Can not merge pull requests after approval due to The merge-base changed after approval.

[dgokcin]

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Hello

Yesterday we noticed that there is a weird message appearing when a PR is approved. We have a feature branch created from main and we are trying to merge it to develop. Once the PR is approved and required checks pass, we see this message suggesting that the merge-base has changed after approval, although it has not.

This has a significant impact on developer experience, so I kindly ask for your support/guidance.

Thanks

[cmhanthorn]

I ran into the same problem. In my case I had issued the pull request and requested a review from someone, then before they got to it I pushed a new commit removing some commented code.

It seems to be related to these security enhancement changes: https://github.blog/changelog/2023-06-06-security-enhancements-to-required-approvals-on-pull-requests/. Since I am an org owner I was able to look at the branch protection settings and saw the setting in the image below.

After I deselected this setting my reviewer was able to approve the PR and merge the changes.

From the wording of the setting I think even with it enabled it should have allowed my reviewer to approve and merge the changes, since I made the later commit before he did the review. I think this is a bug.

[patcharaphong1]

建议更改

[dgokcin]

I also think this is a bug since closing the pr and re-openning it caused the issue to go away without changing any repository settings.

[patcharaphong1]

建议更改

[JonMoore46]

Not sure if this will help anyone but I've just had this happen on a branch where I had branched off from an existing branch (didn't mean to do this......) and then the first brach was merged into master/main.

This seemed to trigger the message appearing.

[adrian-izdebski-lrn]

It looks like the pointer to the baseline branch is fixed in a PR, but then there is some process to check that sha. It fails because the baseline tip moved.
It's not the best behaviour.
Reopening PRs is an unwelcome workaround.

---

You can edit a PR and change a baseline from e.g. staging to .... staging, which will fix this without opening another PR.

[rogerfernandes]

This works for me! Thanks!

[chris-troupe]

This worked for me as well, I would recommend trying this as the first solution.

[davidicus]

This also worked for me! Thanks.

[patcharaphong1]

สิ่งนี้ก็ได้ผลสําหรับฉันเช่นกัน! ขอบคุณ

[VictorNanka]

Thank you very much, this works for me

[Duncan-hrn]

Also getting this happening:

• PR1->develop opened and 1x approved (not merged)
• some other PR is merged to develop
• PR1 approval is now dismissed with message "The merge-base changed after approval."

[tobalsgithub]

We're hitting this now too. Strangely, I turned off the Dismiss stale pull request setting, and now the reviews aren't getting dismissed, but the PR still acts like no one has approved. Closing and re-opening the PR was the only thing that allowed us to move forward.

[adeshmukh-legion]

Closing and reopening the PR did the trick, thanks!

[robindubeyibm]

Yep, Closing and reopening the PR worked. Thanks

[adamreisnz]

This doesn't seem to work (anymore)

[alexmitelman]

Happens to me too. Auto-dismisses my review without any new code.

[jcook-uptycs]

Saw this as well with commits and PR created on Aug 7, 2023.

As soon as a new review was added the review would be dismissed with the message

The merge-base changed after approval.
It was done as if the PR author performed the action themself. (Which they didn't)

Closing the PR and re-opening it did fix the issue.

We do have dismiss stale reviews enabled, but no new commits were added.

[BSmith-87]

We are experiencing this same issue. It requires closing and opening the PR, or having somebody with admin permissions to override the required approval. (Turning off dismiss stale approvals is not something we are willing to do)

According to the git history, there were no commits that triggered this condition.

[dickinr]

I'm experiencing this as well. Can't find a rhyme or reason to it. I'll approve a pull and it will immediately be dismissed seconds later. There aren't any new commits being pushed.

[Penagwin]

We are also seeing this. My PR is from my branch -> dev. The last commit to both master/dev was over an hour ago, and my last commit on my branch was over 30 minutes ago (I double checked). Every review said "Dismissed - The merge-base changed after approval."

• Coworker 1 - 29 minutes ago
• Coworker 2 - 22 minutes ago
• Coworker 3 - 8 minutes ago

[hyungmok]

In my case, I could merge my PR after adding members on the Collaborators and Teams page in Settings. Just FYI.

[rafaelrezend]

In my case, I could merge my PR after adding members on the Collaborators and Teams page in Settings. Just FYI.

This comment was marked as off-topic, but actually this is exactly what worked for me.

My colleague was able to approve my PR because he was part of the Organization. His approval was ignored until I added our Team as a Collaborator in the repo (which I missed earlier). His approval immediately got the green badge as well as the PR.

[akloss-cibo]

Just a "me too" on this. A PR was stuck like this, pushed another branch name (of the same commit) and it approved and merged successfully. If anyone from GitHub actually wants to try to fix, I have left the "dead" PR open. Feel free to reach out.

[duelyy]

Disabling the branch protection for "Dismiss stale pull request approvals when new commits are pushed" allowed us to get pass the message, "the merge-base changed after approval". This is a weird bug because nobody has made any new commits to our PR and it's annoying because it happens randomly.

Any chance that Github Support can investigate this bug?

[Triblo]

Just another person on a team experiencing this bug!

[qhizar]

+1 from my organisation as well.
Is there any work around for this?

[bamiogunfemi]

Bump. Still experiencing this

[McCauliflower]

I got this same thing. Two approvals and it auto dismissed them two times in a row even when I wasnt at my computer. Closing and reopening the PR auto-magically resolved the issue for me, but it still seems to be a defect.

[McCauliflower]

It turns out I think this happened because I made a change to reflect what was just merged into our base branch after getting mixed up with pulling in some recent changes (not sure what I did there) but yeah ultimately I changed some code back to mirror our base branch. However for some reason github didn't properly show the change in the 'files changed' of my open pull request. so every time it was approved it would be auto-dissmissed by me (even though I wasnt changing anything or even at my computer), and still not properly show the change I made. I think maybe when I closed and reopened it it may have started properly tracking the commit where I had changed something back that had already been merged into our base branch (because it shows it now in the 'files changed' now that it was merged)....but yeah ultimately it had to do with some timing of changes in the commit history that were not showing properly in the 'files changed' of the open pull request.

[iansteyn]

Similar thing happened to me I think. Made a commit, pulled in recent changes (which was seen by git as a merge commit from the remote branch), then pushed both of these commits to remote.

[mariuspop86]

Bump

[JohannesArtmeier]

Bump

[matEhickey]

bump

[iansteyn]

Bump. As far as I can tell the merge base did not actually change for us, but we still got the message. We have branch protection rules in place for a reason but this was not expected behaviour.

[StarLightPL]

Had this error happen to me as well, changing base to itself worked.

[adamreisnz]

This problem has started occuring for almost all my PR's since last week. The PR will be approved, and then immediately after, Github will say it's been dismissed (by me lol) due to the base branch changing.

No changes were made, the base branch didn't change. How can we stop this buggy behaviour?

Then after another approval, the PR is in "Approved" state, yet still cannot be merged as it says it needs approval.

Something funky is going on here...

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[dCremins]

Bumping to say this is still an issue. This setting should clear approvals when the branch for the PR changes, to denote that the approvals are for an old version. Instead it also clears any time the base branch gets changed, such as another PR merging, even if there are no conflicts with the in-review PR.

Wiping on base branch changes makes this setting pretty much useless. Please fix this setting to check against the PR branch rather than the base branch the PR is merging into.

[joechchung]

This has also happened to me today, still an issue. Closing and reopening the PR fixes though

[briangtn]

Happened today, closing and reopening PR fixed 🤔

[difhel]

Happened today, reopening PR helped fixing the issue. A very annoying one.

[yoyomeng2]

Still an issue. Unsetting the PR dismissing rule didn't help. Verified no changes to the base branch had been made. Close/reopen on the PR got the approval to stick.