chore!: remove the v2 legacy queue migration for v4

.changeset/v4-remove-legacy-queue-migration.md

@@ -0,0 +1,9 @@
+---
+'posthog-ios': major
+---
+
+**Breaking:** remove the migration of the event queue written by SDK 2.x (`posthog.queue.plist`).
+
+Events still queued on disk by a 2.x SDK are deleted instead of sent when the app updates straight from 2.x to 4.0. Distinct ID, anonymous ID, groups and cached feature flags are still carried over. Events created by a 3.x SDK are not affected.
+
+Queued events are no longer read in the 2.x format: a top-level `$set` and `message_id` are ignored. This includes 2.x events that 3.x imported and had not sent yet when the app updated to 4.0.

PostHog.xcodeproj/project.pbxproj

@@ -23,6 +23,7 @@
 		BF5E00000000000000000002 /* PHObjCExceptionCatcher.h in Headers */ = {isa = PBXBuildFile; fileRef = BF5E00000000000000000006 /* PHObjCExceptionCatcher.h */; settings = {ATTRIBUTES = (Private, ); }; };
 		BF5E00000000000000000003 /* PHObjCExceptionCatcher.m in Sources */ = {isa = PBXBuildFile; fileRef = BF5E00000000000000000007 /* PHObjCExceptionCatcher.m */; };
 		D0E500012FA0000100000002 /* PostHogEventSnapshotTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0E500012FA0000100000001 /* PostHogEventSnapshotTests.swift */; };
+		D0E500022FA0000100000002 /* PostHogEventTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0E500022FA0000100000001 /* PostHogEventTest.swift */; };
 		D0E500012FA0000100000021 /* event-shapes-batch.json in Resources */ = {isa = PBXBuildFile; fileRef = D0E500012FA0000100000011 /* event-shapes-batch.json */; };
 		D0E500012FA0000100000022 /* feature-flags-request.json in Resources */ = {isa = PBXBuildFile; fileRef = D0E500012FA0000100000012 /* feature-flags-request.json */; };
 		D0E500012FA0000100000023 /* session-replay-request.json in Resources */ = {isa = PBXBuildFile; fileRef = D0E500012FA0000100000013 /* session-replay-request.json */; };
@@ -95,8 +96,6 @@
 		6A11C0DE2026092800000011 /* PostHogSurveySheetDetentsTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6A11C0DE2026092800000012 /* PostHogSurveySheetDetentsTest.swift */; };
 		6A11C0DE2026092800000003 /* PostHogHingeStatusTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6A11C0DE2026092800000004 /* PostHogHingeStatusTest.swift */; };
 		690FF0BF2AEFA97F00A0B06B /* FileUtils.swift in Sources */ = {isa = PBXBuildFile; fileRef = 690FF0BE2AEFA97F00A0B06B /* FileUtils.swift */; };
-		690FF0C52AEFAE8200A0B06B /* PostHogLegacyQueue.swift in Sources */ = {isa = PBXBuildFile; fileRef = 690FF0C42AEFAE8200A0B06B /* PostHogLegacyQueue.swift */; };
-		690FF0DF2AEFBC5700A0B06B /* PostHogLegacyQueueTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = 690FF0DE2AEFBC5700A0B06B /* PostHogLegacyQueueTest.swift */; };
 		690FF0E12AEFC59100A0B06B /* PostHogFileBackedQueueTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = 690FF0E02AEFC59100A0B06B /* PostHogFileBackedQueueTest.swift */; };
 		690FF0E32AEFD12900A0B06B /* PostHogConfigTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = 690FF0E22AEFD12900A0B06B /* PostHogConfigTest.swift */; };
 		6A0C1F2E3B4D5A6B7C8D9E02 /* PostHogOptOutPersistenceTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6A0C1F2E3B4D5A6B7C8D9E01 /* PostHogOptOutPersistenceTest.swift */; };
@@ -864,6 +863,7 @@
 		BF5E00000000000000000006 /* PHObjCExceptionCatcher.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = PHObjCExceptionCatcher.h; sourceTree = "<group>"; };
 		BF5E00000000000000000007 /* PHObjCExceptionCatcher.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = PHObjCExceptionCatcher.m; sourceTree = "<group>"; };
 		D0E500012FA0000100000001 /* PostHogEventSnapshotTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PostHogEventSnapshotTests.swift; sourceTree = "<group>"; };
+		D0E500022FA0000100000001 /* PostHogEventTest.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PostHogEventTest.swift; sourceTree = "<group>"; };
 		D0E500012FA0000100000011 /* event-shapes-batch.json */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.json; path = "event-shapes-batch.json"; sourceTree = "<group>"; };
 		D0E500012FA0000100000012 /* feature-flags-request.json */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.json; path = "feature-flags-request.json"; sourceTree = "<group>"; };
 		D0E500012FA0000100000013 /* session-replay-request.json */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.json; path = "session-replay-request.json"; sourceTree = "<group>"; };
@@ -958,8 +958,6 @@
 		6A11C0DE2026092800000012 /* PostHogSurveySheetDetentsTest.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PostHogSurveySheetDetentsTest.swift; sourceTree = "<group>"; };
 		6A11C0DE2026092800000004 /* PostHogHingeStatusTest.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PostHogHingeStatusTest.swift; sourceTree = "<group>"; };
 		690FF0BE2AEFA97F00A0B06B /* FileUtils.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FileUtils.swift; sourceTree = "<group>"; };
-		690FF0C42AEFAE8200A0B06B /* PostHogLegacyQueue.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PostHogLegacyQueue.swift; sourceTree = "<group>"; };
-		690FF0DE2AEFBC5700A0B06B /* PostHogLegacyQueueTest.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PostHogLegacyQueueTest.swift; sourceTree = "<group>"; };
 		690FF0E02AEFC59100A0B06B /* PostHogFileBackedQueueTest.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PostHogFileBackedQueueTest.swift; sourceTree = "<group>"; };
 		690FF0E22AEFD12900A0B06B /* PostHogConfigTest.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PostHogConfigTest.swift; sourceTree = "<group>"; };
 		6A0C1F2E3B4D5A6B7C8D9E01 /* PostHogOptOutPersistenceTest.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PostHogOptOutPersistenceTest.swift; sourceTree = "<group>"; };
@@ -1808,7 +1806,6 @@
 				6926DA8D2ADD2876005760D2 /* PostHogContext.swift */,
 				6A11C0DE2026092800000002 /* PostHogHingeStatusObserver.swift */,
 				69779BEB2AE68E6900D7A48E /* UIViewController.swift */,
-				690FF0C42AEFAE8200A0B06B /* PostHogLegacyQueue.swift */,
 				69F518372BB2BA0100F52C14 /* PostHogSwizzler.swift */,
 				69ED1A5B2C7F15F300FE7A91 /* PostHogSessionManager.swift */,
 				B5EB989F28A201A9F44026EE /* PostHogCompression.swift */,
@@ -1847,6 +1844,7 @@
 				B74800000000000000000004 /* PostHogTests-Bridging-Header.h */,
 				B74800000000000000000003 /* PostHogPushNotificationSwizzlingTest.swift */,
 				D0E500012FA0000100000001 /* PostHogEventSnapshotTests.swift */,
+				D0E500022FA0000100000001 /* PostHogEventTest.swift */,
 				DA27AEC82F56B3F3002A59CE /* PostHogSamplingTest.swift */,
 				DA27AEF12F56B3F3002A59CE /* PostHogGeoIpTest.swift */,
 				DB7100052F80000100000001 /* PostHogTracingHeadersTest.swift */,
@@ -1879,7 +1877,6 @@
 				6A11C0DE2026092300000002 /* PostHogContextScreenSizeTest.swift */,
 				6A11C0DE2026092800000012 /* PostHogSurveySheetDetentsTest.swift */,
 				6A11C0DE2026092800000004 /* PostHogHingeStatusTest.swift */,
-				690FF0DE2AEFBC5700A0B06B /* PostHogLegacyQueueTest.swift */,
 				DA4FFB142DA93C78006BAEEA /* PostHogSessionReplayTest.swift */,
 				DA4FFB182DA93C78006BAEEA /* PostHogReplayScreenshotDedupTest.swift */,
 				EA5700022DA93C78006BAEEA /* PostHogReplayCaptureTouchesTest.swift */,
@@ -3623,7 +3620,6 @@
 				DA3BB5052EDF15320097A97A /* PostHogStackFrame.swift in Sources */,
 				DACC08BB2D6E3C6D00115E46 /* PostHogIntegration.swift in Sources */,
 				DAD5DD0C2CB6DEF30087387B /* PostHogMaskViewModifier.swift in Sources */,
-				690FF0C52AEFAE8200A0B06B /* PostHogLegacyQueue.swift in Sources */,
 				3AE3FB332991388500AFFC18 /* PostHogQueue.swift in Sources */,
 				DA1044882D0B1D2D00C4ACF3 /* View+PostHogLabel.swift in Sources */,
 				DAA1B2F12F8C100000112233 /* View+PostHogNoRageClick.swift in Sources */,
@@ -3751,6 +3747,7 @@
 				BF5E00000000000000000001 /* PHBeforeSendExceptionTestFixture.m in Sources */,
 				B74800000000000000000002 /* PHNotificationDelegateTestFixture.m in Sources */,
 				D0E500012FA0000100000002 /* PostHogEventSnapshotTests.swift in Sources */,
+				D0E500022FA0000100000002 /* PostHogEventTest.swift in Sources */,
 				DA979D7B2CD370B700F56BAE /* PostHogAutocaptureEventTrackerSpec.swift in Sources */,
 				DA0C944B2D54CDD000BFD9FB /* PostHogStorageMigrationTest.swift in Sources */,
 				690FF0F52AF0F06100A0B06B /* PostHogSDKTest.swift in Sources */,
@@ -3809,7 +3806,6 @@
 				DADE7DFE2F7EA90D00C4650C /* PostHogDeepLinkIntegrationTests.swift in Sources */,
 				DA52CAEF2F24319800305F3D /* PostHogSessionReplayPluginTest.swift in Sources */,
 				DA52CAEF2F2431980030AA01 /* PostHogConsoleLogInterceptorTest.swift in Sources */,
-				690FF0DF2AEFBC5700A0B06B /* PostHogLegacyQueueTest.swift in Sources */,
 				DA6F24822D4A6CA100CA2777 /* PostHogApiTest.swift in Sources */,
 				AE3C6A5B6DAB01EF554A0270 /* PostHogPushNotificationTest.swift in Sources */,
 				D36F92424A13D7CE61B6E348 /* PostHogSwizzlerTest.swift in Sources */,

PostHog/Models/PostHogEvent.swift

@@ -62,18 +62,11 @@ import Foundation
 
         let timestampDate = toISO8601Date(timestamp) ?? Date()
 
-        var properties = (json["properties"] as? [String: Any]) ?? [:]
-
-        // back compatibility with v2
-        let setProps = json["$set"] as? [String: Any]
-        if setProps != nil {
-            properties["$set"] = setProps
-        }
+        let properties = (json["properties"] as? [String: Any]) ?? [:]
 
         guard let distinctId = (json["distinct_id"] as? String) ?? (properties["distinct_id"] as? String) else { return nil }
 
-        // `message_id` is deprecated and only accepted for backwards compatibility with legacy persisted events.
-        let uuid = ((json["uuid"] as? String) ?? (json["message_id"] as? String)) ?? UUID.v7String()
+        let uuid = (json["uuid"] as? String) ?? UUID.v7String()
         let uuidObj = UUID(uuidString: uuid) ?? UUID.v7()
 
         // Wire field name remains api_key, but it carries the PostHog project token.

PostHog/PostHogFileBackedQueue.swift

@@ -43,7 +43,7 @@ class PostHogFileBackedQueue {
                     migrateOldQueueFolder(queue: queue, oldQueueFolder: oldQueue)
                 } else {
                     // old plist file
-                    migrateOldQueue(queue: queue, oldQueue: oldQueue)
+                    deleteSafely(oldQueue)
                 }
             }
         }

PostHogTests/PostHogEventTest.swift

@@ -0,0 +1,38 @@
+import Foundation
+@testable import PostHog
+import Testing
+
+@Suite("PostHogEvent JSON decoding")
+struct PostHogEventTest {
+    @Test("ignores the 2.x top-level $set and message_id")
+    func ignoresV2Fields() throws {
+        let messageId = "5CE069F8-E967-4B47-9D89-207EF7519453"
+        let json: [String: Any] = [
+            "event": "test",
+            "distinct_id": "user",
+            "properties": ["key": "value"],
+            "$set": ["plan": "pro"],
+            "message_id": messageId,
+        ]
+
+        let event = try #require(PostHogEvent.fromJSON(json))
+
+        #expect(event.properties["$set"] == nil)
+        #expect(event.properties["key"] as? String == "value")
+        #expect(event.uuid.uuidString != messageId)
+    }
+
+    @Test("reads uuid")
+    func readsUuid() throws {
+        let uuid = "019A0000-0000-7000-8000-000000000001"
+        let json: [String: Any] = [
+            "event": "test",
+            "distinct_id": "user",
+            "uuid": uuid,
+        ]
+
+        let event = try #require(PostHogEvent.fromJSON(json))
+
+        #expect(event.uuid.uuidString == uuid)
+    }
+}

PostHogTests/PostHogFileBackedQueueAlignmentTest.swift

@@ -31,6 +31,22 @@ struct PostHogFileBackedQueueAlignmentTest {
         data.map { String(data: $0, encoding: .utf8)! }
     }
 
+    @Test("deletes a v2 queue file without importing its events")
+    func deletesLegacyQueueFile() throws {
+        let dir = FileManager.default.temporaryDirectory
+            .appendingPathComponent("ph-queue-align-\(UUID().uuidString)")
+        let oldQueue = FileManager.default.temporaryDirectory
+            .appendingPathComponent("ph-queue-plist-\(UUID().uuidString)")
+        defer { try? FileManager.default.removeItem(at: dir) }
+        try Data(#"[{"event":"v2 event","distinct_id":"user","timestamp":"2023-10-25T14:14:04.407Z"}]"#.utf8)
+            .write(to: oldQueue)
+
+        let queue = PostHogFileBackedQueue(queue: dir, oldQueues: [oldQueue])
+
+        #expect(!FileManager.default.fileExists(atPath: oldQueue.path))
+        #expect(queue.depth == 0)
+    }
+
     @Test("a failed write to a full queue preserves existing entries", .enabled(if: geteuid() != 0))
     func failedWritePreservesFullQueue() throws {
         let (queue, dir) = makeQueue()