Fix ABTesting ActivateExperiment runtime drift

docs/firebase-runtime-failure-backlog.md

@@ -6,7 +6,7 @@ This backlog tracks binding drifts that are concrete candidates for the runtime-
 
 | Case id | Target/member | Audit finding reference | Expected runtime failure mechanism | Proof status | Fix PR | Merged commit |
 | --- | --- | --- | --- | --- | --- | --- |
-| `cloudfunctions-usefunctionsemulatororigin` | `Firebase.CloudFunctions.CloudFunctions.UseFunctionsEmulatorOrigin` | Manual runtime candidate from the current binding surface and native `FirebaseFunctions` Swift header | The binding still exports `useFunctionsEmulatorOrigin:` even though the current framework only exposes `useEmulatorWithHost:port:`. Calling the stale selector raises `ObjCRuntime.ObjCException` with an unrecognized-selector native exception. | Proved locally on the unfixed binding. Evidence: `ObjCRuntime.ObjCException`, `NSInvalidArgumentException`, selector `-[FIRFunctions useFunctionsEmulatorOrigin:]`, artifact `tests/E2E/Firebase.Foundation/artifacts/firebase-foundation-result-cloudfunctions-usefunctionsemulatororigin-failure.json`, log `tests/E2E/Firebase.Foundation/artifacts/firebase-foundation-sim-cloudfunctions-usefunctionsemulatororigin-failure.log`. | [#113](https://github.com/AdamEssenmacher/GoogleApisForiOSComponents/pull/113) | - |
+| `abtesting-activateexperiment` | `Firebase.ABTesting.ExperimentController.ActivateExperiment` | `output/firebase-binding-audit/report.json` -> `ABTesting` -> `ActivateExperiment` (`signature-drift`) | The old binding exports `activateExperiment:forServiceOrigin:` as `NSObject` instead of `ABTExperimentPayload`, so callers can send an arbitrary object and native ABTesting immediately raises `ObjCRuntime.ObjCException` when it invokes `ABTExperimentPayload` selectors on that object. | Proved locally on the unfixed binding. Evidence artifact: `tests/E2E/Firebase.Foundation/artifacts/firebase-foundation-result-abtesting-activateexperiment-failure.json`. Regression artifact: `tests/E2E/Firebase.Foundation/artifacts/firebase-foundation-result-abtesting-activateexperiment-success.json`. | - | - |
 
 ## Investigating
 
@@ -16,4 +16,5 @@ No additional runtime-failure candidates are currently promoted.
 
 | Case id | Target/member | Audit finding reference | Runtime failure mechanism | Proof status | Fix PR | Merged commit |
 | --- | --- | --- | --- | --- | --- | --- |
+| `cloudfunctions-usefunctionsemulatororigin` | `Firebase.CloudFunctions.CloudFunctions.UseFunctionsEmulatorOrigin` | Manual runtime candidate from the current binding surface and native `FirebaseFunctions` Swift header | The binding exported `useFunctionsEmulatorOrigin:` even though the current framework only exposes `useEmulatorWithHost:port:`. Calling the stale selector raised `ObjCRuntime.ObjCException` with an unrecognized-selector native exception. | Proved and fixed. Evidence artifact: `tests/E2E/Firebase.Foundation/artifacts/firebase-foundation-result-cloudfunctions-usefunctionsemulatororigin-failure.json`. Regression artifact: `tests/E2E/Firebase.Foundation/artifacts/firebase-foundation-result-cloudfunctions-usefunctionsemulatororigin-success.json`. | [#113](https://github.com/AdamEssenmacher/GoogleApisForiOSComponents/pull/113) | `b6a6c82c74e0cf3645edb9dc5519d4a628f7ed36` |
 | `cloudfirestore-getquerynamed` | `Firebase.CloudFirestore.Firestore.GetQueryNamed` | `output/firebase-binding-audit/report.json` -> `CloudFirestore` -> `GetQueryNamed` (`signature-drift`) | The old binding exported `getQueryNamed:completion:` as `NSInputStream` instead of `NSString`, so native Firestore received `__NSCFInputStream` and threw an Objective-C exception when it treated the argument like a string. | Proved and fixed. Evidence artifact: `tests/E2E/Firebase.Foundation/artifacts/firebase-foundation-result-cloudfirestore-getquerynamed-failure.json`. Regression artifact: `tests/E2E/Firebase.Foundation/artifacts/firebase-foundation-result-cloudfirestore-getquerynamed-success.json`. | [#112](https://github.com/AdamEssenmacher/GoogleApisForiOSComponents/pull/112) | `3077a538a892de0db3350f0a459bf8620729f4db` |

source/Firebase/ABTesting/ApiDefinition.cs

@@ -3,6 +3,11 @@
 using System;
 
 namespace Firebase.ABTesting {
+	// @class ABTExperimentPayload;
+	[BaseType (typeof (NSObject), Name = "ABTExperimentPayload")]
+	interface ExperimentPayload {
+	}
+
 	// @interface FIRExperimentController : NSObject
 	[DisableDefaultCtor]
 	[BaseType (typeof (NSObject), Name = "FIRExperimentController")]
@@ -26,7 +31,7 @@ interface ExperimentController {
 
 		// -(void)activateExperiment:(ABTExperimentPayload * _Nonnull)experimentPayload forServiceOrigin:(NSString * _Nonnull)origin;
 		[Export ("activateExperiment:forServiceOrigin:")]
-		void ActivateExperiment (NSObject experimentPayload, string origin);
+		void ActivateExperiment (ExperimentPayload experimentPayload, string origin);
 	}
 
 	[Static]

tests/E2E/Firebase.Foundation/FirebaseFoundationE2E/FirebaseRuntimeDriftCases.cs

@@ -1,5 +1,11 @@
 using System.Reflection;
 
+#if ENABLE_RUNTIME_DRIFT_CASE_ABTESTING_ACTIVATEEXPERIMENT
+using Firebase.ABTesting;
+using Foundation;
+using ObjCRuntime;
+#endif
+
 #if ENABLE_RUNTIME_DRIFT_CASE_CLOUDFIRESTORE_GETQUERYNAMED
 using Firebase.CloudFirestore;
 using Foundation;
@@ -60,6 +66,66 @@ public static async Task<string> ExecuteConfiguredCaseAsync()
             ?.Value;
     }
 
+#if ENABLE_RUNTIME_DRIFT_CASE_ABTESTING_ACTIVATEEXPERIMENT
+    static Task<string> VerifyABTestingActivateExperimentAsync()
+    {
+        const string selector = "activateExperiment:forServiceOrigin:";
+
+        var controller = ExperimentController.SharedInstance;
+        if (controller is null)
+        {
+            throw new InvalidOperationException("Firebase.ABTesting.ExperimentController.SharedInstance returned null after App.Configure().");
+        }
+
+        var payload = new ExperimentPayload();
+        var origin = "codex";
+        NSException? marshaledException = null;
+        MarshalObjectiveCExceptionMode? marshaledExceptionMode = null;
+
+        void OnMarshalObjectiveCException(object? sender, MarshalObjectiveCExceptionEventArgs args)
+        {
+            marshaledException ??= args.Exception;
+            marshaledExceptionMode ??= args.ExceptionMode;
+        }
+
+        Runtime.MarshalObjectiveCException += OnMarshalObjectiveCException;
+        try
+        {
+            try
+            {
+                controller.ActivateExperiment(payload, origin);
+            }
+            catch (ObjCException ex)
+            {
+                throw new InvalidOperationException(
+                    $"Selector '{selector}' should not throw after the binding fix, but observed {ex.GetType().FullName}. " +
+                    $"Managed payload type: {payload.GetType().FullName}. " +
+                    $"Origin argument type: {origin.GetType().FullName}. " +
+                    $"NSException.Name: {FormatDetail(marshaledException?.Name?.ToString())}. " +
+                    $"NSException.Reason: {FormatDetail(marshaledException?.Reason)}. " +
+                    $"Marshal mode: {FormatDetail(marshaledExceptionMode?.ToString())}.",
+                    ex);
+            }
+
+            if (marshaledException is not null)
+            {
+                throw new InvalidOperationException(
+                    $"Selector '{selector}' completed, but Runtime.MarshalObjectiveCException captured unexpected NSException.Name '{marshaledException.Name}'. " +
+                    $"Reason: {FormatDetail(marshaledException.Reason)}. Marshal mode: {FormatDetail(marshaledExceptionMode?.ToString())}.");
+            }
+
+            return Task.FromResult(
+                $"Selector '{selector}' completed without ObjC exception after the binding fix. " +
+                $"Managed payload type: {payload.GetType().FullName}. " +
+                $"Origin argument type: {origin.GetType().FullName}.");
+        }
+        finally
+        {
+            Runtime.MarshalObjectiveCException -= OnMarshalObjectiveCException;
+        }
+    }
+#endif
+
 #if ENABLE_RUNTIME_DRIFT_CASE_CLOUDFIRESTORE_GETQUERYNAMED
     static async Task<string> VerifyCloudFirestoreGetQueryNamedAsync()
     {

tests/E2E/Firebase.Foundation/runtime-drift-cases.json

@@ -1,5 +1,16 @@
 {
   "cases": [
+    {
+      "id": "abtesting-activateexperiment",
+      "method": "VerifyABTestingActivateExperimentAsync",
+      "bindingPackage": "AdamE.Firebase.iOS.ABTesting",
+      "packages": [
+        {
+          "id": "AdamE.Firebase.iOS.ABTesting",
+          "version": "12.6.0"
+        }
+      ]
+    },
     {
       "id": "cloudfirestore-getquerynamed",
       "method": "VerifyCloudFirestoreGetQueryNamedAsync",