Fix `delete-frame' behavior including Bug#26682

* src/frame.c (other_frames): Accept two arguments now.  Don't
care about minibuffer window.  Don't care about visibility when
called from delete_frame with FORCE true (Bug#26682).
(delete_frame, Fmake_frame_invisible): Adjust other_frames
calls.
* src/w32term.c (w32_read_socket): Don't add a move frame event
for an invisible frame.
* lisp/frame.el (handle-delete-frame): Don't kill Emacs when
attempting to delete a surrogate minibuffer frame.

3 files changed, 25 insertions, 30 deletions

diff --git a/lisp/frame.el b/lisp/frame.el
index cec262499d1..05db8cf6fd4 100644
--- a/lisp/frame.el
+++ b/lisp/frame.el
@@ -118,13 +118,10 @@ appended when the minibuffer frame is created."
   (let* ((frame (posn-window (event-start event))))
     (if (catch 'other-frame
           (dolist (frame-1 (frame-list))
-            ;; A valid "other" frame is visible, owns its minibuffer
-            ;; window, has its `delete-before' parameter unset and is
-            ;; not a child frame.
+            ;; A valid "other" frame is visible, has its `delete-before'
+            ;; parameter unset and is not a child frame.
             (when (and (not (eq frame-1 frame))
                        (frame-visible-p frame-1)
-                       (window-live-p (minibuffer-window frame-1))
-                       (eq (window-frame (minibuffer-window frame-1)) frame-1)
                        (not (frame-parent frame-1))
                        (not (frame-parameter frame-1 'delete-before)))
               (throw 'other-frame t))))
diff --git a/src/frame.c b/src/frame.c
index 681a245ee05..4d17a071dc7 100644
--- a/src/frame.c
+++ b/src/frame.c
@@ -1560,15 +1560,16 @@ DEFUN ("last-nonminibuffer-frame", Flast_nonminibuf_frame,
  * Return true if there exists at least one visible or iconified frame
  * but F.  Return false otherwise.
  *
- * Always return false when all remaining frames are either tooltip or
- * child frames or frames with a non-nil `delete-before' parameter.  If
- * INVISIBLE is false, also return false when the minibuffer window of
- * all remaining frames is on F.
-
+ * INVISIBLE true means we are called from make_frame_invisible where
+ * such a frame must be visible or iconified.  INVISIBLE nil means we
+ * are called from delete_frame.  In that case FORCE true means that the
+ * visibility status of such a frame can be ignored.
+ *
  * If F is the terminal frame and we are using X, return true if at
- * least one X frame exists.  */
+ * least one X frame exists.
+ */
 static bool
-other_frames (struct frame *f, bool invisible)
+other_frames (struct frame *f, bool invisible, bool force)
 {
   Lisp_Object frames, frame, frame1;
   struct frame *f1;
@@ -1591,23 +1592,20 @@ other_frames (struct frame *f, bool invisible)
             x_sync (f1);
 #endif
           if (NILP (Fframe_parameter (frame1, Qtooltip))
-              /* Tooltips and child frames don't count.  */
+              /* Tooltips and child frames count neither for
+                 invisibility nor for deletions.  */
               && !FRAME_PARENT_FRAME (f1)
               /* Frames with a non-nil `delete-before' parameter don't
-                 count - either they depend on us or they depend on a
-                 frame that we will have to find right here.  */
-              && NILP (get_frame_param (f1, Qdelete_before))
-              /* Frames whose minibuffer window is on F don't count
-                 unless INVISIBLE is set - in that case F is either made
-                 invisible and may be autoraised from such a frame or
-                 the FORCE argument of delete_frame was non-nil.  */
-              && (invisible || NILP (minibuffer_window)
-                  || !EQ (FRAME_MINIBUF_WINDOW (f1), minibuffer_window))
-              /* At least one visible/iconified frame must remain.  */
+                 count for deletions.  */
+              && (invisible || NILP (get_frame_param (f1, Qdelete_before)))
+              /* For invisibility and normal deletions, at least one
+                 visible or iconified frame must remain (Bug#26682).  */
               && (FRAME_VISIBLE_P (f1) || FRAME_ICONIFIED_P (f1)
-                  /* Allow deleting the terminal frame when at least one
-                     X frame exists.  */
-                  || (FRAME_WINDOW_P (f1) && !FRAME_WINDOW_P (f))))
+                  || (!invisible
+                      && (force
+                          /* Allow deleting the terminal frame when at
+                             least one X frame exists.  */
+                          || (FRAME_WINDOW_P (f1) && !FRAME_WINDOW_P (f))))))
             return true;
         }
     }
@@ -1680,7 +1678,7 @@ delete_frame (Lisp_Object frame, Lisp_Object force)
 
   if (!FRAME_LIVE_P (f))
     return Qnil;
-  else if (!EQ (force, Qnoelisp) && !other_frames (f, !NILP (force)))
+  else if (!EQ (force, Qnoelisp) && !other_frames (f, false, !NILP (force)))
     {
       if (NILP (force))
         error ("Attempt to delete the sole visible or iconified frame");
@@ -1752,7 +1750,7 @@ delete_frame (Lisp_Object frame, Lisp_Object force)
      one.  */
   if (!FRAME_LIVE_P (f))
     return Qnil;
-  else if (!EQ (force, Qnoelisp) && !other_frames (f, !NILP (force)))
+  else if (!EQ (force, Qnoelisp) && !other_frames (f, false, !NILP (force)))
     {
       if (NILP (force))
         error ("Attempt to delete the sole visible or iconified frame");
@@ -2275,7 +2273,7 @@ displayed in the terminal.  */)
 {
   struct frame *f = decode_live_frame (frame);
 
-  if (NILP (force) && !other_frames (f, true))
+  if (NILP (force) && !other_frames (f, true, false))
     error ("Attempt to make invisible the sole visible or iconified frame");
 
   /* Don't allow minibuf_window to remain on an invisible frame.  */
diff --git a/src/w32term.c b/src/w32term.c
index 6b0da0cb3e9..b3608accb34 100644
--- a/src/w32term.c
+++ b/src/w32term.c
@@ -5110,7 +5110,7 @@ w32_read_socket (struct terminal *terminal,
         case WM_MOVE:
           f = x_window_to_frame (dpyinfo, msg.msg.hwnd);
 
-          if (f && !FRAME_ICONIFIED_P (f))
+          if (f && FRAME_VISIBLE_P (f) && !FRAME_ICONIFIED_P(f))
             {
               x_real_positions (f, &f->left_pos, &f->top_pos);
               inev.kind = MOVE_FRAME_EVENT;