fix(webhooks): never replay completed poll work or mask a retryable fan-out failure

A poller stops its batch on a deterministic refusal only while nothing in the
batch has completed; once an item has run, the refusal is an ordinary item
failure, so the poller saves its completed work exactly as before and no
completed event can replay after the idempotency window.

In a multi-target delivery a missing block's no-retry 404 no longer stands in
for a target that failed and needs the sender to retry. A source's Retry-After
is counted from its answer rather than the poll's start. The RSS backoff keys
are cleared by RSS's own state write, so other pollers' success path is
unchanged, and two fields nothing reads are dropped.

Author: waleedlatif1

apps/sim/app/api/webhooks/trigger/[path]/route.test.ts

@@ -742,6 +742,49 @@ describe('Webhook Trigger API Route', () => {
     expect(response.status).toBe(503)
   })
 
+  it('answers with a failing target rather than a missing block so the sender retries', async () => {
+    testData.webhooks.push(
+      {
+        id: 'missing-block-webhook',
+        provider: 'generic',
+        path: 'mixed-path',
+        isActive: true,
+        providerConfig: {},
+        workflowId: 'test-workflow-id',
+      },
+      {
+        id: 'failing-webhook',
+        provider: 'generic',
+        path: 'mixed-path',
+        isActive: true,
+        providerConfig: {},
+        workflowId: 'test-workflow-id',
+      }
+    )
+    dispatchResolvedWebhookTargetMock
+      .mockResolvedValueOnce({
+        outcome: 'ignored',
+        reason: 'block-missing',
+        response: new NextResponse('Trigger block not found in deployment', {
+          status: 404,
+          headers: { 'x-slack-no-retry': '1' },
+        }),
+      })
+      .mockResolvedValueOnce({
+        outcome: 'failed',
+        reason: 'queue-failed',
+        response: new NextResponse(null, { status: 500 }),
+      })
+
+    const response = await POST(
+      createMockRequest('POST', { event: 'x' }),
+      createRouteContext({ path: 'mixed-path' })
+    )
+
+    expect(response.status).toBe(500)
+    expect(response.headers.get('x-slack-no-retry')).toBeNull()
+  })
+
   it('tells Slack not to redeliver a POST to a path with no webhook', async () => {
     const req = createMockRequest('POST', { type: 'event_callback' })
 

apps/sim/app/api/webhooks/trigger/[path]/route.ts

@@ -265,6 +265,8 @@ async function handleWebhookDelivery(
    */
   const responses: NextResponse[] = []
   const failures: NextResponse[] = []
+  /** Kept apart so a missing block's no-retry 404 never stands in for a target that must retry. */
+  const blockMissingResponses: NextResponse[] = []
   let hasDroppedTarget = false
   for (const dispatchResult of legacySlackDispatchResults) {
     if (dispatchResult.outcome === 'failed') {
@@ -348,7 +350,11 @@ async function handleWebhookDelivery(
           `[${requestId}] Webhook dispatch failed for ${foundWebhook.id}, continuing to next`,
           { reason: dispatchResult.reason, status: dispatchResult.response.status }
         )
-        failures.push(dispatchResult.response)
+        if (dispatchResult.outcome === 'failed') {
+          failures.push(dispatchResult.response)
+        } else {
+          blockMissingResponses.push(dispatchResult.response)
+        }
         continue
       }
       return dispatchResult.response
@@ -361,6 +367,9 @@ async function handleWebhookDelivery(
     if (failures.length > 0) {
       return failures[0]
     }
+    if (blockMissingResponses.length > 0) {
+      return blockMissingResponses[0]
+    }
     if (hasDroppedTarget) {
       return new NextResponse(null, { status: 200 })
     }

apps/sim/lib/execution/preprocessing.test.ts

@@ -1039,7 +1039,7 @@ describe('preprocessExecution admission rejection codes and blocked-run log thro
     expect(result).toMatchObject({ success: false, error: expected })
   })
 
-  it('leaves an unreadable usage ledger untagged and retryable', async () => {
+  it('leaves an unreadable usage ledger untagged so unattended senders retry', async () => {
     mockCheckAttributedUsageLimits.mockResolvedValue({
       isExceeded: true,
       reason: 'usage_unavailable',
@@ -1049,7 +1049,7 @@ describe('preprocessExecution admission rejection codes and blocked-run log thro
 
     const result = await refuse('workflow-1')
 
-    expect(result).toMatchObject({ success: false, error: { statusCode: 402, retryable: true } })
+    expect(result).toMatchObject({ success: false, error: { statusCode: 402 } })
     expect(result.success === false && result.error.code).toBeUndefined()
   })
 

apps/sim/lib/execution/preprocessing.ts

@@ -767,7 +767,7 @@ export async function preprocessExecution(
                 statusCode: 402,
                 // An unreadable ledger fails closed; that is no verdict on the payer, so senders retry.
                 ...(usageCheck.reason === 'usage_unavailable'
-                  ? { retryable: true }
+                  ? {}
                   : { code: ADMISSION_REJECTION_CODE.USAGE_LIMIT_EXCEEDED }),
               },
             },

apps/sim/lib/webhooks/polling/gmail.ts

@@ -568,7 +568,7 @@ async function processEmails(
       )
       processedCount++
     } catch (error) {
-      if (error instanceof PollAdmissionRefusedError) throw error
+      if (error instanceof PollAdmissionRefusedError && processedCount === 0) throw error
       const errorMessage = getErrorMessage(error, 'Unknown error')
       logger.error(`[${requestId}] Error processing email ${email.id}:`, errorMessage)
       failedCount++

apps/sim/lib/webhooks/polling/google-calendar.test.ts

@@ -98,4 +98,15 @@ describe('Google Calendar polling when execution admission refuses events', () =
     expect(cursorUpdates).toEqual([])
     expect(mockMarkFailed).not.toHaveBeenCalled()
   })
+
+  it('saves the completed work as before when a refusal follows a completed event', async () => {
+    mockProcessEvent.mockResolvedValueOnce({ success: true, executionId: 'execution-1' })
+
+    expect(await googleCalendarPollingHandler.pollWebhook(context())).not.toBe('skipped')
+
+    const cursorUpdates = mockUpdateConfig.mock.calls.filter(
+      ([, update]) => 'lastCheckedTimestamp' in (update as Record<string, unknown>)
+    )
+    expect(cursorUpdates).toHaveLength(1)
+  })
 })

apps/sim/lib/webhooks/polling/google-calendar.ts

@@ -354,7 +354,7 @@ async function processEvents(
       )
       processedCount++
     } catch (error) {
-      if (error instanceof PollAdmissionRefusedError) throw error
+      if (error instanceof PollAdmissionRefusedError && processedCount === 0) throw error
       const errorMessage = getErrorMessage(error, 'Unknown error')
       logger.error(`[${requestId}] Error processing event ${event.id}:`, errorMessage)
       failedCount++

apps/sim/lib/webhooks/polling/google-drive.ts

@@ -421,7 +421,7 @@ async function processChanges(
       )
       processedCount++
     } catch (error) {
-      if (error instanceof PollAdmissionRefusedError) throw error
+      if (error instanceof PollAdmissionRefusedError && processedCount === 0) throw error
       const errorMessage = getErrorMessage(error, 'Unknown error')
       logger.error(
         `[${requestId}] Error processing change for file ${change.fileId}:`,

apps/sim/lib/webhooks/polling/google-sheets.ts

@@ -451,7 +451,7 @@ async function processRows(
       )
       processedCount++
     } catch (error) {
-      if (error instanceof PollAdmissionRefusedError) throw error
+      if (error instanceof PollAdmissionRefusedError && processedCount === 0) throw error
       const errorMessage = getErrorMessage(error, 'Unknown error')
       logger.error(`[${requestId}] Error processing row ${rowNumber}:`, errorMessage)
       failedCount++

apps/sim/lib/webhooks/polling/hubspot.ts

@@ -467,7 +467,7 @@ async function pollListMembership(
       )
       processedCount++
     } catch (error) {
-      if (error instanceof PollAdmissionRefusedError) throw error
+      if (error instanceof PollAdmissionRefusedError && processedCount === 0) throw error
       failedCount++
       logger.error(
         `[${requestId}] Error processing HubSpot list membership ${member.recordId}:`,
@@ -854,7 +854,7 @@ async function processRecords(
           snapshot.values.set(record.id, propertyValue ?? null)
         }
       } catch (error) {
-        if (error instanceof PollAdmissionRefusedError) throw error
+        if (error instanceof PollAdmissionRefusedError && processedCount === 0) throw error
         failedCount++
         cursorFrozen = true
         logger.error(