I think you are misunderstanding the code. "0".repeat(40) just generates a string with 40 zeros, basically a null hash.

Looping to find the common ancestor is one way of doing it, but I would recommend checking out git merge-base. There is a method for it already on GitRepository.

[magicus]

I see. Yes, I misunderstood the code as looping backwards for a maximum of 40. Don't know how I got to that conclusion. My brain is apparently still partially stuck in vacation mode. I don't think I'm used to methods being called on a string literal.

[lgxbslgx]

Looping to find the common ancestor is one way of doing it, but I would recommend checking out git merge-base. There is a method for it already on GitRepository.

Thanks for reminding me. I change the code to use the method mergeBase just now.

[magicus]

Much better.

[openjdk]

@lgxbslgx This change now passes all automated pre-integration checks.

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After integration, the commit message for the final commit will be:

1431: The method TestPullRequest#diff sometimes returns wrong information

Reviewed-by: ihse, erikj

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[lgxbslgx]

Thanks for the review. Integrating.

/integrate

[openjdk]

Going to push as commit cd765e9.

[openjdk]

@lgxbslgx Pushed as commit cd765e9.

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