fix: if a state older than the currentState is put into handleState, a B-A-B sequence of state changes can happen (SOFIE-3889)

packages/timeline-state-resolver/package.json

@@ -109,7 +109,7 @@
 		"p-timeout": "^3.2.0",
 		"simple-oauth2": "^5.0.0",
 		"sprintf-js": "^1.1.3",
-		"superfly-timeline": "9.0.2",
+		"superfly-timeline": "9.1.2",
 		"threadedclass": "^1.2.1",
 		"timeline-state-resolver-types": "9.2.0",
 		"tslib": "^2.6.2",

packages/timeline-state-resolver/src/service/__tests__/stateHandler.spec.ts

@@ -203,6 +203,78 @@ describe('stateHandler', () => {
 			},
 		})
 	})
+
+	test('ignore transitions to states older than current state', async () => {
+		const stateHandler = getNewStateHandler()
+
+		stateHandler
+			.setCurrentState({
+				entry1: { value: true },
+			})
+			.catch((e) => {
+				console.error('Error while setting current state', e)
+			})
+
+		stateHandler.handleState(createTimelineState(10000, {}), {}).catch((e) => {
+			console.error('Error while handling state', e)
+		})
+
+		await mockTime.tick()
+
+		expect(MOCK_COMMAND_RECEIVER).toHaveBeenCalledTimes(1)
+		expect(MOCK_COMMAND_RECEIVER).toHaveBeenCalledWith({
+			command: {
+				type: 'removed',
+				property: 'entry1',
+			},
+		})
+
+		stateHandler
+			.handleState(
+				createTimelineState(10100, {
+					entry1: { value: true },
+				}),
+				{}
+			)
+			.catch((e) => {
+				console.error('Error while handling state', e)
+			})
+
+		await mockTime.tick()
+
+		// do not expect to be called because this is in the future
+		expect(MOCK_COMMAND_RECEIVER).toHaveBeenCalledTimes(1)
+
+		// advance time
+		MOCK_COMMAND_RECEIVER.mockReset()
+		await mockTime.advanceTimeTicks(100)
+
+		// now expect to be called with new commands
+		expect(MOCK_COMMAND_RECEIVER).toHaveBeenCalledTimes(1)
+		expect(MOCK_COMMAND_RECEIVER).toHaveBeenCalledWith({
+			command: {
+				type: 'added',
+				property: 'entry1',
+			},
+		})
+
+		//
+		MOCK_COMMAND_RECEIVER.mockReset()
+
+		stateHandler.handleState(createTimelineState(10000, {}), {}).catch((e) => {
+			console.error('Error while handling state', e)
+		})
+
+		await mockTime.tick()
+
+		// do not expect to be called because new state is in the past
+		expect(MOCK_COMMAND_RECEIVER).toHaveBeenCalledTimes(0)
+
+		await mockTime.advanceTimeTicks(100)
+
+		// still no new commands to be received
+		expect(MOCK_COMMAND_RECEIVER).toHaveBeenCalledTimes(0)
+	})
 })
 
 function createTimelineState(

packages/timeline-state-resolver/src/service/stateHandler.ts

@@ -77,6 +77,8 @@ export class StateHandler<DeviceState, Command extends CommandWithContext> {
 	}
 
 	async handleState(state: Timeline.TimelineState<TSRTimelineContent>, mappings: Mappings) {
+		if (this.currentState?.state && this.currentState.state.time > state.time) return // the incoming state is stale, we ignore it
+
 		const nextState = this.stateQueue[0]
 
 		const trace = startTrace('device:convertTimelineStateToDeviceState', { deviceId: this.context.deviceId })
@@ -109,8 +111,8 @@ export class StateHandler<DeviceState, Command extends CommandWithContext> {
 		this.currentState = {
 			commands: [],
 			deviceState: state,
-			state: this.currentState?.state || { time: this.context.getCurrentTime(), layers: {}, nextEvents: [] },
-			mappings: this.currentState?.mappings || {},
+			state: this.currentState?.state ?? { time: this.context.getCurrentTime(), layers: {}, nextEvents: [] },
+			mappings: this.currentState?.mappings ?? {},
 		}
 		await this.calculateNextStateChange()
 	}
@@ -142,7 +144,11 @@ export class StateHandler<DeviceState, Command extends CommandWithContext> {
 			nextState.commands = []
 		}
 
-		if (nextState.state.time - (nextState.preliminary ?? 0) <= this.context.getCurrentTime() && this.currentState) {
+		if (
+			!this._executingStateChange &&
+			nextState === this.stateQueue[0] &&
+			nextState.state.time - (nextState.preliminary ?? 0) <= this.context.getCurrentTime()
+		) {
 			await this.executeNextStateChange()
 		}
 	}

yarn.lock

@@ -11110,12 +11110,12 @@ asn1@evs-broadcast/node-asn1:
   languageName: node
   linkType: hard
 
-"superfly-timeline@npm:9.0.2":
-  version: 9.0.2
-  resolution: "superfly-timeline@npm:9.0.2"
+"superfly-timeline@npm:9.1.2":
+  version: 9.1.2
+  resolution: "superfly-timeline@npm:9.1.2"
   dependencies:
     tslib: ^2.6.0
-  checksum: d628d467d5384f5667bc10b877478c5b8b0a91774b5d5c5e9d9d3134b8f1b760225f2fbbb0f9ccd3e55f930c9f3719f81b9347b94ea853fbc0a18bc121d97665
+  checksum: c195d3e65fd3d63223dd2a008facb32850b71da0355b258c0a08e1417bd447b144e01088f28e8e71fe8c240885c2bc5f73e8df7c84f131e963521510edf8bde2
   languageName: node
   linkType: hard
 
@@ -11415,7 +11415,7 @@ asn1@evs-broadcast/node-asn1:
     p-timeout: ^3.2.0
     simple-oauth2: ^5.0.0
     sprintf-js: ^1.1.3
-    superfly-timeline: 9.0.2
+    superfly-timeline: 9.1.2
     threadedclass: ^1.2.1
     timeline-state-resolver-types: 9.2.0
     tslib: ^2.6.2