bug#52881: setting tab-line-separator to any value breaks clicking tabs with mouse

bug#52881: setting tab-line-separator to any value breaks clicking tabs with mouse

[Ben Sferrazza]

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This is using Emacs 27.2 on a CentOS8 machine at work. I use Emacs exclusively with -nw in a terminal with mouse support enabled.

Using something like

(setq tab-line-separator " | ")

breaks the ability to click on a tab to select it. Leaving it at the default value avoids the bug.

Thanks,
Ben

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bug#52881: setting tab-line-separator to any value breaks clicking tabs with mouse

[Juri Linkov]

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> This is using Emacs 27.2 on a CentOS8 machine at work. I use Emacs
> exclusively with -nw in a terminal with mouse support enabled.
>
> Using something like
>
> (setq tab-line-separator " | ")
>
> breaks the ability to click on a tab to select it. Leaving it at the
> default value avoids the bug.

Sorry, tab-line had hard-coded assumption on separators
no longer than 1 character wide.

Eli, is it ok to push this patch to the release branch
to support longer separators:


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diff --git a/lisp/tab-line.el b/lisp/tab-line.el
index af0647acf7..5eae2eb7c4 100644
--- a/lisp/tab-line.el
+++ b/lisp/tab-line.el
@@ -636,7 +638,10 @@ tab-line-auto-hscroll
                  (not (integerp hscroll)))
         (let ((selected (seq-position strings 'selected
                                       (lambda (str prop)
-                                        (get-pos-property 1 prop str)))))
+                                        (or (get-pos-property 0 prop str)
+                                            (and (next-single-property-change 0 prop str)
+                                                 (get-pos-property (next-single-property-change 0 prop str)
+                                                                   prop str)))))))
           (cond
            ((null selected)
             ;; Do nothing if no tab is selected
@@ -656,7 +661,11 @@ tab-line-auto-hscroll
                        (new-hscroll (when tab-prop
                                       (seq-position strings tab-prop
                                                     (lambda (str tab)
-                                                      (eq (get-pos-property 1 'tab str) tab))))))
+                                                      (eq (or (get-pos-property 0 'tab str)
+                                                              (and (next-single-property-change 0 'tab str)
+                                                                   (get-pos-property (next-single-property-change 0 'tab str)
+                                                                                     'tab str)))
+                                                          tab))))))
                   (when new-hscroll
                     (setq hscroll (float new-hscroll))
                     (set-window-parameter nil 'tab-line-hscroll hscroll)))
@@ -683,7 +692,11 @@ tab-line-auto-hscroll
                        (new-hscroll (when tab-prop
                                       (seq-position strings tab-prop
                                                     (lambda (str tab)
-                                                      (eq (get-pos-property 1 'tab str) tab))))))
+                                                      (eq (or (get-pos-property 0 'tab str)
+                                                              (and (next-single-property-change 0 'tab str)
+                                                                   (get-pos-property (next-single-property-change 0 'tab str)
+                                                                                     'tab str)))
+                                                          tab))))))
                   (when new-hscroll
                     (setq hscroll (float new-hscroll))
                     (set-window-parameter nil 'tab-line-hscroll hscroll)))))))))
@@ -742,7 +755,10 @@ tab-line-select-tab
 using the `previous-buffer' command."
   (interactive "e")
   (let* ((posnp (event-start event))
-         (tab (get-pos-property 1 'tab (car (posn-string posnp))))
+         (tab (or (get-pos-property 0 'tab (car (posn-string posnp)))
+                  (and (next-single-property-change 0 'tab (car (posn-string posnp)))
+                       (get-pos-property (next-single-property-change 0 'tab (car (posn-string posnp)))
+                                         'tab (car (posn-string posnp))))))
          (buffer (if (bufferp tab) tab (cdr (assq 'buffer tab)))))
     (if buffer
         (tab-line-select-tab-buffer buffer (posn-window posnp))
@@ -858,7 +874,10 @@ tab-line-close-tab
   (interactive (list last-nonmenu-event))
   (let* ((posnp (and (listp event) (event-start event)))
          (window (and posnp (posn-window posnp)))
-         (tab (get-pos-property 1 'tab (car (posn-string posnp))))
+         (tab (or (get-pos-property 0 'tab (car (posn-string posnp)))
+                  (and (next-single-property-change 0 'tab (car (posn-string posnp)))
+                       (get-pos-property (next-single-property-change 0 'tab (car (posn-string posnp)))
+                                         'tab (car (posn-string posnp))))))
          (buffer (if (bufferp tab) tab (cdr (assq 'buffer tab))))
          (close-function (unless (bufferp tab) (cdr (assq 'close tab)))))
     (with-selected-window (or window (selected-window))

bug#52881: setting tab-line-separator to any value breaks clicking tabs with mouse

[Eli Zaretskii]

> From: Juri Linkov <juri@linkov.net>
> Date: Thu, 30 Dec 2021 10:05:24 +0200
> Cc: 52881@debbugs.gnu.org
> 
> > This is using Emacs 27.2 on a CentOS8 machine at work. I use Emacs
> > exclusively with -nw in a terminal with mouse support enabled.
> >
> > Using something like
> >
> > (setq tab-line-separator " | ")
> >
> > breaks the ability to click on a tab to select it. Leaving it at the
> > default value avoids the bug.
> 
> Sorry, tab-line had hard-coded assumption on separators
> no longer than 1 character wide.
> 
> Eli, is it ok to push this patch to the release branch
> to support longer separators:

Yes, but can you make it a bit cleaner?  Like having a single function
to do that, and also not calling next-single-property-change twice an
a row?

Thanks.

bug#52881: setting tab-line-separator to any value breaks clicking tabs with mouse

[Juri Linkov]

>> Eli, is it ok to push this patch to the release branch
>> to support longer separators:
>
> Yes, but can you make it a bit cleaner?  Like having a single function
> to do that, and also not calling next-single-property-change twice an
> a row?

I could optimize this, but I wonder why there is no simple function
to find a text property and its first value in the string?

bug#52881: setting tab-line-separator to any value breaks clicking tabs with mouse

[Eli Zaretskii]

> From: Juri Linkov <juri@linkov.net>
> Cc: ben.sferrazza@aeonsemi.com,  52881@debbugs.gnu.org
> Date: Thu, 30 Dec 2021 18:08:12 +0200
> 
> >> Eli, is it ok to push this patch to the release branch
> >> to support longer separators:
> >
> > Yes, but can you make it a bit cleaner?  Like having a single function
> > to do that, and also not calling next-single-property-change twice an
> > a row?
> 
> I could optimize this, but I wonder why there is no simple function
> to find a text property and its first value in the string?

I don't know.  We could add something like that, but that would not be
for the release branch.

bug#52881: setting tab-line-separator to any value breaks clicking tabs with mouse

[Juri Linkov]

close 52881 28.0.90
quit

>> >> Eli, is it ok to push this patch to the release branch
>> >> to support longer separators:
>> >
>> > Yes, but can you make it a bit cleaner?  Like having a single function
>> > to do that, and also not calling next-single-property-change twice an
>> > a row?
>> 
>> I could optimize this, but I wonder why there is no simple function
>> to find a text property and its first value in the string?
>
> I don't know.  We could add something like that, but that would not be
> for the release branch.

Now fixed in Emacs 28 with an internal function.

bug#52881: setting tab-line-separator to any value breaks clicking tabs with mouse

[Juri Linkov]

>>> >> Eli, is it ok to push this patch to the release branch
>>> >> to support longer separators:
>>> >
>>> > Yes, but can you make it a bit cleaner?  Like having a single function
>>> > to do that, and also not calling next-single-property-change twice an
>>> > a row?
>>>
>>> I could optimize this, but I wonder why there is no simple function
>>> to find a text property and its first value in the string?
>>
>> I don't know.  We could add something like that, but that would not be
>> for the release branch.
>
> Now fixed in Emacs 28 with an internal function.

Oh no, 'get-text-property' can't replace 'get-pos-property'
because it fails after 'previous-single-property-change':

  (progn
    (insert (concat "(" (propertize "1" 'tab 1) ")"))
    (let ((pos (previous-single-property-change (point) 'tab)))
      (cons (get-text-property pos 'tab)
            (get-pos-property pos 'tab))))

in *scratch* it returns (nil . 1).  So now the recent fix was fixed on emacs-28.