autocompletion for 'git submodule' commands is broken

[Phil Hord]

Autocompletion in bash for subomdules works by completing simple file paths.

    $ git clone https://gerrit.googlesource.com/gerrit && cd gerrit
    $ git submodule init plugins/<TAB><TAB>
    commit-message-length-validator/ README reviewnotes/
    helloworld/ replication/

In zsh the completion tries to be clever and list the submodule names only. But it collects too much information and tries to complete submodule name + commit description. So, I expect this:

    % git submodule init plugins/<TAB>
    plugins/commit-message-length-validator plugins/reviewnotes
    plugins/replication

Instead I get this:

    % git submodule init plugins/<TAB>
    plugins/commit-message-length-validator\ \(v1.0-rc1-9-g545000b\) plugins/reviewnotes\ \(v1.0-rc1-8-ge984300\)
    plugins/replication\ \(v1.1-rc0-13-g4c3f4c9\)

If I use --noglobalrcs I get the bash-style simple pathname behavior:

    $ zsh --noglobalrcs
    % git submodule init plugins/<TAB>
    commit-message-length-validator/ README reviewnotes/
    helloworld/ replication/

I believe this bug is new in 14.04. I did not see it until I updated from 13.10 to 14.04.
I tried different versions of git (going back to 1.7.6) and the bug persisted. I did not try different versions of zsh.

$ lsb_release -rd
Description: Ubuntu 14.04 LTS
Release: 14.04

$ apt-cache policy zsh
zsh:
  Installed: 5.0.2-3ubuntu6
  Candidate: 5.0.2-3ubuntu6
  Version table:
 *** 5.0.2-3ubuntu6 0
        500 http://us.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages
        100 /var/lib/dpkg/status
$ apt-cache policy git
git:
  Installed: 1:1.9.1-1
  Candidate: 1:1.9.1-1
  Version table:
 *** 1:1.9.1-1 0
        500 http://us.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages
        100 /var/lib/dpkg/status

[Axel Beckert (xtaran)]

Can't reproduce this in Debian Unstable with zsh 5.0.5-2, hence this is likely fixed already and an update of Ubuntu's zsh package to 5.0.5-2 should fix it in Ubuntu, too.