Re: VC registered, but ignored

[Dmitry Gutov <dmitry@gutov.dev>]

On 01/09/2023 09:29, Eli Zaretskii wrote:
>> Date: Fri, 1 Sep 2023 04:03:43 +0300
>> Cc: emacs-devel@gnu.org
>> From: Dmitry Gutov <dmitry@gutov.dev>
>>
>> On 31/08/2023 18:24, Eli Zaretskii wrote:
>>> In a repository where *.txt files are ignored, I added to VC a file
>>> with the .txt extension, and was surprised to see the ':' indicator on
>>> the mode line although the file was up-to-date.  Moreover, the tooltip
>>> said the file was "locally modified".  That had me puzzled for a few
>>> minutes, until I saw the code in vc-hooks.el.
>>
>> You added it with 'C-x v v'?
> 
> No, from the shell prompt.  Would the result have been different if I
> did that with "C-x v v"?

Not 100% sure, but that's not important -- I have my answer.

>> We have a problem of sorts, or a break in the abstration, where
>> (vc-state buffer-file-name) would return nil instead of 'ignored.
> 
> Only if the file is not registered, right?  Most/all ignored files are
> not registered, they are generated files that we don't want to see in
> VC status displays.  Here I describe a situation that shouldn't
> happen, but did.

Apparently so.

> The value nil is the expected value for a file that is not registered.

It's more subtle that that, (vc-state buffer-file-name) would return nil 
in that case, but (vc-state buffer-file-name 'Git) would return 
'ignored. That hasn't affected any practical code so far (AFAIK), but 
something to keep in mind.

> In the case I described above, vc-state returns 'ignored, not nil.
> And the result was that, instead of seeing no VC information on the
> mode line, I saw a revision ID preceded by ':', as if the file was
> locally modified.

Ok.

>> So the problem is your annotation won't show up if you just open an
>> ignored file (for Git backend, at least). Is that okay for your purposes?
> 
> No, see above.

IIUC, you mean yes, the combined solution is okay for your purposes (if 
you open an unregistered ignored file, the annotation won't be there, 
and the whole mode-line item will be absent as well).

>> As for which character to use, maybe a period? Although that depends on
>> what you want to bring attention to: usually people are happy to keep
>> ignored files ignored.
> 
> Again, the file was NOT supposed to be ignored!  I deliberately added
> it to the repository, I just forgot that it had an extension of
> ignored files.  (The solution, once I relized the cause, was to exempt
> that one file from the otherwise ignored *.txt files.)

In that case, that indeed sounds like a situation that warrants 
additional attention, and "!" might be a good choice.

So I think we can push the patch, and just be on the lookout for cases 
where it misfires. Thank you.