{"record":{"id":"49d51fa108d71023","repo":"facebook/react","slug":"handlepostcommitfiberroot-not-supported-by-this-re","errorCode":null,"errorMessage":"handlePostCommitFiberRoot not supported by this renderer","messagePattern":"handlePostCommitFiberRoot not supported by this renderer","errorType":"exception","errorClass":"Error","httpStatus":null,"severity":"error","filePath":"packages/react-devtools-shared/src/backend/legacy/renderer.js","lineNumber":1198,"sourceCode":"            forceUpdate(publicInstance);\n            break;\n        }\n      }\n    }\n  }\n\n  // v16+ only features\n  const getProfilingData = () => {\n    throw new Error('getProfilingData not supported by this renderer');\n  };\n  const handleCommitFiberRoot = () => {\n    throw new Error('handleCommitFiberRoot not supported by this renderer');\n  };\n  const handleCommitFiberUnmount = () => {\n    throw new Error('handleCommitFiberUnmount not supported by this renderer');\n  };\n  const handlePostCommitFiberRoot = () => {\n    throw new Error('handlePostCommitFiberRoot not supported by this renderer');\n  };\n  const overrideError = () => {\n    throw new Error('overrideError not supported by this renderer');\n  };\n  const overrideSuspense = () => {\n    throw new Error('overrideSuspense not supported by this renderer');\n  };\n  const overrideSuspenseMilestone = () => {\n    throw new Error('overrideSuspenseMilestone not supported by this renderer');\n  };\n  const startProfiling = () => {\n    // Do not throw, since this would break a multi-root scenario where v15 and v16 were both present.\n  };\n  const stopProfiling = () => {\n    // Do not throw, since this would break a multi-root scenario where v15 and v16 were both present.\n  };\n\n  function getBestMatchForTrackedPath(): PathMatch | null {","sourceCodeStart":1180,"sourceCodeEnd":1216,"githubUrl":"https://github.com/facebook/react/blob/eafeac097ba51e1eab809c07102126bd5f8e5425/packages/react-devtools-shared/src/backend/legacy/renderer.js#L1180-L1216","documentation":"The legacy renderer adapter stubs handlePostCommitFiberRoot as a throwing no-op. Post-commit notifications exist only in the fiber reconciler (React 16+), where they drive Profiler timing; the stack reconciler never sends them. Seeing this error means a post-commit fiber notification reached a legacy renderer interface, which points at id mixups or version skew.","triggerScenarios":"A caller invokes rendererInterface.handlePostCommitFiberRoot() — reached via __REACT_DEVTOOLS_GLOBAL_HOOK__.onPostCommitFiberRoot dispatch or custom hook wiring — against an interface created by the legacy (v15) adapter.","commonSituations":"Multi-root pages mixing React 15 and 16+ where the renderer id is crossed; duplicated React installs; custom renderers or test harnesses imitating the fiber hook protocol.","solutions":["Ensure only one React copy per page registers with the DevTools hook (dedupe dependencies).","Update/align DevTools frontend and backend versions.","Upgrade the legacy app to React 16+.","For embedders: feature-detect fiber support before invoking post-commit handlers."],"exampleFix":"// before\nrendererInterface.handlePostCommitFiberRoot();\n\n// after\nif (typeof renderer.findFiberByHostInstance === 'function') {\n  rendererInterface.handlePostCommitFiberRoot();\n}","handlingStrategy":"validation","validationCode":"const isFiberRenderer = renderer =>\n  typeof renderer.findFiberByHostInstance === 'function';\nif (isFiberRenderer(renderer)) {\n  rendererInterface.handlePostCommitFiberRoot();\n}","typeGuard":"function isFiberRenderer(renderer) {\n  return typeof renderer.findFiberByHostInstance === 'function';\n}","tryCatchPattern":"try {\n  rendererInterface.handlePostCommitFiberRoot();\n} catch (error) {\n  if (/not supported by this renderer/.test(error.message)) return;\n  throw error;\n}","preventionTips":["Only wire onPostCommitFiberRoot through for fiber renderers.","Audit custom hook wiring that broadcasts commit events to all renderer interfaces.","Deduplicate React copies on mixed-version pages."],"tags":["devtools","fiber","commit","legacy-renderer","profiler"],"backgroundTag":"unsupported-renderer-feature","analyzedSha":"eafeac097ba51e1eab809c07102126bd5f8e5425","analyzedAt":"2026-08-21T22:01:08.818Z","schemaVersion":2},"datasetVersion":"2026-08-21T23:17:16.201Z"}