Merge pull request #111 from ably/AIT-255-fix-replace-data-events

[AIT-255] Fix events emitted upon sync

Author: lawrence-forooghian

Sources/AblyLiveObjects/Internal/InternalDefaultLiveCounter.swift

@@ -331,19 +331,23 @@ internal final class InternalDefaultLiveCounter: Sendable {
                 return .update(.init(amount: -dataBeforeTombstoning))
             }
 
+            // RTLC6g: Store the current data value as previousData for use in RTLC6h
+            let previousData = data
+
             // RTLC6b: Set the private flag createOperationIsMerged to false
             liveObjectMutableState.createOperationIsMerged = false
 
             // RTLC6c: Set data to the value of ObjectState.counter.count, or to 0 if it does not exist
             data = state.counter?.count?.doubleValue ?? 0
 
             // RTLC6d: If ObjectState.createOp is present, merge the initial value into the LiveCounter as described in RTLC10
-            return if let createOp = state.createOp {
-                mergeInitialValue(from: createOp)
-            } else {
-                // TODO: I assume this is what to do, clarify in https://github.com/ably/specification/pull/346/files#r2201363446
-                .noop
+            // Discard the LiveCounterUpdate object returned by the merge operation
+            if let createOp = state.createOp {
+                _ = mergeInitialValue(from: createOp)
             }
+
+            // RTLC6h: Calculate the diff between previousData and the current data per RTLC14
+            return ObjectDiffHelpers.calculateCounterDiff(previousData: previousData, newData: data)
         }
 
         /// Merges the initial value from an ObjectOperation into this LiveCounter, per RTLC10.

Sources/AblyLiveObjects/Internal/InternalDefaultLiveMap.swift

@@ -468,6 +468,9 @@ internal final class InternalDefaultLiveMap: Sendable {
                 return .update(.init(update: dataBeforeTombstoning.mapValues { _ in .removed }))
             }
 
+            // RTLM6g: Store the current data value as previousData for use in RTLM6h
+            let previousData = data
+
             // RTLM6b: Set the private flag createOperationIsMerged to false
             liveObjectMutableState.createOperationIsMerged = false
 
@@ -493,19 +496,20 @@ internal final class InternalDefaultLiveMap: Sendable {
             } ?? [:]
 
             // RTLM6d: If ObjectState.createOp is present, merge the initial value into the LiveMap as described in RTLM17
-            return if let createOp = state.createOp {
-                mergeInitialValue(
+            // Discard the LiveMapUpdate object returned by the merge operation
+            if let createOp = state.createOp {
+                _ = mergeInitialValue(
                     from: createOp,
                     objectsPool: &objectsPool,
                     logger: logger,
                     internalQueue: internalQueue,
                     userCallbackQueue: userCallbackQueue,
                     clock: clock,
                 )
-            } else {
-                // TODO: I assume this is what to do, clarify in https://github.com/ably/specification/pull/346/files#r2201363446
-                .noop
             }
+
+            // RTLM6h: Calculate the diff between previousData and the current data per RTLM22
+            return ObjectDiffHelpers.calculateMapDiff(previousData: previousData, newData: data)
         }
 
         /// Merges the initial value from an ObjectOperation into this LiveMap, per RTLM17.

Sources/AblyLiveObjects/Internal/ObjectDiffHelpers.swift

@@ -0,0 +1,57 @@
+import Foundation
+
+/// Helper methods for calculating diffs between LiveObject data values.
+internal enum ObjectDiffHelpers {
+    /// Calculates the diff between two LiveCounter data values, per RTLC14.
+    ///
+    /// - Parameters:
+    ///   - previousData: The previous `data` value (RTLC14a1).
+    ///   - newData: The new `data` value (RTLC14a2).
+    /// - Returns: Per RTLC14b.
+    internal static func calculateCounterDiff(
+        previousData: Double,
+        newData: Double,
+    ) -> LiveObjectUpdate<DefaultLiveCounterUpdate> {
+        // RTLC14b
+        .update(DefaultLiveCounterUpdate(amount: newData - previousData))
+    }
+
+    /// Calculates the diff between two LiveMap data values, per RTLM22.
+    ///
+    /// - Parameters:
+    ///   - previousData: The previous `data` value (RTLM22a1).
+    ///   - newData: The new `data` value (RTLM22a2).
+    /// - Returns: Per RTLM22b.
+    internal static func calculateMapDiff(
+        previousData: [String: InternalObjectsMapEntry],
+        newData: [String: InternalObjectsMapEntry],
+    ) -> LiveObjectUpdate<DefaultLiveMapUpdate> {
+        // RTLM22b
+        let previousNonTombstonedKeys = Set(previousData.filter { !$0.value.tombstone }.keys)
+        let newNonTombstonedKeys = Set(newData.filter { !$0.value.tombstone }.keys)
+
+        var update: [String: LiveMapUpdateAction] = [:]
+
+        // RTLM22b1
+        for key in previousNonTombstonedKeys.subtracting(newNonTombstonedKeys) {
+            update[key] = .removed
+        }
+
+        // RTLM22b2
+        for key in newNonTombstonedKeys.subtracting(previousNonTombstonedKeys) {
+            update[key] = .updated
+        }
+
+        // RTLM22b3
+        for key in previousNonTombstonedKeys.intersection(newNonTombstonedKeys) {
+            let previousEntry = previousData[key]!
+            let newEntry = newData[key]!
+
+            if previousEntry.data != newEntry.data {
+                update[key] = .updated
+            }
+        }
+
+        return .update(DefaultLiveMapUpdate(update: update))
+    }
+}

Tests/AblyLiveObjectsTests/InternalDefaultLiveCounterTests.swift

@@ -149,6 +149,64 @@ struct InternalDefaultLiveCounterTests {
                 #expect(counter.testsOnly_createOperationIsMerged)
             }
         }
+
+        /// Tests for RTLC6h (diff calculation on replaceData)
+        struct DiffCalculationTests {
+            // @specOneOf(1/2) RTLC6h - Tests that replaceData returns the diff calculated via RTLC14
+            @Test
+            func returnsCorrectDiffWithoutCreateOp() throws {
+                let logger = TestLogger()
+                let internalQueue = TestFactories.createInternalQueue()
+                let counter = InternalDefaultLiveCounter.createZeroValued(objectID: "arbitrary", logger: logger, internalQueue: internalQueue, userCallbackQueue: .main, clock: MockSimpleClock())
+                let coreSDK = MockCoreSDK(channelState: .attaching, internalQueue: internalQueue)
+
+                // Set initial data to 10
+                internalQueue.ably_syncNoDeadlock {
+                    _ = counter.nosync_replaceData(using: TestFactories.counterObjectState(count: 10), objectMessageSerialTimestamp: nil)
+                }
+                #expect(try counter.value(coreSDK: coreSDK) == 10)
+
+                // Replace data with count 25 (no createOp)
+                let update = internalQueue.ably_syncNoDeadlock {
+                    counter.nosync_replaceData(using: TestFactories.counterObjectState(count: 25), objectMessageSerialTimestamp: nil)
+                }
+
+                // RTLC6h: Should return diff from previousData (10) to newData (25) = 15
+                #expect(try #require(update.update).amount == 15)
+                #expect(try counter.value(coreSDK: coreSDK) == 25)
+            }
+
+            // @specOneOf(2/2) RTLC6h - Tests that replaceData returns the diff after merging createOp
+            @Test
+            func returnsCorrectDiffWithCreateOp() throws {
+                let logger = TestLogger()
+                let internalQueue = TestFactories.createInternalQueue()
+                let counter = InternalDefaultLiveCounter.createZeroValued(objectID: "arbitrary", logger: logger, internalQueue: internalQueue, userCallbackQueue: .main, clock: MockSimpleClock())
+                let coreSDK = MockCoreSDK(channelState: .attaching, internalQueue: internalQueue)
+
+                // Set initial data to 10
+                internalQueue.ably_syncNoDeadlock {
+                    _ = counter.nosync_replaceData(using: TestFactories.counterObjectState(count: 10), objectMessageSerialTimestamp: nil)
+                }
+                #expect(try counter.value(coreSDK: coreSDK) == 10)
+
+                // Replace data with count 5 and createOp with count 8
+                // This should set data to 5, then add 8 (mergeInitialValue), resulting in 13
+                let update = internalQueue.ably_syncNoDeadlock {
+                    counter.nosync_replaceData(
+                        using: TestFactories.counterObjectState(
+                            createOp: TestFactories.counterCreateOperation(count: 8),
+                            count: 5,
+                        ),
+                        objectMessageSerialTimestamp: nil,
+                    )
+                }
+
+                // RTLC6h: Should return diff from previousData (10) to newData (13) = 3
+                #expect(try #require(update.update).amount == 3)
+                #expect(try counter.value(coreSDK: coreSDK) == 13)
+            }
+        }
     }
 
     /// Tests for the `mergeInitialValue` method, covering RTLC10 specification points

Tests/AblyLiveObjectsTests/InternalDefaultLiveMapTests.swift

@@ -293,6 +293,107 @@ struct InternalDefaultLiveMapTests {
             #expect(try map.get(key: "keyFromCreateOp", coreSDK: coreSDK, delegate: delegate)?.stringValue == "valueFromCreateOp")
             #expect(map.testsOnly_createOperationIsMerged)
         }
+
+        /// Tests for RTLM6h (diff calculation on replaceData)
+        struct DiffCalculationTests {
+            // @specOneOf(1/2) RTLM6h - Tests that replaceData returns the diff calculated via RTLM22
+            @Test
+            func returnsCorrectDiffWithoutCreateOp() throws {
+                let logger = TestLogger()
+                let internalQueue = TestFactories.createInternalQueue()
+                let map = InternalDefaultLiveMap.createZeroValued(objectID: "arbitrary", logger: logger, internalQueue: internalQueue, userCallbackQueue: .main, clock: MockSimpleClock())
+
+                // Set initial data
+                var pool = ObjectsPool(logger: logger, internalQueue: internalQueue, userCallbackQueue: .main, clock: MockSimpleClock())
+                internalQueue.ably_syncNoDeadlock {
+                    _ = map.nosync_replaceData(
+                        using: TestFactories.mapObjectState(
+                            objectId: "arbitrary-id",
+                            entries: [
+                                "key1": TestFactories.stringMapEntry(key: "key1", value: "value1").entry,
+                                "key2": TestFactories.stringMapEntry(key: "key2", value: "value2").entry,
+                            ],
+                        ),
+                        objectMessageSerialTimestamp: nil,
+                        objectsPool: &pool,
+                    )
+                }
+
+                // Replace data with modified entries (no createOp)
+                let update = internalQueue.ably_syncNoDeadlock {
+                    map.nosync_replaceData(
+                        using: TestFactories.mapObjectState(
+                            objectId: "arbitrary-id",
+                            entries: [
+                                "key1": TestFactories.stringMapEntry(key: "key1", value: "updatedValue").entry,
+                                "key3": TestFactories.stringMapEntry(key: "key3", value: "value3").entry,
+                            ],
+                        ),
+                        objectMessageSerialTimestamp: nil,
+                        objectsPool: &pool,
+                    )
+                }
+
+                // RTLM6h: Should return diff per RTLM22
+                // key1: updated (changed value), key2: removed, key3: added
+                let updateDict = try #require(update.update).update
+                #expect(updateDict["key1"] == .updated) // value changed
+                #expect(updateDict["key2"] == .removed) // removed
+                #expect(updateDict["key3"] == .updated) // added
+            }
+
+            // @specOneOf(2/2) RTLM6h - Tests that replaceData returns the diff after merging createOp
+            @Test
+            func returnsCorrectDiffWithCreateOp() throws {
+                let logger = TestLogger()
+                let internalQueue = TestFactories.createInternalQueue()
+                let map = InternalDefaultLiveMap.createZeroValued(objectID: "arbitrary", logger: logger, internalQueue: internalQueue, userCallbackQueue: .main, clock: MockSimpleClock())
+
+                // Set initial data
+                var pool = ObjectsPool(logger: logger, internalQueue: internalQueue, userCallbackQueue: .main, clock: MockSimpleClock())
+                internalQueue.ably_syncNoDeadlock {
+                    _ = map.nosync_replaceData(
+                        using: TestFactories.mapObjectState(
+                            objectId: "arbitrary-id",
+                            entries: [
+                                "existing": TestFactories.stringMapEntry(key: "existing", value: "value").entry,
+                            ],
+                        ),
+                        objectMessageSerialTimestamp: nil,
+                        objectsPool: &pool,
+                    )
+                }
+
+                // Replace data with entries and createOp
+                let update = internalQueue.ably_syncNoDeadlock {
+                    map.nosync_replaceData(
+                        using: TestFactories.objectState(
+                            objectId: "arbitrary-id",
+                            createOp: TestFactories.mapCreateOperation(
+                                objectId: "arbitrary-id",
+                                entries: [
+                                    "fromCreateOp": TestFactories.stringMapEntry(key: "fromCreateOp", value: "value").entry,
+                                ],
+                            ),
+                            map: ObjectsMap(
+                                semantics: .known(.lww),
+                                entries: [
+                                    "fromEntries": TestFactories.stringMapEntry(key: "fromEntries", value: "value").entry,
+                                ],
+                            ),
+                        ),
+                        objectMessageSerialTimestamp: nil,
+                        objectsPool: &pool,
+                    )
+                }
+
+                // RTLM6h: Should return diff from previousData to final data (after createOp merge)
+                let updateDict = try #require(update.update).update
+                #expect(updateDict["existing"] == .removed) // removed
+                #expect(updateDict["fromEntries"] == .updated) // added
+                #expect(updateDict["fromCreateOp"] == .updated) // added via createOp
+            }
+        }
     }
 
     /// Tests for the `size`, `entries`, `keys`, and `values` properties, covering RTLM10, RTLM11, RTLM12, and RTLM13 specification points