bug#67226: 30.0.50; Regression in previous-complete-history-element with empty input

bug#67226: 30.0.50; Regression in previous-complete-history-element with empty input

[Ergus via Bug reports for GNU Emacs, the Swiss army knife of text editors]

When using previous-complete-history-element like:

The behavior changed sometime recently, because

When the input is empty it shows:

 [No earlier matching history item]

Previously it behaved like `previous-history-element` in that case.

Is this intended due to some recent change or is it an issue?

```
Emacs -Q

M-: (keymap-set minibuffer-local-map "<up>" #'previous-complete-history-element)

M-x some-command1
M-x some-command2
M-x some-command3
M-x <up-arrow>
```





In GNU Emacs 30.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version
 3.24.38, cairo version 1.18.0) of 2023-11-12 built on Ergus
Repository revision: 0bfe764fe5691a76c1c12557b6b0b5bfa9cbc012
Repository branch: master
System Description: Arch Linux

Configured using:
 'configure --prefix=/home/ergo/.local/ --with-mailutils --with-json
 --with-x-toolkit=gtk3 --with-xft --with-modules --with-cairo
 --with-harfbuzz --with-native-compilation
 '--program-transform-name=s/^ctags$/ctags.emacs/''

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Load-path shadows:
/mnt/casa/gits/emacs_clones/gtags-mode/gtags-mode hides /home/ergo/.config/emacs/elpa/gtags-mode-1.0/gtags-mode
/home/ergo/.config/emacs/elpa/transient-20231103.2312/transient hides /home/ergo/.local/share/emacs/30.0.50/lisp/transient

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bug#67226: 30.0.50; Regression in previous-complete-history-element with empty input

[Juri Linkov]

> When using previous-complete-history-element like:
>
> The behavior changed sometime recently, because
>
> When the input is empty it shows:
>
>  [No earlier matching history item]
>
> Previously it behaved like `previous-history-element` in that case.
>
> Is this intended due to some recent change or is it an issue?
>
> ```
> Emacs -Q
>
> M-: (keymap-set minibuffer-local-map "<up>" #'previous-complete-history-element)
>
> M-x some-command1
> M-x some-command2
> M-x some-command3
> M-x <up-arrow>
> ```

The regression is on this line in `previous-matching-history-element`:

  (string-match (concat ".*\\(" regexp "\\)") match-string)

In GNU Emacs 29.1.90

  (string-match ".*\\(^\\)" "foo")
  => 0

But in GNU Emacs 30.0.50

  (string-match ".*\\(^\\)" "foo")
  => nil

Cc:ing Stefan.

bug#67226: 30.0.50; Regression in previous-complete-history-element with empty input

[Eli Zaretskii]

Stefan, any comments?

> Cc: Stefan Monnier <monnier@iro.umontreal.ca>, 67226@debbugs.gnu.org
> From: Juri Linkov <juri@linkov.net>
> Date: Thu, 16 Nov 2023 19:32:13 +0200
> 
> > When using previous-complete-history-element like:
> >
> > The behavior changed sometime recently, because
> >
> > When the input is empty it shows:
> >
> >  [No earlier matching history item]
> >
> > Previously it behaved like `previous-history-element` in that case.
> >
> > Is this intended due to some recent change or is it an issue?
> >
> > ```
> > Emacs -Q
> >
> > M-: (keymap-set minibuffer-local-map "<up>" #'previous-complete-history-element)
> >
> > M-x some-command1
> > M-x some-command2
> > M-x some-command3
> > M-x <up-arrow>
> > ```
> 
> The regression is on this line in `previous-matching-history-element`:
> 
>   (string-match (concat ".*\\(" regexp "\\)") match-string)
> 
> In GNU Emacs 29.1.90
> 
>   (string-match ".*\\(^\\)" "foo")
>   => 0
> 
> But in GNU Emacs 30.0.50
> 
>   (string-match ".*\\(^\\)" "foo")
>   => nil
> 
> Cc:ing Stefan.
> 
> 
> 
> 

bug#67226: 30.0.50; Regression in previous-complete-history-element with empty input

[Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors]

> Stefan, any comments?

Looks like a bug in my new regexp code.  Hmm...


        Stefan

bug#67226: 30.0.50; Regression in previous-complete-history-element with empty input

[Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors]

> The regression is on this line in `previous-matching-history-element`:
>
>   (string-match (concat ".*\\(" regexp "\\)") match-string)
>
> In GNU Emacs 29.1.90
>
>   (string-match ".*\\(^\\)" "foo")
>   => 0
>
> But in GNU Emacs 30.0.50
>
>   (string-match ".*\\(^\\)" "foo")
>   => nil
>
> Cc:ing Stefan.

Thanks, I believe this is now fixed on `master`.


        Stefan

bug#67226: 30.0.50; Regression in previous-complete-history-element with empty input

[Juri Linkov]

close 67226 30.0.50
thanks

>> The regression is on this line in `previous-matching-history-element`:
>>
>>   (string-match (concat ".*\\(" regexp "\\)") match-string)
>>
>> In GNU Emacs 29.1.90
>>
>>   (string-match ".*\\(^\\)" "foo")
>>   => 0
>>
>> But in GNU Emacs 30.0.50
>>
>>   (string-match ".*\\(^\\)" "foo")
>>   => nil
>>
>> Cc:ing Stefan.
>
> Thanks, I believe this is now fixed on `master`.

I confirm it's fixed, so closing now.