simstudioai · waleedlatif1 · Sep 15, 2026 · Sep 15, 2026
diff --git a/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/workflow.tsx b/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/workflow.tsx
@@ -71,7 +71,10 @@ import {
   type ConnectionBlockSelectorData,
 } from '@/app/workspace/[workspaceId]/w/[workflowId]/components/connection-block-selector/connection-block-selector'
 import { Cursors } from '@/app/workspace/[workspaceId]/w/[workflowId]/components/cursors/cursors'
-import { ErrorBoundary } from '@/app/workspace/[workspaceId]/w/[workflowId]/components/error/index'
+import {
+  ErrorBoundary,
+  ErrorUI,
+} from '@/app/workspace/[workspaceId]/w/[workflowId]/components/error/index'
 import { FocusBlockDeepLink } from '@/app/workspace/[workspaceId]/w/[workflowId]/components/focus-block-deep-link'
 import { WorkflowSearchReplace } from '@/app/workspace/[workspaceId]/w/[workflowId]/components/search-replace/workflow-search-replace'
 import { WorkflowControls } from '@/app/workspace/[workspaceId]/w/[workflowId]/components/workflow-controls/workflow-controls'
@@ -2668,6 +2671,10 @@ const WorkflowContent = React.memo(
     const loadingWorkflowRef = useRef<string | null>(null)
     const currentWorkflowExists =
       !isWorkflowMapPlaceholderData && Boolean(workflows[workflowIdParam])
+    const workflowLoadError =
+      hydration.phase === 'error' && hydration.workflowId === workflowIdParam
+        ? hydration.error
+        : null
 
     useEffect(() => {
       const currentId = workflowIdParam
@@ -5126,16 +5133,28 @@ const WorkflowContent = React.memo(
           >
             {!isWorkflowReady && (
               <div className='absolute inset-0 z-[5] flex items-center justify-center bg-[var(--bg)]'>
-                <div
-                  className='size-[18px] animate-spin rounded-full'
-                  style={{
-                    background:
-                      'conic-gradient(from 0deg, hsl(var(--muted-foreground)) 0deg 120deg, transparent 120deg 180deg, hsl(var(--muted-foreground)) 180deg 300deg, transparent 300deg 360deg)',
-                    mask: 'radial-gradient(farthest-side, transparent calc(100% - 1.5px), black calc(100% - 1.5px))',
-                    WebkitMask:
-                      'radial-gradient(farthest-side, transparent calc(100% - 1.5px), black calc(100% - 1.5px))',
-                  }}
-                />
+                {workflowLoadError ? (
+                  <ErrorUI
+                    title='Unable to load workflow'
+                    message={workflowLoadError}
+                    onReset={() => {
+                      setActiveWorkflow(workflowIdParam).catch((error) => {
+                        logger.error(`Failed to retry workflow ${workflowIdParam}:`, error)
+                      })
+                    }}
+                  />
+                ) : (
+                  <div
+                    className='size-[18px] animate-spin rounded-full'
+                    style={{
+                      background:
+                        'conic-gradient(from 0deg, hsl(var(--muted-foreground)) 0deg 120deg, transparent 120deg 180deg, hsl(var(--muted-foreground)) 180deg 300deg, transparent 300deg 360deg)',
+                      mask: 'radial-gradient(farthest-side, transparent calc(100% - 1.5px), black calc(100% - 1.5px))',
+                      WebkitMask:
+                        'radial-gradient(farthest-side, transparent calc(100% - 1.5px), black calc(100% - 1.5px))',
+                    }}
+                  />
+                )}
               </div>
             )}
 

diff --git a/apps/sim/executor/orchestrators/loop.test.ts b/apps/sim/executor/orchestrators/loop.test.ts
@@ -154,7 +154,7 @@ describe('LoopOrchestrator', () => {
     expect(loopEnd.incomingEdges.has(parallelEndId)).toBe(true)
   })
 
-  it('resolves forEach collections with the loop start sentinel scope', async () => {
+  it('resolves forEach collections with the loop start sentinel scope independently of the count', async () => {
     const loopId = 'loop-1'
     const dag: DAG = {
       nodes: new Map(),
@@ -165,14 +165,15 @@ describe('LoopOrchestrator', () => {
             id: loopId,
             nodes: ['task-1'],
             loopType: 'forEach',
+            iterations: 1,
             forEachItems: '<Producer.items>',
           },
         ],
       ]),
       parallelConfigs: new Map(),
     }
     const resolver = {
-      resolveSingleReference: vi.fn().mockResolvedValue(['item-1']),
+      resolveSingleReference: vi.fn().mockResolvedValue(['item-1', 'item-2', 'item-3']),
     }
     const orchestrator = new LoopOrchestrator(dag, createState(), resolver as any, {}, {
       clearDeactivatedEdgesForNodes: vi.fn(),
@@ -188,7 +189,8 @@ describe('LoopOrchestrator', () => {
       undefined,
       { allowLargeValueRefs: true }
     )
-    expect(scope.maxIterations).toBe(1)
+    expect(scope.maxIterations).toBe(3)
+    expect(scope.items).toEqual(['item-1', 'item-2', 'item-3'])
   })
 
   it('projects forEach resolution failures before logging or persisting them', async () => {

diff --git a/apps/sim/lib/workflows/persistence/utils.test.ts b/apps/sim/lib/workflows/persistence/utils.test.ts
@@ -23,10 +23,12 @@ import {
   schemaMock,
 } from '@sim/testing'
 import { afterAll, beforeEach, describe, expect, it, vi } from 'vitest'
+import { workflowStateSchema } from '@/lib/api/contracts/workflows'
 import type {
   BlockState as AppBlockState,
   WorkflowState as AppWorkflowState,
 } from '@/stores/workflows/workflow/types'
+import { generateLoopBlocks } from '@/stores/workflows/workflow/utils'
 
 /**
  * Type helper for converting test workflow state to app workflow state.
@@ -348,6 +350,110 @@ describe('Database Helpers', () => {
   })
 
   describe('loadWorkflowFromNormalizedTables', () => {
+    it.each(['for', 'forEach', 'while', 'doWhile'] as const)(
+      'preserves valid block counts and expressions for %s loops even when subflow counts differ',
+      async (loopType) => {
+        const data = {
+          count: 9,
+          loopType,
+          collection: '<source.items>',
+          whileCondition: '<source.hasMore>',
+          doWhileCondition: '<source.hasMore>',
+          width: 600,
+          parentId: 'outer-loop',
+          extent: 'parent' as const,
+        }
+        queueLoadFixtures({
+          blocks: [{ ...toDbBlock(createLoopBlock({ id: 'loop-1' }), mockWorkflowId), data }],
+          subflows: [
+            {
+              id: 'loop-1',
+              type: 'loop',
+              config: {
+                nodes: [],
+                loopType,
+                iterations: 3,
+                forEachItems: data.collection,
+                whileCondition: data.whileCondition,
+                doWhileCondition: data.doWhileCondition,
+              },
+            },
+          ],
+        })
+
+        const loaded = await dbHelpers.loadWorkflowFromNormalizedTables(mockWorkflowId)
+        const parsed = workflowStateSchema.parse(loaded)
+
+        expect(parsed.blocks['loop-1'].data).toEqual(data)
+        expect(parsed.loops?.['loop-1'].iterations).toBe(3)
+        expect(generateLoopBlocks(loaded!.blocks)['loop-1']).toMatchObject({
+          iterations: 9,
+          loopType,
+          forEachItems: data.collection,
+          whileCondition: data.whileCondition,
+          doWhileCondition: data.doWhileCondition,
+        })
+        expect(dbChainMockFns.update).not.toHaveBeenCalled()
+      }
+    )
+
+    it('keeps an absent block count absent so serialization retains its existing default', async () => {
+      queueLoadFixtures({
+        blocks: [
+          {
+            ...toDbBlock(createLoopBlock({ id: 'loop-1' }), mockWorkflowId),
+            data: { loopType: 'for' },
+          },
+        ],
+        subflows: [
+          { id: 'loop-1', type: 'loop', config: { nodes: [], loopType: 'for', iterations: 3 } },
+        ],
+      })
+
+      const loaded = await dbHelpers.loadWorkflowFromNormalizedTables(mockWorkflowId)
+
+      expect(loaded?.blocks['loop-1'].data?.count).toBeUndefined()
+      expect(loaded?.loops['loop-1'].iterations).toBe(3)
+      expect(generateLoopBlocks(loaded!.blocks)['loop-1'].iterations).toBe(5)
+      expect(dbChainMockFns.update).not.toHaveBeenCalled()
+    })
+
+    it('serves a legacy forEach loop with a string count through the workflow read contract', async () => {
+      const collection = '<source.items>'
+      const loopRow = toDbBlock(createLoopBlock({ id: 'loop-1' }), mockWorkflowId)
+      queueLoadFixtures({
+        blocks: [
+          {
+            ...loopRow,
+            data: { ...loopRow.data, loopType: 'forEach', count: collection, collection },
+          },
+        ],
+        subflows: [
+          {
+            id: 'loop-1',
+            type: 'loop',
+            config: {
+              nodes: [],
+              loopType: 'forEach',
+              iterations: collection,
+              forEachItems: collection,
+            },
+          },
+        ],
+      })
+
+      const loaded = await dbHelpers.loadWorkflowFromNormalizedTables(mockWorkflowId)
+      const parsed = workflowStateSchema.parse(loaded)
+
+      expect(parsed.blocks['loop-1'].data).toMatchObject({ count: 1, collection })
+      expect(parsed.loops?.['loop-1']).toMatchObject({
+        loopType: 'forEach',
+        iterations: 1,
+        forEachItems: collection,
+      })
+      expect(dbChainMockFns.update).not.toHaveBeenCalled()
+    })
+
     it('should successfully load workflow data from normalized tables', async () => {
       queueLoadFixtures({
         blocks: mockBlocksFromDb,
@@ -401,6 +507,7 @@ describe('Database Helpers', () => {
         whileCondition: '',
         enabled: true,
       })
+      expect(result?.blocks['loop-1'].data?.count).toBe(3)
 
       expect(result?.parallels['parallel-1']).toEqual({
         id: 'parallel-1',

diff --git a/apps/sim/stores/workflows/registry/store.test.ts b/apps/sim/stores/workflows/registry/store.test.ts
@@ -228,6 +228,35 @@ describe('registry store loadWorkflowState (collapsed cache)', () => {
     expect(mockRequestJson).toHaveBeenCalledTimes(2)
   })
 
+  it('exposes a failed load and recovers when the user retries the same workflow', async () => {
+    mockRequestJson.mockRejectedValueOnce(new Error('Unable to fetch workflow'))
+
+    await expect(useWorkflowRegistry.getState().setActiveWorkflow('wf-1')).rejects.toThrow(
+      'Unable to fetch workflow'
+    )
+    expect(useWorkflowRegistry.getState().hydration).toMatchObject({
+      phase: 'error',
+      workflowId: 'wf-1',
+      error: 'Unable to fetch workflow',
+    })
+    expect(replaceWorkflowState).not.toHaveBeenCalled()
+
+    mockRequestJson.mockResolvedValueOnce({ data: makeEnvelope() })
+    const retry = useWorkflowRegistry.getState().setActiveWorkflow('wf-1')
+    expect(useWorkflowRegistry.getState().hydration).toMatchObject({
+      phase: 'state-loading',
+      error: null,
+    })
+    await retry
+
+    expect(mockRequestJson).toHaveBeenCalledTimes(2)
+    expect(useWorkflowRegistry.getState().hydration).toMatchObject({
+      phase: 'ready',
+      workflowId: 'wf-1',
+      error: null,
+    })
+  })
+
   it('discards a superseded response via the staleness guard', async () => {
     // First load (wf-1) is in-flight; a second load (wf-2) supersedes the
     // hydration workflowId, then wf-1 finally resolves. The guard compares the
@@ -256,4 +285,26 @@ describe('registry store loadWorkflowState (collapsed cache)', () => {
     expect(replaceWorkflowState.mock.calls.length).toBe(projectionsAfterSecond)
     expect(useWorkflowRegistry.getState().activeWorkflowId).toBe('wf-2')
   })
+
+  it('does not show a stale load error after switching to another workflow', async () => {
+    let rejectFirst: (reason: Error) => void = () => {}
+    const firstPending = new Promise<never>((_resolve, reject) => {
+      rejectFirst = reject
+    })
+    mockRequestJson
+      .mockImplementationOnce(() => firstPending)
+      .mockResolvedValueOnce({ data: makeEnvelope({ id: 'wf-2' }) })
+
+    const firstLoad = useWorkflowRegistry.getState().setActiveWorkflow('wf-1')
+    await useWorkflowRegistry.getState().setActiveWorkflow('wf-2')
+    rejectFirst(new Error('Previous workflow failed to load'))
+    await firstLoad
+
+    expect(useWorkflowRegistry.getState().activeWorkflowId).toBe('wf-2')
+    expect(useWorkflowRegistry.getState().hydration).toMatchObject({
+      phase: 'ready',
+      workflowId: 'wf-2',
+      error: null,
+    })
+  })
 })
diff --git a/packages/workflow-persistence/src/load.ts b/packages/workflow-persistence/src/load.ts
@@ -204,6 +204,11 @@ export async function loadWorkflowFromNormalizedTablesRaw(
             ...block,
             data: {
               ...block.data,
+              /** Repair legacy values without changing valid counts used by serialization. */
+              count:
+                block.data?.count === undefined || typeof block.data.count === 'number'
+                  ? block.data?.count
+                  : loop.iterations,
               collection: loop.forEachItems ?? block.data?.collection ?? '',
               whileCondition: loop.whileCondition ?? block.data?.whileCondition ?? '',
               doWhileCondition: loop.doWhileCondition ?? block.data?.doWhileCondition ?? '',