I have two different local git repos, which we'll call a and b. They are both in a projects folder in my home directory. I want to get a diff between a particular file in both repos, let's call it foo, and apply that diff to a.
if I run git diff ./foo ../b/foo > diff.diff from inside a I can look at the diff and confirm that it contains the changes I want to apply, but when I run git apply diff.diff then I get this error:
fatal: invalid path './foo'
If I try running git diff ~/projects/a/foo ~/projects/b/foo > diff.diff, then when I try to apply the diff I get this error:
error: home/ryan/projects/a/foo: No such file or directory
Now, I can just copy the file to get the same effect as applying the diff, but is there a good reason why this isn't working?
To compare foo file between repo a and repo b and apply the changes to repo a, you just need to use below commands:
# In ~/projects/a (local repo a)
git remote add repob ~/projects/b -f
git diff master repob/master -- foo > diff.patch
git apply diff.patch
Now the foo in repo a change to the version of repo b. Then you can commit and push:
git add foo
git commit -m 'change foo as the version in repo b'
git push