fix(tables): map row-limit errors to 400 in create-from-CSV import

Author: TheodoreSpeaks

apps/sim/app/api/table/import-csv/route.test.ts

@@ -39,6 +39,12 @@ vi.mock('@/app/api/table/utils', async () => {
         { error: error.message },
         { status: error.code === 'FILE_TOO_LARGE' ? 413 : 400 }
       ),
+    rowWriteErrorResponse: (error: unknown) => {
+      const message = error instanceof Error ? error.message : String(error)
+      return message.includes('row limit')
+        ? NextResponse.json({ error: message }, { status: 400 })
+        : null
+    },
   }
 })
 vi.mock('@/lib/workspaces/permissions/utils', () => permissionsMock)
@@ -175,6 +181,17 @@ describe('POST /api/table/import-csv', () => {
     expect(mockCreateTable).not.toHaveBeenCalled()
   })
 
+  it('returns 400 with the reason when an insert exceeds the plan row limit', async () => {
+    mockBatchInsertRows.mockRejectedValueOnce(
+      new Error('This table has reached its row limit (1,000 rows) on your current plan.')
+    )
+    const response = await POST(makeRequest(uploadParts(csvWithRows(250))))
+    const data = await response.json()
+
+    expect(response.status).toBe(400)
+    expect(data.error).toMatch(/row limit/)
+  })
+
   it('rolls back the created table when a batch insert fails mid-stream', async () => {
     mockBatchInsertRows
       .mockResolvedValueOnce(Array.from({ length: 100 }, () => ({ id: 'row' })))

apps/sim/app/api/table/import-csv/route.ts

@@ -30,6 +30,7 @@ import {
   csvProxyBodyCapResponse,
   multipartErrorResponse,
   normalizeColumn,
+  rowWriteErrorResponse,
 } from '@/app/api/table/utils'
 
 const logger = createLogger('TableImportCSV')
@@ -205,9 +206,13 @@ export const POST = withRouteHandler(async (request: NextRequest) => {
   } catch (error) {
     if (isMultipartError(error)) return multipartErrorResponse(error)
 
-    const message = toError(error).message
     logger.error(`[${requestId}] CSV import failed:`, error)
 
+    // Row-write failures (e.g. the plan row-limit check) map to a 400 with the real reason.
+    const rowWriteError = rowWriteErrorResponse(error)
+    if (rowWriteError) return rowWriteError
+
+    const message = toError(error).message
     const isClientError =
       message.includes('maximum table limit') ||
       message.includes('CSV file has no') ||