fix(crashlytics, ios): init w/componentsToRegister vs configureWithApp

configureWithApp is scheduled for removal upstream

initialization logic we need to execute is moved to componentsToRegister,
but componentsToRegister runs earlier in app init lifecycle than configureWithApp

so we use a deferred execution block to make sure crashlytics component
exists before trying to configure it

packages/crashlytics/ios/RNFBCrashlytics/RNFBCrashlyticsInitProvider.h

@@ -30,8 +30,4 @@
 /// FIRApp and participate in dependency resolution and injection.
 + (NSArray<FIRComponent *> *)componentsToRegister;
 
-/// Implement this method if the library needs notifications for lifecycle events. This method is
-/// called when the developer calls `FirebaseApp.configure()`.
-+ (void)configureWithApp:(FIRApp *)app;
-
 @end

packages/crashlytics/ios/RNFBCrashlytics/RNFBCrashlyticsInitProvider.m

@@ -18,6 +18,11 @@
 #import "RNFBCrashlyticsInitProvider.h"
 #import <Firebase/Firebase.h>
 #import <FirebaseCoreExtension/FIRAppInternal.h>
+#import <FirebaseCoreExtension/FIRComponent.h>
+#import <FirebaseCoreExtension/FIRComponentContainer.h>
+#import <FirebaseCoreExtension/FIRComponentType.h>
+#import <FirebaseCoreExtension/FIRLibrary.h>
+#import <FirebaseCrashlytics/FIRCrashlytics.h>
 #import "RNFBJSON.h"
 #import "RNFBMeta.h"
 #import "RNFBPreferences.h"
@@ -32,6 +37,19 @@
 NSString *const KEY_CRASHLYTICS_JAVASCRIPT_EXCEPTION_HANDLER_CHAINING_ENABLED =
     @"crashlytics_javascript_exception_handler_chaining_enabled";
 
+/// Empty protocol to register this provider as a component with Core.
+@protocol RNFBCrashlyticsInitProviderProtocol
+@end
+
+/// The name of the Crashlytics component in FirebaseCore's component system. Reference:
+// https://github.com/firebase/firebase-ios-sdk/blob/main/Crashlytics/Crashlytics/FIRCrashlytics.m#L87-L89
+@protocol FIRCrashlyticsInstanceProvider <NSObject>
+@end
+
+/// Privately conform to the protocol for component registration.
+@interface RNFBCrashlyticsInitProvider () <RNFBCrashlyticsInitProviderProtocol, FIRLibrary>
+@end
+
 @implementation RNFBCrashlyticsInitProvider
 
 + (void)load {
@@ -79,26 +97,47 @@ + (BOOL)isCrashlyticsJavascriptExceptionHandlerChainingEnabled {
 }
 
 + (NSArray<FIRComponent *> *)componentsToRegister {
-  return @[];
-}
+  // Goal: enable or disable crashlytics logging based on firebase.json settings at app startup
+  //
+  // Problem: We need a correctly instantiated Crashlytics component in order to configure it
+  //
+  // Solution:
+  // 1) put the desired startup logic that requires Crashlytics dependency in deferrable block...
+  FIRComponentCreationBlock creationBlock =
+      ^id _Nullable(FIRComponentContainer *container, BOOL *isCacheable) {
+    if (!container.app.isDefaultApp) {
+      return nil;
+    }
 
-/*
- * configureWithApp is automatically invoked by Firebase as this app is a registered FIRLibrary with
- * the SDK.
- *
- * At this point "configure" has already been called on the FIRApp instance. This behavior is meant
- * to mirror what is done in ReactNativeFirebaseCrashlyticsInitProvider.java
- *
- * This pattern may not be supported long term
- * https://github.com/firebase/firebase-ios-sdk/issues/2933
- */
-+ (void)configureWithApp:(FIRApp *)app {
-  // This setting is sticky. setCrashlyticsCollectionEnabled persists the setting to disk until it
-  // is explicitly set otherwise or the app is deleted. Jump to the setCrashlyticsCollectionEnabled
-  // definition to see implementation details.
-  [[FIRCrashlytics crashlytics]
-      setCrashlyticsCollectionEnabled:self.isCrashlyticsCollectionEnabled];
-  DLog(@"RNFBCrashlyticsInit initialization successful");
+    // Ensure it's cached so it returns the same instance every time messaging is called.
+    *isCacheable = YES;
+
+    // 2) ... ask the SDK component system to get a correctly running dependency...
+    // Note: This is a FIRCrashlytics *, directly cast it later for practical use, reference:
+    // https://github.com/firebase/firebase-ios-sdk/blob/main/Crashlytics/Crashlytics/FIRCrashlytics.m#L282-L284
+    id<FIRCrashlyticsInstanceProvider> crashlytics =
+        FIR_COMPONENT(FIRCrashlyticsInstanceProvider, container);
+
+    // This setting is sticky. setCrashlyticsCollectionEnabled persists the setting to disk until it
+    // is explicitly set otherwise or the app is deleted. Jump to the
+    // setCrashlyticsCollectionEnabled definition to see implementation details.
+    [(FIRCrashlytics *)crashlytics
+        setCrashlyticsCollectionEnabled:self.isCrashlyticsCollectionEnabled];
+
+    // For testing: filter for this in logs to make sure this block executes via
+    // xcrun simctl spawn booted log stream --level debug --style compact |grep RNFBCrashlyticsInit
+    DLog(@"RNFBCrashlyticsInit initialization successful");
+    return nil;
+  };
+
+  // 3) ...finally: register startup block to run w/Crashlytics dependency when ready
+  FIRComponent *crashlyticsInitProvider =
+      [FIRComponent componentWithProtocol:@protocol(RNFBCrashlyticsInitProviderProtocol)
+                      instantiationTiming:FIRInstantiationTimingEagerInDefaultApp
+                             dependencies:@[]  // note this will go away in firebase-ios-sdk v11+
+                            creationBlock:creationBlock];
+
+  return @[ crashlyticsInitProvider ];
 }
 
 @end