Subject: bug#11339: 24.1.50; read-{buffer,file-name}-completion-ignore-case fails on non-ascii

From: Stefan Kangas <[email-masked]>
Date: Fri, 01 Nov 2019 20:57:30 +0100

found 11339 27.0.50
thanks

Stephen Berman <[email-masked]> writes:

> -1. cd /tmp; touch bäh bÄh bla
> 0. emacs -Q
> 1. M-x customize-option RET read-buffer-completion-ignore-case RET.
>    Toggle to "on", set for the current session.
>    M-x customize-option RET read-file-name-completion-ignore-case RET.
>    Toggle to "on", set for the current session.
> 2. C-x C-f b TAB => *Completions* buffer contains, as expected: bla bÄh bäh.         
> 3. Visit files `bla', `bäh' and `bÄh', switch to buffer *scratch* and
>    repeat step 2, replacing `C-x C-f' with `C-x b' => same results.
> 4. C-x C-f bä TAB => Emacs completes the input to "bäh".               
> 5. TAB => Emacs incorrectly reports: "[Sole completion]".                 
> 6. C-x C-f bÄ TAB => Emacs completes the input to "bÄh".
> 7. TAB => Emacs incorrectly reports: "[Sole completion]".                 
> 8. Switch to buffer *scratch* and repeat step 4-7, replacing `C-x C-f'
>    with `C-x b' => same results.

I can reproduce this on current master using the simpler recipe:

0. emacs -Q
1. Evaluate (setq read-buffer-completion-ignore-case t)
2. C-x b bäh RET
3. C-x b bÄh RET
4. C-x b bä TAB TAB

Result: Completes to "bäh" on first TAB, and on second TAB [Sole
completion] is displayed in minibuffer.

Expected result: The "*Completion*" buffer is displayed.

Best regards,
Stefan Kangas