Merging one file from one branch to another has been asked before with the rather concise solution to do:
git checkout A
git checkout --patch B f
But how does one do this effectively across two repositories?
Asked
Active
Viewed 67 times
1
-
Push or fetch the commits. – jthill Sep 08 '15 at 15:36
-
@jthill: It's not that easy: You could cherrypick the individual commits, but if one of those affects more than the file of interest, you import/merge unwanted changes. The fetch alone imports the full history of one branch of the remote/source repository. If the two repos are unrelated with unrelated files and unrelated history, then this is a huge disk space overhead which you have to cleanup afterwards. – cfi Sep 09 '15 at 06:16
1 Answers
1
There is a simple solution, too and it involves patching. git can handles patches sent in by email very well. That is one of the important initial use cases by Linus Torvalds. So we first generate such a patchfile in the source repo, then consume it in the destination:
cd source_repository/
git log --reverse --follow -p --format=email filename > patch
cd other_repository/
git am --whitespace=nowarn source_repository/patch
rm source_repository/patch
Some explanation:
git amstands for “git apply mailbox file” and is used to integrate patches that someone sends by emailgit log –pcan create such a patch file with option--format=email- The
--followis used to keep track of the full history of the file even if it got renamed.--followpreventsgit logfrom accepting multiple file names. But it is an important switch and that is why I recommend to use this method in a loop for multiple files. - The
--reverseis required becausegit amrequires the commits to be in chronological order withgit logby default does not output. - By default
git amwarns about lines with trailing whitespaces.--whitespace=nowarnsuppresses those warnings. You might want to not use this and clean you whitespaces, but that's a matter of style guidelines
cfi
- 10,915
- 8
- 57
- 103