Fixed incorrect value returned as public instance from reconciler

packages/react-native-renderer/src/ReactFabric.js

@@ -90,15 +90,6 @@ function findHostInstance_DEPRECATED<TElementType: ElementType>(
     hostInstance = findHostInstance(componentOrHandle);
   }
 
-  if (hostInstance == null) {
-    return hostInstance;
-  }
-  if ((hostInstance: any).canonical) {
-    // Fabric
-    return (hostInstance: any).canonical;
-  }
-  // $FlowFixMe[incompatible-return]
-  // $FlowFixMe[incompatible-exact]
   return hostInstance;
 }
 
@@ -146,12 +137,7 @@ function findNodeHandle(componentOrHandle: any): ?number {
   if (hostInstance == null) {
     return hostInstance;
   }
-  // TODO: the code is right but the types here are wrong.
-  // https://github.com/facebook/react/pull/12863
-  if ((hostInstance: any).canonical) {
-    // Fabric
-    return (hostInstance: any).canonical._nativeTag;
-  }
+
   return hostInstance._nativeTag;
 }
 

packages/react-native-renderer/src/ReactFabricHostConfig.js

@@ -110,7 +110,7 @@ if (registerEventHandler) {
 /**
  * This is used for refs on host components.
  */
-class ReactFabricHostComponent {
+class ReactFabricHostComponent implements NativeMethods {
   _nativeTag: number;
   viewConfig: ViewConfig;
   currentProps: Props;
@@ -215,10 +215,6 @@ class ReactFabricHostComponent {
   }
 }
 
-// $FlowFixMe[class-object-subtyping] found when upgrading Flow
-// $FlowFixMe[method-unbinding] found when upgrading Flow
-(ReactFabricHostComponent.prototype: $ReadOnly<{...NativeMethods, ...}>);
-
 export * from 'react-reconciler/src/ReactFiberHostConfigWithNoMutation';
 export * from 'react-reconciler/src/ReactFiberHostConfigWithNoHydration';
 export * from 'react-reconciler/src/ReactFiberHostConfigWithNoScopes';
@@ -342,8 +338,17 @@ export function getChildHostContext(
   }
 }
 
-export function getPublicInstance(instance: Instance): * {
-  return instance.canonical;
+export function getPublicInstance(instance: Instance): null | PublicInstance {
+  if (instance.canonical) {
+    return instance.canonical;
+  }
+
+  // For compatibility with Paper
+  if (instance._nativeTag != null) {
+    return instance;
+  }
+
+  return null;
 }
 
 export function prepareForCommit(containerInfo: Container): null | Object {

packages/react-native-renderer/src/ReactNativeFiberHostComponent.js

@@ -30,7 +30,7 @@ import {
   warnForStyleProps,
 } from './NativeMethodsMixinUtils';
 
-class ReactNativeFiberHostComponent {
+class ReactNativeFiberHostComponent implements NativeMethods {
   _children: Array<Instance | number>;
   _nativeTag: number;
   _internalFiberInstanceHandleDEV: Object;
@@ -127,8 +127,4 @@ class ReactNativeFiberHostComponent {
   }
 }
 
-// $FlowFixMe[class-object-subtyping] found when upgrading Flow
-// $FlowFixMe[method-unbinding] found when upgrading Flow
-(ReactNativeFiberHostComponent.prototype: $ReadOnly<{...NativeMethods, ...}>);
-
 export default ReactNativeFiberHostComponent;

packages/react-native-renderer/src/ReactNativeHostConfig.js

@@ -217,6 +217,11 @@ export function getChildHostContext(
 }
 
 export function getPublicInstance(instance: Instance): * {
+  // $FlowExpectedError[prop-missing] For compatibility with Fabric
+  if (instance.canonical) {
+    return instance.canonical;
+  }
+
   return instance;
 }
 

packages/react-native-renderer/src/ReactNativeRenderer.js

@@ -89,15 +89,6 @@ function findHostInstance_DEPRECATED(
     hostInstance = findHostInstance(componentOrHandle);
   }
 
-  if (hostInstance == null) {
-    return hostInstance;
-  }
-  if ((hostInstance: any).canonical) {
-    // Fabric
-    return (hostInstance: any).canonical;
-  }
-  // $FlowFixMe[incompatible-return]
-  // $FlowFixMe[incompatible-exact]
   return hostInstance;
 }
 
@@ -145,10 +136,7 @@ function findNodeHandle(componentOrHandle: any): ?number {
   if (hostInstance == null) {
     return hostInstance;
   }
-  if ((hostInstance: any).canonical) {
-    // Fabric
-    return (hostInstance: any).canonical._nativeTag;
-  }
+
   return hostInstance._nativeTag;
 }
 

packages/react-native-renderer/src/ReactNativeTypes.js

@@ -95,18 +95,18 @@ export type PartialViewConfig = $ReadOnly<{
   validAttributes?: PartialAttributeConfiguration,
 }>;
 
-export type NativeMethods = $ReadOnly<{
-  blur(): void,
-  focus(): void,
-  measure(callback: MeasureOnSuccessCallback): void,
-  measureInWindow(callback: MeasureInWindowOnSuccessCallback): void,
+export interface NativeMethods {
+  blur(): void;
+  focus(): void;
+  measure(callback: MeasureOnSuccessCallback): void;
+  measureInWindow(callback: MeasureInWindowOnSuccessCallback): void;
   measureLayout(
     relativeToNativeNode: number | ElementRef<HostComponent<mixed>>,
     onSuccess: MeasureLayoutOnSuccessCallback,
     onFail?: () => void,
-  ): void,
-  setNativeProps(nativeProps: {...}): void,
-}>;
+  ): void;
+  setNativeProps(nativeProps: {...}): void;
+}
 
 export type HostComponent<T> = AbstractComponent<T, $ReadOnly<NativeMethods>>;
 

packages/react-reconciler/src/ReactFiberReconciler.js

@@ -175,7 +175,7 @@ function findHostInstance(component: Object): PublicInstance | null {
   if (hostFiber === null) {
     return null;
   }
-  return hostFiber.stateNode;
+  return getPublicInstance(hostFiber.stateNode);
 }
 
 function findHostInstanceWithWarning(
@@ -240,7 +240,7 @@ function findHostInstanceWithWarning(
         }
       }
     }
-    return hostFiber.stateNode;
+    return getPublicInstance(hostFiber.stateNode);
   }
   return findHostInstance(component);
 }
@@ -524,7 +524,7 @@ export function findHostInstanceWithNoPortals(
   if (hostFiber === null) {
     return null;
   }
-  return hostFiber.stateNode;
+  return getPublicInstance(hostFiber.stateNode);
 }
 
 let shouldErrorImpl: Fiber => ?boolean = fiber => null;