I'm trying to break "git pull --rebase"

I'm trying to break "git pull --rebase"

[Julius Musseau]

Hi, Git Developers,

I'm currently writing a blog post about "git pull --rebase".   The
point of the blog post is to examine scenarios where two people are
working together on a short-lived feature branch, where history
rewrites are allowed, and where both are using "git pull --rebase" to
stay in sync with each other.

I was hoping to concoct a situation where "git pull --rebase" makes a
mess of things.

So far I have been unable to do this.  I tried version v1.7.2 of Git
as well as version v2.14.1, and as far as I can tell, "git pull
--rebase" is bulletproof.

Does anyone here happen to know a situation where "git pull --rebase"
makes a mess?

Here's a draft of the blog post:

Title:  "(Too much) fun with git pull --rebase"

https://mergebase.com/doing-git-wrong/2018/02/17/fun-with-git-pull-rebase/


Here are the "git pull --rebase" scenarios I've tested so far:

1.  origin/feature rebased against origin/master

2.  origin/feature squash-merged against origin/master

3.  origin/feature squashed in-place`

4.  origin/feature dropped a commit

5.  origin/feature insanity (adjusted merge-base, reversed commits,
squashed some commits)

6.  undo of 5


So far "git pull --rebase" does the exact right thing in every case!

If anyone knows a scenario where "git pull --rebase" fails to do the
right thing, I would be very grateful to hear of it.



Thanks!

yours sincerely,

Julius Musseau

Re: I'm trying to break "git pull --rebase"

[Stefan Beller]

On Tue, Feb 20, 2018 at 2:00 PM, Julius Musseau <julius@mergebase.com> wrote:
> Hi, Git Developers,
>
> I'm currently writing a blog post about "git pull --rebase".   The
> point of the blog post is to examine scenarios where two people are
> working together on a short-lived feature branch, where history
> rewrites are allowed, and where both are using "git pull --rebase" to
> stay in sync with each other.
>
> I was hoping to concoct a situation where "git pull --rebase" makes a
> mess of things.
>
> So far I have been unable to do this.  I tried version v1.7.2 of Git
> as well as version v2.14.1, and as far as I can tell, "git pull
> --rebase" is bulletproof.
>
> Does anyone here happen to know a situation where "git pull --rebase"
> makes a mess?

If you are inclined to experiment with submodules,
I would have an easy answer for you. :)

But instead of giving an answer myself (as I love reading about
things the usual mailing list folks miss),
maybe this is a good starting point to poke at things
https://github.com/git/git/commit/a6d7eb2c7a6a402a938824bcf1c5f331dd1a06bb

For the non-submodule use case, I would think pull is pretty solid,
as you lay out in your blog draft.

(If you finish by Wednesday 21st), you may be interested in
submitting to Git rev-news (or a later edition if you take time writing)
https://public-inbox.org/git/CAP8UFD1HPruE3N_0k8_TFreBML9V8K=SS8LqD-XkeEuheSmGvw@mail.gmail.com/

Thanks,
Stefan

Re: I'm trying to break "git pull --rebase"

[Martin Langhoff]

On Tue, Feb 20, 2018 at 5:00 PM, Julius Musseau <julius@mergebase.com> wrote:
> I was hoping to concoct a situation where "git pull --rebase" makes a
> mess of things.

It breaks quite easily with some workflows. They are all in the "don't
do that" territory.

Open a long-lived feature-dev branch, work on it. Other folks are
working on master. Merge master into feature-dev. Make sure some
merges might need conflict resolution.

Reorg some code on master, move files around. Code some more on
feature-dev branch. Merge master into feature-dev; the merge machinery
will probably cope with the code move, file renames. If it doesn't,
resolve it by hand.

Let all that simmer for a little bit.

Then try to rebase.

"Doctor, it hurts when I rebase after merging with conflict resolution... "

cheers,



m