{"record":{"id":"f5ca927811928456","repo":"facebook/react","slug":"not-yet-implemented","errorCode":null,"errorMessage":"Not yet implemented.","messagePattern":"Not yet implemented\\.","errorType":"exception","errorClass":"Error","httpStatus":null,"severity":"error","filePath":"packages/react-native-renderer/src/ReactFiberConfigFabric.js","lineNumber":558,"sourceCode":"  props: Props,\n): Instance {\n  const viewConfig = instance.canonical.viewConfig;\n  const node = instance.node;\n  const updatePayload = createAttributePayload(\n    {style: {display: 'none'}},\n    viewConfig.validAttributes,\n  );\n  return {\n    node: cloneNodeWithNewProps(node, updatePayload),\n    canonical: instance.canonical,\n  };\n}\n\nexport function cloneHiddenTextInstance(\n  instance: Instance,\n  text: string,\n): TextInstance {\n  throw new Error('Not yet implemented.');\n}\n\nexport function createContainerChildSet(): ChildSet {\n  if (passChildrenWhenCloningPersistedNodes) {\n    return [];\n  } else {\n    return createChildNodeSet();\n  }\n}\n\nexport function appendChildToContainerChildSet(\n  childSet: ChildSet,\n  child: Instance | TextInstance,\n): void {\n  if (passChildrenWhenCloningPersistedNodes) {\n    childSet.push(child.node);\n  } else {\n    appendChildNodeToSet(childSet, child.node);","sourceCodeStart":540,"sourceCodeEnd":576,"githubUrl":"https://github.com/facebook/react/blob/eafeac097ba51e1eab809c07102126bd5f8e5425/packages/react-native-renderer/src/ReactFiberConfigFabric.js#L540-L576","documentation":"Fabric maintains a copy-on-write 'persisted' tree; when a text instance becomes hidden (Activity/Offscreen hidden mode), the renderer must clone it via cloneHiddenTextInstance - which Fabric deliberately has not implemented, so it always throws 'Not yet implemented.'. Hiding raw text subtrees is simply unsupported on this renderer.","triggerScenarios":"Rendering bare text (a string child) inside a subtree that Activity/Offscreen places into hidden mode (e.g. <Activity mode='hidden'>Loading...</Activity>) on the New Architecture/Fabric renderer with the persisted-node cloning path active.","commonSituations":"Experimenting with the experimental Activity/Offscreen APIs on React Native before Fabric implements hidden-text cloning; prerendering hidden content for instant reveal.","solutions":["Avoid Activity mode='hidden' / Offscreen around raw text on Fabric until RN ships support.","Render conditionally (return null when hidden) instead of hiding the text subtree.","Track the React Native issue for cloneHiddenTextInstance on Fabric and keep the feature behind a flag."],"exampleFix":"// before\n<Activity mode='hidden'>Loading...</Activity>\n\n// after - avoid hiding a raw text subtree on Fabric\n{isHidden ? null : 'Loading...'}","handlingStrategy":"fallback","validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":["Do not use Activity mode='hidden' / Offscreen around raw text on Fabric.","Prefer conditional rendering (null) over hiding text subtrees.","Track Fabric support for cloneHiddenTextInstance before adopting hidden-subtree prerendering."],"tags":["react-native","fabric","offscreen","activity","not-implemented"],"backgroundTag":"unsupported-platform-feature","analyzedSha":"eafeac097ba51e1eab809c07102126bd5f8e5425","analyzedAt":"2026-08-21T22:01:08.818Z","schemaVersion":2},"datasetVersion":"2026-08-21T23:17:16.201Z"}