bug#49776: 28.0.50; Incorrect username completion results reported by `read-file-name-interal`

[Stefan Monnier via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

Lars Ingebrigtsen [2021-07-30 19:18:53] wrote:
> Daniel Mendler <mail@daniel-mendler.de> writes:
>> I am not looking at this as a user. I am investigating odd completion
>> results in my Vertico completion UI (on GNU ELPA), when completing file
>> names. If you type "~/etc/~man", you see these odd candidates
>> "/etc/~man", where "/etc/" is actually part of the shadowed path. So to
>> say it differently, I don't expect the shadowed path to take part in the
>> completion.
>
> Ah, right.
>
>> Maybe Stefan can chime in here and explain some of the background. I've
>> corresponded with him before a few times regarding how the completion
>> machinery works internally.
>
> Right.  Stefan, in short -- the thing we're wondering is whether this is
> correct: 
>
> (read-file-name-internal "~/foo/~man" nil t)
> => (#("/foo/~man/" 0 9 (face completions-common-part)))

Yup,. that's wrong.

> (read-file-name-internal "./foo/~man" nil t)
> => (#("man/" 0 3 (face completions-common-part)))

This one looks right.

> I'd kinda expect both to give the same result (i.e., the latter result)?

Agreed.


        Stefan