Subject: Re: How to pre-empt git pull merge error?

From: Thomas Rast <[email-masked]>
Date: Wed, 27 Nov 2013 20:06:59 +0100

Antoine Pelisse <[email-masked]> writes:

>>> On Wed, 27 Nov 2013 15:17:27 +0000
>>> Pete Forman <[email-masked]> wrote:
>>>
>>>> I am looking for a way of detecting up front whether a git pull or git
>>>> merge would fail. The sort of script I want to perform is to update a
>>>> server.
>>>>
>>>>     git fetch
>>>>     git okay
>>>>     stop server
>>>>     backup data
>>>>     git merge
>>>>     start server
>>>>
>> I don't know a simple way to do the pre-merge check without actually
>> doing the merge (other than patching git merge to add a --dry-run
>> option)
>
> Wouldn't that be a nice use-case for git-recursive-merge --index-only
> ($gmane/236753) ?

Possibly, but most of the use-cases for merge --dry-run are better
answered by the XY Problem question:

Can you step back and explain what the *underlying* goal is?

The above sounds a lot like a deployment script, and such scripts are
almost always better served by using an actual deployment tool, or
failing that, by using some form of checkout -f instead, to ensure that
they get whatever they are supposed to deploy.

(Using a merge to update is really terrible in the face of
non-fast-forward updates, especially when caused by rewriting history to
not include some commits.)

-- 
Thomas Rast
[email-masked]