git pull versus fetch/merge

Good day.

A while ago I was here asking about "git pull" versus "git merge" for local branches -- now I see a difference for remote ones that I'm not sure should be there.

I gathered before that "git pull <remote> <branch>" should basically be shorthand for "git fetch <remote>, git merge <remote>/<branch>". Is that correct?

I'm seeing a problem I believe with a specific repository:

rene@7ixe4:~/src/linux/7ixe4$ git remote show tiwai
* remote tiwai
  URL: git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6
  Tracked remote branches
    devel dma-fix for-linus master upstream

with "git pull tiwai devel" everything goes well:

rene@7ixe4:~/src/linux/7ixe4$ git status
# On branch master
nothing to commit (working directory clean)
rene@7ixe4:~/src/linux/7ixe4$ git branch tmp0 v2.6.26
rene@7ixe4:~/src/linux/7ixe4$ git branch tmp1 v2.6.26
rene@7ixe4:~/src/linux/7ixe4$ git checkout tmp0
Switched to branch "tmp0"
rene@7ixe4:~/src/linux/7ixe4$ git pull tiwai devel
Updating bce7f79..e0bf09b
Fast forward
 Documentation/sound/alsa/ALSA-Configuration.txt    |   17 +-
 [ ... ]

and I get a clean merge.

On the other hand, if I try to do this with a fetch/merge, I get:

rene@7ixe4:~/src/linux/7ixe4$ git checkout tmp1
Switched to branch "tmp1"
rene@7ixe4:~/src/linux/7ixe4$ git fetch tiwai
From git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6
 ! [rejected]        devel      -> tiwai/devel  (non fast forward)
 ! [rejected]        dma-fix    -> tiwai/dma-fix  (non fast forward)
 ! [rejected]        master     -> tiwai/master  (non fast forward)

rene@7ixe4:~/src/linux/7ixe4$ git merge tiwai/devel
Auto-merged sound/pci/ac97/ac97_patch.c
Auto-merged sound/pci/emu10k1/emu10k1_main.c
Auto-merged sound/pci/hda/patch_analog.c
Auto-merged sound/pci/hda/patch_realtek.c
CONFLICT (content): Merge conflict in sound/pci/hda/patch_realtek.c
Auto-merged sound/pci/hda/patch_sigmatel.c
Automatic merge failed; fix conflicts and then commit the result.

and me no happy...

It probably has something to do with that " ! [rejected]" but what is that about? Is the repo bad? (and if so, I suspect owner will want to know how to avoid it in the future).

And if it is bad, should I be seeing something with the pull method also? Moreover... can I now trust my tmp0 branch?

Your fetch/merge approach was different from what your pull approach did. tiwai/devel did not get updated by the fetch, which means that you tried to merge the old state of that branch and that caused some conflicts. OTOH the pull did fetch the latest state from the remote repo and merged that cleanly.

Your fetch/merge approach was more like "git pull" without any arguments, but with the current branch setup to track tiwai/devel. In that case, pull really does a "git fetch tiwai", and it should fail
in the same way.

Thank you. Also due to a reply on the ALSA list by Mark brown I now get this. Yes, the remote was rebased while I had it setup as a remote here it seems; only recently have it under this name, so I didn't think that was the case. After a "git remote rm tiwai, git remote add tiwai <url>" things work fine again as it fetched a completely new branch.

Not that adding the remote with "git remote add" will add a fetchspec

Quoted 1 line · Rene Herman

Thank you. Also due to a reply on the ALSA list by Mark brown I now get this. Yes, the remote was rebased while I had it setup as a remote here it seems; only recently have it under this name, so I didn't think that was the case. After a "git remote rm tiwai, git remote add tiwai <url>" things work fine again as it fetched a completely new branch.

Note that adding the remote with "git remote add" will add a fetchspec line like this:

[remote "tiwai"]
fetch = +refs/heads/*:+refs/remotes/tiwai/*

where the '+' means to force fetching rewound branches instead of rejecting them (this is safe, since you are just overwriting tracking branches, not your local work).

So this should not come up again; presumably your previous remote configuration was set up differently.

Quoted 12 lines · Jeff King

Quoted 6 lines · Rene Herman

Thank you. Also due to a reply on the ALSA list by Mark brown I now get this. Yes, the remote was rebased while I had it setup as a remote here it seems; only recently have it under this name, so I didn't think that was the case. After a "git remote rm tiwai, git remote add tiwai <url>" things work fine again as it fetched a completely new branch.

Note that adding the remote with "git remote add" will add a fetchspec line like this:

Quoted 6 lines

[remote "tiwai"]
fetch = +refs/heads/*:+refs/remotes/tiwai/*

where the '+' means to force fetching rewound branches instead of rejecting them (this is safe, since you are just overwriting tracking branches, not your local work).

Not here...

rene@7ixe4:~/src/linux/7ixe4$ git remote add tmp  
git://git.alsa-project.org/alsa-kernel.git
rene@7ixe4:~/src/linux/7ixe4$ tail -3 .git/config 

[remote "tmp"]
url = git://git.alsa-project.org/alsa-kernel.git
fetch = refs/heads/*:refs/remotes/tmp/*

rene@7ixe4:~/src/linux/7ixe4$ git --version
git version 1.5.5

Quoted 2 lines

rene@7ixe4:~/src/linux/7ixe4$ git --version
git version 1.5.5

Broken in 1.5.5 and 1.5.5.1, Jeff's fix went into 1.5.5.2. Bad luck ;-)