Re: Stop frames stealing eachothers' minibuffers!

[Alan Mackenzie <acm@muc.de>]

Hello, Martin and Eli.

On Sat, Nov 14, 2020 at 20:24:32 +0100, martin rudalics wrote:
>  > Arguably, Fset_window_configuration selecting the pertinent frame is a
>  > bug in the specification of that function - one should be able to restore
>  > a frame's configuration without selecting the frame as well.  However,
>  > backwards compatibility, and all that....

> You'd first have to get rid of the two select_window calls which select
> the frame whose configuration gets restored.  Fset_window_configuration
> is a PITA.

Actually, I just put in a do_switch_frame back to the frame which was
the selected one at the beginning of the function.

But I agree with you about Fset_window_configuration.

Anyway, here's a provisional patch.  I realise that my amendment to the
doc string of Fset_window_configuration is poor, but it's too late to
fix it tonight.  ;-(  I also realise I'll need to amend the Elisp manual
and NEWS, but also not tonight.

The patch seems to fix the bug (the one about a "recursive" C-x b
displaying its error message in the wrong frame).

Comments are welcome.



diff --git a/src/keyboard.c b/src/keyboard.c
index 49a0a8bd23..1579c007ec 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -2122,7 +2122,7 @@ read_char_help_form_unwind (void)
   Lisp_Object window_config = XCAR (help_form_saved_window_configs);
   help_form_saved_window_configs = XCDR (help_form_saved_window_configs);
   if (!NILP (window_config))
-    Fset_window_configuration (window_config);
+    Fset_window_configuration (window_config, Qnil);
 }
 
 #define STOP_POLLING					\
diff --git a/src/minibuf.c b/src/minibuf.c
index 8c19559b08..acb633c583 100644
--- a/src/minibuf.c
+++ b/src/minibuf.c
@@ -501,14 +501,15 @@ read_minibuf (Lisp_Object map, Lisp_Object initial, Lisp_Object prompt,
   record_unwind_protect_void (choose_minibuf_frame);
 
   record_unwind_protect (restore_window_configuration,
-			 Fcurrent_window_configuration (Qnil));
+                         Fcons (Qt, Fcurrent_window_configuration (Qnil)));
 
   /* If the minibuffer window is on a different frame, save that
      frame's configuration too.  */
   mini_frame = WINDOW_FRAME (XWINDOW (minibuf_window));
   if (!EQ (mini_frame, selected_frame))
     record_unwind_protect (restore_window_configuration,
-			   Fcurrent_window_configuration (mini_frame));
+			   Fcons (Qt,
+                                  Fcurrent_window_configuration (mini_frame)));
 
   /* If the minibuffer is on an iconified or invisible frame,
      make it visible now.  */
diff --git a/src/window.c b/src/window.c
index a6de34f3db..3187720f89 100644
--- a/src/window.c
+++ b/src/window.c
@@ -6824,19 +6826,24 @@ DEFUN ("window-configuration-frame", Fwindow_configuration_frame, Swindow_config
 }
 
 DEFUN ("set-window-configuration", Fset_window_configuration,
-       Sset_window_configuration, 1, 1, 0,
+       Sset_window_configuration, 1, 2, 0,
        doc: /* Set the configuration of windows and buffers as specified by CONFIGURATION.
 CONFIGURATION must be a value previously returned
 by `current-window-configuration' (which see).
+
+Normally, the original frame of CONFIGURATION gets selected, but if DONT-SET-FRAME is
+non-nil, the frame selected at the beginning of this function remains selected.
+
 If CONFIGURATION was made from a frame that is now deleted,
 only frame-independent values can be restored.  In this case,
 the return value is nil.  Otherwise the value is t.  */)
-  (Lisp_Object configuration)
+  (Lisp_Object configuration, Lisp_Object dont_set_frame)
 {
   register struct save_window_data *data;
   struct Lisp_Vector *saved_windows;
   Lisp_Object new_current_buffer;
   Lisp_Object frame;
+  Lisp_Object old_frame = selected_frame;
   struct frame *f;
   ptrdiff_t old_point = -1;
   USE_SAFE_ALLOCA;
@@ -7153,7 +7160,10 @@ the return value is nil.  Otherwise the value is t.  */)
 	 select_window above totally superfluous; it still sets f's
 	 selected window.  */
       if (FRAME_LIVE_P (XFRAME (data->selected_frame)))
-	do_switch_frame (data->selected_frame, 0, 0, Qnil);
+	do_switch_frame (NILP (dont_set_frame)
+                         ? data->selected_frame
+                         : old_frame
+                         , 0, 0, Qnil);
     }
 
   FRAME_WINDOW_CHANGE (f) = true;
@@ -7191,7 +7201,10 @@ the return value is nil.  Otherwise the value is t.  */)
 void
 restore_window_configuration (Lisp_Object configuration)
 {
-  Fset_window_configuration (configuration);
+  if (CONSP (configuration))
+    Fset_window_configuration (XCDR (configuration), XCAR (configuration));
+  else
+    Fset_window_configuration (configuration, Qnil);
 }
 
 


> martin

-- 
Alan Mackenzie (Nuremberg, Germany).