[webview_flutter_wkwebview] Fixes inspectable compile-time error and crash from equal NSURLs (#4340)

Fixes flutter/flutter#128422 by using pointer equality in the `NSMapTable`. From my understanding and testing it seems that the default mode for [NSMapTable](https://developer.apple.com/documentation/foundation/nsmaptable?language=objc) is to copy objects that implement `NSCopyable`. The only class we wrap that does seems to implement `NSCopyable` is `NSURL` so this class eventually led to a race condition where adding an `NSURL` that was equivalent to an already added one would replace the original.

Note that we should probably now add an error when adding an already present instance. However, a clear method needs to be added to the `InstanceManager` first so that hot reload will continue working. This is the current solution on Android.

Fixes flutter/flutter#129587 by adding a compile-time check around the use of `WKWebView.inspectable`. Solution used from:

https://stackoverflow.com/questions/76216183/how-to-debug-wkwebview-in-ios-16-4-1-using-xcode-14-2

Author: bparrishMines

packages/webview_flutter/webview_flutter_wkwebview/CHANGELOG.md

@@ -1,3 +1,9 @@
+## 3.6.1
+
+* Fixes bug where a native `NSURL` could be removed from an `InstanceManager` if it is equal to an
+  already present `NSURL`.
+* Fixes compile-time error from using `WKWebView.inspectable` on unsupported Xcode versions.
+
 ## 3.6.0
 
 * Adds support to enable debugging of web contents on the latest versions of WebKit. See

packages/webview_flutter/webview_flutter_wkwebview/example/ios/RunnerTests/FWFInstanceManagerTests.m

@@ -52,4 +52,20 @@ - (void)testDeallocCallbackIsIgnoredIfNull {
   // Tests that this doesn't cause a EXC_BAD_ACCESS crash.
   [instanceManager removeInstanceWithIdentifier:0];
 }
+
+- (void)testObjectsAreStoredWithPointerHashcode {
+  FWFInstanceManager *instanceManager = [[FWFInstanceManager alloc] init];
+
+  NSURL *url1 = [NSURL URLWithString:@"https://www.flutter.dev"];
+  NSURL *url2 = [NSURL URLWithString:@"https://www.flutter.dev"];
+
+  // Ensure urls are considered equal.
+  XCTAssertTrue([url1 isEqual:url2]);
+
+  [instanceManager addHostCreatedInstance:url1];
+  [instanceManager addHostCreatedInstance:url2];
+
+  XCTAssertNotEqual([instanceManager identifierWithStrongReferenceForInstance:url1],
+                    [instanceManager identifierWithStrongReferenceForInstance:url2]);
+}
 @end

packages/webview_flutter/webview_flutter_wkwebview/example/ios/RunnerTests/FWFWebViewHostApiTests.m

@@ -465,7 +465,7 @@ - (void)testContentInsetsSumAlwaysZeroAfterSetFrame {
   XCTAssertTrue(CGRectEqualToRect(webView.frame, CGRectMake(0, 0, 300, 100)));
 }
 
-- (void)testSetInspectable API_AVAILABLE(ios(16.4), macos(13.3), tvos(16.4)) {
+- (void)testSetInspectable API_AVAILABLE(ios(16.4), macos(13.3)) {
   FWFWebView *mockWebView = OCMClassMock([FWFWebView class]);
 
   FWFInstanceManager *instanceManager = [[FWFInstanceManager alloc] init];

packages/webview_flutter/webview_flutter_wkwebview/ios/Classes/FWFInstanceManager.m

@@ -67,9 +67,17 @@ - (instancetype)init {
     _deallocCallback = _deallocCallback ? _deallocCallback : ^(long identifier) {
     };
     _lockQueue = dispatch_queue_create("FWFInstanceManager", DISPATCH_QUEUE_SERIAL);
-    _identifiers = [NSMapTable weakToStrongObjectsMapTable];
-    _weakInstances = [NSMapTable strongToWeakObjectsMapTable];
-    _strongInstances = [NSMapTable strongToStrongObjectsMapTable];
+    // Pointer equality is used to prevent collisions of objects that override the `isEqualTo:`
+    // method.
+    _identifiers =
+        [NSMapTable mapTableWithKeyOptions:NSMapTableWeakMemory | NSMapTableObjectPointerPersonality
+                              valueOptions:NSMapTableStrongMemory];
+    _weakInstances = [NSMapTable
+        mapTableWithKeyOptions:NSMapTableStrongMemory
+                  valueOptions:NSMapTableWeakMemory | NSMapTableObjectPointerPersonality];
+    _strongInstances = [NSMapTable
+        mapTableWithKeyOptions:NSMapTableStrongMemory
+                  valueOptions:NSMapTableStrongMemory | NSMapTableObjectPointerPersonality];
     _nextIdentifier = FWFMinHostCreatedIdentifier;
   }
   return self;

packages/webview_flutter/webview_flutter_wkwebview/ios/Classes/FWFWebViewHostApi.m

@@ -201,7 +201,9 @@ - (void)setInspectableForWebViewWithIdentifier:(NSNumber *)identifier
                                    inspectable:(NSNumber *)inspectable
                                          error:(FlutterError *_Nullable *_Nonnull)error {
   if (@available(macOS 13.3, iOS 16.4, tvOS 16.4, *)) {
+#if __MAC_OS_X_VERSION_MAX_ALLOWED >= 130300 || __IPHONE_OS_VERSION_MAX_ALLOWED >= 160400
     [[self webViewForIdentifier:identifier] setInspectable:inspectable.boolValue];
+#endif
   } else {
     *error = [FlutterError errorWithCode:@"FWFUnsupportedVersionError"
                                  message:@"setInspectable is only supported on versions 16.4+."

packages/webview_flutter/webview_flutter_wkwebview/pubspec.yaml

@@ -2,7 +2,7 @@ name: webview_flutter_wkwebview
 description: A Flutter plugin that provides a WebView widget based on Apple's WKWebView control.
 repository: https://github.com/flutter/packages/tree/main/packages/webview_flutter/webview_flutter_wkwebview
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+webview%22
-version: 3.6.0
+version: 3.6.1
 
 environment:
   sdk: ">=2.18.0 <4.0.0"