Junio C Hamano <gitster@xxxxxxxxx> writes:
> If you want to prevent a branch whose tip commit is on more than one
> branches from being rebased, I think something like this would suffice.
>
> #!/bin/sh
> LF='
> '
> in_branches=$(git branch -a --with "${2-HEAD}")
> case "$in_branches" in
> *"$LF"*)
> : this commit is on more than two branches
> exit 1
> ;;
> esac
> exit 0
>
> But I didn't test it.
Actually, the above cannot possibly be right. To decide whether to allow
rebasing of a branch or not, you need to also give it from which commit
the rebase will rewrite.
For example, suppose you have a branch "topic", that was forked from
"master" and built two commits, then another branch "side" was forked from
that, and you have three more commits on "topic" since then:
o "side"
/
A---B---C---D---E "topic"
/
---o---o---o---o "master"
Now, can I allow you to rebase "topic"? It depends. These should be
allowed:
git rebase B "topic"
git rebase C "topic"
git rebase D "topic"
but rebasing "topic" on top of "master", or anything that changes the fact
that "topic" contains commits A and B, should be prohibited, because it
will interfere with "side". For example,
git rebase A "topic"
would make this history:
B---o "side"
/
A---B'--C'--D'--E' "topic"
/
---o---o---o---o "master"
where B' and B are different commits.
So you need to check all the commits that will be affected by the rebase
to see if any of them is on a branch other than the one that is being
rebased. The set of commits that needs to be checked are:
git rev-list "$1..${2-HEAD}"
so a naive implementation that is based on brnach --with would probably
look like:
#!/bin/sh
: allow rebasing a detached HEAD
git symbolic-ref -q HEAD || exit 0
LF='
'
git rev-list "$1..${2-HEAD}" |
while read commit
do
case "$(git branch -a --with $commit)" in
*"$LF"*)
: this is on two or more branches
exit 1
;;
esac
done
--
To unsubscribe from this list: send the line "unsubscribe git" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
