feat(spm): rn-tester + helloworld SPM consumption & test library

SPM-mode consumption for the example apps: rn-tester and helloworld each get a
Package.swift + *-SPM xcodeproj that consume React via SwiftPM product deps
(zero header search paths). Adds react-native-test-library (apple + common) and
its rn-tester example, plus the react-native.config.js spmModules wiring.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: chrfalch

packages/react-native-test-library/.gitignore

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+# Generated SPM artifacts (written by setup-ios-spm.js's earlier in-place
+# layout). The current autolinker emits these under the consumer app's
+# build/generated/autolinking/ tree instead, so any copy that lands here is
+# stale and should not be committed.
+Package.swift
+Package.resolved
+include/
+
+# SwiftPM caches
+.build/
+.swiftpm/

packages/react-native-test-library/apple/TestLibraryApple.h

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+/*
+ * 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.
+ */
+
+#import <React/RCTBridgeModule.h>
+
+@interface TestLibraryApple : NSObject <RCTBridgeModule>
+@end

packages/react-native-test-library/apple/TestLibraryApple.mm

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+/*
+ * 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.
+ */
+
+#import "TestLibraryApple.h"
+
+// Synth library products are emitted as .library(type: .dynamic, ...), so SPM
+// wraps each autolinked dep as a Foo.framework under PackageFrameworks/. That
+// gives angle-bracket imports the standard <Module/Header.h> resolution path,
+// matching how most React Native libraries already organize their headers.
+#import <ReactNativeTestLibraryCommon/TestLibraryCommon.h>
+
+@implementation TestLibraryApple
+
+RCT_EXPORT_MODULE()
+
+RCT_EXPORT_METHOD(echo
+                  : (NSString *)message resolve
+                  : (RCTPromiseResolveBlock)resolve reject
+                  : (RCTPromiseRejectBlock)reject)
+{
+  NSString *prefix = [TestLibraryCommon defaultPrefix];
+  resolve([NSString stringWithFormat:@"%@apple: %@", prefix, message]);
+}
+
+@end

packages/react-native-test-library/apple/TestLibraryApple.podspec

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+# 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.
+
+require "json"
+
+package = JSON.parse(File.read(File.join(__dir__, "package.json")))
+
+Pod::Spec.new do |s|
+  s.name            = "TestLibraryApple"
+  s.version         = package["version"]
+  s.summary         = package["description"]
+  s.homepage        = "https://github.com/facebook/react-native"
+  s.license         = "MIT"
+  s.platforms       = min_supported_versions
+  s.author          = "Meta Platforms, Inc. and its affiliates"
+  s.source          = { :git => "https://github.com/facebook/react-native.git", :tag => "#{s.version}" }
+  s.source_files    = "*.{h,m,mm,swift}"
+  s.requires_arc    = true
+
+  install_modules_dependencies(s)
+end

packages/react-native-test-library/apple/__tests__/TestLibraryAppleTests.cpp

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+/*
+ * 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.
+ *
+ * Smoke test that the SPM autolinker excludes `__tests__/` directories from
+ * the `sources:` allowlist. If this file ever ends up in a target's sources,
+ * the build fails immediately with an unresolved header — making the
+ * regression loud.
+ */
+
+#include <this/header/intentionally/does/not/exist.h>
+
+static_assert(false, "TestLibraryAppleTests.cpp must not be compiled by the SPM autolinker");

packages/react-native-test-library/apple/index.d.ts

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+import type {Greeting} from 'react-native-test-library-common';
+
+export function greet(g: Greeting): Promise<string>;

packages/react-native-test-library/apple/index.js

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+/**
+ * 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.
+ *
+ * @flow strict-local
+ * @format
+ */
+
+'use strict';
+
+import type {Greeting} from 'react-native-test-library-common';
+
+import {formatGreeting} from 'react-native-test-library-common';
+import {NativeModules, Platform} from 'react-native';
+
+export function greet(g: Greeting): Promise<string> {
+  const TestLibraryApple = NativeModules.TestLibraryApple;
+  if (TestLibraryApple == null) {
+    return Promise.reject(
+      new Error(
+        `react-native-test-library-apple: native module unavailable on ${Platform.OS}. This package is iOS-only; install a platform-specific sibling (e.g. react-native-test-library-android) for cross-platform coverage.`,
+      ),
+    );
+  }
+  return TestLibraryApple.echo(formatGreeting(g));
+}

packages/react-native-test-library/apple/package.json

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+{
+  "name": "react-native-test-library-apple",
+  "version": "0.87.0-main",
+  "description": "Apple platform implementation for the React Native autolinking fixture. Depends on react-native-test-library-common; used to validate iOS/macOS autolinking discovery and transitive native dependency resolution.",
+  "private": true,
+  "main": "index.js",
+  "types": "index.d.ts",
+  "license": "MIT",
+  "files": [
+    "index.js",
+    "index.d.ts",
+    "react-native.config.js",
+    "TestLibraryApple.podspec",
+    "TestLibraryApple.h",
+    "TestLibraryApple.mm"
+  ],
+  "keywords": [
+    "react-native",
+    "fixture",
+    "autolinking",
+    "ios",
+    "macos"
+  ],
+  "dependencies": {
+    "react-native-test-library-common": "0.87.0-main"
+  },
+  "peerDependencies": {
+    "react": "*",
+    "react-native": "1000.0.0"
+  }
+}

packages/react-native-test-library/apple/react-native.config.js

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+/**
+ * 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.
+ *
+ * @format
+ * @noflow
+ */
+
+'use strict';
+
+module.exports = {
+  dependency: {
+    platforms: {
+      ios: {},
+    },
+  },
+  spm: {
+    dependencies: ['react-native-test-library-common'],
+  },
+};

packages/react-native-test-library/common/TestLibraryCommon.h

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+/*
+ * 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.
+ */
+
+#import <React/RCTBridgeModule.h>
+
+@interface TestLibraryCommon : NSObject <RCTBridgeModule>
+
+/** Shared prefix used by other test-library packages that depend on common. */
++ (NSString *)defaultPrefix;
+
+@end