Re: When does git check for branch-X being uptodate with origin/branch-X?

From: Jeff King <peff@peff.net>
Date: Mar 21, 2016, 20:28 UTC
Message-ID: <20160321202810.GD32071@sigill.intra.peff.net>
In-Reply-To: <CA+39Oz4izkhtxbUH8cQoD5-DLKAtv9KnC9OkG_ZhFw6Ysg0+gw@mail.gmail.com>

On Mon, Mar 21, 2016 at 08:21:46PM +0000, Thomas Adam wrote:

Show 27 quoted lines

> Something I've seen a few times of late (although I doubt that's any
> indication that the code has changed in Git) is the reporting of
> branch-X being uptodate with origin/branch-X when it isn't.
> 
> When does git check to see if branch-X has a remote tracking branch
> and that it has changes on it?  Only, the output below is misleading:
> 
> % git checkout master
> Switched to branch 'master'
> Your branch is up-to-date with 'fvwmorg/master'.
> 
> [fvwm-cvs-to-git/docs]{10345}[0][master] % git pull
> remote: Counting objects: 26, done.
> remote: Compressing objects: 100% (12/12), done.
> remote: Total 26 (delta 18), reused 22 (delta 14), pack-reused 0
> Unpacking objects: 100% (26/26), done.
> From github.com:fvwmorg/fvwm
>    c029868..36cc898  master     -> fvwmorg/master
>    4f0c7ec..36cc898  ta/git-docs -> fvwmorg/ta/git-docs
> Updating c029868..36cc898
> Fast-forward
> [...]
> 
> Clearly, it's obvious that "Your branch is up-to-date with
> 'fvwmorg/master'." is misleading.  Note that in this case, there's no
> passwords or other hindrances to Git being able to work out that a
> branch is behind another.

The message from checking is looking only at your local refs/remotes/fvwmorg/master branch, which is essentially a cache of what is in the actual remote repository.

We never contact other repositories unless explicitly asked to by fetch, pull, push, etc. If you want to have the most up-to-date value without merging, you can just "git fetch" to update the tracking branches.

-Peff