Subject: bug#18788: 24.4; vc-git-working-revision vs mode-line gives error

From: Kevin Brubeck Unhammer <[email-masked]>
Date: Sat, 31 Jan 2015 14:09:45 +0100

I had this bug pop up again, after having been away for many months.

Dmitry Gutov <[email-masked]> writes:

> Kevin Brubeck Unhammer <[email-masked]> writes:
>
>> Whenever I try to save a git-registered file under emacs 24.4, I get
>>
>>     apply: Args out of range: #("Git@" 0 4 (help-echo "Locally added
>>     file under the Git version control system")), 0, 7
>
> I don't see that.
>
> Does that happen in a bare session (started with `emacs -Q')?
>
> Is there anything special about the repository, or its current local state?

The repo I've seen it with under ~ if that makes any difference (ie.
~/.git) – I can't remember if I've seen it other places.

>> The function vc-git-mode-line-string tries to get the revision using
>> vc-working-revision, which returns nil. Instead of checking the `rev'
>> variable for nil, it checks `detached', before calling substring. It
>> should probably do
>>
>>     (if (and detached rev)
>>         (substring …) 
>>      …)
>>
>> instead. I don't know why vc-working-revision returns nil though
>> (there's a whole lot of indirection to dig through there).
>
> Does (vc-git-working-revision buffer-file-name) return nil in the same buffer?

Yes.

I followed the calls a bit more this time and (vc-git--out-ok
"rev-parse" "HEAD") also gives nil, while (apply 'vc-git--call '(t nil)
"rev-parse" "HEAD") gives 128; this is the return value of

    (apply 'process-file "git" nil '(t nil) nil "rev-parse" '("HEAD"))

When I keep stderr by doing

    (apply 'process-file "git" nil '(t nil) nil "rev-parse" '("HEAD"))

I get

    fatal: Not a git repository: .git

Notably, this only happens with files that are in subdirectories of ~
(but still tracked by the ~ repo), not with files that are directly
inside ~. E.g. it happens with ~/org/gtd.org, but not with ~/.gitignore.

Also, I've never seen that exact error message from git before. I've
seen

    fatal: Not a git repository (or any of the parent directories): .git

and

    fatal: Not a git repository (or any parent up to mount point /tmp)

but only from this emacs bug have I seen the no-parenthesis

    fatal: Not a git repository: .git

When I restarted emacs to see if it had anything to do with my init.el,
the bug was gone again.

-- 
Kevin Brubeck Unhammer

GPG: 0x766AC60C