Fix: Session replay opacity animation masking

CHANGELOG.md

@@ -12,7 +12,8 @@
 - UIViewController with Xcode 16 in debug (#4523). The Xcode 16 build setting [ENABLE_DEBUG_DYLIB](https://developer.apple.com/documentation/xcode/build-settings-reference#Enable-Debug-Dylib-Support), which is turned on by default only in debug, could lead to missing UIViewController traces.
 - Concurrency crash with Swift 6 (#4512)
 - Make `Scope.span` fully thread safe (#4519)
-- - Finish TTFD when not calling reportFullyDisplayed before binding a new transaction to the scope (#4526).
+- Session replay opacity animation masking (#4532)
+- Finish TTFD when not calling reportFullyDisplayed before binding a new transaction to the scope (#4526).
 
 ## 8.40.1
 

Sources/Swift/Tools/UIRedactBuilder.swift

@@ -238,9 +238,8 @@ class UIRedactBuilder {
     }
 
     private func mapRedactRegion(fromView view: UIView, relativeTo parentLayer: CALayer?, redacting: inout [RedactRegion], rootFrame: CGRect, forceRedact: Bool = false) {
-        guard !redactClassesIdentifiers.isEmpty && !view.isHidden && view.alpha != 0 else { return }
-
         let layer = view.layer.presentation() ?? view.layer
+        guard !redactClassesIdentifiers.isEmpty && !layer.isHidden && layer.opacity != 0 else { return }
 
         let newTransform = getTranform(from: layer, withParent: parentLayer)
 
@@ -308,7 +307,8 @@ class UIRedactBuilder {
      Indicates whether the view is opaque and will block other view behind it
      */
     private func isOpaque(_ view: UIView) -> Bool {
-        return SentryRedactViewHelper.shouldClipOut(view) || (view.alpha == 1 && view.backgroundColor != nil && (view.backgroundColor?.cgColor.alpha ?? 0) == 1)
+        let layer = view.layer.presentation() ?? view.layer
+        return SentryRedactViewHelper.shouldClipOut(view) || (layer.opacity == 1 && view.backgroundColor != nil && (view.backgroundColor?.cgColor.alpha ?? 0) == 1)
     }
 }
 

Tests/SentryTests/UIRedactBuilderTests.swift

@@ -20,6 +20,17 @@ class RedactOptions: SentryRedactOptions {
 }
 
 class UIRedactBuilderTests: XCTestCase {
+    private class CustomVisibilityView: UIView {
+        class CustomLayer: CALayer {
+            override var opacity: Float {
+                get { 0.5 }
+                set { }
+            }
+        }
+        override class var layerClass: AnyClass {
+            return CustomLayer.self
+        }
+    }
 
     private let rootView = UIView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
 
@@ -394,6 +405,32 @@ class UIRedactBuilderTests: XCTestCase {
             XCTAssertTrue(sut.containsIgnoreClass(element), "\(element) not found")
         }
     }
+
+    func testLayerIsNotFullyTransparentRedacted() {
+        let sut = getSut()
+        let view = CustomVisibilityView(frame: CGRect(x: 20, y: 20, width: 40, height: 40))
+        view.alpha = 0
+        view.sentryReplayMask()
+
+        view.backgroundColor = .purple
+        rootView.addSubview(view)
+
+        let result = sut.redactRegionsFor(view: rootView)
+        XCTAssertEqual(result.count, 1)
+    }
+
+    func testViewLayerOnTopIsNotFullyTransparentRedacted() {
+        let sut = getSut()
+        let view = CustomVisibilityView(frame: CGRect(x: 20, y: 20, width: 40, height: 40))
+        let label = UILabel(frame: CGRect(x: 20, y: 20, width: 40, height: 40))
+        view.backgroundColor = .purple
+        rootView.addSubview(label)
+        rootView.addSubview(view)
+
+        let result = sut.redactRegionsFor(view: rootView)
+        XCTAssertEqual(result.first?.type, .redact)
+        XCTAssertEqual(result.count, 1)
+    }
 }
 
 #endif