Subject: Re: bug#26066: 26.0.50; vc-git-status gives wrong result

From: Jonathan Ganc <[email-masked]>
Date: Wed, 22 Mar 2017 22:18:25 -0400

Hi,

Thanks for both responses.

>> 3. It would be nice to be able to show mutiple directory trees at 
>> once in Neotree, though this is not as important.
>
> If it's unable to show the non-current projects, how is the bug 
> triggered? default-directory would have to be outside of the project.

I'm not actually sure why it is causing me problems. I just tried using 
Neotree and encountered this problem. I didn't try anything special 
besides opening the window. I'm not sure how/why Neotree sets 
default-directory. I need to look into this.

> The problem might have gone unnoticed until now because file's status 
> is cached, and because it can only be apparent if several projects are 
> opened at the same time.
>
> While the problem is fairly obvious, a proper fix would most likely 
> touch other backends and commands, to the point that the 
> default-directory binding might have to be done inside vc-call-backend.

Yeah, I'm not really sure what the workflow should be; I'm just getting 
started with the vc functions in emacs. One issue, though, is that 
default-directory can only be set for functions that identify a 
filename, because we need to have a directory to set things to. For this 
reason, I don't know that one could generally set default-directory in 
vc-call-backend. It could make sense to set default-directory for 
vc-git--run-command-string (although to get vc-git-state to work, one 
would still need to set it for vc-git--empty-db-p).

It's worth nothing there seems to be inconsistency within vc-git. Some 
commands like vc-git-checkin, vc-git-next-revision, do set 
default-directory to the directory of the input file; other comands like 
vc-git-merge-branch seem to do the opposite and assume the root is 
already given by default-directory.

At the very least, the documentation for vc-git-state should note that 
default-directory needs to be set.

>
> There is a very simple workaround on the caller's side, though: bind 
> default-directory inside the Neotree code, to the respective project 
> root (or just the file's parent directory). That will be necessary 
> anyway for it to work in the released Emacs versions.
>

That may be the best answer. I am not so familiar with the Neotree code 
but it should be doable.

>> 2. I would like to be able to color directories as well as files. I 
>> don't know if that is something that would have a component in 
>> vc-git.el / vc-....el or would go entirely in some package (e.g. 
>> Neotree)
>
> This differs from one version control system to another, but Git 
> doesn't actually track directories. So the notion of "directory 
> status" is poorly defined. But see the previously mentioned 
> diff-hl-dired-mode.
>

You're right, in principle, but atom handles it by coloring directories 
based on if they have modified files within. I don't know if there is a 
"canonical" way to do this, although one idea would be to return a list 
of all file status in the directory, e.g. `(up-to-date modified ignored)`.

I started looking through diff-hl. It looks like it has a bunch of neat 
and useful features, though I admit I was a bit confused by the workflow.