Fix Connect to Metro after Reload in Bridgeless mode (#43994)

Summary: Pull Request resolved: https://github.com/facebook/react-native/pull/43994 We received [this issue](https://github.com/facebook/react-native/issues/43764) from OSS where an app can't connect to Metro on reloads in the following scenario: * Start the App when metro does not run. * Observe the error screen * Start Metro * Press Reload * Observe the error message again While the desired behavior should be to connect to Metro now that this is running. The root cause of the problem is that the RCTHost is initialized with a value of the `bundleURL` that is `nil`. Upon reload, the RCTHost is **not** recreated: the instance is restarted, but with the previous `bundleURL`, which is still `nil`. The solution is to initialize the `RCTHost` with a closure that re-evaluate the `bundleURL` whenever it is invoked and to evaluate it only on `start`, to keep the initialization path light. This way, when the app is started with Metro not running, the `bundleURL` is `nil`. But when it is reloaded with Metro starting, the `bundleURL` is properly initialized. Note that the changes in this diff are not breaking as I reimplemented (and deprecated) the old initializer so that they should work in the same way. ## Changelog: [iOS][Fixed] - Let RCTHost be initialized with a function to provide the `bundleURL` so that it can connect to metro on Reload when the url changes. Reviewed By: dmytrorykun Differential Revision: D55916135 fbshipit-source-id: 6927b2154870245f28f42d26bd0209b28c9518f2
2025-11-01 09:14:26 +00:00 · 2024-04-09 08:54:33 -07:00
parent a98c54f616
commit 8b8b85bb1f
6 changed files with 74 additions and 26 deletions
@@ -248,13 +248,18 @@

 - (RCTRootViewFactory *)createRCTRootViewFactory
 {
-  RCTRootViewFactoryConfiguration *configuration =
-      [[RCTRootViewFactoryConfiguration alloc] initWithBundleURL:self.bundleURL
-                                                  newArchEnabled:self.fabricEnabled
-                                              turboModuleEnabled:self.turboModuleEnabled
-                                               bridgelessEnabled:self.bridgelessEnabled];
-
  __weak __typeof(self) weakSelf = self;
+  RCTBundleURLBlock bundleUrlBlock = ^{
+    RCTAppDelegate *strongSelf = weakSelf;
+    return strongSelf.bundleURL;
+  };
+
+  RCTRootViewFactoryConfiguration *configuration =
+      [[RCTRootViewFactoryConfiguration alloc] initWithBundleURLBlock:bundleUrlBlock
+                                                       newArchEnabled:self.fabricEnabled
+                                                   turboModuleEnabled:self.turboModuleEnabled
+                                                    bridgelessEnabled:self.bridgelessEnabled];
+
  configuration.createRootViewWithBridge = ^UIView *(RCTBridge *bridge, NSString *moduleName, NSDictionary *initProps)
  {
    return [weakSelf createRootViewWithBridge:bridge moduleName:moduleName initProps:initProps];
@@ -24,6 +24,7 @@ typedef UIView *_Nonnull (
 typedef RCTBridge *_Nonnull (
    ^RCTCreateBridgeWithDelegateBlock)(id<RCTBridgeDelegate> delegate, NSDictionary *launchOptions);
 typedef NSURL *_Nullable (^RCTSourceURLForBridgeBlock)(RCTBridge *bridge);
+typedef NSURL *_Nullable (^RCTBundleURLBlock)(void);
 typedef NSArray<id<RCTBridgeModule>> *_Nonnull (^RCTExtraModulesForBridgeBlock)(RCTBridge *bridge);
 typedef NSDictionary<NSString *, Class> *_Nonnull (^RCTExtraLazyModuleClassesForBridge)(RCTBridge *bridge);
 typedef BOOL (^RCTBridgeDidNotFindModuleBlock)(RCTBridge *bridge, NSString *moduleName);
@@ -41,7 +42,7 @@ typedef BOOL (^RCTBridgeDidNotFindModuleBlock)(RCTBridge *bridge, NSString *modu
@property (nonatomic, assign, readonly) BOOL turboModuleEnabled;

 /// Return the bundle URL for the main bundle.
-@property (nonatomic) NSURL *bundleURL;
+@property (nonatomic, nonnull) RCTBundleURLBlock bundleURLBlock;

 /**
 * Use this method to initialize a new instance of `RCTRootViewFactoryConfiguration` by passing a `bundleURL`
@@ -52,10 +53,15 @@ typedef BOOL (^RCTBridgeDidNotFindModuleBlock)(RCTBridge *bridge, NSString *modu
 * pointing to a path inside the app resources, e.g. `file://.../main.jsbundle`.
 *
 */
+- (instancetype)initWithBundleURLBlock:(RCTBundleURLBlock)bundleURLBlock
+                        newArchEnabled:(BOOL)newArchEnabled
+                    turboModuleEnabled:(BOOL)turboModuleEnabled
+                     bridgelessEnabled:(BOOL)bridgelessEnabled NS_DESIGNATED_INITIALIZER;
+
 - (instancetype)initWithBundleURL:(NSURL *)bundleURL
                   newArchEnabled:(BOOL)newArchEnabled
               turboModuleEnabled:(BOOL)turboModuleEnabled
-                bridgelessEnabled:(BOOL)bridgelessEnabled;
+                bridgelessEnabled:(BOOL)bridgelessEnabled __deprecated;

 /**
 * Block that allows to override logic of creating root view instance.
@@ -57,9 +57,23 @@ static NSDictionary *updateInitialProps(NSDictionary *initialProps, BOOL isFabri
                   newArchEnabled:(BOOL)newArchEnabled
               turboModuleEnabled:(BOOL)turboModuleEnabled
                bridgelessEnabled:(BOOL)bridgelessEnabled
+{
+  return [self
+      initWithBundleURLBlock:^{
+        return bundleURL;
+      }
+              newArchEnabled:newArchEnabled
+          turboModuleEnabled:turboModuleEnabled
+           bridgelessEnabled:bridgelessEnabled];
+}
+
+- (instancetype)initWithBundleURLBlock:(RCTBundleURLBlock)bundleURLBlock
+                        newArchEnabled:(BOOL)newArchEnabled
+                    turboModuleEnabled:(BOOL)turboModuleEnabled
+                     bridgelessEnabled:(BOOL)bridgelessEnabled
 {
  if (self = [super init]) {
-    _bundleURL = bundleURL;
+    _bundleURLBlock = bundleURLBlock;
    _fabricEnabled = newArchEnabled;
    _turboModuleEnabled = turboModuleEnabled;
    _bridgelessEnabled = bridgelessEnabled;
@@ -214,13 +228,13 @@ static NSDictionary *updateInitialProps(NSDictionary *initialProps, BOOL isFabri
  }

  __weak __typeof(self) weakSelf = self;
-  _reactHost = [[RCTHost alloc] initWithBundleURL:[self bundleURL]
-                                     hostDelegate:nil
-                       turboModuleManagerDelegate:_turboModuleManagerDelegate
-                                 jsEngineProvider:^std::shared_ptr<facebook::react::JSRuntimeFactory>() {
-                                   return [weakSelf createJSRuntimeFactory];
-                                 }
-                                    launchOptions:launchOptions];
+  _reactHost = [[RCTHost alloc] initWithBundleURLProvider:self->_configuration.bundleURLBlock
+                                             hostDelegate:nil
+                               turboModuleManagerDelegate:_turboModuleManagerDelegate
+                                         jsEngineProvider:^std::shared_ptr<facebook::react::JSRuntimeFactory>() {
+                                           return [weakSelf createJSRuntimeFactory];
+                                         }
+                                            launchOptions:launchOptions];
  [_reactHost setBundleURLProvider:^NSURL *() {
    return [weakSelf bundleURL];
  }];
@@ -276,7 +290,7 @@ static NSDictionary *updateInitialProps(NSDictionary *initialProps, BOOL isFabri

 - (NSURL *)bundleURL
 {
-  return self->_configuration.bundleURL;
+  return self->_configuration.bundleURLBlock();
 }

@end
@@ -9,8 +9,6 @@

 #import "RCTContextContainerHandling.h"

-typedef NSURL * (^RCTHostBundleURLProvider)(void);
-
@interface RCTHost (Internal)

 - (void)registerSegmentWithId:(NSNumber *)segmentId path:(NSString *)path;
@@ -21,6 +21,8 @@ NS_ASSUME_NONNULL_BEGIN

@protocol RCTTurboModuleManagerDelegate;

+typedef NSURL *_Nullable (^RCTHostBundleURLProvider)(void);
+
 // Runtime API

@protocol RCTHostDelegate <NSObject>
@@ -45,11 +47,17 @@ typedef std::shared_ptr<facebook::react::JSRuntimeFactory> (^RCTHostJSEngineProv

@interface RCTHost : NSObject

+- (instancetype)initWithBundleURLProvider:(RCTHostBundleURLProvider)provider
+                             hostDelegate:(id<RCTHostDelegate>)hostDelegate
+               turboModuleManagerDelegate:(id<RCTTurboModuleManagerDelegate>)turboModuleManagerDelegate
+                         jsEngineProvider:(RCTHostJSEngineProvider)jsEngineProvider
+                            launchOptions:(nullable NSDictionary *)launchOptions NS_DESIGNATED_INITIALIZER;
+
 - (instancetype)initWithBundleURL:(NSURL *)bundleURL
                     hostDelegate:(id<RCTHostDelegate>)hostDelegate
       turboModuleManagerDelegate:(id<RCTTurboModuleManagerDelegate>)turboModuleManagerDelegate
                 jsEngineProvider:(RCTHostJSEngineProvider)jsEngineProvider
-                    launchOptions:(nullable NSDictionary *)launchOptions NS_DESIGNATED_INITIALIZER;
+                    launchOptions:(nullable NSDictionary *)launchOptions __deprecated;

@property (nonatomic, weak, nullable) id<RCTHostRuntimeDelegate> runtimeDelegate;

@@ -79,15 +79,31 @@ class RCTHostHostTargetDelegate : public facebook::react::jsinspector_modern::Ho
  _RCTInitializeJSThreadConstantInternal();
 }

-/**
- Host initialization should not be resource intensive. A host may be created before any intention of using React Native
- has been expressed.
- */
 - (instancetype)initWithBundleURL:(NSURL *)bundleURL
                     hostDelegate:(id<RCTHostDelegate>)hostDelegate
       turboModuleManagerDelegate:(id<RCTTurboModuleManagerDelegate>)turboModuleManagerDelegate
                 jsEngineProvider:(RCTHostJSEngineProvider)jsEngineProvider
                    launchOptions:(nullable NSDictionary *)launchOptions
+{
+  return [self
+       initWithBundleURLProvider:^{
+         return bundleURL;
+       }
+                    hostDelegate:hostDelegate
+      turboModuleManagerDelegate:turboModuleManagerDelegate
+                jsEngineProvider:jsEngineProvider
+                   launchOptions:launchOptions];
+}
+
+/**
+ Host initialization should not be resource intensive. A host may be created before any intention of using React Native
+ has been expressed.
+ */
+- (instancetype)initWithBundleURLProvider:(RCTHostBundleURLProvider)provider
+                             hostDelegate:(id<RCTHostDelegate>)hostDelegate
+               turboModuleManagerDelegate:(id<RCTTurboModuleManagerDelegate>)turboModuleManagerDelegate
+                         jsEngineProvider:(RCTHostJSEngineProvider)jsEngineProvider
+                            launchOptions:(nullable NSDictionary *)launchOptions
 {
  if (self = [super init]) {
    _hostDelegate = hostDelegate;
@@ -99,7 +115,6 @@ class RCTHostHostTargetDelegate : public facebook::react::jsinspector_modern::Ho
    _launchOptions = [launchOptions copy];

    __weak RCTHost *weakSelf = self;
-
    auto bundleURLGetter = ^NSURL *()
    {
      RCTHost *strongSelf = weakSelf;
@@ -124,7 +139,6 @@ class RCTHostHostTargetDelegate : public facebook::react::jsinspector_modern::Ho
      return strongSelf->_bundleURLProvider();
    };

-    [self _setBundleURL:bundleURL];
    [_bundleManager setBridgelessBundleURLGetter:bundleURLGetter
                                       andSetter:bundleURLSetter
                                andDefaultGetter:defaultBundleURLGetter];
@@ -170,6 +184,9 @@ class RCTHostHostTargetDelegate : public facebook::react::jsinspector_modern::Ho

 - (void)start
 {
+  if (_bundleURLProvider) {
+    [self _setBundleURL:_bundleURLProvider()];
+  }
  auto &inspectorFlags = jsinspector_modern::InspectorFlags::getInstance();
  if (inspectorFlags.getEnableModernCDPRegistry() && !_inspectorPageId.has_value()) {
    _inspectorTarget =