fix: feature_flag_called after reloadFeatureFlags

CHANGELOG.md

@@ -1,5 +1,7 @@
 ## Next
 
+- fix $feature_flag_called not captured after reloading flags ([#232](https://github.com/PostHog/posthog-ios/pull/232))
+
 ## 3.14.1 - 2024-11-05
 
 - recording: fix RN iOS masking ([#230](https://github.com/PostHog/posthog-ios/pull/230))

PostHog/PostHogSDK.swift

@@ -30,6 +30,7 @@ let maxRetryDelay = 30.0
     private let setupLock = NSLock()
     private let optOutLock = NSLock()
     private let groupsLock = NSLock()
+    private let featureFlagsLock = NSLock()
     private let personPropsLock = NSLock()
 
     private var queue: PostHogQueue?
@@ -345,7 +346,9 @@ let maxRetryDelay = 30.0
         // storage also removes all feature flags
         storage?.reset()
         config.storageManager?.reset()
-        flagCallReported.removeAll()
+        featureFlagsLock.withLock {
+            flagCallReported.removeAll()
+        }
         PostHogSessionManager.shared.endSession {
             self.resetViews()
         }
@@ -791,7 +794,12 @@ let maxRetryDelay = 30.0
             distinctId: storageManager.getDistinctId(),
             anonymousId: storageManager.getAnonymousId(),
             groups: groups ?? [:],
-            callback: callback
+            callback: {
+                self.featureFlagsLock.withLock {
+                    self.flagCallReported.removeAll()
+                }
+                callback()
+            }
         )
     }
 
@@ -844,15 +852,17 @@ let maxRetryDelay = 30.0
     }
 
     private func reportFeatureFlagCalled(flagKey: String, flagValue: Any?) {
-        if !flagCallReported.contains(flagKey) {
-            let properties: [String: Any] = [
-                "$feature_flag": flagKey,
-                "$feature_flag_response": flagValue ?? "",
-            ]
+        featureFlagsLock.withLock {
+            if !flagCallReported.contains(flagKey) {
+                let properties: [String: Any] = [
+                    "$feature_flag": flagKey,
+                    "$feature_flag_response": flagValue ?? "",
+                ]
 
-            flagCallReported.insert(flagKey)
+                flagCallReported.insert(flagKey)
 
-            capture("$feature_flag_called", properties: properties)
+                capture("$feature_flag_called", properties: properties)
+            }
         }
     }
 
@@ -926,7 +936,9 @@ let maxRetryDelay = 30.0
                 self.reachability?.stopNotifier()
                 reachability = nil
             #endif
-            flagCallReported.removeAll()
+            featureFlagsLock.withLock {
+                flagCallReported.removeAll()
+            }
             context = nil
             PostHogSessionManager.shared.endSession {
                 self.resetViews()

PostHogTests/PostHogSDKTest.swift

@@ -10,18 +10,21 @@ import Nimble
 import Quick
 
 @testable import PostHog
+import XCTest
 
 class PostHogSDKTest: QuickSpec {
     func getSut(preloadFeatureFlags: Bool = false,
                 sendFeatureFlagEvent: Bool = false,
                 captureApplicationLifecycleEvents: Bool = false,
                 flushAt: Int = 1,
+                maxBatchSize: Int = 50,
                 optOut: Bool = false,
                 propertiesSanitizer: PostHogPropertiesSanitizer? = nil,
                 personProfiles: PostHogPersonProfiles = .identifiedOnly) -> PostHogSDK
     {
         let config = PostHogConfig(apiKey: "123", host: "http://localhost:9001")
         config.flushAt = flushAt
+        config.maxBatchSize = maxBatchSize
         config.preloadFeatureFlags = preloadFeatureFlags
         config.sendFeatureFlagEvent = sendFeatureFlagEvent
         config.disableReachabilityForTesting = true
@@ -847,6 +850,51 @@ class PostHogSDKTest: QuickSpec {
             sut.reset()
             sut.close()
         }
+
+        it("captures $feature_flag_called when getFeatureFlag is called") {
+            let sut = self.getSut(sendFeatureFlagEvent: true)
+            let group = DispatchGroup()
+            group.enter()
+
+            _ = sut.getFeatureFlag("some_key")
+
+            let event = getBatchedEvents(server)
+            expect(event.first!.event).to(equal("$feature_flag_called"))
+        }
+
+        it("does not capture $feature_flag_called when getFeatureFlag is called twice") {
+            let sut = self.getSut(
+                sendFeatureFlagEvent: true,
+                flushAt: 2
+            )
+
+            _ = sut.getFeatureFlag("some_key")
+            _ = sut.getFeatureFlag("some_key")
+            sut.capture("force_batch_flush")
+
+            let event = getBatchedEvents(server)
+            expect(event.count).to(equal(2))
+            expect(event[0].event).to(equal("$feature_flag_called"))
+            expect(event[1].event).to(equal("force_batch_flush"))
+        }
+
+        it("captures $feature_flag_called when getFeatureFlag called twice after reloading flags") {
+            let sut = self.getSut(
+                sendFeatureFlagEvent: true,
+                flushAt: 2
+            )
+
+            _ = sut.getFeatureFlag("some_key")
+
+            sut.reloadFeatureFlags {
+                _ = sut.getFeatureFlag("some_key")
+            }
+
+            let event = getBatchedEvents(server)
+            expect(event.count).to(equal(2))
+            expect(event[0].event).to(equal("$feature_flag_called"))
+            expect(event[1].event).to(equal("$feature_flag_called"))
+        }
     }
 }