Code

Prevent force-updating of the current branch
authorConrad Irwin <conrad.irwin@gmail.com>
Sat, 20 Aug 2011 21:49:48 +0000 (14:49 -0700)
committerJunio C Hamano <gitster@pobox.com>
Mon, 22 Aug 2011 23:00:36 +0000 (16:00 -0700)
commit55c4a673070f40f2ef12d0be269e95f1df6825a9
treef3167659326c1308f6dfe3600ec0b57200cef335
parent1be9d84b2ed18c2b2e2d6a459d2b6d48d5ab86e5
Prevent force-updating of the current branch

"git branch -M <foo> <current-branch>" allows updating the current branch
which HEAD points, without the necessary house-keeping that git reset
normally does to make this operation sensible. It also leaves the reflog
in a confusing state (you would be warned when trying to read it).

"git checkout -B <current branch> <foo>" is also partly vulnerable to this
bug; due to inconsistent pre-flight checks it would perform half of its
task and then abort just before rewriting the branch. Again this
manifested itself as the index file getting out-of-sync with HEAD.

"git branch -f" already guarded against this problem, and aborts with
a fatal error.

Update "git branch -M", "git checkout -B" and "git branch -f" to share the
same check before allowing a branch to be created. These prevent you from
updating the current branch.

We considered suggesting the use of "git reset" in the failure message
but concluded that it was not possible to discern what the user was
actually trying to do.

Signed-off-by: Conrad Irwin <conrad.irwin@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
branch.c
branch.h
builtin/branch.c
builtin/checkout.c
t/t2018-checkout-branch.sh
t/t3200-branch.sh