extracting commits from Elpa to original repo

[Eric Abrahamsen <eric@ericabrahamsen.net>]

Here's another addressed-to-stefan-but-probably-of-general-interest
question:

I first put my "Gnorb" package into Elpa using the git subtree approach.
Stefan made a commit into it, fixing up some compilation issues and code
style stuff. When I went to pull my latest changes into Elpa I got
conflicts (I wasn't expecting anyone else to be committing into that
package!), assumed I'd screwed something up, backed out about half the
changes, and didn't figure out what had happened until after I'd pushed
again.

I keep Gnorb in a separate repo which I consider its home. I have added
that repo to my local Elpa repo as a remote, and have been pulling
changes from there into the Elpa repo.

Stefan you made another similar commit a month or so ago (which I
appreciate!), which I'd like to have in my main repo, but now I'm not
sure how to handle it.

Here's what I do in Elpa to get my changes:

git fetch gnorb
git subtree pull --prefix=packages/gnorb gnorb master --squash

(I've been using the instructions found here[1])

I also used the "subtree split" command to create a separate branch
within Elpa containing only the commits made on "packages/gnorb".

I'd like to get Stefan's patch into my general Gnorb repo, in such a way
that it doesn't create any conflicts or confusion the next time I pull
into Elpa. I created a patch for his commit, but it doesn't apply
cleanly to my other repo, and I suspect that fixing it up so that it
does will simply defer the mess. I'll admit I've reached the limit of my
git abilities.

Can anyone provide some advice on what to do in this situation? Besides
"develop your next package directly in the Elpa tree"?

Thanks in advance,

Eric

[1]: https://hpc.uni.lu/blog/2014/understanding-git-subtree/