Enable RCT_USE_RN_DEP in test app and assert RCT_USE_PREBUILT_RNCORE != 1

apps/test-app/ios/Podfile

@@ -1,3 +1,6 @@
+# Opt into prebuilds of RN dependencies
+ENV['RCT_USE_RN_DEP'] = ENV['RCT_USE_RN_DEP'] || '1'
+
 ws_dir = Pathname.new(__dir__)
 ws_dir = ws_dir.parent until
   File.exist?("#{ws_dir}/node_modules/react-native-test-app/test_app.rb") ||

packages/host/react-native-node-api.podspec

@@ -41,26 +41,11 @@ Pod::Spec.new do |s|
     CMD
   }
 
-  # Use install_modules_dependencies helper to install the dependencies if React Native version >=0.71.0.
+  # Use install_modules_dependencies helper to install the dependencies (requires React Native version >=0.71.0).
   # See https://github.com/facebook/react-native/blob/febf6b7f33fdb4904669f99d795eba4c0f95d7bf/scripts/cocoapods/new_architecture.rb#L79.
   if respond_to?(:install_modules_dependencies, true)
     install_modules_dependencies(s)
   else
-    s.dependency "React-Core"
-    # Don't install the dependencies when we run `pod install` in the old architecture.
-    if ENV['RCT_NEW_ARCH_ENABLED'] == '1' then
-      # TODO: Re-visit these dependencies and flags and remove them if not needed.
-      s.compiler_flags = folly_compiler_flags + " -DRCT_NEW_ARCH_ENABLED=1"
-      s.pod_target_xcconfig    = {
-          "HEADER_SEARCH_PATHS" => "\"$(PODS_ROOT)/boost\"",
-          "OTHER_CPLUSPLUSFLAGS" => "-DFOLLY_NO_CONFIG -DFOLLY_MOBILE=1 -DFOLLY_USE_LIBCPP=1",
-          "CLANG_CXX_LANGUAGE_STANDARD" => "c++17"
-      }
-      s.dependency "React-Codegen"
-      s.dependency "RCT-Folly"
-      s.dependency "RCTRequired"
-      s.dependency "RCTTypeSafety"
-      s.dependency "ReactCommon/turbomodule/core"
-    end
+    raise "This version of React Native is too old for React Native Node-API."
   end
 end

packages/host/scripts/patch-hermes.rb

@@ -1,5 +1,9 @@
 Pod::UI.warn "!!! PATCHING HERMES WITH NODE-API SUPPORT !!!"
 
+if ENV['RCT_USE_PREBUILT_RNCORE'] == '1'
+  raise "React Native Node-API cannot reliably patch JSI when React Native Core is prebuilt."
+end
+
 VENDORED_HERMES_DIR ||= `npx react-native-node-api vendor-hermes --silent '#{Pod::Config.instance.installation_root}'`.strip
 if Dir.exist?(VENDORED_HERMES_DIR)
   Pod::UI.info "Hermes vendored into #{VENDORED_HERMES_DIR.inspect}"

packages/host/src/node/podspec.test.ts

@@ -0,0 +1,24 @@
+import assert from "node:assert/strict";
+import { describe, it } from "node:test";
+import cp from "node:child_process";
+
+describe("Podspec", () => {
+  // We cannot support prebuilds of React Native Core since we're patching JSI
+  it(
+    "should error when RCT_USE_PREBUILT_RNCORE is set",
+    // We cannot call `pod` on non-macOS systems
+    { skip: process.platform !== "darwin" },
+    () => {
+      const { status, stdout } = cp.spawnSync("pod", ["spec", "lint"], {
+        env: { ...process.env, RCT_USE_PREBUILT_RNCORE: "1" },
+        encoding: "utf-8",
+      });
+
+      assert.notEqual(status, 0);
+      assert.match(
+        stdout,
+        /React Native Node-API cannot reliably patch JSI when React Native Core is prebuilt/,
+      );
+    },
+  );
+});