bug#23966: 25.1.50; Frame resizing due to tool bar + Gnus

[martin rudalics]

> I did in fact see this lack of height change, but only once among the
> probably dozens of times I executed that code before filing the bug
> report; I was surprised but since I couldn't reproduce it, I thought it
> was a fluke.  All the other times, *Messages* showed this with emacs-25
> and master:
>
> Emacs started; frame height: 36
> Gnus started; frame height: 36
> Reading /home/steve/.newsrc.eld...
> Opening nnfolder server on archive...done
> No new newsgroups
> Checking new news...
> Reading active file via nnnil...done
> Reading active file from archive via nnfolder...done
> Reading active file via nndraft...done
> Checking new news...done
> Opening nndoc server on /home/steve/tool-bar-Gnus-frame-bug...done
> Tool bar disabled; frame height: 36
> Entered Summary buffer; frame height: 36
> Tool bar enabled; frame height: 36
> Other buffer; frame height: 38
> Back to Summary buffer; frame height: 38

‘frame-height’ is not necessarily a reliable reflection of what you see
on screen.

> With 24.5 the frame height numbers were 35 (five times) followed by 37
> (twice).
>
> When the tool bar was enabled in the Gnus Summary buffer, did you see it
> displayed as I describe in the OP: an empty 8-pixel high strip?

No.  I see a 35-pixel high strip.  With the following definitions
adapted from yours


(defun gtk-tool-bar-height (&optional frame)
  (let* ((frame (window-normalize-frame frame))
         (geometry (frame-geometry frame)))
    (cddr (assq 'tool-bar-size geometry))))

(let ((testfile "~/tool-bar-Gnus-frame-bug"))
  (with-temp-file testfile
    (insert "From nobody Wed Jul 13 13:55:54 CEST 2016
To: stephen.berman@gmx.net
Subject: bug test message
From: Stephen Berman <stephen.berman@gmx.net>
Date: Wed Jul 13 13:55:54 CEST 2016
Message-ID: <87twg9y16a.fsf@gmx.net>
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1.50 (gnu/linux)
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Lines: 1

test
"))
  (sit-for 0.1) (message "Emacs started; frame pixel height: %d  toolbar height: 
%d" (frame-pixel-height) (gtk-tool-bar-height))
  (require 'gnus)
  (let ((gnus-select-method '(nnnil "")))
    (sit-for 0.1) (message "Gnus started; frame pixel height: %d  toolbar height: 
%d" (frame-pixel-height) (gtk-tool-bar-height))
    (gnus-1)
    (gnus-group-make-doc-group testfile 'mbox)
    (tool-bar-mode -1)
    (sit-for 0.1) (message "Tool bar disabled; frame pixel height: %d  toolbar 
height: %d" (frame-pixel-height) (gtk-tool-bar-height))
    (sit-for 1)
    (gnus-group-select-group)
    (sit-for 0.1) (message "Entered Summary buffer; frame pixel height: %d  toolbar 
height: %d" (frame-pixel-height) (gtk-tool-bar-height))
    (sit-for 1)
    ;; Uncommenting these three lines and commenting out the same three
    ;; lines above results in a normal tool bar and no resizing.
    ;; (tool-bar-mode -1)
    ;; (sit-for 0.1) (message "Tool bar disabled; frame pixel height: %d  toolbar 
height: %d" (frame-pixel-height) (gtk-tool-bar-height))
    ;; (sit-for 1)
    (tool-bar-mode 1)
    (sit-for 0.1) (message "Tool bar enabled; frame pixel height: %d  toolbar 
height: %d" (frame-pixel-height) (gtk-tool-bar-height))
    (sit-for 3)
    (switch-to-buffer (other-buffer))
    (sit-for 0.1) (message "Other buffer; frame pixel height: %d  toolbar height: 
%d" (frame-pixel-height) (gtk-tool-bar-height))
    (sit-for 3)
    (switch-to-buffer (other-buffer))
    (sit-for 0.1) (message "Back to Summary buffer; frame pixel height: %d  toolbar 
height: %d" (frame-pixel-height) (gtk-tool-bar-height)))
    (sit-for 3)
  ;; Suppress further messages and clean up in order to repeat the test
  ;; simply by evaluating this sexp.
  (let (message-log-max)
    (gnus-summary-exit-no-update t)
    (goto-char (point-min))
    (gnus-group-kill-group)
    (let ((gnus-expert-user t))
      (gnus-group-quit))
    (delete-file testfile)
    (when (file-exists-p (gnus-dribble-file-name))
      (delete-file (gnus-dribble-file-name))))
  (sit-for 0.1) (message "Final; frame pixel height: %d  toolbar height: %d" 
(frame-pixel-height) (gtk-tool-bar-height))
  (sit-for 5)
  (switch-to-buffer "*Messages*"))


and `eval-buffer' of these in an emacs -Q of the release version I get


Emacs started; frame pixel height: 648  toolbar height: 44
Gnus started; frame pixel height: 648  toolbar height: 44
Opening nnfolder server on archive...done
No new newsgroups
Checking new news...
Reading active file via nnnil...done
Checking new news...done
No news is good news
Opening nndoc server on /home/martin/tool-bar-Gnus-frame-bug...done
Tool bar disabled; frame pixel height: 648  toolbar height: 0
Entered Summary buffer; frame pixel height: 648  toolbar height: 0
Tool bar enabled; frame pixel height: 657  toolbar height: 35
Other buffer; frame pixel height: 648  toolbar height: 44
Back to Summary buffer; frame pixel height: 657  toolbar height: 35
Final; frame pixel height: 648  toolbar height: 44
You can run the command ‘eval-buffer’ with M-x ev-b RET
Final; frame pixel height: 648  toolbar height: 44


So the "empty strips" here have a height of 35 pixels while the "normal"
toolbar has 44 pixels.  BTW, before getting the "Tool bar enabled"
message I briefly see some toolbar contents flashing and getting erased
immediately thereafter.

The entire frame height doesn't change here probably due to rounding and
size hints.  However, when I set `frame-resize-pixelwise' to t it
changes as follows:


Emacs started; frame pixel height: 648  toolbar height: 44
Gnus started; frame pixel height: 648  toolbar height: 44
Opening nnfolder server on archive...done
No new newsgroups
Checking new news...
Reading active file via nnnil...done
Checking new news...done
No news is good news
Opening nndoc server on /home/martin/tool-bar-Gnus-frame-bug...done
Tool bar disabled; frame pixel height: 648  toolbar height: 0
Entered Summary buffer; frame pixel height: 648  toolbar height: 0
Tool bar enabled; frame pixel height: 657  toolbar height: 35
Other buffer; frame pixel height: 657  toolbar height: 44
Back to Summary buffer; frame pixel height: 666  toolbar height: 35
Final; frame pixel height: 666  toolbar height: 44


So the pixel height of my frame has increased by 18 (2 times 9 pixels
from the difference between 44 and 35).

What do you get with my modifications?

martin