Initial support for Feature Flags

.gitignore

@@ -32,3 +32,6 @@ profile
 Carthage/Build/
 
 MixpanelDemo/build/
+
+# Claude.ai instructions
+CLAUDE.md

Mixpanel-swift.podspec

@@ -19,9 +19,9 @@ Pod::Spec.new do |s|
   base_source_files = ['Sources/Network.swift', 'Sources/FlushRequest.swift', 'Sources/PrintLogging.swift', 'Sources/FileLogging.swift',
     'Sources/MixpanelLogger.swift', 'Sources/JSONHandler.swift', 'Sources/Error.swift', 'Sources/AutomaticProperties.swift',
     'Sources/Constants.swift', 'Sources/MixpanelType.swift', 'Sources/Mixpanel.swift', 'Sources/MixpanelInstance.swift',
-    'Sources/Flush.swift','Sources/Track.swift', 'Sources/People.swift', 'Sources/AutomaticEvents.swift',
-    'Sources/Group.swift',
-    'Sources/ReadWriteLock.swift', 'Sources/SessionMetadata.swift', 'Sources/MPDB.swift', 'Sources/MixpanelPersistence.swift', 'Sources/Data+Compression.swift']
+    'Sources/Flush.swift', 'Sources/Track.swift', 'Sources/People.swift', 'Sources/AutomaticEvents.swift',
+    'Sources/Group.swift', 'Sources/ReadWriteLock.swift', 'Sources/SessionMetadata.swift', 'Sources/MPDB.swift', 'Sources/MixpanelPersistence.swift', 
+    'Sources/Data+Compression.swift', 'Sources/MixpanelOptions.swift', 'Sources/FeatureFlags.swift']
   s.tvos.deployment_target = '11.0'
   s.tvos.frameworks = 'UIKit', 'Foundation'
   s.tvos.pod_target_xcconfig = {

Mixpanel.xcodeproj/project.pbxproj

@@ -7,6 +7,14 @@
 	objects = {
 
 /* Begin PBXBuildFile section */
+		171E4C122DAF108400B7CB11 /* FeatureFlags.swift in Sources */ = {isa = PBXBuildFile; fileRef = 171E4C112DAF108400B7CB11 /* FeatureFlags.swift */; };
+		171E4C132DAF108400B7CB11 /* FeatureFlags.swift in Sources */ = {isa = PBXBuildFile; fileRef = 171E4C112DAF108400B7CB11 /* FeatureFlags.swift */; };
+		171E4C142DAF108400B7CB11 /* FeatureFlags.swift in Sources */ = {isa = PBXBuildFile; fileRef = 171E4C112DAF108400B7CB11 /* FeatureFlags.swift */; };
+		171E4C152DAF108400B7CB11 /* FeatureFlags.swift in Sources */ = {isa = PBXBuildFile; fileRef = 171E4C112DAF108400B7CB11 /* FeatureFlags.swift */; };
+		171E4C172DAF2B3100B7CB11 /* MixpanelOptions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 171E4C162DAF2B3100B7CB11 /* MixpanelOptions.swift */; };
+		171E4C182DAF2B3100B7CB11 /* MixpanelOptions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 171E4C162DAF2B3100B7CB11 /* MixpanelOptions.swift */; };
+		171E4C192DAF2B3100B7CB11 /* MixpanelOptions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 171E4C162DAF2B3100B7CB11 /* MixpanelOptions.swift */; };
+		171E4C1A2DAF2B3100B7CB11 /* MixpanelOptions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 171E4C162DAF2B3100B7CB11 /* MixpanelOptions.swift */; };
 		17C6547A2BB1F15C00C8A126 /* PrivacyInfo.xcprivacy in Resources */ = {isa = PBXBuildFile; fileRef = 1728208D2BA8BDE4002CD973 /* PrivacyInfo.xcprivacy */; };
 		17C6547B2BB1F16000C8A126 /* PrivacyInfo.xcprivacy in Resources */ = {isa = PBXBuildFile; fileRef = 1728208D2BA8BDE4002CD973 /* PrivacyInfo.xcprivacy */; };
 		17C6547C2BB1F16400C8A126 /* PrivacyInfo.xcprivacy in Resources */ = {isa = PBXBuildFile; fileRef = 1728208D2BA8BDE4002CD973 /* PrivacyInfo.xcprivacy */; };
@@ -103,6 +111,8 @@
 /* End PBXBuildFile section */
 
 /* Begin PBXFileReference section */
+		171E4C112DAF108400B7CB11 /* FeatureFlags.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeatureFlags.swift; sourceTree = "<group>"; };
+		171E4C162DAF2B3100B7CB11 /* MixpanelOptions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MixpanelOptions.swift; sourceTree = "<group>"; };
 		1728208D2BA8BDE4002CD973 /* PrivacyInfo.xcprivacy */ = {isa = PBXFileReference; lastKnownFileType = text.xml; name = PrivacyInfo.xcprivacy; path = Sources/Mixpanel/PrivacyInfo.xcprivacy; sourceTree = SOURCE_ROOT; };
 		51DD56791D306B740045D3DB /* MixpanelLogger.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = MixpanelLogger.swift; sourceTree = "<group>"; };
 		51DD56801D306B7B0045D3DB /* PrintLogging.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = PrintLogging.swift; sourceTree = "<group>"; };
@@ -226,12 +236,14 @@
 		E11594881CFF14D3007F8B4F /* Source */ = {
 			isa = PBXGroup;
 			children = (
+				171E4C162DAF2B3100B7CB11 /* MixpanelOptions.swift */,
 				17C654792BB1EF6700C8A126 /* Mixpanel */,
 				E189D8FB1D5A6943007F3F29 /* Networking */,
 				51DD56771D306B620045D3DB /* Log */,
 				E189D8FA1D5A692A007F3F29 /* Utilities */,
 				E115948A1CFF1538007F8B4F /* Mixpanel.swift */,
 				E115948D1D000709007F8B4F /* MixpanelInstance.swift */,
+				171E4C112DAF108400B7CB11 /* FeatureFlags.swift */,
 				E115949E1D01BE14007F8B4F /* Flush.swift */,
 				E11594A01D01C597007F8B4F /* Track.swift */,
 				E15FF7C71D0435670076CDE3 /* People.swift */,
@@ -488,13 +500,15 @@
 				86F86EC722443A3C00B69832 /* FileLogging.swift in Sources */,
 				86F86EC622443A3100B69832 /* Error.swift in Sources */,
 				86F86EC522443A2C00B69832 /* People.swift in Sources */,
+				171E4C172DAF2B3100B7CB11 /* MixpanelOptions.swift in Sources */,
 				86F86EC422443A2300B69832 /* ReadWriteLock.swift in Sources */,
 				8625BEBE26D045CE0009BAA9 /* MPDB.swift in Sources */,
 				95ECF06B2C9B851C006364D2 /* Data+Compression.swift in Sources */,
 				86F86EC222443A1300B69832 /* Track.swift in Sources */,
 				86F86EC122443A0E00B69832 /* JSONHandler.swift in Sources */,
 				86F86EC022443A0800B69832 /* MixpanelType.swift in Sources */,
 				86F86EBE224439FA00B69832 /* Network.swift in Sources */,
+				171E4C142DAF108400B7CB11 /* FeatureFlags.swift in Sources */,
 				86F86EBD224439F500B69832 /* Flush.swift in Sources */,
 				86F86EBC224439F100B69832 /* PrintLogging.swift in Sources */,
 				868550AF2699096F001FCDDC /* MixpanelPersistence.swift in Sources */,
@@ -517,13 +531,15 @@
 				E1D335CE1D30578E00E68E12 /* Constants.swift in Sources */,
 				E115949F1D01BE14007F8B4F /* Flush.swift in Sources */,
 				E11594971D006022007F8B4F /* Network.swift in Sources */,
+				171E4C182DAF2B3100B7CB11 /* MixpanelOptions.swift in Sources */,
 				E15FF7C81D0435670076CDE3 /* People.swift in Sources */,
 				673ABE3A21360CBE00B1784B /* Group.swift in Sources */,
 				95ECF0682C9B851A006364D2 /* Data+Compression.swift in Sources */,
 				E11594A11D01C597007F8B4F /* Track.swift in Sources */,
 				E11594991D01689F007F8B4F /* JSONHandler.swift in Sources */,
 				E1D335D01D3059A800E68E12 /* AutomaticProperties.swift in Sources */,
 				51DD567C1D306B740045D3DB /* MixpanelLogger.swift in Sources */,
+				171E4C122DAF108400B7CB11 /* FeatureFlags.swift in Sources */,
 				E165228F1D6781DF000D5949 /* MixpanelType.swift in Sources */,
 				BB9614171F3BB87700C3EF3E /* ReadWriteLock.swift in Sources */,
 				E190522D1F9FC1BC00900E5D /* SessionMetadata.swift in Sources */,
@@ -546,13 +562,15 @@
 				E12782BD1D4AB5CB0025FB05 /* MixpanelLogger.swift in Sources */,
 				E12782BE1D4AB5CB0025FB05 /* Mixpanel.swift in Sources */,
 				E12782BF1D4AB5CB0025FB05 /* MixpanelInstance.swift in Sources */,
+				171E4C192DAF2B3100B7CB11 /* MixpanelOptions.swift in Sources */,
 				E12782C11D4AB5CB0025FB05 /* Network.swift in Sources */,
 				8625BEBC26D045CE0009BAA9 /* MPDB.swift in Sources */,
 				95ECF0692C9B851B006364D2 /* Data+Compression.swift in Sources */,
 				E12782C21D4AB5CB0025FB05 /* JSONHandler.swift in Sources */,
 				E12782C31D4AB5CB0025FB05 /* Flush.swift in Sources */,
 				E12782C41D4AB5CB0025FB05 /* FlushRequest.swift in Sources */,
 				E12782C51D4AB5CB0025FB05 /* Track.swift in Sources */,
+				171E4C132DAF108400B7CB11 /* FeatureFlags.swift in Sources */,
 				E12782C61D4AB5CB0025FB05 /* People.swift in Sources */,
 				E19052001F9548F000900E5D /* ReadWriteLock.swift in Sources */,
 				868550AD2699096F001FCDDC /* MixpanelPersistence.swift in Sources */,
@@ -575,13 +593,15 @@
 				E1F15FDC1E64B60A00391AE3 /* AutomaticProperties.swift in Sources */,
 				E1F15FD91E64B60600391AE3 /* MixpanelLogger.swift in Sources */,
 				E1F15FD61E64B5FC00391AE3 /* FlushRequest.swift in Sources */,
+				171E4C1A2DAF2B3100B7CB11 /* MixpanelOptions.swift in Sources */,
 				E1F15FD71E64B60200391AE3 /* PrintLogging.swift in Sources */,
 				8625BEBD26D045CE0009BAA9 /* MPDB.swift in Sources */,
 				95ECF06A2C9B851B006364D2 /* Data+Compression.swift in Sources */,
 				E1F15FE21E64B60D00391AE3 /* Flush.swift in Sources */,
 				E1F15FD51E64B5F800391AE3 /* Network.swift in Sources */,
 				E1F15FDE1E64B60A00391AE3 /* MixpanelType.swift in Sources */,
 				E1F15FDA1E64B60A00391AE3 /* JSONHandler.swift in Sources */,
+				171E4C152DAF108400B7CB11 /* FeatureFlags.swift in Sources */,
 				E1F15FE31E64B60D00391AE3 /* Track.swift in Sources */,
 				E19052011F9548F000900E5D /* ReadWriteLock.swift in Sources */,
 				868550AE2699096F001FCDDC /* MixpanelPersistence.swift in Sources */,

MixpanelDemo/MixpanelDemo.xcodeproj/project.pbxproj

@@ -7,6 +7,7 @@
 	objects = {
 
 /* Begin PBXBuildFile section */
+		171E4C1C2DB055BC00B7CB11 /* MixpanelFeatureFlagTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 171E4C1B2DB055A900B7CB11 /* MixpanelFeatureFlagTests.swift */; };
 		51DD568A1D3077390045D3DB /* LoggerTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 51DD56891D3077390045D3DB /* LoggerTests.swift */; };
 		60CB587123D77F9200F1632B /* LoginViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 60CB587023D77F9200F1632B /* LoginViewController.swift */; };
 		671EECAF21432E5F006DD9FA /* GroupsViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 671EECAE21432E5F006DD9FA /* GroupsViewController.swift */; };
@@ -249,6 +250,7 @@
 /* End PBXCopyFilesBuildPhase section */
 
 /* Begin PBXFileReference section */
+		171E4C1B2DB055A900B7CB11 /* MixpanelFeatureFlagTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MixpanelFeatureFlagTests.swift; sourceTree = "<group>"; };
 		51DD56891D3077390045D3DB /* LoggerTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = LoggerTests.swift; sourceTree = "<group>"; };
 		60CB587023D77F9200F1632B /* LoginViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LoginViewController.swift; sourceTree = "<group>"; };
 		671EECAE21432E5F006DD9FA /* GroupsViewController.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = GroupsViewController.swift; sourceTree = "<group>"; };
@@ -590,6 +592,7 @@
 		E15FF7EA1D0461130076CDE3 /* MixpanelDemoTests */ = {
 			isa = PBXGroup;
 			children = (
+				171E4C1B2DB055A900B7CB11 /* MixpanelFeatureFlagTests.swift */,
 				E124061F1D249B2500383635 /* MixpanelBaseTests.swift */,
 				E15FF7EB1D0461130076CDE3 /* MixpanelDemoTests.swift */,
 				E1C61EB91D22F6470056C56C /* MixpanelPeopleTests.swift */,
@@ -1114,6 +1117,7 @@
 				E12406201D249B2500383635 /* MixpanelBaseTests.swift in Sources */,
 				E17AA05E1EC6234E0066EFE8 /* MixpanelAutomaticEventsTests.swift in Sources */,
 				E15FF7EC1D0461130076CDE3 /* MixpanelDemoTests.swift in Sources */,
+				171E4C1C2DB055BC00B7CB11 /* MixpanelFeatureFlagTests.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};

MixpanelDemo/MixpanelDemo/AppDelegate.swift

@@ -17,7 +17,8 @@ class AppDelegate: UIResponder, UIApplicationDelegate {
     func application(_ application: UIApplication,
                      didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) -> Bool {
         var ADD_YOUR_MIXPANEL_TOKEN_BELOW_🛠🛠🛠🛠🛠🛠: String
-        Mixpanel.initialize(token: "MIXPANEL_TOKEN", trackAutomaticEvents: true)
+        let mixpanelOptions = MixpanelOptions(token: "MIXPANEL_TOKEN", trackAutomaticEvents: true)
+        Mixpanel.initialize(options: mixpanelOptions)
         Mixpanel.mainInstance().loggingEnabled = true
 
         return true

MixpanelDemo/MixpanelDemoTests/MixpanelDemoTests.swift

@@ -179,8 +179,51 @@ class MixpanelDemoTests: MixpanelBaseTests {
         removeDBfile(testMixpanel.apiToken)
     }
 
+    // Mock implementation of MixpanelFlags to track loadFlags calls
+    class MockMixpanelFlags: MixpanelFlags {
+        var delegate: MixpanelFlagDelegate?
+        var loadFlagsCallCount = 0
+
+        func loadFlags() {
+            loadFlagsCallCount += 1
+        }
+
+        func areFlagsReady() -> Bool {
+            return true
+        }
+
+        func getVariantSync(_ flagName: String, fallback: MixpanelFlagVariant) -> MixpanelFlagVariant {
+            return fallback
+        }
+
+        func getVariant(_ flagName: String, fallback: MixpanelFlagVariant, completion: @escaping (MixpanelFlagVariant) -> Void) {
+            completion(fallback)
+        }
+
+        func getVariantValueSync(_ flagName: String, fallbackValue: Any?) -> Any? {
+            return fallbackValue
+        }
+
+        func getVariantValue(_ flagName: String, fallbackValue: Any?, completion: @escaping (Any?) -> Void) {
+            completion(fallbackValue)
+        }
+
+        func isEnabledSync(_ flagName: String, fallbackValue: Bool) -> Bool {
+            return fallbackValue
+        }
+
+        func isEnabled(_ flagName: String, fallbackValue: Bool, completion: @escaping (Bool) -> Void) {
+            completion(fallbackValue)
+        }
+    }
+
     func testIdentify() {
         let testMixpanel = Mixpanel.initialize(token: randomId(), trackAutomaticEvents: true, flushInterval: 60)
+
+        // Inject our mock flags object
+        let mockFlags = MockMixpanelFlags()
+        testMixpanel.flags = mockFlags
+
         for _ in 0..<2 {
             // run this twice to test reset works correctly wrt to distinct ids
             let distinctId: String = "d1"
@@ -221,8 +264,16 @@ class MixpanelDemoTests: MixpanelBaseTests {
             XCTAssertEqual(unidentifiedQueue.last?["$token"] as? String,
                            testMixpanel.apiToken,
                            "incorrect project token in people record")
+            // Record the loadFlags call count before identify
+            let loadFlagsCallCountBefore = mockFlags.loadFlagsCallCount
+
             testMixpanel.identify(distinctId: distinctId)
             waitForTrackingQueue(testMixpanel)
+
+            // Assert that loadFlags was called when distinctId changed
+            XCTAssertEqual(mockFlags.loadFlagsCallCount, loadFlagsCallCountBefore + 1,
+                          "loadFlags should be called when distinctId changes during identify")
+
             let anonymousId = testMixpanel.anonymousId
             peopleQueue_value = peopleQueue(token: testMixpanel.apiToken)
             unidentifiedQueue = unIdentifiedPeopleQueue(token: testMixpanel.apiToken)
@@ -263,6 +314,14 @@ class MixpanelDemoTests: MixpanelBaseTests {
             let newDistinctId = (eventQueue(token: testMixpanel.apiToken).last?["properties"] as? InternalProperties)?["distinct_id"] as? String
             XCTAssertEqual(newDistinctId, distinctId,
                            "events should use new distinct id after identify:")
+
+            // Test that calling identify with the same distinctId does NOT trigger loadFlags
+            let loadFlagsCountBeforeSameId = mockFlags.loadFlagsCallCount
+            testMixpanel.identify(distinctId: distinctId) // Same distinctId
+            waitForTrackingQueue(testMixpanel)
+            XCTAssertEqual(mockFlags.loadFlagsCallCount, loadFlagsCountBeforeSameId,
+                          "loadFlags should NOT be called when distinctId doesn't change")
+
             testMixpanel.reset()
             waitForTrackingQueue(testMixpanel)
         }