{"record":{"id":"473bf9799a1d232a","repo":"firecrawl/open-lovable","slug":"finaldata-error-failed-to-apply-code","errorCode":null,"errorMessage":"${finalData?.error || 'Failed to apply code'}","messagePattern":"\\$\\{finalData\\?\\.error \\|\\| 'Failed to apply code'\\}","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"app/generation/page.tsx","lineNumber":1051,"sourceCode":"              // Remove old iframe\n              iframeRef.current.remove();\n              \n              // Add new iframe\n              newIframe.src = `${currentSandboxData.url}?t=${Date.now()}&recreated=true`;\n              parent?.appendChild(newIframe);\n              \n              // Update ref\n              (iframeRef as any).current = newIframe;\n              \n              console.log('[applyGeneratedCode] Iframe recreated with new content');\n            } else {\n              console.error('[applyGeneratedCode] No iframe or sandbox URL available for refresh');\n            }\n          }, refreshDelay); // Dynamic delay based on whether packages were installed\n        }\n        \n        } else {\n          throw new Error(finalData?.error || 'Failed to apply code');\n        }\n      } else {\n        // If no final data was received, still close loading\n        addChatMessage('Code application may have partially succeeded. Check the preview.', 'system');\n      }\n    } catch (error: any) {\n      log(`Failed to apply code: ${error.message}`, 'error');\n    } finally {\n      setLoading(false);\n      // Clear isEdit flag after applying code\n      setGenerationProgress(prev => ({\n        ...prev,\n        isEdit: false\n      }));\n    }\n  };\n\n  const fetchSandboxFiles = async () => {","sourceCodeStart":1033,"sourceCodeEnd":1069,"githubUrl":"https://github.com/firecrawl/open-lovable/blob/69bd93bae7a9c97ef989eb70aabe6797fb3dac89/app/generation/page.tsx#L1033-L1069","documentation":"This error is thrown after the /api/apply-ai-code-stream stream completed: the client parsed the final streamed JSON payload (finalData) and found it flagged an application failure (finalData.error set), or the stream ended without a success marker. Unlike error 40 (HTTP-level failure), this is an application-level failure reported inside an otherwise successful HTTP 200 stream — the server started applying the code but reported an error in its terminal event.","triggerScenarios":"The streamed final JSON message contains { error: '...' } (e.g. file write failed, sandbox command exited non-zero, package installation failed mid-apply), or finalData is truthy but does not represent a successful application.","commonSituations":"Generated code contains a syntax error the sandbox builder rejects; installing pendingPackages fails partway (registry outage, peer-dependency conflict); sandbox container runs out of disk/memory during apply; WebSocket to the sandbox drops mid-write; version skew between client payload format and what the server expects.","solutions":["Read finalData.error (and server logs) for the specific apply failure — it is included in the thrown message","Retry the apply once; transient sandbox/connection failures often succeed on a second attempt","If the error mentions packages, verify each entry in pendingPackages is a valid installable package name/version","If the error mentions a specific file, inspect the generated code being applied for syntax issues","Recreate the sandbox (fresh sandboxId) and re-apply if the sandbox state appears corrupted"],"exampleFix":"// before\n} else {\n  throw new Error(finalData?.error || 'Failed to apply code');\n}\n// after\n} else {\n  const reason = finalData?.error || 'Failed to apply code';\n  addChatMessage(`Apply failed: ${reason}. Retrying...`, 'system');\n  throw new Error(reason);\n}","handlingStrategy":"type-guard","validationCode":"// after reading the stream, before trusting finalData\nconst finalData = JSON.parse(lastChunk);\nif (!finalData || typeof finalData !== 'object' || finalData.error) {\n  throw new Error(finalData?.error || 'Stream ended without a success payload');\n}","typeGuard":"interface ApplyResult { success: boolean; error?: string; [k: string]: unknown }\nfunction isSuccessfulApply(d: unknown): d is ApplyResult & { success: true } {\n  return typeof d === 'object' && d !== null &&\n    (d as ApplyResult).success === true && !(d as ApplyResult).error;\n}","tryCatchPattern":"try {\n  // stream apply...\n  if (!isSuccessfulApply(finalData)) {\n    throw new Error(finalData?.error || 'Failed to apply code');\n  }\n} catch (err: any) {\n  addChatMessage(`Apply failed: ${err.message}. You can retry.`, 'system');\n  // offer a one-click retry that re-POSTs the same payload\n}","preventionTips":["Always type-check/validate the final streamed payload before treating the apply as successful","Surface finalData.error to the user instead of a generic message","Retry once automatically for transient sandbox failures","Validate pendingPackages before sending to avoid mid-apply install errors","Log the full finalData payload to correlate with server-side apply logs"],"tags":["streaming","sandbox","application-error","code-apply"],"backgroundTag":"stream-payload-error","analyzedSha":"69bd93bae7a9c97ef989eb70aabe6797fb3dac89","analyzedAt":"2026-08-28T22:20:32.339Z","schemaVersion":2},"datasetVersion":"2026-08-29T02:17:18.158Z"}