Crash in createNSWindowSnapshot when targeting older macOS

MacOSX and iOS
1

It’s possible for this to crash if the image can’t be created. This patch just guards against the crash:

diff --git a/modules/juce_gui_basics/native/juce_Windowing_mac.mm b/modules/juce_gui_basics/native/juce_Windowing_mac.mm
index 6a1cc594df..8851f696e3 100644
--- a/modules/juce_gui_basics/native/juce_Windowing_mac.mm
+++ b/modules/juce_gui_basics/native/juce_Windowing_mac.mm
@@ -525,9 +525,10 @@ static Image createNSWindowSnapshot (NSWindow* nsWindow)
 {
     JUCE_AUTORELEASEPOOL
     {
-        const auto createImageFromCGImage = [&] (CGImageRef cgImage)
+        const auto createImageFromCGImage = [&] (CGImageRef cgImage) -> Image
         {
-            jassert (cgImage != nullptr);
+            if (cgImage == nullptr)
+                return {};
 
             const auto width = CGImageGetWidth (cgImage);
             const auto height = CGImageGetHeight (cgImage);
@@ -612,10 +613,16 @@ static Image createNSWindowSnapshot (NSWindow* nsWindow)
        #else
 
         JUCE_BEGIN_IGNORE_DEPRECATION_WARNINGS
-        return createImageFromCGImage ((CGImageRef) CFAutorelease (CGWindowListCreateImage (CGRectNull,
-                                                                                            kCGWindowListOptionIncludingWindow,
-                                                                                            (CGWindowID) [nsWindow windowNumber],
-                                                                                            kCGWindowImageBoundsIgnoreFraming)));
+        // N.B. CGWindowListCreateImage returns null on macOS versions where this
+        // deprecated API is restricted (e.g. without Screen Recording permission).
+        // Passing null to CFAutorelease aborts in CoreFoundation, so guard it.
+        if (auto cgImage = CGWindowListCreateImage (CGRectNull,
+                                                    kCGWindowListOptionIncludingWindow,
+                                                    (CGWindowID) [nsWindow windowNumber],
+                                                    kCGWindowImageBoundsIgnoreFraming))
+            return createImageFromCGImage ((CGImageRef) CFAutorelease (cgImage));
+
+        return {};
         JUCE_END_IGNORE_DEPRECATION_WARNINGS
 
        #endif
2

Thanks for reporting. I believe this was fixed on the juce9 branch here:

…and on develop here: