feat(spm): wire ReactNativeDependenciesHeaders as the 5th binaryTarget

ReactNativeHeaders is pure-RN after the deps-headers split: the
third-party namespaces (folly/glog/boost/fmt/double-conversion/
fast_float/SocketRocket) ship in the ReactNativeDependenciesHeaders
sidecar the deps prebuild emits (the binary deps xcframework is
framework-type — invisible to SwiftPM binaryTargets).

- download-spm-artifacts: headers-only companions are staged out of
  their parent tarball (ReactNativeHeaders from the ReactCore tarball,
  the sidecar from the deps tarball) on fresh extracts, with fast-path
  backfill — generalizing the hermes-headers pattern. This retires the
  --headers-tarball priming workaround for ReactNativeHeaders; the
  override remains for testing, joined by --deps-headers-tarball /
  RN_DEPS_HEADERS_TARBALL_PATH. Both companions register in
  artifacts.json fail-closed (pre-companion tarballs die with
  actionable advice). REQUIRED_ARTIFACTS now lists all five artifacts,
  fixing the inconsistency where generate-spm-package hard-required
  ReactNativeHeaders but cache validation never checked it.
- generate-spm-package needs no code change: it renders one product +
  binaryTarget per artifacts.json entry.
- Product consumers add the ReactNativeDependenciesHeaders product
  wherever deps namespaces must resolve: reactProductDeps()
  (autolinking), the codegen Package.swift template, and scaffolded
  community-library manifests (SCAFFOLDER_VERSION 17 -> 18 so existing
  scaffolds regenerate).

Verified: fresh-app E2E (verdaccio -> cli init -> spm add -> build),
rn-tester and helloworld in-place migrations, 350 spm jest tests.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: chrfalch

packages/react-native/scripts/codegen/templates/Package.swift.spm-template

@@ -14,11 +14,14 @@ import PackageDescription
 
 // React headers need NO search paths: React/react namespaces come from the
 // React binaryTarget (auto -F; headers + module map inside the framework),
-// every other namespace from the ReactNativeHeaders binaryTarget, and the
-// per-app generated headers from the ReactAppHeaders target below — all
-// auto-served by SPM through product/target dependencies.
+// every other RN namespace from the ReactNativeHeaders binaryTarget
+// (pure-RN), the third-party deps namespaces (folly/glog/boost/...) from the
+// ReactNativeDependenciesHeaders sidecar, and the per-app generated headers
+// from the ReactAppHeaders target below — all auto-served by SPM through
+// product/target dependencies.
 let headersDep: [Target.Dependency] = [
     .product(name: "ReactNativeHeaders", package: "ReactNative"),
+    .product(name: "ReactNativeDependenciesHeaders", package: "ReactNative"),
     "ReactAppHeaders",
 ]
 

packages/react-native/scripts/spm/__tests__/download-spm-artifacts-test.js

@@ -708,7 +708,9 @@ describe('validateArtifactsCache', () => {
   it('returns null when the cache is complete and on disk', () => {
     seedCache({
       React: true,
+      ReactNativeHeaders: true,
       ReactNativeDependencies: true,
+      ReactNativeDependenciesHeaders: true,
       'hermes-engine': true,
     });
     seedHermesHeaders();
@@ -718,7 +720,9 @@ describe('validateArtifactsCache', () => {
   it('reports unstaged Hermes public headers', () => {
     seedCache({
       React: true,
+      ReactNativeHeaders: true,
       ReactNativeDependencies: true,
+      ReactNativeDependenciesHeaders: true,
       'hermes-engine': true,
     });
     // No hermes-headers/hermes dir.
@@ -727,6 +731,21 @@ describe('validateArtifactsCache', () => {
     );
   });
 
+  it('reports a missing headers companion (pure-RN split)', () => {
+    // ReactNativeDependenciesHeaders is the deps sidecar — without it no
+    // <folly/...>-style include resolves (ReactNativeHeaders is pure-RN).
+    seedCache({
+      React: true,
+      ReactNativeHeaders: true,
+      ReactNativeDependencies: true,
+      'hermes-engine': true,
+    });
+    seedHermesHeaders();
+    expect(validateArtifactsCache(tempDir)).toMatch(
+      /missing entry for "ReactNativeDependenciesHeaders"/,
+    );
+  });
+
   it('reports a missing artifacts.json', () => {
     expect(validateArtifactsCache(tempDir)).toMatch(/artifacts.json missing/);
   });
@@ -737,7 +756,12 @@ describe('validateArtifactsCache', () => {
   });
 
   it('reports a missing required entry', () => {
-    seedCache({React: true, ReactNativeDependencies: true});
+    seedCache({
+      React: true,
+      ReactNativeHeaders: true,
+      ReactNativeDependencies: true,
+      ReactNativeDependenciesHeaders: true,
+    });
     expect(validateArtifactsCache(tempDir)).toMatch(
       /missing entry for "hermes-engine"/,
     );
@@ -746,7 +770,9 @@ describe('validateArtifactsCache', () => {
   it('reports an entry whose xcframework dir is gone', () => {
     seedCache({
       React: true,
+      ReactNativeHeaders: true,
       ReactNativeDependencies: true,
+      ReactNativeDependenciesHeaders: true,
       'hermes-engine': false,
     });
     expect(validateArtifactsCache(tempDir)).toMatch(

packages/react-native/scripts/spm/__tests__/generate-spm-package-test.js

@@ -179,6 +179,7 @@ describe('main', () => {
       'ReactNativeDependencies',
       'hermes-engine',
       'ReactNativeHeaders',
+      'ReactNativeDependenciesHeaders',
     ]);
     try {
       run(artifactsDir);
@@ -194,6 +195,15 @@ describe('main', () => {
       expect(fs.existsSync(pkgSwift)).toBe(true);
       const contents = fs.readFileSync(pkgSwift, 'utf8');
       expect(contents).toContain('.binaryTarget(name: "React"');
+      // All five artifacts render as binary targets + products — the two
+      // headers-only companions included.
+      expect(contents).toContain('.binaryTarget(name: "ReactNativeHeaders"');
+      expect(contents).toContain(
+        '.binaryTarget(name: "ReactNativeDependenciesHeaders"',
+      );
+      expect(contents).toContain(
+        '.library(name: "ReactNativeDependenciesHeaders"',
+      );
       // The slot comment is derived from the artifacts dir's trailing path
       // segments (version/flavor), not the --version flag.
       expect(contents).toContain('Cache slot:');
@@ -217,6 +227,7 @@ describe('main', () => {
     const artifactsDir = writeArtifacts([
       'React',
       'ReactNativeDependencies',
+      'ReactNativeDependenciesHeaders',
       'hermes-engine',
     ]);
     try {