From: Neal Kreitzinger <nkreitzinger@gmail.com>
Date: Fri, 02 Dec 2011 01:37:14 GMT
Subject: Re: Anyone have a commit hook for forbidding old branches from being merged in?
Message-ID: <4ED82BCA.5080909@gmail.com>
In-Reply-To: <CACBZZX4LyTaz=fU1vvgpeL904QFjJULCMVSP0uutcuxZT+-vWQ@mail.gmail.com>

On 12/1/2011 9:34 AM, Ævar Arnfjörð Bjarmason wrote:
> I work on a web application that due to underlying database schema
> changes etc only even compiles and runs for a given 2 week moving
> window.
>
> Thus if someone started a branch say 1 month ago, works on it one and
> off, and then merges it back into the mainline it becomes impossible
> to bisect that code if it has a problem. You either have to:
>
> * Revert the whole merge * Manually eyeball the code to see where
> the error might be * Brute-force manually bisect it by checking out
> only the files altered in those commits instead of the commit at a
> given data. Usually individual files are still compatible with the
> new code.
>
> But the whole reason this is a problem is because people don't rebase
> their branches before merging them in, unintentionally causing
> problems.
>
> So before I write a hook to do this, is there anything that
> implements a hook that:
>
> * Checks if you're pushing a merge commit * If so, is that merge
> based off and old version of $MAINBRANCH * Is the base of that
> branch more than N days old? * If so reject the push

It sounds like you're saying that people should rebase before merging to 
main.  That means their merge would be a fast-forward.  You could just 
reject anyone who has not done a current rebase.  Then you could use 
this technique from the pre-rebase.sample hook to enforce up-to-date 
rebases:

only_in_main='git rev-list "^$topic" main'
if test -z "$only-in-main"
then
     exit 0
else
     echo >&2 "error: please rebase on main before merging to main."
     exit 1
fi

v/r,
neal