Re: Patch proposal: display symbol source code in help buffers

[martin rudalics <rudalics@gmx.at>]

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 > I guess this feature has effect when display-buffer-alist is customized
 > to contain (window-height . nil)?  Then I confirm it works, thanks!

It's inherently flawed because it works only for 'display-buffer-alist'
- I couldn't justify that when documenting it.  I attached a patch that
addresses that (and fixes some other unrelated bugs).

martin

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diff --git a/doc/lispref/display.texi b/doc/lispref/display.texi
index 510efaf271..a5abfdb4c0 100644
--- a/doc/lispref/display.texi
+++ b/doc/lispref/display.texi
@@ -1334,6 +1334,11 @@ Temporary Displays
 (@pxref{Resizing Windows}) for resizing.  You can specify a different
 function by customizing the options @code{temp-buffer-max-height} and
 @code{temp-buffer-max-width} below.
+
+The effect of this option can be overridden by providing a suitable
+@code{window-height}, @code{window-width} or @code{window-size} action
+alist entry for @code{display-buffer} (@pxref{Buffer Display Action
+Alists}).
 @end defopt

 @defopt temp-buffer-max-height
diff --git a/doc/lispref/windows.texi b/doc/lispref/windows.texi
index 679744884a..63af4c5fd9 100644
--- a/doc/lispref/windows.texi
+++ b/doc/lispref/windows.texi
@@ -2924,9 +2924,9 @@ Buffer Display Action Alists
 selected, if the window chosen by @code{display-buffer} is displayed
 there.  Primarily affected by this are
 @code{display-buffer-use-some-frame} and
-@code{display-buffer-reuse-window}.
-@code{display-buffer-pop-up-frame} should be affected as well, but
-there is no guarantee that the window manager will comply.
+@code{display-buffer-reuse-window}.  Ideally,
+@code{display-buffer-pop-up-frame} should be affected as well, but there
+is no guarantee that the window manager will comply.

 @vindex window-parameters@r{, a buffer display action alist entry}
 @item window-parameters
@@ -2972,8 +2972,8 @@ Buffer Display Action Alists
 If the value specifies a function, that function is called with one
 argument---the chosen window.  The function is supposed to adjust the
 height of the window; its return value is ignored.  Suitable functions
-are @code{shrink-window-if-larger-than-buffer} and
-@code{fit-window-to-buffer}, see @ref{Resizing Windows}.
+are @code{fit-window-to-buffer} and
+@code{shrink-window-if-larger-than-buffer}, see @ref{Resizing Windows}.
 @end itemize

 By convention, the height of the chosen window is adjusted only if the
@@ -3007,11 +3007,31 @@ Buffer Display Action Alists
 width of the window; its return value is ignored.
 @end itemize

-By convention, the width of the chosen window is adjusted only if the
-window is part of a horizontal combination (@pxref{Windows and
-Frames}) to avoid changing the width of other, unrelated windows.
-Also, this entry should be processed under only certain conditions
-which are specified right below this list.
+@vindex window-size@r{, a buffer display action alist entry}
+@item window-size
+This entry is a combination of the two preceding ones and can be used to
+adjust the chosen window's height and width.  Since windows can be
+resized in one direction only without affecting other windows,
+@code{window-size} is effective only to set up the size of a window
+appearing alone on a frame.  The value can be one of the following:
+
+@itemize @bullet
+@item
+@code{nil} means to leave the size of the chosen window alone.
+
+@item
+A cons cell of two integers specifies the desired total width and height
+of the chosen window in lines and columns.  It's effect is to adjust the
+size of the frame accordingly.
+
+@item
+If the value specifies a function, that function is called with one
+argument---the chosen window.  The function is supposed to adjust the
+size of the window's frame; its return value is ignored.
+@end itemize
+
+This entry should be processed under only certain conditions which are
+specified right below this list.

 @vindex dedicated@r{, a buffer display action alist entry}
 @item dedicated
@@ -3112,6 +3132,14 @@ Buffer Display Action Alists
 buffer and never was used to show another buffer until it was reused
 by the current invocation of @code{display-buffer}.

+If no @code{window-height}, @code{window-width} or @code{window-size}
+entry was specified, the window may still be resized automatically when
+the buffer is temporary and @code{temp-buffer-resize-mode} has been
+enabled, @ref{Temporary Displays}.  In that case, the @sc{cdr} of a
+@code{window-height}, @code{window-height} or @code{window-size} entry
+can be used to inhibit or override the default behavior of
+@code{temp-buffer-resize-mode} for specific buffers or invocations of
+@code{display-buffer}.

 @node Choosing Window Options
 @subsection Additional Options for Displaying Buffers
diff --git a/lisp/help.el b/lisp/help.el
index 8f77167040..a5cdc9b786 100644
--- a/lisp/help.el
+++ b/lisp/help.el
@@ -1589,10 +1589,16 @@ temp-buffer-resize-mode
       (add-hook 'temp-buffer-show-hook 'resize-temp-buffer-window 'append)
     (remove-hook 'temp-buffer-show-hook 'resize-temp-buffer-window)))

+(defvar resize-temp-buffer-window-inhibit nil
+  "Non-nil means `resize-temp-buffer-window' should not resize.")
+
 (defun resize-temp-buffer-window (&optional window)
   "Resize WINDOW to fit its contents.
 WINDOW must be a live window and defaults to the selected one.
-Do not resize if WINDOW was not created by `display-buffer'.
+Do not resize if WINDOW was not created by `display-buffer'.  Do
+not resize either if a `window-height', `window-width' or
+`window-size' entry in `display-buffer-alist' prescribes some
+alternative resizing for WINDOW's buffer.

 If WINDOW is part of a vertical combination, restrain its new
 size by `temp-buffer-max-height' and do not resize if its minimum
@@ -1607,27 +1613,33 @@ resize-temp-buffer-window
 This function may call `preserve-window-size' to preserve the
 size of WINDOW."
   (setq window (window-normalize-window window t))
-  (let ((height (if (functionp temp-buffer-max-height)
+  (let* ((buffer (window-buffer window))
+         (height (if (functionp temp-buffer-max-height)
+		     (with-selected-window window
+		       (funcall temp-buffer-max-height buffer))
+		   temp-buffer-max-height))
+	 (width (if (functionp temp-buffer-max-width)
 		    (with-selected-window window
-		      (funcall temp-buffer-max-height (window-buffer)))
-		  temp-buffer-max-height))
-	(width (if (functionp temp-buffer-max-width)
-		   (with-selected-window window
-		     (funcall temp-buffer-max-width (window-buffer)))
-		 temp-buffer-max-width))
-	(quit-cadr (cadr (window-parameter window 'quit-restore))))
-    ;; Resize WINDOW iff it was made by `display-buffer'.
+		      (funcall temp-buffer-max-width buffer))
+		  temp-buffer-max-width))
+	 (quit-cadr (cadr (window-parameter window 'quit-restore))))
+    ;; Resize WINDOW only if it was made by `display-buffer'.
     (when (or (and (eq quit-cadr 'window)
 		   (or (and (window-combined-p window)
 			    (not (eq fit-window-to-buffer-horizontally
 				     'only))
-			    (pos-visible-in-window-p (point-min) window))
+			    (pos-visible-in-window-p
+                             (with-current-buffer buffer (point-min))
+                             window)
+                            (not resize-temp-buffer-window-inhibit))
 		       (and (window-combined-p window t)
-			    fit-window-to-buffer-horizontally)))
+			    fit-window-to-buffer-horizontally
+                            (not resize-temp-buffer-window-inhibit))))
 	      (and (eq quit-cadr 'frame)
                    fit-frame-to-buffer
-                   (eq window (frame-root-window window))))
-	(fit-window-to-buffer window height nil width nil t))))
+                   (eq window (frame-root-window window))
+                   (not resize-temp-buffer-window-inhibit)))
+      (fit-window-to-buffer window height nil width nil t))))

 ;;; Help windows.
 (defcustom help-window-select nil
diff --git a/lisp/window.el b/lisp/window.el
index b240b16f24..0eb26b0644 100644
--- a/lisp/window.el
+++ b/lisp/window.el
@@ -108,11 +108,15 @@ temp-buffer-window-setup
       ;; Return the buffer.
       buffer)))

+;; Defined in help.el.
+(defvar resize-temp-buffer-window-inhibit)
+
 (defun temp-buffer-window-show (buffer &optional action)
   "Show temporary buffer BUFFER in a window.
 Return the window showing BUFFER.  Pass ACTION as action argument
 to `display-buffer'."
-  (let (window frame)
+  (let ((resize-temp-buffer-window-inhibit nil)
+        window)
     (with-current-buffer buffer
       (set-buffer-modified-p nil)
       (setq buffer-read-only t)
@@ -130,9 +134,9 @@ temp-buffer-window-show
 		       t
 		     window-combination-limit)))
 	      (setq window (display-buffer buffer action)))
-	(setq frame (window-frame window))
-	(unless (eq frame (selected-frame))
-	  (raise-frame frame))
+        ;; We used to raise the window's frame here.  Do not do that
+        ;; since it would override an `inhibit-switch-frame' entry
+        ;; specified for the action alist used by `display-buffer'.
 	(setq minibuffer-scroll-window window)
 	(set-window-hscroll window 0)
 	(with-selected-window window
@@ -7245,11 +7249,14 @@ window--display-buffer
             (inhibit-modification-hooks t))
         (funcall (cdr (assq 'body-function alist)) window)))

-    (let ((quit-restore (window-parameter window 'quit-restore))
-	  (height (cdr (assq 'window-height alist)))
-	  (width (cdr (assq 'window-width alist)))
-	  (size (cdr (assq 'window-size alist)))
-	  (preserve-size (cdr (assq 'preserve-size alist))))
+    (let* ((quit-restore (window-parameter window 'quit-restore))
+	   (window-height (assq 'window-height alist))
+           (height (cdr window-height))
+	   (window-width (assq 'window-width alist))
+           (width (cdr window-width))
+           (window-size (assq 'window-size alist))
+           (size (cdr window-size))
+	   (preserve-size (cdr (assq 'preserve-size alist))))
       (cond
        ((or (eq type 'frame)
 	    (and (eq (car quit-restore) 'same)
@@ -7266,14 +7273,18 @@ window--display-buffer
 		(height (cdr size))
 		(frame (window-frame window)))
 	    (when (and (numberp width) (numberp height))
-	      (set-frame-height
-	       frame (+ (frame-height frame)
-			(- height (window-total-height window))))
-	      (set-frame-width
-	       frame (+ (frame-width frame)
-			(- width (window-total-width window)))))))
+              ;; Modifying the parameters of a newly created frame might
+              ;; not work everywhere, but then `temp-buffer-resize-mode'
+              ;; will certainly fail in a similar fashion.
+	      (modify-frame-parameters
+	       frame `((height . ,(+ (frame-height frame)
+			             (- height (window-total-height window))))
+                       (width . ,(+ (frame-width frame)
+			            (- width (window-total-width window))))))))
+          (setq resize-temp-buffer-window-inhibit t))
 	 ((functionp size)
-	  (ignore-errors (funcall size window)))))
+	  (ignore-errors (funcall size window))
+          (setq resize-temp-buffer-window-inhibit t))))
        ((or (eq type 'window)
 	    (and (eq (car quit-restore) 'same)
 		 (eq (nth 1 quit-restore) 'window)))
@@ -7293,9 +7304,11 @@ window--display-buffer
 		 (delta (- new-height (window-total-height window))))
 	    (when (and (window--resizable-p window delta nil 'safe)
 		       (window-combined-p window))
-	      (window-resize window delta nil 'safe))))
+	      (window-resize window delta nil 'safe)))
+          (setq resize-temp-buffer-window-inhibit 'vertical))
 	 ((functionp height)
-	  (ignore-errors (funcall height window))))
+	  (ignore-errors (funcall height window))
+          (setq resize-temp-buffer-window-inhibit 'vertical)))
 	;; Adjust width of window if asked for.
 	(cond
 	 ((not width))
@@ -7309,9 +7322,11 @@ window--display-buffer
 		 (delta (- new-width (window-total-width window))))
 	    (when (and (window--resizable-p window delta t 'safe)
 		       (window-combined-p window t))
-	      (window-resize window delta t 'safe))))
+	      (window-resize window delta t 'safe)))
+          (setq resize-temp-buffer-window-inhibit 'horizontal))
 	 ((functionp width)
-	  (ignore-errors (funcall width window))))
+	  (ignore-errors (funcall width window))
+          (setq resize-temp-buffer-window-inhibit 'horizontal)))
 	;; Preserve window size if asked for.
 	(when (consp preserve-size)
 	  (window-preserve-size window t (car preserve-size))
@@ -7556,9 +7571,11 @@ display-buffer
 Action alist entries are:
  `inhibit-same-window' -- A non-nil value prevents the same
     window from being used for display.
- `inhibit-switch-frame' -- A non-nil value prevents any frame
-    used for showing the buffer from being raised or selected.
- `reusable-frames' -- The value specifies the set of frames to
+`inhibit-switch-frame' -- A non-nil value prevents any frame used
+    for showing the buffer from being raised or selected.  Note
+    that a window manager may still raise a new frame and give it
+    focus, effectively overriding the value specified here.
+`reusable-frames' -- The value specifies the set of frames to
     search for a window that already displays the buffer.
     Possible values are nil (the selected frame), t (any live
     frame), visible (any visible frame), 0 (any visible or
@@ -7581,7 +7598,16 @@ display-buffer
     window) or a function to be called with one argument - the
     chosen window.  The function is supposed to adjust the width
     of the window; its return value is ignored.
- `preserve-size' -- The value should be either (t . nil) to
+
+ `window-size' -- This entry is only useful for windows appearing
+    alone on their frame and specifies the desired size of that
+    window either as a cons of integers (the total width and
+    height of the window on that frame), or a function to be
+    called with one argument - the chosen window.  The function
+    is supposed to adjust the size of the frame; its return value
+    is ignored.
+
+`preserve-size' -- The value should be either (t . nil) to
     preserve the width of the chosen window, (nil . t) to
     preserve its height or (t . t) to preserve its height and
     width in future changes of the window configuration.