Re: [PATCH 1/2] checkout,clone: check return value of create_symref

On 01/11/2016 04:49 PM, Jeff King wrote:

It's unlikely that we would fail to create or update a
symbolic ref (especially HEAD), but if we do, we should
notice and complain. Note that there's no need to give more
details in our error message; create_symref will already
have done so.

While we're here, let's also fix a minor memory leak in
clone.

Signed-off-by: Jeff King <redacted>

LGTM.

---
This patch could go to maint. I don't know if it's worth the trouble. I
was unable to figure out a way to trigger this reliably (hence no
tests). The two ways I considered were:

  - "chmod -w .git", but it results in a die() already

  - the bug I'm fixing in 2/2; but we don't want to rely on that in our
    test suite, since I'm about to fix it. :-/

A locking conflict is an easy way to trigger this error:

$ git --version
git version 2.7.0.rc2.31.g396da8f
$ git branch foo
$ touch .git/HEAD.lock
$ git checkout foo
error: Unable to create '/home/mhagger/tmp/brokhead/.git/HEAD.lock':
File exists.

If no other git process is currently running, this probably means a
git process crashed in this repository earlier. Make sure no other git
process is running and remove the file manually to continue.
Switched to branch 'foo'
$ echo $?
0

After this patch, the above "checkout" command fails with retcode=128.

Michael

-- 
Michael Haggerty
mhagger@alum.mit.edu