# Squash & Merge Implementation 3 messages from 2018-08-03 to 2018-08-03. Participants: Vadim Belov, Jeff King. Thread: https://gitlist.dev/t/49016 ## Vadim Belov, 2018-08-03 12:01 Subject: Squash & Merge Implementation Message-ID: URL: https://gitlist.dev/e/CALr1GiFBm9zJ1v-UWuVLWJJ%2BzFh-iTKOv%3DT4KETLN8qkW_0pAg%40mail.gmail.com ``` Hello, I'm trying to manually implement Github's *Squash&Merge *functionality. After looking many forums like stackoverflow.com I'm still struggling with the issue. *The scenario is as follows*: - master is a protected branch (configured on github) - a service user *svc *is permitted to push to master (configured on github) - other users don't have such permissions - github PR status check is set to SUCCESS before execution of any set of git commands below 1. This merges successfully without squash: git checkout origin/master git merge ${PR-Branch} git push origin HEAD:master git push origin --delete ${PR-Branch} 2. This closes the PR, but there is no update seen on master: git checkout origin/master git merge --squash --commit ${PR-Branch} git push origin HEAD:master git push origin --delete ${PR-Branch} 3. This fails to push to master with the error "GH006: Protected branch update failed" (despite that the PR is set to SUCCESS): git checkout origin/master git merge --squash ${PR-Branch} git commit -am"comment" git push origin HEAD:${m_mainBranch} git push origin --delete ${m_prBranch} Will appreciate your help on this. Thanks, Vadim ``` ## Jeff King, 2018-08-03 13:49 Subject: Re: Squash & Merge Implementation Message-ID: <20180803134901.GC28939@sigill.intra.peff.net> URL: https://gitlist.dev/e/20180803134901.GC28939%40sigill.intra.peff.net In-Reply-To: ``` On Fri, Aug 03, 2018 at 03:01:15PM +0300, Vadim Belov wrote: > 1. This merges successfully without squash: > git checkout origin/master > git merge ${PR-Branch} > git push origin HEAD:master > git push origin --delete ${PR-Branch} Right, this is a normal merge. > 2. This closes the PR, but there is no update seen on master: > git checkout origin/master > git merge --squash --commit ${PR-Branch} > git push origin HEAD:master > git push origin --delete ${PR-Branch} Doing "merge --squash --commit" doesn't do what you expect; namely "--commit" does not override the non-committing nature of "--squash". It only override a "--no-commit" found elsewhere. IMHO this is something that could be improved in Git (i.e., telling the difference between "the user did not say --no-commit" and "the user said --commit" and respecting it for --squash). But that explains what you see. The push to master is a noop, since you didn't make a new commit. And then deleting the PR branch on GitHub auto-closes the PR. > 3. This fails to push to master with the error "GH006: Protected branch > update failed" (despite that the PR is set to SUCCESS): > git checkout origin/master > git merge --squash ${PR-Branch} > git commit -am"comment" > git push origin HEAD:${m_mainBranch} > git push origin --delete ${m_prBranch} So here you _do_ make an actual commit. But that commit doesn't look like a merge to the receiver; it just looks like a single commit that has all the changes there were on PR-Branch. The tree of that commit should be the same tree that would result from a real merge. So in theory things like protected-branch status checks could handle that, but I suspect they use the actual commit id (the tree id is fine if you're just doing CI, but if you wanted to have a status check for commit messages, say, you'd obviously want that to be tied to the actual commit object). I don't offhand recall how that is implemented (and you could also be falling afoul of other checks, like required reviews). But this is a GitHub-specific question, and you should probably ask GitHub support to go further. -Peff ``` ## Vadim Belov, 2018-08-03 17:23 Subject: Re: Squash & Merge Implementation Message-ID: URL: https://gitlist.dev/e/CALr1GiFjqR%2BdyP6vCah7H3bhurbcwp2zfrxRfBkd1wnkSQDZCQ%40mail.gmail.com In-Reply-To: <20180803134901.GC28939@sigill.intra.peff.net> ``` Thanks, Peff! I'm just doing the CI and the status check is for testing each commit to the PR-Branch. I'll try to get response from github on this as you suggested. Thanks again, Vadim On Fri, Aug 3, 2018 at 4:49 PM Jeff King wrote: > On Fri, Aug 03, 2018 at 03:01:15PM +0300, Vadim Belov wrote: > > > 1. This merges successfully without squash: > > git checkout origin/master > > git merge ${PR-Branch} > > git push origin HEAD:master > > git push origin --delete ${PR-Branch} > > Right, this is a normal merge. > > > 2. This closes the PR, but there is no update seen on master: > > git checkout origin/master > > git merge --squash --commit ${PR-Branch} > > git push origin HEAD:master > > git push origin --delete ${PR-Branch} > > Doing "merge --squash --commit" doesn't do what you expect; namely > "--commit" does not override the non-committing nature of "--squash". It > only override a "--no-commit" found elsewhere. > > IMHO this is something that could be improved in Git (i.e., telling the > difference between "the user did not say --no-commit" and "the user said > --commit" and respecting it for --squash). > > But that explains what you see. The push to master is a noop, since you > didn't make a new commit. And then deleting the PR branch on GitHub > auto-closes the PR. > > > 3. This fails to push to master with the error "GH006: Protected branch > > update failed" (despite that the PR is set to SUCCESS): > > git checkout origin/master > > git merge --squash ${PR-Branch} > > git commit -am"comment" > > git push origin HEAD:${m_mainBranch} > > git push origin --delete ${m_prBranch} > > So here you _do_ make an actual commit. But that commit doesn't look > like a merge to the receiver; it just looks like a single commit that > has all the changes there were on PR-Branch. > > The tree of that commit should be the same tree that would result from a > real merge. So in theory things like protected-branch status checks > could handle that, but I suspect they use the actual commit id (the tree > id is fine if you're just doing CI, but if you wanted to have a status > check for commit messages, say, you'd obviously want that to be tied to > the actual commit object). > > I don't offhand recall how that is implemented (and you could also be > falling afoul of other checks, like required reviews). But this is a > GitHub-specific question, and you should probably ask GitHub support to > go further. > > -Peff > ```