bug#59208: 29.0.50; tab-bar-auto-width plus display space cpu spin

bug#59208: 29.0.50; tab-bar-auto-width plus display space cpu spin

[Aaron Jensen]

My tab-bar-tab-name-format-function causes 100% cpu spin as of
ca3763af5c. Disabling tab-bar-auto-width fixes it.

To repro: emacs -Q -l repro.el

repro.el:

(defun aj/tab-bar-tab-name-format (tab i)
  (propertize
   (propertize " " 'display '(space :width (8)))
   'face (funcall tab-bar-tab-face-function tab)))

(setq tab-bar-tab-name-format-function #'aj/tab-bar-tab-name-format)

(tab-bar-mode)




In GNU Emacs 29.0.50 (build 1, aarch64-apple-darwin21.6.0, NS
 appkit-2113.60 Version 12.6 (Build 21G115)) of 2022-09-28 built on
 aaron-m1.local
Windowing system distributor 'Apple', version 10.3.2113
System Description:  macOS 12.6.1

Configured using:
 'configure --disable-dependency-tracking --disable-silent-rules
 --enable-locallisppath=/opt/homebrew/share/emacs/site-lisp
 --infodir=/opt/homebrew/Cellar/emacs-plus@29/29.0.50/share/info/emacs
 --prefix=/opt/homebrew/Cellar/emacs-plus@29/29.0.50 --with-xml2
 --with-gnutls --with-native-compilation --without-compress-install
 --without-dbus --without-imagemagick --with-modules --with-rsvg
 --with-ns --disable-ns-self-contained 'CFLAGS=-Os -w -pipe
 -mmacosx-version-min=12
 -isysroot/Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk
 -DFD_SETSIZE=10000 -DDARWIN_UNLIMITED_SELECT'
 'CPPFLAGS=-I/opt/homebrew/opt/zlib/include
 -I/opt/homebrew/opt/jpeg/include -I/opt/homebrew/opt/icu4c/include
 -I/opt/homebrew/opt/openssl@1.1/include
 -I/opt/homebrew/opt/readline/include -isystem/opt/homebrew/include
 -F/opt/homebrew/Frameworks
 -isysroot/Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk'
 'LDFLAGS=-L/opt/homebrew/opt/zlib/lib -L/opt/homebrew/opt/jpeg/lib
 -L/opt/homebrew/opt/icu4c/lib -L/opt/homebrew/opt/openssl@1.1/lib
 -L/opt/homebrew/opt/readline/lib -L/opt/homebrew/lib
 -F/opt/homebrew/Frameworks -Wl,-headerpad_max_install_names
 -isysroot/Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk''

bug#59208: 29.0.50; tab-bar-auto-width plus display space cpu spin

[Juri Linkov]

> My tab-bar-tab-name-format-function causes 100% cpu spin as of
> ca3763af5c. Disabling tab-bar-auto-width fixes it.
>
> To repro: emacs -Q -l repro.el
>
> repro.el:
>
> (defun aj/tab-bar-tab-name-format (tab i)
>   (propertize
>    (propertize " " 'display '(space :width (8)))
>    'face (funcall tab-bar-tab-face-function tab)))
>
> (setq tab-bar-tab-name-format-function #'aj/tab-bar-tab-name-format)
>
> (tab-bar-mode)

Thanks for the bug report.  Since with
  (propertize " " 'display '(space :width (8)))
the tab width can't grow more than 8 pixels,
a possible fix would be on every iteration
that adds more spaces to the tab name
to check if the tab width remains the same.

bug#59208: 29.0.50; tab-bar-auto-width plus display space cpu spin

[Aaron Jensen]

[-- Attachment #1: Type: text/plain, Size: 982 bytes --]

 Apologies for top posting, on my phone. I should note that my actual tab
function has text as well (the tab name) and then I add a space at the end.
The spaces are just visual padding.


Aaron

On Sat, Nov 12 2022 at 1:33 PM, Juri Linkov <juri@linkov.net> wrote:

> My tab-bar-tab-name-format-function causes 100% cpu spin as of ca3763af5c.
> Disabling tab-bar-auto-width fixes it.
>
> >
>
> To repro: emacs -Q -l repro.el
>
> >
>
> repro.el:
>
> >
>
> (defun aj/tab-bar-tab-name-format (tab i)
> (propertize
> (propertize " " 'display '(space :width (8)))
> 'face (funcall tab-bar-tab-face-function tab)))
>
> >
>
> (setq tab-bar-tab-name-format-function #'aj/tab-bar-tab-name-format)
>
> >
>
> (tab-bar-mode)
>
> Thanks for the bug report. Since with
> (propertize " " 'display '(space :width (8))) the tab width can't grow
> more than 8 pixels,
> a possible fix would be on every iteration
> that adds more spaces to the tab name
> to check if the tab width remains the same.
>

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bug#59208: 29.0.50; tab-bar-auto-width plus display space cpu spin

[Juri Linkov]

close 59208 29.0.50
thanks

> I should note that my actual tab function has text as well (the tab
> name) and then I add a space at the end.  The spaces are just visual
> padding.

I didn't try with text, I tried only with spaces as in your test case:

>         (defun aj/tab-bar-tab-name-format (tab i)
>         (propertize
>         (propertize " " 'display '(space :width (8)))
>         'face (funcall tab-bar-tab-face-function tab)))

But I believe that all cases should be fixed now
by the commit 443bd35e86.

bug#59208: 29.0.50; tab-bar-auto-width plus display space cpu spin

[Aaron Jensen]

On Sun, Nov 13, 2022 at 1:18 PM Juri Linkov <juri@linkov.net> wrote:
>
> close 59208 29.0.50
> thanks
>
> > I should note that my actual tab function has text as well (the tab
> > name) and then I add a space at the end.  The spaces are just visual
> > padding.
>
> I didn't try with text, I tried only with spaces as in your test case:
>
> >         (defun aj/tab-bar-tab-name-format (tab i)
> >         (propertize
> >         (propertize " " 'display '(space :width (8)))
> >         'face (funcall tab-bar-tab-face-function tab)))
>
> But I believe that all cases should be fixed now
> by the commit 443bd35e86.

Thanks, confirmed.

As an aside, auto-width doesn't work very well when using a
variable-pitch font for your tab bar. Specifically, for me it doesn't
take up the full width when I have enough tabs that would fill that
width.

Aaron

bug#59208: 29.0.50; tab-bar-auto-width plus display space cpu spin

[Juri Linkov]

>> But I believe that all cases should be fixed now
>> by the commit 443bd35e86.
>
> Thanks, confirmed.
>
> As an aside, auto-width doesn't work very well when using a
> variable-pitch font for your tab bar. Specifically, for me it doesn't
> take up the full width when I have enough tabs that would fill that
> width.

Sorry, I don't understand the problem.  It doesn't take up the full width
of the tab bar?  Does it fill the whole tab bar when you customize
tab-bar-auto-width-max to nil?

bug#59208: 29.0.50; tab-bar-auto-width plus display space cpu spin

[Aaron Jensen]

On Mon, Nov 14, 2022 at 2:54 AM Juri Linkov <juri@linkov.net> wrote:
>
> >> But I believe that all cases should be fixed now
> >> by the commit 443bd35e86.
> >
> > Thanks, confirmed.
> >
> > As an aside, auto-width doesn't work very well when using a
> > variable-pitch font for your tab bar. Specifically, for me it doesn't
> > take up the full width when I have enough tabs that would fill that
> > width.
>
> Sorry, I don't understand the problem.  It doesn't take up the full width
> of the tab bar?  Does it fill the whole tab bar when you customize
> tab-bar-auto-width-max to nil?

No, it does not. It's not computing the overall width of the window
correctly or something like that: https://share.cleanshot.com/otuZj4

bug#59208: 29.0.50; tab-bar-auto-width plus display space cpu spin

[Juri Linkov]

>> > As an aside, auto-width doesn't work very well when using a
>> > variable-pitch font for your tab bar. Specifically, for me it doesn't
>> > take up the full width when I have enough tabs that would fill that
>> > width.
>>
>> Sorry, I don't understand the problem.  It doesn't take up the full width
>> of the tab bar?  Does it fill the whole tab bar when you customize
>> tab-bar-auto-width-max to nil?
>
> No, it does not. It's not computing the overall width of the window
> correctly or something like that: https://share.cleanshot.com/otuZj4

Could you show the minimal tab function that reproduces the problem.
Is it more like this?

(defun aj/tab-bar-tab-name-format (tab i)
  (propertize
   (concat (alist-get 'name tab)
           (propertize " " 'display '(space :width (8))))
   'face (funcall tab-bar-tab-face-function tab)))

(setq tab-bar-tab-name-format-function #'aj/tab-bar-tab-name-format)

bug#59208: 29.0.50; tab-bar-auto-width plus display space cpu spin

[Aaron Jensen]

On Mon, Nov 14, 2022 at 12:38 PM Juri Linkov <juri@linkov.net> wrote:
>
> >> > As an aside, auto-width doesn't work very well when using a
> >> > variable-pitch font for your tab bar. Specifically, for me it doesn't
> >> > take up the full width when I have enough tabs that would fill that
> >> > width.
> >>
> >> Sorry, I don't understand the problem.  It doesn't take up the full width
> >> of the tab bar?  Does it fill the whole tab bar when you customize
> >> tab-bar-auto-width-max to nil?
> >
> > No, it does not. It's not computing the overall width of the window
> > correctly or something like that: https://share.cleanshot.com/otuZj4
>
> Could you show the minimal tab function that reproduces the problem.
> Is it more like this?
>
> (defun aj/tab-bar-tab-name-format (tab i)
>   (propertize
>    (concat (alist-get 'name tab)
>            (propertize " " 'display '(space :width (8))))
>    'face (funcall tab-bar-tab-face-function tab)))
>
> (setq tab-bar-tab-name-format-function #'aj/tab-bar-tab-name-format)

It happens with the default. The issue is the variable pitch font.