completion: checkout.* not being completed in zsh

[Pratyush Yadav <me@yadavpratyush.com>]

Hi everyone,

I just noticed that checkout.* is not being completed in zsh. I wanted 
to set checkout.defaultRemote, but zsh would not auto-complete it.

When I do:

$ git config check<Tab>

zsh does not auto-fill "checkout."

Doing the same in bash works, so the functionality is there, it just 
doesn't work in zsh.

Once I add checkout.defaultRemote to my git config, autocompletion 
starts working, but only for defaultRemote, even though checkout has two 
options: defaultRemote and optimizeNewBranch.

To make it clear, this is what happens once I have added 
checkout.defaultRemote to my config:

$ git config check<Tab>
$ git config checkout.  # Completes to "checkout.". Correct behaviour.
$ git config checkout.<Tab>

# Completes to defaultRemote, even though it should ask between 
# defaultRemote and optimizeNewBranch
$ git config checkout.defaultRemote

I tried looking at contrib/completion, and I can see that zsh completion 
works on top of bash completion, so I don't know why exactly it works 
for bash but not for zsh.

I am not too familiar with how these auto completion scripts work, so if 
someone can point me in the right direction, I'll see if I can figure 
out a fix and submit it here.

-- 
Regards,
Pratyush Yadav