CODEWITHSUNDEEP
gitgit-subtree
Matthijs
Matthijs

Reputation: 609

git subtree error "fatal: refusing to merge unrelated histories"

I'm trying to figure out how 'git subtree' works. I've followed all directions on this page, but I always get an error trying to merge the subtree project in my own repo ('Step 2'): fatal: refusing to merge unrelated histories.

I've read this post, and when I use the --allow-unrelated-histories option, it seems to work fine. However, I'm not sure whether I should use this...My impression is that the whole point of subtrees is to have unrelated histories within one repository, so it feels strange to have to add the option. Should I add it nevertheless, or am I doing something wrong?

I'm using git v2.9.3 on osx 10.11.6

Upvotes: 27

Views: 21532

Answers (5)

leoschet
leoschet

Reputation: 1866

What worked for me was using git merge with subtree strategy:

git merge -s subtree -Xsubtree="$prefix" subremote/branch --allow-unrelated-histories

git subtree uses something similar to that under the hood.

Upvotes: 8

granadaCoder
granadaCoder

Reputation: 27862

I am not expert.

But I found something. I was originally trying just a normal pull. But I found this specific subtree pull.

git subtree pull --prefix myPrefixname https://github.com/subTreeRepo.git master --squash

where master is the branch name of course

(from

https://developer.atlassian.com/blog/2015/05/the-power-of-git-subtree/

)

Upvotes: 0

PencilBow
PencilBow

Reputation: 1078

If the subtree was added using --squash, you need to also use --squash when you pull

git subtree pull --prefix=<folder-goes-here> <remote-goes-here> <branch-goes-here> --squash

Upvotes: 50

Cyrus
Cyrus

Reputation: 59

I've been struggling with this for a while and think I found the solution.

I'm pretty new to git so forgive me if I use the wrong names for things.

The problem may have come from you using the --squash option when you ran the git subtree add command.

Try removing the subtree (remove the remote repository and delete all the local files, commit, and push). Then redo the subtree add without the --squash option.

I then jumped over to my subtree repository, made some changes, committed and pushed, then hopped back to my main superproject repository and did a git subtree pull. It gave me some error about the working tree having modifications. To get around that I did a git checkout master, then a git push, then tried the subtree pull again. It worked.

Hope that helps.

Upvotes: 5

daurnimator
daurnimator

Reputation: 4311

This was a bug in git, it was fixed in https://github.com/git/git/commit/0f12c7d4d175bb0566208213b1b340b6794f305c

See also: https://www.spinics.net/lists/git/msg282340.html

Upvotes: 2

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