Re: how to check remote git repo for updates without pull/fetch

From: David Aguilar <davvid@gmail.com>
Date: Dec 20, 2008, 23:41 UTC
Message-ID: <402731c90812201541r510170tbe1d56b7261e8146@mail.gmail.com>
In-Reply-To: <m3skoi21m3.fsf@lugabout.jhcloos.org>

2008/12/20 James Cloos <cloos@jhcloos.com>:

Show 15 quoted lines

>
> #!/bin/bash
> #
> # does this git repo need a pull?
> #
> l=$(git log|head -1|awk '{print $NF}')
> r=$(git ls-remote origin heads/master|awk '{print $1}')
> test "${r}" != "${l}"
>
>
> -JimC
> --
> James Cloos <cloos@jhcloos.com>         OpenPGP: 1024D/ED7DAEA6
>
>

Hello

Your script will report false positives if you run that in a branch where you've made local commits since git log's output will list a commit that's not on the remote side. Thus it'lll say 'you need to pull' when really what happened was that you committed locally and the sha1 test is no longer equal. This is one of the reasons why it's a good idea to always keep your local master clean.

There's two things you can do:

1. assume that you always keep your local 'master' branch clean.
That'll let you quickly compare your local master versus origin's
master:

#!/bin/sh remotemaster=$(git ls-remote origin heads/master | awk '{print $1}') localmaster=$(git rev-parse master) test "$remotemaster" = "$localmaster"

2. You might have a local branch that's not called master but is
tracking origin/master.  Or, your master branch might not be clean.
You can accomodate that workflow with:

#!/bin/sh remotemaster=$(git ls-remote origin heads/master | awk '{print $1}') branchpoint=$(git merge-base origin/master HEAD) test "$remotemaster" = "$branchpoint"

The difference is that we're checking against the branch point. If origin/master is beyond the branch point then chances are you need to pull.

---- off topic, but related ----

BTW one sound recommendation that I've heard on this list is that your topic branches should really be free of any unrelated changes. Pulling stuff in "just because" changes the branch. It's no longer just "topic" -- it's now "topic" + whatever they happened to push upstream. That has some implications in that it makes it harder to review what exactly went into the specific topic/feature since the branch's history now contains unrelated changes.

An advantage of keeping your topic branches clean is that you can run:

    git diff $(git merge-base HEAD origin/master)

in your topic branch and you'll see *only* the changes that went into that branch. If you get into the habit of pulling stuff in then you'll see your changes *and* stuff you've pulled in, which probably has nothing to do with the original topic/feature, etc. etc.

Anyways, this is an entirely different topic/conversation and might not apply to your specific circumstance but I figured I'd mention it nonetheless.

-- 
    David