bug#25607: 26.0.50; Ido does not work with tramp anymore

[Michael Albinus <michael.albinus@gmx.de>]

Dmitry Gutov <dgutov@yandex.ru> writes:

> Hi Michael,

Hi Dmitry,

>>> emacs -Q
>>> M-x ido-mode
>>> C-x C-f
>>> (Here ido completion works)
>>> Press backspace until you only have 'Find file: /' as prompt
>>> (Here completion still works)
>>> Type sudo:root@localhost:/
>>> (No completion)
>>>
>>> It used to ask sudo password and then completion was working.
>>
>> Likely, the changed behaviour comes from my commit
>> 6653bb45d3697c9372cc77773c49f52399740b51, fixing bug#24947.
>
> This commit may be going in the right direction, but do you know why
> even pressing TAB at the end of the offered scenario doesn't make
> Emacs ask for password?

It's a Tramp feature. When it is in `tramp-completion-mode'
(`non-essential' is an indicator for it), Tramp never opens a new
connection on its own. So it doesn't come to the point the remote end
asks for the password.

> The patch below makes Ido ask for password if I type TAB twice. But
> not after I do that once, which is puzzling. But maybe the function
> uses the completions already completed for the minibuffer, as a kind
> of optimization.

Well, but it still doesn't comlete "/sudo:" and alike.

I made a test with the emacs-25 branch; ido completion behaves
differently, when I use the Tramp libraries from the master branch
there. So looks like I must dig into Tramp for understanding the
differences.

Will do, but it might take time. I'm offline next days.

Best regards, Michael.