You can use --allow-unrelated-histories to force the merge to happen.
The reason behind this is that default behavior has changed since Git 2.9:
"git merge" used to allow merging two branches that have no common base by default, which led to a brand new history of an existing project created and then get pulled by an unsuspecting maintainer, which allowed an unnecessary parallel history merged into the existing project. The command has been taught not to allow this by default, with an escape hatch
--allow-unrelated-historiesoption to be used in a rare event that merges histories of two projects that started their lives independently.
See the Git release changelog for more information.
More information can be found in this answer.
Answer from blue112 on Stack OverflowYou can use --allow-unrelated-histories to force the merge to happen.
The reason behind this is that default behavior has changed since Git 2.9:
"git merge" used to allow merging two branches that have no common base by default, which led to a brand new history of an existing project created and then get pulled by an unsuspecting maintainer, which allowed an unnecessary parallel history merged into the existing project. The command has been taught not to allow this by default, with an escape hatch
--allow-unrelated-historiesoption to be used in a rare event that merges histories of two projects that started their lives independently.
See the Git release changelog for more information.
More information can be found in this answer.
In my case, the error was just fatal: refusing to merge unrelated histories on every try, especially the first pull request after remotely adding a Git repository.
Using the --allow-unrelated-histories flag worked with a pull request in this way:
git pull origin branchname --allow-unrelated-histories
As per 2.9.0 release notes - git pull has been taught to pass the --allow-unrelated-histories option to underlying git merge
Merging unrelated histories
What can cause Git's "unrelated histories" (other than force-pushing)?
I created the following repository on GitHub: https://github.com/james/test.git.
Then I proceeded with:
user@guest:~/.../gits$ git config --global init.defaultBranch main user@guest:~/.../gits$ mkdir test && cd test user@guest:~/.../test$ echo "# test" >> README.md user@guest:~/.../test$ git init user@guest:~/.../test$ git add README.md user@guest:~/.../test$ git commit -m "First commit" user@guest:~/.../test$ git remote add origin https://github.com/james/test.git user@guest:~/.../test$ git push -u origin main
And then:
user@guest:~/.../test$ git commit --amend user@guest:~/.../test$ git log --oneline --graph --all * ca82a6d (HEAD -> main) First commit * 085bb3b (origin/main) First commit user@guest:~/.../test$ git merge origin/main fatal: refusing to merge unrelated histories
What did I do wrong and what is the best solution in this case?
Hi,
I've been working on a website with someone for a few weeks, and every now-and-then we come across an issue with unrelated histories.
I know my way around Git, for the most part, but the other developer doesn't, so I've mostly been giving the instructions. However, there was a time where he had merge conflicts and decided to force-push to our GitHub repo. Obviously, this messed everything up, and to be honest I forgot that force-pushing was even a thing Git could do.
Anyway, it's happened again. And this time I don't think it's due to a force-push... even though there's only 1 commit in git log.
So my question is, what else can cause unrelated histories in Git?