Patch for fit-window-to-buffer

Patch for fit-window-to-buffer

[Justin Burkett]

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Hello,

I found a bug in the master and emacs-27 versions of fit-window-to-buffer.
Another window's data might be used to determine the new width. I'm
attaching a patch which I believe fixes the issue.

Justin

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From 02915c7c1b2b166d7dd0302bfac3f9ef880cbe59 Mon Sep 17 00:00:00 2001
From: Justin Burkett <justin@burkett.cc>
Date: Tue, 3 Mar 2020 22:01:29 -0500
Subject: [PATCH] * lisp/window.el (fit-window-to-buffer): Don't use wrong
 window data

---
 lisp/window.el | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lisp/window.el b/lisp/window.el
index bd825c09e1..61c32ac72f 100644
--- a/lisp/window.el
+++ b/lisp/window.el
@@ -9124,7 +9124,8 @@ fit-window-to-buffer
 	       ;; wider than its frame's pixel width, its height
 	       ;; remains unaltered.
 	       (width (+ (car (window-text-pixel-size
-			       window (window-start) (point-max)
+			       window (window-start window)
+                               (with-selected-window window (point-max))
 			       (frame-pixel-width)
 			       ;; Add one line-height to assure that
 			       ;; we're on the safe side.  This
-- 
2.21.1 (Apple Git-122.3)

Re: Patch for fit-window-to-buffer

[martin rudalics]

 > I found a bug in the master and emacs-27 versions of fit-window-to-buffer.
 > Another window's data might be used to determine the new width. I'm
 > attaching a patch which I believe fixes the issue.

Thanks for finding these blatant bugs.  The 'window-start' fix is OK.

The 'point-max' fix could be improved: Since 'window-text-pixel-size'
has to make the buffer shown in WINDOW current before processing its
text anyway, it would IMO be more efficient to wrap the entire
'window-text-pixel-size' call into a

(with-current-buffer (window-buffer window)

form and thus avoid selecting WINDOW while providing the right buffer
for 'window-text-pixel-size' right away.  Can you try that?

Finally, the (frame-pixel-width) argument looks fishy too - it should
probably be (frame-pixel-width (window-frame window)).  Can you verify
that as well?

Thanks, martin

Re: Patch for fit-window-to-buffer

[Justin Burkett]

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> The 'point-max' fix could be improved: Since 'window-text-pixel-size'
> has to make the buffer shown in WINDOW current before processing its
> text anyway, it would IMO be more efficient to wrap the entire
> 'window-text-pixel-size' call into a
>
> (with-current-buffer (window-buffer window)
>
> form and thus avoid selecting WINDOW while providing the right buffer
> for 'window-text-pixel-size' right away.  Can you try that?
>

I think the (point-max) is unnecessary here actually. According to the
docstring for window-text-pixel-size, nil should work here, no?

> Finally, the (frame-pixel-width) argument looks fishy too - it should
> probably be (frame-pixel-width (window-frame window)).  Can you verify
> that as well?

Yes, I made that change and the previous one in the patch attached. Both
work with my test case.

Thanks,
Justin

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From 604bde6aae93934f8e67d0cda70f0e4004b50cc8 Mon Sep 17 00:00:00 2001
From: Justin Burkett <justin@burkett.cc>
Date: Tue, 3 Mar 2020 22:01:29 -0500
Subject: [PATCH] * lisp/window.el (fit-window-to-buffer): Don't use wrong
 window data

---
 lisp/window.el | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lisp/window.el b/lisp/window.el
index bd825c09e1..039b133744 100644
--- a/lisp/window.el
+++ b/lisp/window.el
@@ -9124,8 +9124,8 @@ fit-window-to-buffer
 	       ;; wider than its frame's pixel width, its height
 	       ;; remains unaltered.
 	       (width (+ (car (window-text-pixel-size
-			       window (window-start) (point-max)
-			       (frame-pixel-width)
+			       window (window-start window) nil
+			       (frame-pixel-width (window-frame window))
 			       ;; Add one line-height to assure that
 			       ;; we're on the safe side.  This
 			       ;; overshoots when the first line below
-- 
2.21.1 (Apple Git-122.3)

Re: Patch for fit-window-to-buffer

[martin rudalics]

 > I think the (point-max) is unnecessary here actually. According to the
 > docstring for window-text-pixel-size, nil should work here, no?

It should work.

 >> Finally, the (frame-pixel-width) argument looks fishy too - it should
 >> probably be (frame-pixel-width (window-frame window)).  Can you verify
 >> that as well?
 >
 > Yes, I made that change and the previous one in the patch attached. Both
 > work with my test case.

Applied to Emacs-27 (without asking for Eli's permission because the
bugs were all to obvious).

Thanks, martin

Re: Patch for fit-window-to-buffer

[Eli Zaretskii]

> From: martin rudalics <rudalics@gmx.at>
> Date: Thu, 5 Mar 2020 10:12:57 +0100
> Cc: emacs-devel <emacs-devel@gnu.org>
> 
> Applied to Emacs-27 (without asking for Eli's permission because the
> bugs were all to obvious).

No need to ask questions whose answers are obvious.