Prevent application crashes from MAUI ScreenshotImplementation (#4069)

Author: jamescrosswell

CHANGELOG.md

@@ -8,6 +8,7 @@
 - Target `net9.0` on Sentry.Google.Cloud.Functions to avoid conflict with Sentry.AspNetCore ([#4039](https://github.com/getsentry/sentry-dotnet/pull/4039))
 - Changed default value for `SentryOptions.EnableAppHangTrackingV2` to `false` ([#4042](https://github.com/getsentry/sentry-dotnet/pull/4042))
 - Missing MAUI `Shell` navigation breadcrumbs on iOS ([#4006](https://github.com/getsentry/sentry-dotnet/pull/4006))
+- Prevent application crashes when capturing screenshots on iOS ([#4069](https://github.com/getsentry/sentry-dotnet/pull/4069))
 
 ### Features
 

src/Sentry.Maui/Internal/ScreenshotAttachment.cs

@@ -39,6 +39,22 @@ public ScreenshotAttachmentContent(SentryMauiOptions options)
     }
 
     public Stream GetStream()
+    {
+        try
+        {
+            return GetStreamInternal();
+        }
+        catch (Exception ex)
+        {
+            // See https://github.com/getsentry/sentry-dotnet/issues/3880#issuecomment-2640159466
+            _options.LogError("Failed to capture screenshot", ex);
+            // Return empty stream since calling code may assume a non-null return value
+            // E.g. https://github.com/getsentry/sentry-dotnet/blob/db5606833a4b0662c6bea0663cca10cb05fb5157/src/Sentry/Protocol/Envelopes/EnvelopeItem.cs#L332-L333
+            return new MemoryStream();
+        }
+    }
+
+    private Stream GetStreamInternal()
     {
         var stream = Stream.Null;
         // Not including this on Windows specific build because on WinUI this can deadlock.

test/Sentry.Maui.Tests/SentryMauiScreenshotTests.cs

@@ -34,12 +34,20 @@ public Fixture()
     private readonly Fixture _fixture = new();
 
 #if __MOBILE__
+    // TODO: This test doesn't work on Android or iOS, so isn't much use. We should consider replacing it with some
+    // more granular tests that test SentryMauiOptionsSetup, SentryMauiScreenshotProcessor and ScreenshotAttachment
+    // in isolation. It's generally hard to test any of this functionality since ScreenshotImplementation relies of
+    // various static members like ActivityStateManager.Default:
+    // https://github.com/dotnet/maui/blob/3c7b65264d2f341a48db32263a271fd8718cfd23/src/Essentials/src/Screenshot/Screenshot.android.cs#L28
     [SkippableFact]
     public async Task CaptureException_WhenAttachScreenshots_ContainsScreenshotAttachmentAsync()
     {
 #if __IOS__
         Skip.If(true, "Flaky on iOS");
 #endif
+#if ANDROID
+        Skip.If(true, "Doesn't work on Android");
+#endif
 
         // Arrange
         var builder = _fixture.Builder.UseSentry();
@@ -133,12 +141,20 @@ public async Task CaptureException_BeforeCaptureScreenshot_DisableCaptureAsync()
         envelopeItem.Should().BeNull();
     }
 
+    // TODO: This test doesn't work on Android or iOS, so isn't much use. We should consider replacing it with some
+    // more granular tests that test SentryMauiOptionsSetup, SentryMauiScreenshotProcessor and ScreenshotAttachment
+    // in isolation. It's generally hard to test any of this functionality since ScreenshotImplementation relies of
+    // various static members like ActivityStateManager.Default:
+    // https://github.com/dotnet/maui/blob/3c7b65264d2f341a48db32263a271fd8718cfd23/src/Essentials/src/Screenshot/Screenshot.android.cs#L28
     [SkippableFact]
     public async Task CaptureException_BeforeCaptureScreenshot_DefaultAsync()
     {
 #if __IOS__
         Skip.If(true, "Flaky on iOS");
 #endif
+#if ANDROID
+        Skip.If(true, "Doesn't work on Android");
+#endif
 
         // Arrange
         var builder = _fixture.Builder.UseSentry(options => options.SetBeforeScreenshotCapture((e, hint) =>