bug#34622: Find file prompt should indicate sole completion by appending a blank

[Eli Zaretskii <eliz@gnu.org>]

tags 34622 notabug
thanks

> From: 積丹尼 Dan Jacobson
> 	<jidanni@jidanni.org>
> Date: Sat, 23 Feb 2019 05:40:07 +0800
> 
> With emacs, one can never be sure if the expansion
> Find file or URL: ~/bin/wwzz
> is the sole completion or not, without needing a second TAB press to get
> "[Sole completion]" shown.

Which command did that?  "C-x C-f" shows just the directory, so
there's no question of completions with the initial prompt.  The
situation you describe is thus not entirely clear.

But in general, this default behavior is on purpose (there are add-on
packages which give you immediate feedback about candidates).
File-name completion is special, by design.

> With bash, there is always a space added at end,
> "$ wc ~/bin/wwzz "
> so we know right away.

Bash is not an editor, so the considerations are different.  For
example, Bash doesn't need to consider the possibility that the user
would like to create a new file.

> I propose that emacs do the same:
> "Find file or URL: ~/bin/wwzz "
> and if they really want to enter a file with a " " at the end, well they
> could use C-q (quoted-insert).

Asking users to use C-q for whitespace embedded in a file name is a
non-starter.  We did the opposite change several Emacs versions ago.