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.

[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.

[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.

[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!

[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.

[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!

[fredrikwallenius]

+1 from me, same issue just now.

Thanks for the tips above on closing and opening it again. I still had to get a new approval, but at least it realized that the branch I'd based my branch on (which wasn't master) had been merged.

[muawiakh]

+1, Opened a PR(X) -> got one approval -> needed more changes -> Converted to draft -> another PR(Y) got merged -> Converted PR(X) to Review again but it couldn't be merged even though all new approvals were there. I also saw the changes from PR(Y) in PR(X).

Thanks for the workaround.

[buphoff-villagemd]

Is there a GitHub bug ticket for this issue?

[georgekronberg]

Experiencing this too, PR approval gets auto-dismissed for no reason:

How is this has been around for more than 6 months and there's no actual bug ticket? Or is there?

[luke-mckee-ol]

+1 for this issue. resetting the base didn't help. Closing and reopening PR resolved it. 🤷

[dvmcconnell]

Our team had this happen recently, too.

The diff also looked incorrect, with changes that were already incorporated in the base branch showing up as a change being added from the head branch. Closing and reopening the PR both fixed the approval dismissal, and the incorrect PR diff.

[1121589]

Bump, also have this problem.
Currently in Github Enterprise version 3.10.5.
Closing and opening both solves the diff problem mentioned above and fixes the review bug.

[siddrcrelias]

faced this issue today...closing and re-opening the Pr fixed it...

[fletchgqc]

A bit strange that this bug exists for so long, I would have thought it would affect a large group of users, that is:

1. Require approvals before merging: active
2. Dismiss stale approvals when new commits pushed: active
3. create PR1 for branch a, then create branch b from branch a and PR2 for branch b, then merge PR1.

I guess point three is quite rare. Strangely.

[tenfoldsec]

Bump, because we are experiencing the same problem on GitHub Enterprise 3.11.5.
Closing and opening, or updating the branch fixes the auto dismissal of reviews.

[Vetrano89]

We experienced this as well. Each approval results in Github reporting "The merge-base changed after approval." and then un-approving the PR.

Closing and reopening the PR fixed the issue.

[fletchgqc]

I would say that closing and reopening "worked around" the issue :-).

[sam-netlogix]

+1 for this, just happened in our org.

Workaround of closing/re-opening the PR worked for us too.

[travisTheOrange]

+1 for us as well.

[hanseltime]

+1 for my org as well. This can be a productivity killer

[jpicht]

Bump. Happening to my org as well.

[AngieWongHeb]

same here