fix(execution): never classify the stream layer's own errors as transport drops

An ExecutionStreamHttpError or SSEEventHandlerError whose message happened to
contain a browser transport phrase ("Failed to fetch workflow state") would
have been re-wrapped as a stream interruption, losing the HTTP status and
taking the recovery path for a run that never started. The predicate now
excludes the stream layer's typed errors before looking at message text.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

Author: icecrasher321

apps/sim/app/workspace/[workspaceId]/w/[workflowId]/utils/workflow-execution-utils.test.ts

@@ -14,7 +14,8 @@ import {
 } from '@/app/workspace/[workspaceId]/w/[workflowId]/utils/workflow-execution-utils'
 import type { BlockLog } from '@/executor/types'
 import {
-  type ExecutionStreamHttpError,
+  ExecutionStreamHttpError,
+  SSEEventHandlerError,
   SSEStreamInterruptedError,
 } from '@/hooks/use-execution-stream'
 import { useExecutionStore } from '@/stores/execution'
@@ -131,6 +132,20 @@ describe('workflow-execution-utils', () => {
     it.each([
       ['a nullish rejection', null],
       ['a client abort', new DOMException('Aborted', 'AbortError')],
+      [
+        'an HTTP rejection whose message mentions a transport phrase',
+        new ExecutionStreamHttpError('Failed to fetch workflow state', 500),
+      ],
+      [
+        'a handler failure whose message mentions a transport phrase',
+        new SSEEventHandlerError(
+          'network error while persisting console rows',
+          'block:completed',
+          3,
+          'exec-server',
+          new Error('persist failed')
+        ),
+      ],
       [
         'the run tool stop reason, which aborts with a plain string',
         'user_stop:cancelRunToolExecution',

apps/sim/hooks/use-execution-stream.ts

@@ -84,8 +84,23 @@ const TRANSPORT_FAILURE_MESSAGE_PATTERNS = [
   /load failed/,
 ] as const
 
+/**
+ * Errors the stream layer raises itself carry their own meaning (an HTTP
+ * rejection, a handler failure, an already classified drop), so their message
+ * text must never be mistaken for a transport failure.
+ */
+function isStreamLayerError(error: unknown): boolean {
+  return (
+    error instanceof ExecutionStreamHttpError ||
+    error instanceof SSEEventHandlerError ||
+    error instanceof SSEStreamInterruptedError
+  )
+}
+
 function isRecoverableStreamError(error: unknown): boolean {
-  if (!isRecordLike(error) || isClientDisconnectError(error)) return false
+  if (!isRecordLike(error) || isClientDisconnectError(error) || isStreamLayerError(error)) {
+    return false
+  }
   const msg = typeof error.message === 'string' ? error.message.toLowerCase() : ''
   return TRANSPORT_FAILURE_MESSAGE_PATTERNS.some((pattern) => pattern.test(msg))
 }