bug#62592: Not creating new Tabs with small window

[martin rudalics]

>>>> 1. ~ $ emacs -Q
>>>> 2. Menu -> Options -> Show/Hide -> Tab Bar (gives Tab *scratch*)
>>>> 3. resize the Emacs window to a small one, but large enough to show some 
Tab labels
>>>> 3. 1x click on rightmost * in the Tab Bar to create a new Tab
>>>>
>>>> The bug: No new Tab will be created and the minibuf and*Messages*  show:
>>>>
>>>>     split-window: Window #<window 3 on*Messages*> too small for splitting
>>>
>>> Thanks for the bug report.  It is related to bug#62427 where
>>> we need to find a way to create a new window without using
>>> delete-windows and split-window.
>
> The patch below still fails when the height of the window is 1 line.
>
> Maybe Martin could help?
>
>> diff --git a/lisp/tab-bar.el b/lisp/tab-bar.el
>> index 35474e1c674..08f904ec73d 100644
>> --- a/lisp/tab-bar.el
>> +++ b/lisp/tab-bar.el
>> @@ -1586,7 +1595,8 @@ tab-bar-new-tab-to
>>                 (window-state-put (window-state-get))
>>               ;; Create a new window to get rid of old window parameters
>>               ;; (e.g. prev/next buffers) of old window.
>> -            (split-window) (delete-window))))
>> +            (let ((window-min-height 1)) (split-window))
>> +            (delete-window))))
>>
>>         (let ((buffer
>>                (if (and (functionp tab-bar-new-tab-choice)
>> diff --git a/lisp/window.el b/lisp/window.el
>> index aa7520f30fa..b2ee869940a 100644
>> --- a/lisp/window.el
>> +++ b/lisp/window.el
>> @@ -6391,7 +6396,8 @@ window-state-put
>>                        (selected-window)))
>>         (delete-other-windows-internal window root)
>>         ;; Create a new window to replace the existing one.
>> -      (setq window (prog1 (split-window window)
>> +      (setq window (prog1 (let ((window-min-height 1))
>> +                            (split-window window))
>>                        (delete-window window)))))
>>
>>     (set-window-dedicated-p window nil)

Split the window horizontally.  If a user can see the "+" button on the
tab bar, the containing frame should be wide enough to accommodate two
side-by-side windows.  Also it's always better to specify an explicit
SIZE argument to make a small window than to bind 'window-min-height'.

For Emacs 30 I'd recommend a new routine say 'clean-window' to make its
argument window pristine.  The way you do it now loses all overlays with
a window property in the window's buffer.

martin