fix(executor): stop HITL error edges from firing on successful resume

apps/sim/executor/execution/edge-manager.test.ts

@@ -875,6 +875,117 @@ describe('EdgeManager', () => {
     })
   })
 
+  describe('deactivateResumedEdge', () => {
+    it('prunes a resumed pause block error edge without firing the error target', () => {
+      // Models the HITL-resume bug: a pause block and a regular block both feed
+      // an error-notifier via `error` handles. On a fully successful run the
+      // notifier must never run.
+      const pauseId = 'pause-block'
+      const regularId = 'regular-block'
+      const notifyId = 'error-notify'
+
+      const pauseNode = createMockNode(
+        pauseId,
+        [
+          { target: 'next', sourceHandle: EDGE.SOURCE },
+          { target: notifyId, sourceHandle: EDGE.ERROR },
+        ],
+        []
+      )
+      const regularNode = createMockNode(regularId, [
+        { target: notifyId, sourceHandle: EDGE.ERROR },
+      ])
+      const notifyNode = createMockNode(notifyId, [], [pauseId, regularId])
+
+      const dag = createMockDAG(
+        new Map<string, DAGNode>([
+          [pauseId, pauseNode],
+          [regularId, regularNode],
+          [notifyId, notifyNode],
+        ])
+      )
+      const edgeManager = new EdgeManager(dag)
+
+      // Resume releases the pause block's error edge as deactivated.
+      edgeManager.deactivateResumedEdge(pauseId, notifyId, EDGE.ERROR)
+
+      expect(edgeManager.getDeactivatedEdges()).toContain(
+        JSON.stringify([pauseId, notifyId, EDGE.ERROR])
+      )
+      expect(edgeManager.getNodesWithActivatedEdge()).not.toContain(notifyId)
+
+      // The regular block then completes successfully → its error edge deactivates too.
+      const readyNodes = edgeManager.processOutgoingEdges(regularNode, { result: 'ok' })
+
+      // With no error edge ever activated, the notifier is never scheduled.
+      expect(readyNodes).not.toContain(notifyId)
+      expect(edgeManager.getNodesWithActivatedEdge()).not.toContain(notifyId)
+    })
+
+    it('still fires the error target when a real upstream block errors', () => {
+      // Same topology, but here the regular block genuinely errors — the notifier
+      // must fire even though the pause block's error edge was pruned on resume.
+      const pauseId = 'pause-block'
+      const regularId = 'regular-block'
+      const notifyId = 'error-notify'
+
+      const regularNode = createMockNode(regularId, [
+        { target: notifyId, sourceHandle: EDGE.ERROR },
+      ])
+      const notifyNode = createMockNode(notifyId, [], [pauseId, regularId])
+
+      const dag = createMockDAG(
+        new Map<string, DAGNode>([
+          [regularId, regularNode],
+          [notifyId, notifyNode],
+        ])
+      )
+      const edgeManager = new EdgeManager(dag)
+
+      edgeManager.deactivateResumedEdge(pauseId, notifyId, EDGE.ERROR)
+
+      const readyNodes = edgeManager.processOutgoingEdges(regularNode, { error: 'boom' })
+
+      expect(readyNodes).toContain(notifyId)
+      expect(edgeManager.getNodesWithActivatedEdge()).toContain(notifyId)
+    })
+
+    it('leaves a convergence join ready+activated after pruning a pause error edge', () => {
+      // Join `C` is fed by `B.source` (succeeds) and `P.error` (pause block).
+      // After B activates and P's error edge is pruned on resume, C must be both
+      // activated and ready so the engine re-queues it.
+      const sourceId = 'block-b'
+      const pauseId = 'pause-block'
+      const joinId = 'join-c'
+
+      const sourceNode = createMockNode(sourceId, [{ target: joinId, sourceHandle: EDGE.SOURCE }])
+      const pauseNode = createMockNode(pauseId, [{ target: joinId, sourceHandle: EDGE.ERROR }])
+      const joinNode = createMockNode(joinId, [], [sourceId, pauseId])
+
+      const edgeManager = new EdgeManager(
+        createMockDAG(
+          new Map<string, DAGNode>([
+            [sourceId, sourceNode],
+            [pauseId, pauseNode],
+            [joinId, joinNode],
+          ])
+        )
+      )
+
+      // Phase 1: B succeeds → activates B→C, but C still waits on the pause edge.
+      const readyAfterB = edgeManager.processOutgoingEdges(sourceNode, { result: 'ok' })
+      expect(readyAfterB).not.toContain(joinId)
+      expect(edgeManager.hasActivatedEdge(joinId)).toBe(true)
+      expect(edgeManager.isNodeReady(joinNode)).toBe(false)
+
+      // Resume: pause block's error edge is pruned → C is now ready (and stays
+      // activated), which is exactly the state the engine uses to re-queue it.
+      edgeManager.deactivateResumedEdge(pauseId, joinId, EDGE.ERROR)
+      expect(edgeManager.hasActivatedEdge(joinId)).toBe(true)
+      expect(edgeManager.isNodeReady(joinNode)).toBe(true)
+    })
+  })
+
   describe('Diamond pattern (convergent paths)', () => {
     it('should handle diamond: condition splits then converges at merge point', () => {
       const conditionId = 'condition-1'

apps/sim/executor/execution/edge-manager.ts

@@ -134,6 +134,10 @@ export class EdgeManager {
     return Array.from(this.nodesWithActivatedEdge)
   }
 
+  hasActivatedEdge(nodeId: string): boolean {
+    return this.nodesWithActivatedEdge.has(nodeId)
+  }
+
   restoreDeactivatedEdges(edgeKeys?: string[], activatedNodeIds?: string[]): void {
     this.deactivatedEdges = new Set(
       (edgeKeys ?? []).map((edgeKey) => this.normalizeSerializedEdgeKey(edgeKey))
@@ -145,17 +149,10 @@ export class EdgeManager {
     this.nodesWithActivatedEdge.add(nodeId)
   }
 
-  /**
-   * Clear deactivated edges for a set of nodes (used when restoring loop state for next iteration).
-   *
-   * Only clears edges whose SOURCE is in the provided set. Edges pointing INTO a node in the set
-   * whose source lives outside (e.g. an external branch whose path was cascade-deactivated) must
-   * remain deactivated — otherwise `countActiveIncomingEdges` would count a source that will never
-   * fire again, stalling the loop on its next iteration.
-   *
-   * Deactivated edge keys encode the source separately so node IDs with shared prefixes
-   * cannot clear each other's deactivated edges.
-   */
+  deactivateResumedEdge(sourceId: string, targetId: string, sourceHandle?: string): void {
+    this.deactivateEdgeAndDescendants(sourceId, targetId, sourceHandle)
+  }
+
   clearDeactivatedEdgesForNodes(nodeIds: Set<string>): void {
     const edgesToRemove: string[] = []
     for (const edgeKey of this.deactivatedEdges) {
@@ -182,11 +179,6 @@ export class EdgeManager {
     return targetNode ? this.isNodeReady(targetNode) : false
   }
 
-  /**
-   * Checks if the cascade target sentinel belongs to the same subflow as the source node.
-   * A condition inside a loop that hits a dead-end should still allow the enclosing
-   * loop's sentinel to fire so the loop can continue or exit.
-   */
   private isEnclosingSentinel(sourceNode: DAGNode, sentinelId: string): boolean {
     const sentinel = this.dag.nodes.get(sentinelId)
     if (!sentinel?.metadata.isSentinel) return false
@@ -321,9 +313,6 @@ export class EdgeManager {
     }
   }
 
-  /**
-   * Checks if a node has any active incoming edges besides the one being excluded.
-   */
   private hasActiveIncomingEdges(node: DAGNode, excludeEdgeKey: string): boolean {
     for (const incomingSourceId of node.incomingEdges) {
       const incomingNode = this.dag.nodes.get(incomingSourceId)

apps/sim/executor/execution/engine.test.ts

@@ -112,6 +112,8 @@ function createMockEdgeManager(
     getDeactivatedEdges: vi.fn(() => []),
     getNodesWithActivatedEdge: vi.fn(() => []),
     markNodeWithActivatedEdge: vi.fn(),
+    deactivateResumedEdge: vi.fn(),
+    hasActivatedEdge: vi.fn(() => false),
   } as unknown as MockEdgeManager
 }
 
@@ -231,6 +233,136 @@ describe('ExecutionEngine', () => {
       expect(nodeOrchestrator.executeNode).not.toHaveBeenCalled()
     })
 
+    it('deactivates a resumed pause block error edge instead of firing it', async () => {
+      // Pause block has two outgoing edges: a `source` continuation edge and an
+      // `error` edge to an error-notifier. On a successful resume the error edge
+      // must be deactivated (never marked/queued); only the continuation fires.
+      const pauseNode = createMockNode('pause-block', 'human_in_the_loop')
+      pauseNode.outgoingEdges.set('pause-block→next-source', {
+        target: 'next',
+        sourceHandle: EDGE.SOURCE,
+      })
+      pauseNode.outgoingEdges.set('pause-block→notify-error', {
+        target: 'error-notify',
+        sourceHandle: EDGE.ERROR,
+      })
+
+      const nextNode = createMockNode('next', 'function')
+      nextNode.incomingEdges.add('pause-block')
+
+      const errorNotifyNode = createMockNode('error-notify', 'gmail')
+      errorNotifyNode.incomingEdges.add('pause-block')
+
+      const dag = createMockDAG([pauseNode, nextNode, errorNotifyNode])
+      const context = createMockContext({
+        metadata: {
+          executionId: 'test-execution',
+          startTime: new Date().toISOString(),
+          pendingBlocks: [],
+          // remainingEdges omit sourceHandle (as persisted snapshots do), forcing
+          // the engine to resolve the handle from the live DAG.
+          remainingEdges: [
+            { source: 'pause-block', target: 'next' },
+            { source: 'pause-block', target: 'error-notify' },
+          ],
+        } as any,
+      })
+      const edgeManager = createMockEdgeManager(() => [])
+      const nodeOrchestrator = createMockNodeOrchestrator()
+
+      const engine = new ExecutionEngine(context, dag, edgeManager, nodeOrchestrator)
+      await engine.run()
+
+      // Continuation edge fires; error edge is deactivated, not activated/queued.
+      expect(edgeManager.markNodeWithActivatedEdge).toHaveBeenCalledWith('next')
+      expect(edgeManager.markNodeWithActivatedEdge).not.toHaveBeenCalledWith('error-notify')
+      expect(edgeManager.deactivateResumedEdge).toHaveBeenCalledWith(
+        'pause-block',
+        'error-notify',
+        EDGE.ERROR
+      )
+      // A pure error-handler target (never activated) must not be executed.
+      expect(nodeOrchestrator.executeNode).not.toHaveBeenCalledWith(context, 'error-notify')
+    })
+
+    it('re-queues a convergence target when a resumed pause error edge is pruned', async () => {
+      // The join is fed by a succeeding block's `source` edge (activated in
+      // phase 1) AND the pause block's `error` edge. On resume the error edge is
+      // pruned, but the join must still run because it already had a genuine
+      // activation — otherwise it would be silently stranded.
+      const pauseNode = createMockNode('pause-block', 'human_in_the_loop')
+      pauseNode.outgoingEdges.set('pause-block→join-error', {
+        target: 'join',
+        sourceHandle: EDGE.ERROR,
+      })
+      const joinNode = createMockNode('join', 'function')
+      joinNode.incomingEdges.add('pause-block')
+
+      const dag = createMockDAG([pauseNode, joinNode])
+      const context = createMockContext({
+        metadata: {
+          executionId: 'test-execution',
+          startTime: new Date().toISOString(),
+          pendingBlocks: [],
+          remainingEdges: [{ source: 'pause-block', target: 'join' }],
+        } as any,
+      })
+      const edgeManager = createMockEdgeManager(() => [])
+      // Join already received a genuine activation in phase 1 and is now ready.
+      vi.mocked(edgeManager.hasActivatedEdge).mockReturnValue(true)
+      vi.mocked(edgeManager.isNodeReady).mockReturnValue(true)
+      const nodeOrchestrator = createMockNodeOrchestrator()
+
+      const engine = new ExecutionEngine(context, dag, edgeManager, nodeOrchestrator)
+      await engine.run()
+
+      expect(edgeManager.deactivateResumedEdge).toHaveBeenCalledWith(
+        'pause-block',
+        'join',
+        EDGE.ERROR
+      )
+      // Pruning is via deactivation, never force-activation...
+      expect(edgeManager.markNodeWithActivatedEdge).not.toHaveBeenCalledWith('join')
+      // ...but the already-activated convergence node still runs.
+      expect(nodeOrchestrator.executeNode).toHaveBeenCalledWith(context, 'join')
+    })
+
+    it('prefers the continuation handle when a pause block also errors into the same target', async () => {
+      // Pause block wires BOTH source and error into the same target. The error
+      // edge is registered first, but on a successful resume the continuation
+      // (source) handle must win, so the target is activated, not pruned.
+      const pauseNode = createMockNode('pause-block', 'human_in_the_loop')
+      pauseNode.outgoingEdges.set('pause-block→both-error', {
+        target: 'both',
+        sourceHandle: EDGE.ERROR,
+      })
+      pauseNode.outgoingEdges.set('pause-block→both-source', {
+        target: 'both',
+        sourceHandle: EDGE.SOURCE,
+      })
+      const bothNode = createMockNode('both', 'function')
+      bothNode.incomingEdges.add('pause-block')
+
+      const dag = createMockDAG([pauseNode, bothNode])
+      const context = createMockContext({
+        metadata: {
+          executionId: 'test-execution',
+          startTime: new Date().toISOString(),
+          pendingBlocks: [],
+          remainingEdges: [{ source: 'pause-block', target: 'both' }],
+        } as any,
+      })
+      const edgeManager = createMockEdgeManager(() => [])
+      const nodeOrchestrator = createMockNodeOrchestrator()
+
+      const engine = new ExecutionEngine(context, dag, edgeManager, nodeOrchestrator)
+      await engine.run()
+
+      expect(edgeManager.markNodeWithActivatedEdge).toHaveBeenCalledWith('both')
+      expect(edgeManager.deactivateResumedEdge).not.toHaveBeenCalled()
+      expect(nodeOrchestrator.executeNode).toHaveBeenCalledWith(context, 'both')
+    })
+
     it('should execute all nodes in a multi-node workflow', async () => {
       const nodes = [
         createMockNode('start', 'starter'),

apps/sim/executor/execution/engine.ts

@@ -287,17 +287,33 @@ export class ExecutionEngine {
 
       for (const edge of remainingEdges) {
         const targetNode = this.dag.nodes.get(edge.target)
-        if (targetNode) {
-          const hadEdge = targetNode.incomingEdges.has(edge.source)
-          targetNode.incomingEdges.delete(edge.source)
-          if (hadEdge) {
-            this.edgeManager.markNodeWithActivatedEdge(targetNode.id)
-          }
-
-          if (this.edgeManager.isNodeReady(targetNode)) {
-            this.execLogger.info('Node became ready after edge removal', { nodeId: targetNode.id })
+        if (!targetNode) continue
+
+        const sourceHandle = this.resolveRemainingEdgeHandle(edge)
+        if (sourceHandle === EDGE.ERROR) {
+          this.edgeManager.deactivateResumedEdge(edge.source, targetNode.id, sourceHandle)
+
+          if (
+            this.edgeManager.hasActivatedEdge(targetNode.id) &&
+            this.edgeManager.isNodeReady(targetNode)
+          ) {
+            this.execLogger.info('Convergence node ready after pruning resumed error edge', {
+              nodeId: targetNode.id,
+            })
             this.addToQueue(targetNode.id)
           }
+          continue
+        }
+
+        const hadEdge = targetNode.incomingEdges.has(edge.source)
+        targetNode.incomingEdges.delete(edge.source)
+        if (hadEdge) {
+          this.edgeManager.markNodeWithActivatedEdge(targetNode.id)
+        }
+
+        if (this.edgeManager.isNodeReady(targetNode)) {
+          this.execLogger.info('Node became ready after edge removal', { nodeId: targetNode.id })
+          this.addToQueue(targetNode.id)
         }
       }
 
@@ -351,6 +367,35 @@ export class ExecutionEngine {
     }
   }
 
+  /**
+   * Resolves the source handle for an edge released during pause/resume.
+   * Persisted `remainingEdges` may omit the handle, so fall back to the live DAG
+   * edge. When a source has both a continuation and an `error` edge to the same
+   * target, the continuation handle wins — a successful resume must not prune it.
+   */
+  private resolveRemainingEdgeHandle(edge: {
+    source: string
+    target: string
+    sourceHandle?: string
+  }): string | undefined {
+    if (edge.sourceHandle !== undefined) return edge.sourceHandle
+
+    const sourceNode = this.dag.nodes.get(edge.source)
+    if (!sourceNode) return undefined
+
+    let hasErrorEdge = false
+    for (const [, outgoing] of sourceNode.outgoingEdges) {
+      if (outgoing.target !== edge.target) continue
+      if (outgoing.sourceHandle === EDGE.ERROR) {
+        hasErrorEdge = true
+        continue
+      }
+      return outgoing.sourceHandle
+    }
+
+    return hasErrorEdge ? EDGE.ERROR : undefined
+  }
+
   private async processQueue(): Promise<void> {
     while (this.readyQueue.length > 0) {
       if (this.checkCancellation() || this.errorFlag) {