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bug#25380: 25.1; save-window-excursion problem in batch mode
From: |
martin rudalics |
Subject: |
bug#25380: 25.1; save-window-excursion problem in batch mode |
Date: |
Mon, 09 Jan 2017 17:19:29 +0100 |
>> IIUC the pixel comes from a menubar line which gets spuriously added.
>
> I believe you are right, see the backtrace below from the place which
> changes the value from 0 to 1 (it's not pixel units, btw, it's
> character units, AFAIU).
At the time the comparison fails in ‘compare-window-configurations’ it's
at !EQ (sw1->pixel_top, sw2->pixel_top) so it's off by one pixel. It
probably would fail later at !EQ (sw1->top_line, sw2->top_line) as well.
> More accurately, the initial current-window-configuration call happens
> so early that the basic geometry of the "windows" is not yet set, and
> in particular the menu bar is not yet computed and accounted for.
> This is indeed where Emacs 25 behaves differently from previous
> versions, and for a very good reason.
Does the basic geometry of the "windows" ever get set? Would I have to
create a frame manually for that?
>> If someone told me how to debug this, I might be able to tell more.
>
> I just ran Emacs under a debugger with a breakpoint in
> Fcurrent_window_configuration, then put a watchpoint on every top_line
> member of every window that got saved there, and waited for it to
> break.
That's obvious. But how do I find out where that menubar line gets set?
>> I have no idea how the frame seen by ‘current-window-configuration’
>> gets created in batch mode.
>
> It comes from temacs, AFAIR.
Hmm... the normal "F1" frame made by ‘make_initial_frame’. Still: Who
adds the menubar line? AFAIK neither NS nor GTK should.
> I'm not actually certain we should try fixing this, unless Martin can
> do that in some easy and safe way. The code involved in this is quite
> fragile, because Emacs creates its first frame without knowing
> anything about its geometry and the window-system. That code took a
> long time to get right on all systems; I'd hate to break it to cater
> to (IMO) much less important use cases. I'd rather people wouldn't
> count on anything related to "frames" and "windows" in the batch
> session, except that they exist. (They must exist because some
> functions will simply not work without a frame or a window.)
So far I can't do anything here - this is code I cannot debug. At the
time ‘compare-window-configurations’ gets called it's already much too
late :-(
> IOW, I think unit tests that must compare windows cannot be naïvely
> run in batch mode; you need to use tricks. For example:
>
> emacs -batch -eval "(progn (save-window-excursion (current-window-configuration))
(print (equal (save-window-excursion (current-window-configuration))
(current-window-configuration))))" => t
emacs -batch -eval "(progn (menu-bar-mode -1) (print (equal (save-window-excursion
(current-window-configuration)) (current-window-configuration))))"
works here too.
martin
- bug#25380: 25.1; save-window-excursion problem in batch mode, Philipp Stephani, 2017/01/06
- bug#25380: 25.1; save-window-excursion problem in batch mode, Glenn Morris, 2017/01/08
- bug#25380: 25.1; save-window-excursion problem in batch mode, Philipp Stephani, 2017/01/08
- bug#25380: 25.1; save-window-excursion problem in batch mode, martin rudalics, 2017/01/09
- bug#25380: 25.1; save-window-excursion problem in batch mode, Eli Zaretskii, 2017/01/09
- bug#25380: 25.1; save-window-excursion problem in batch mode,
martin rudalics <=
- bug#25380: 25.1; save-window-excursion problem in batch mode, Eli Zaretskii, 2017/01/09
- bug#25380: 25.1; save-window-excursion problem in batch mode, martin rudalics, 2017/01/10
- bug#25380: 25.1; save-window-excursion problem in batch mode, Eli Zaretskii, 2017/01/10
- bug#25380: 25.1; save-window-excursion problem in batch mode, martin rudalics, 2017/01/10
- bug#25380: 25.1; save-window-excursion problem in batch mode, Eli Zaretskii, 2017/01/10