fix(ios): warn when Expo linkage restore cannot run

Surface unsupported CocoaPods hook drift instead of silently allowing the duplicate-symbol regression to return.

Author: russellwheatley

okf-bundle/ios-spm-native-imports.md

@@ -457,6 +457,11 @@ targets to dynamic linkage and eliminating the embedded SPM duplicate. Bare
 CocoaPods (no SPM), source-built Expo, non-Expo apps, and already-dynamic
 targets are unaffected.
 
+If CocoaPods no longer exposes `generate_pods_project`, RNFB cannot install
+the restore at the required boundary. Expo-precompiled installs warn once per
+installer class and continue without the restore; non-Expo and source-built
+Expo paths do not warn.
+
 ### Regression check
 
 The documented Podfile configuration does not change: SPM on,
@@ -466,6 +471,9 @@ Link success confirms both RNFB framework products are in dynamic form and
 duplicate Firebase symbols are absent, while still validating the app target's
 own FirebaseCore dependency (the original purpose of that fixture). See
 [Maintainer check of the Expo documented path](#app-target-firebasecore-link-package-dependency-alone-is-not-enough).
+The [#9202](https://github.com/invertase/react-native-firebase/issues/9202)
+regression signature is duplicate `_FIRFirebaseVersion` symbols from
+`libRNFBApp.a` and `libRNFBMessaging.a`.
 
 ## Review invariants
 

okf-bundle/packages/app/index.md

@@ -12,11 +12,11 @@ Knowledge for the core app package: Firebase app lifecycle, Expo config plugin,
 
 **Policy:** [OKF documentation and commit policy](../../documentation-policy.md). Agent shell commands: [agent command policy](../../testing/agent-command-policy.md) only.
 
-The workspace Expo documented-path iOS **link** fixture (`test-expo/`) is not Detox e2e. Canonical command: `yarn test-expo:ios:link` ([agent command policy](../../testing/agent-command-policy.md)). App-target FirebaseCore linking and CocoaPods hook order: [iOS SPM native integration](../../ios-spm-native-imports.md#app-target-firebasecore-link-package-dependency-alone-is-not-enough). Expo precompiled RNCore linkage repair: [iOS SPM native integration § Expo precompiled module linkage repair](../../ios-spm-native-imports.md#expo-precompiled-module-linkage-repair). Do not treat duplicate `_FIRFirebaseVersion` ([#9202](https://github.com/invertase/react-native-firebase/issues/9202)) as that closer.
+The workspace Expo documented-path iOS **link** fixture (`test-expo/`) is not Detox e2e. Canonical command: `yarn test-expo:ios:link` ([agent command policy](../../testing/agent-command-policy.md)). App-target FirebaseCore linking and CocoaPods hook order: [iOS SPM native integration](../../ios-spm-native-imports.md#app-target-firebasecore-link-package-dependency-alone-is-not-enough). Expo precompiled RNCore linkage repair and duplicate-symbol regression: [iOS SPM native integration § Expo precompiled module linkage repair](../../ios-spm-native-imports.md#expo-precompiled-module-linkage-repair).
 
 ## Documents
 
-* Cross-cutting durable SPM decisions: [iOS SPM native integration](../../ios-spm-native-imports.md) ([app-target FirebaseCore link](../../ios-spm-native-imports.md#app-target-firebasecore-link-package-dependency-alone-is-not-enough))
+* Cross-cutting durable SPM decisions: [iOS SPM native integration](../../ios-spm-native-imports.md) ([app-target FirebaseCore link](../../ios-spm-native-imports.md#app-target-firebasecore-link-package-dependency-alone-is-not-enough); [Expo precompiled linkage repair](../../ios-spm-native-imports.md#expo-precompiled-module-linkage-repair))
 
 ## Related repository files
 

packages/app/__tests__/firebase_spm_test.rb

@@ -1632,6 +1632,58 @@ def test_generate_pods_project_hook_is_idempotent_across_repeated_podspec_requir
     assert_equal [instance], restore_calls
   end
 
+  def test_hook_warns_once_when_generate_pods_project_is_unavailable_for_expo
+    load_firebase_spm
+    stub_expo_precompiled_modules(enabled: true, linkage: :dynamic)
+    klass = new_fake_cocoapods_installer_class
+    klass.send(:remove_method, :generate_pods_project)
+
+    rnfirebase_hook_cocoapods_post_install!(klass)
+    rnfirebase_hook_cocoapods_post_install!(klass)
+    instance = klass.new
+
+    result = instance.send(:run_podfile_post_install_hooks)
+
+    assert_equal :original_result, result
+    assert_equal 1, instance.original_hook_calls
+    warnings = Pod::UI.warnings.select { |warning| warning.include?('generate_pods_project') }
+    assert_equal 1, warnings.length
+    assert_includes warnings[0], 'Expo prebuilt RNFB dynamic-linkage restoration was not hooked'
+  end
+
+  def test_hook_does_not_warn_when_generate_pods_project_is_unavailable_and_expo_prebuilt_is_disabled
+    load_firebase_spm
+    stub_expo_precompiled_modules(enabled: false, linkage: :dynamic)
+    klass = new_fake_cocoapods_installer_class
+    klass.send(:remove_method, :generate_pods_project)
+
+    rnfirebase_hook_cocoapods_post_install!(klass)
+
+    refute(Pod::UI.warnings.any? { |warning| warning.include?('generate_pods_project') })
+  end
+
+  def test_hook_does_not_warn_when_generate_pods_project_is_unavailable_outside_expo
+    load_firebase_spm
+    klass = new_fake_cocoapods_installer_class
+    klass.send(:remove_method, :generate_pods_project)
+
+    rnfirebase_hook_cocoapods_post_install!(klass)
+
+    refute(Pod::UI.warnings.any? { |warning| warning.include?('generate_pods_project') })
+  end
+
+  def test_hook_does_not_warn_when_expo_precompiled_enabled_api_is_unavailable
+    load_firebase_spm
+    ensure_expo_module!
+    Expo.const_set(:PrecompiledModules, Module.new)
+    klass = new_fake_cocoapods_installer_class
+    klass.send(:remove_method, :generate_pods_project)
+
+    rnfirebase_hook_cocoapods_post_install!(klass)
+
+    refute(Pod::UI.warnings.any? { |warning| warning.include?('generate_pods_project') })
+  end
+
   # The generate_pods_project wrapper must not call the original generate method
   # after a restore failure: it must warn with a directed message identifying
   # Expo prebuilt dynamic-linkage restoration and re-raise the original error.

packages/app/firebase_spm.rb

@@ -715,6 +715,22 @@ def rnfirebase_hook_cocoapods_post_install!(installer_class = (Pod::Installer if
   integrate_was_private = installer_class.private_method_defined?(integrate_hook_method)
   post_integrate_available = integrate_was_private || installer_class.method_defined?(integrate_hook_method)
 
+  generate_unavailable_warning = :@rnfirebase_generate_pods_project_unavailable_warning
+  if !already_hooked_generate &&
+     !generate_available &&
+     defined?(Expo::PrecompiledModules) &&
+     Expo::PrecompiledModules.respond_to?(:enabled?) &&
+     Expo::PrecompiledModules.enabled? &&
+     defined?(Pod::UI) &&
+     !installer_class.instance_variable_defined?(generate_unavailable_warning)
+    Pod::UI.warn '[react-native-firebase] `Pod::Installer#generate_pods_project` does not exist ' \
+                 '(a CocoaPods release may have renamed or removed it) -- Expo prebuilt RNFB ' \
+                 'dynamic-linkage restoration was not hooked into `pod install`. Use the CocoaPods ' \
+                 'version required by your Expo SDK and report this version combination if the app ' \
+                 'links duplicate Firebase symbols.'
+    installer_class.instance_variable_set(generate_unavailable_warning, true)
+  end
+
   # Already hooked -- e.g. a second RNFB podspec also `require`d this same
   # file within one `pod install` process. Expected and idempotent.
   return if (already_hooked_generate || !generate_available) &&