From a95f9f1b08a27165ffce03db777aad7e1660a3b0 Mon Sep 17 00:00:00 2001
From: marc_culler <marc.culler@gmail.com>
Date: Sun, 19 Dec 2021 22:01:59 +0000
Subject: Add a property to TKWindow which indicates that the associated Tk
 window is being destroyed.

---
 macosx/tkMacOSXMouseEvent.c | 32 ++++++++++++++++++++------------
 macosx/tkMacOSXPrivate.h    |  2 ++
 macosx/tkMacOSXWm.c         |  2 ++
 3 files changed, 24 insertions(+), 12 deletions(-)

diff --git a/macosx/tkMacOSXMouseEvent.c b/macosx/tkMacOSXMouseEvent.c
index 29a57aa..b96d487 100644
--- a/macosx/tkMacOSXMouseEvent.c
+++ b/macosx/tkMacOSXMouseEvent.c
@@ -124,6 +124,14 @@ enum {
 	if (!isTestingEvent && !isMotionEvent) {
 	    return theEvent;
 	}
+    } else if ([(TKWindow *) eventWindow isDead]) {
+	if ([eventWindow isKeyWindow]) {
+	    [eventWindow resignKey];
+	}
+	dragTarget = NULL;
+	target = TkMacOSXGetTkWindow([NSApp keyWindow]);
+	isDragging = NO;
+	[NSApp setTkEventTarget: target];
     } else if (!NSPointInRect(viewLocation, [contentView bounds])) {
 	isOutside = YES;
     }
@@ -142,6 +150,7 @@ enum {
 	}
 	isDragging = YES;
 	dragTarget = target;
+	break;
     case NSRightMouseDragged:
     case NSOtherMouseDragged:
 	isMotionEvent = YES;
@@ -291,20 +300,19 @@ enum {
 	    return theEvent;
 	}
     } else {
-	if (isDragging) {
-
-	    /*
-	     * The dragTarget window can be destroyed during a mouse drag by
-	     * pressing Cmd-W without releasing the mouse button.  This can
-	     * lead to a crash.  See [6be8b0b48c].
-	     */
-
+	if (isDragging && dragTarget) {
 	    TkWindow *dragPtr = (TkWindow *) dragTarget;
-	    if(dragPtr == NULL || dragPtr->flags & TK_ALREADY_DEAD) {
-		target = (TkWindow *) TkMacOSXGetTkWindow([NSApp keyWindow]);
-		return theEvent;
+	    TKWindow *dragWindow = nil;
+	    if (dragPtr) {
+	    	dragWindow = (TKWindow *)TkMacOSXGetNSWindowForDrawable(
+	    	    dragPtr->window);
+	    }
+	    if (!dragWindow) {
+	    	dragTarget = NULL;
+		target = NULL;
+	    	return theEvent;
 	    }
-	    winPtr = TkMacOSXGetHostToplevel(dragPtr)->winPtr;
+	    winPtr = TkMacOSXGetHostToplevel((TkWindow *) dragTarget)->winPtr;
 	} else if (eventType == NSScrollWheel) {
 	    winPtr = scrollTarget;
 	} else {
diff --git a/macosx/tkMacOSXPrivate.h b/macosx/tkMacOSXPrivate.h
index de0f5fd..c3b364f 100644
--- a/macosx/tkMacOSXPrivate.h
+++ b/macosx/tkMacOSXPrivate.h
@@ -451,9 +451,11 @@ VISIBILITY_HIDDEN
 #ifdef __i386__
     /* The Objective C runtime used on i386 requires this. */
     Window _tkWindow;
+    Bool _isDead;
 #endif
 }
 @property Window tkWindow;
+@property Bool isDead;
 @end
 
 @interface TKWindow(TKWm)
diff --git a/macosx/tkMacOSXWm.c b/macosx/tkMacOSXWm.c
index c065d6c..cdfc1a1 100644
--- a/macosx/tkMacOSXWm.c
+++ b/macosx/tkMacOSXWm.c
@@ -363,6 +363,7 @@ static void             RemoveTransient(TkWindow *winPtr);
 
 @implementation TKWindow: NSWindow
 @synthesize tkWindow = _tkWindow;
+@synthesize isDead = _isDead;
 @end
 
 #pragma mark TKWindow(TKWm)
@@ -1057,6 +1058,7 @@ TkWmDeadWindow(
      */
 
     deadNSWindow = (TKWindow *)wmPtr->window;
+    [deadNSWindow setIsDead:YES];
     if (deadNSWindow && !Tk_IsEmbedded(winPtr)) {
 	NSWindow *parent = [deadNSWindow parentWindow];
 	[deadNSWindow setTkWindow:None];
-- 
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