Refactor MobileConfig Access for "react_fabric: treat_auto_as_undefined" (#37208)

Summary: Pull Request resolved: https://github.com/facebook/react-native/pull/37208

Reviewed By: javache

Differential Revision: D45434603

fbshipit-source-id: 9081ea11c87a05e0d8ff95e55d8aa8bcd52b4c39

packages/react-native/ReactCommon/react/renderer/components/view/conversions.h

@@ -11,7 +11,6 @@
 #include <folly/Conv.h>
 #include <folly/dynamic.h>
 #include <glog/logging.h>
-#include <react/config/ReactNativeConfig.h>
 #include <react/debug/react_native_expect.h>
 #include <react/renderer/components/view/primitives.h>
 #include <react/renderer/core/LayoutMetrics.h>
@@ -408,19 +407,14 @@ inline void fromRawValue(
     const PropsParserContext &context,
     const RawValue &value,
     YGStyle::ValueRepr &result) {
-  // For bug compatibility, pass "auto" as YGValueUndefined
-  static bool treatAutoAsUndefined =
-      context.contextContainer
-          .at<std::shared_ptr<ReactNativeConfig const>>("ReactNativeConfig")
-          ->getBool("react_fabric:treat_auto_as_undefined");
-
   if (value.hasType<Float>()) {
     result = yogaStyleValueFromFloat((Float)value);
     return;
   } else if (value.hasType<std::string>()) {
     const auto stringValue = (std::string)value;
     if (stringValue == "auto") {
-      result = treatAutoAsUndefined ? YGValueUndefined : YGValueAuto;
+      result = context.treatAutoAsYGValueUndefined() ? YGValueUndefined
+                                                     : YGValueAuto;
       return;
     } else {
       if (stringValue.back() == '%') {

packages/react-native/ReactCommon/react/renderer/core/CMakeLists.txt

@@ -23,6 +23,7 @@ target_link_libraries(react_render_core
         folly_runtime
         glog
         jsi
+        react_config
         react_debug
         react_render_debug
         react_render_graphics

packages/react-native/ReactCommon/react/renderer/core/PropsParserContext.cpp

@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include "PropsParserContext.h"
+
+#include <react/config/ReactNativeConfig.h>
+
+namespace facebook::react {
+
+bool PropsParserContext::treatAutoAsYGValueUndefined() const {
+  if (treatAutoAsYGValueUndefined_ == std::nullopt) {
+    auto config = contextContainer.at<std::shared_ptr<const ReactNativeConfig>>(
+        "ReactNativeConfig");
+    treatAutoAsYGValueUndefined_ = config
+        ? config->getBool("react_fabric:treat_auto_as_undefined")
+        : false;
+  }
+
+  return *treatAutoAsYGValueUndefined_;
+}
+
+} // namespace facebook::react

packages/react-native/ReactCommon/react/renderer/core/PropsParserContext.h

@@ -7,6 +7,8 @@
 
 #pragma once
 
+#include <optional>
+
 #include <react/renderer/core/ReactPrimitives.h>
 #include <react/utils/ContextContainer.h>
 
@@ -16,12 +18,23 @@ namespace facebook::react {
 // It should be used as infrequently as possible - most props can and should
 // be parsed without any context.
 struct PropsParserContext {
+  PropsParserContext(
+      SurfaceId const surfaceId,
+      ContextContainer const &contextContainer)
+      : surfaceId(surfaceId), contextContainer(contextContainer) {}
+
   // Non-copyable
   PropsParserContext(const PropsParserContext &) = delete;
   PropsParserContext &operator=(const PropsParserContext &) = delete;
 
   SurfaceId const surfaceId;
   ContextContainer const &contextContainer;
+
+  // Temporary feature flags
+  bool treatAutoAsYGValueUndefined() const;
+
+ private:
+  mutable std::optional<bool> treatAutoAsYGValueUndefined_;
 };
 
 } // namespace facebook::react