bug#69993: Wrap window buffers while cycling

[martin rudalics]

>> But this would mean to change the ordering of elements on the tab line
>> whenever C-x b switches to a buffer already present on the tab line.
>
> Indeed, some hook is needed to restore the previous order after C-x b.
> Maybe 'window-buffer-change-functions' like you suggested.

And I think that in such case 'tab-line-switch-to-prev-tab' and
'switch-to-prev-buffer' should simply show different buffers.  That is,
'tab-line-switch-to-prev-tab' should _not_ use 'window-prev-buffers' to
get the buffer to switch to but simply use the buffer represented by the
tab visually preceding the current one on the tab line (stopping or
using the last one on the tab line if there is no preceding one).

> So keeping the stable order of window prev/next buffers after C-x b
> with a hook should be implemented in tab-line.el, not in window.el?

I don't know how you currently handle C-x <left>, C-x b or
'rename-buffer' or whether a buffer is modified on the tab line so I
can't tell whether you would need a hook for these.  But this issue is
IMHO not connected to whether getting the previous or next buffer should
wrap or be restricted to buffers previously shown in a window.

martin