Mitigate a corner case of ReactNativeFeatureFlags late initialization…

… order (#39106)

Summary:
Pull Request resolved: #39106

## Changelog:
[Internal] -

`ReactNativeFeatureFlags` are not guaranteed to be initialized before everything else, and one case popped up with this being a problem, in particular when creating `GlobalPerformanceLogger` instance (which may be created quite early on).

If the order of initialization of `ReactNativeFeatureFlags` and reading a value from there is flipped, then we'd just get a default value, without using any `MobileConfig` backing or anything.

This diff works this around for the particular case of `GlobalPerformanceLogger` initialization by making the corresponding flag tri-state (unititalized/true/false) and making sure that its value is only really taken into account after its initialized.

Reviewed By: ryancat

Differential Revision: D48559981

fbshipit-source-id: 7fa842d3b845866e15f89731c7e5c9036b83fb24

packages/react-native/Libraries/ReactNative/ReactNativeFeatureFlags.js

@@ -38,9 +38,10 @@ export type FeatureFlags = {|
   animatedShouldUseSingleOp: () => boolean,
   /**
    * Enables GlobalPerformanceLogger replacement with a WebPerformance API based
-   * implementation
+   * implementation. Tri-state due to being sensitive to initialization order
+   * vs the platform-specific ReactNativeFeatureFlags implementation.
    */
-  isGlobalWebPerformanceLoggerEnabled: () => boolean,
+  isGlobalWebPerformanceLoggerEnabled: () => ?boolean,
   /**
    * Enables access to the host tree in Fabric using DOM-compatible APIs.
    */
@@ -69,7 +70,7 @@ const ReactNativeFeatureFlags: FeatureFlags = {
   shouldPressibilityUseW3CPointerEventsForHover: () => false,
   animatedShouldDebounceQueueFlush: () => false,
   animatedShouldUseSingleOp: () => false,
-  isGlobalWebPerformanceLoggerEnabled: () => false,
+  isGlobalWebPerformanceLoggerEnabled: () => undefined,
   enableAccessToHostTreeInFabric: () => false,
   shouldUseAnimatedObjectForTransform: () => false,
   shouldUseSetNativePropsInFabric: () => false,

packages/react-native/Libraries/Utilities/GlobalPerformanceLogger.js

@@ -10,26 +10,16 @@
 
 import type {IPerformanceLogger} from './createPerformanceLogger';
 
-import ReactNativeFeatureFlags from '../ReactNative/ReactNativeFeatureFlags';
-import NativePerformance from '../WebPerformance/NativePerformance';
 import createPerformanceLogger from './createPerformanceLogger';
 
-function isLoggingForWebPerformance(): boolean {
-  return (
-    NativePerformance != null &&
-    ReactNativeFeatureFlags.isGlobalWebPerformanceLoggerEnabled()
-  );
-}
-
 /**
  * This is a global shared instance of IPerformanceLogger that is created with
  * createPerformanceLogger().
  * This logger should be used only for global performance metrics like the ones
  * that are logged during loading bundle. If you want to log something from your
  * React component you should use PerformanceLoggerContext instead.
  */
-const GlobalPerformanceLogger: IPerformanceLogger = createPerformanceLogger(
-  isLoggingForWebPerformance(),
-);
+const GlobalPerformanceLogger: IPerformanceLogger =
+  createPerformanceLogger(true);
 
 module.exports = GlobalPerformanceLogger;

packages/react-native/Libraries/Utilities/createPerformanceLogger.js

@@ -16,6 +16,8 @@ import type {
 } from './IPerformanceLogger';
 
 import * as Systrace from '../Performance/Systrace';
+import ReactNativeFeatureFlags from '../ReactNative/ReactNativeFeatureFlags';
+import NativePerformance from '../WebPerformance/NativePerformance';
 import infoLog from './infoLog';
 
 const _cookies: {[key: string]: number, ...} = {};
@@ -35,10 +37,22 @@ class PerformanceLogger implements IPerformanceLogger {
   _points: {[key: string]: ?number} = {};
   _pointExtras: {[key: string]: ?Extras, ...} = {};
   _closed: boolean = false;
-  _isLoggingForWebPerformance: boolean = false;
+  _isGlobalLogger: boolean = false;
+  _isGlobalWebPerformanceLoggerEnabled: ?boolean;
 
-  constructor(isLoggingForWebPerformance?: boolean) {
-    this._isLoggingForWebPerformance = isLoggingForWebPerformance === true;
+  constructor(isGlobalLogger?: boolean) {
+    this._isGlobalLogger = isGlobalLogger === true;
+  }
+
+  _isLoggingForWebPerformance(): boolean {
+    if (!this._isGlobalLogger || NativePerformance == null) {
+      return false;
+    }
+    if (this._isGlobalWebPerformanceLoggerEnabled == null) {
+      this._isGlobalWebPerformanceLoggerEnabled =
+        ReactNativeFeatureFlags.isGlobalWebPerformanceLoggerEnabled();
+    }
+    return this._isGlobalWebPerformanceLoggerEnabled === true;
   }
 
   // NOTE: The Performance.mark/measure calls are wrapped here to ensure that
@@ -49,7 +63,7 @@ class PerformanceLogger implements IPerformanceLogger {
   // In most of the other cases this kind of check for `performance` being defined
   // wouldn't be necessary.
   _performanceMark(key: string, startTime: number) {
-    if (this._isLoggingForWebPerformance) {
+    if (this._isLoggingForWebPerformance()) {
       global.performance?.mark?.(key, {
         startTime,
       });
@@ -61,7 +75,7 @@ class PerformanceLogger implements IPerformanceLogger {
     start: number | string,
     end: number | string,
   ) {
-    if (this._isLoggingForWebPerformance) {
+    if (this._isLoggingForWebPerformance()) {
       global.performance?.measure?.(key, {
         start,
         end,
@@ -351,7 +365,7 @@ export type {Extras, ExtraValue, IPerformanceLogger, Timespan};
  * The loggers need to have minimal overhead since they're used in production.
  */
 export default function createPerformanceLogger(
-  isLoggingForWebPerformance?: boolean,
+  isGlobalLogger?: boolean,
 ): IPerformanceLogger {
-  return new PerformanceLogger(isLoggingForWebPerformance);
+  return new PerformanceLogger(isGlobalLogger);
 }