[[ Bug 22705 ]] Resolve crash focusing on unopen stack

montegoulding · montegoulding · commit e46e53aaee76 · 2020-07-03T20:08:16.000+10:00
This patch resolves a crash where `controlgainedfocus` is called with a stack
parameter which is unopened and therefore `p_stack -&gt; getwindow()` returns
`nullptr`.
diff --git a/docs/notes/bugfix-22705.md b/docs/notes/bugfix-22705.md
@@ -0,0 +1 @@
+# Fix crash focusing on an unopen stack
diff --git a/engine/src/desktop-dc.cpp b/engine/src/desktop-dc.cpp
@@ -1114,7 +1114,11 @@ MCImageBitmap *MCScreenDC::snapshot(MCRectangle &p_rect, uint4 p_window, MCStrin
 
 void MCScreenDC::controlgainedfocus(MCStack *p_stack, uint32_t p_id)
 {
-	MCPlatformSwitchFocusToView(p_stack -> getwindow(), p_id);
+	MCPlatformWindowRef t_window = p_stack -> getwindow();
+	if (t_window != nullptr)
+	{
+		MCPlatformSwitchFocusToView(p_stack -> getwindow(), p_id);
+	}
 }
 
 void MCScreenDC::controllostfocus(MCStack *p_stack, uint32_t p_id)

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	`+# Fix crash focusing on an unopen stack`
Original file line number	Diff line number	Diff line change
`@@ -1114,7 +1114,11 @@ MCImageBitmap *MCScreenDC::snapshot(MCRectangle &p_rect, uint4 p_window, MCStrin`
`1114`	`1114`
`1115`	`1115`	`void MCScreenDC::controlgainedfocus(MCStack *p_stack, uint32_t p_id)`
`1116`	`1116`	`{`
`1117`		`- MCPlatformSwitchFocusToView(p_stack -> getwindow(), p_id);`
	`1117`	`+ MCPlatformWindowRef t_window = p_stack -> getwindow();`
	`1118`	`+ if (t_window != nullptr)`
	`1119`	`+ {`
	`1120`	`+ MCPlatformSwitchFocusToView(p_stack -> getwindow(), p_id);`
	`1121`	`+ }`
`1118`	`1122`	`}`
`1119`	`1123`
`1120`	`1124`	`void MCScreenDC::controllostfocus(MCStack *p_stack, uint32_t p_id)`