Introduce "codegenConfig.includesGeneratedCode" property (#41655)

Summary:
Pull Request resolved: #41655

This diff adds support for checked-in codegen artifacts for libraries.
It introduces a new property to `codegenConfig`, called `includesGeneratedCode`. If codegen sees `includesGeneratedCode: true` in a project's dependency, it assumes that the library has codegen artifacts in it, and will not generate any code.

Changelog: [General][Added] - Introduce "codegenConfig.includesGeneratedCode" property.

Reviewed By: cipolleschi

Differential Revision: D51207265

fbshipit-source-id: 65855fd846e24a53cb18008839121e99eeb59309

packages/react-native-gradle-plugin/src/main/kotlin/com/facebook/react/ReactPlugin.kt

@@ -161,14 +161,16 @@ class ReactPlugin : Plugin<Project> {
               val parsedPackageJson = packageJson?.let { JsonUtils.fromPackageJson(it) }
 
               val jsSrcsDirInPackageJson = parsedPackageJson?.codegenConfig?.jsSrcsDir
+              val includesGeneratedCode =
+                  parsedPackageJson?.codegenConfig?.includesGeneratedCode ?: false
               if (jsSrcsDirInPackageJson != null) {
                 it.jsRootDir.set(File(packageJson.parentFile, jsSrcsDirInPackageJson))
               } else {
                 it.jsRootDir.set(localExtension.jsRootDir)
               }
               val needsCodegenFromPackageJson =
                   project.needsCodegenFromPackageJson(rootExtension.root)
-              it.onlyIf { isLibrary || needsCodegenFromPackageJson }
+              it.onlyIf { (isLibrary || needsCodegenFromPackageJson) && !includesGeneratedCode }
             }
 
     // We create the task to generate Java code from schema.
@@ -188,7 +190,11 @@ class ReactPlugin : Plugin<Project> {
               // Therefore, the appNeedsCodegen needs to be invoked inside this lambda.
               val needsCodegenFromPackageJson =
                   project.needsCodegenFromPackageJson(rootExtension.root)
-              it.onlyIf { isLibrary || needsCodegenFromPackageJson }
+              val packageJson = findPackageJsonFile(project, rootExtension.root)
+              val parsedPackageJson = packageJson?.let { JsonUtils.fromPackageJson(it) }
+              val includesGeneratedCode =
+                  parsedPackageJson?.codegenConfig?.includesGeneratedCode ?: false
+              it.onlyIf { (isLibrary || needsCodegenFromPackageJson) && !includesGeneratedCode }
             }
 
     // We update the android configuration to include the generated sources.

packages/react-native-gradle-plugin/src/main/kotlin/com/facebook/react/model/ModelCodegenConfig.kt

@@ -11,5 +11,6 @@ data class ModelCodegenConfig(
     val name: String?,
     val type: String?,
     val jsSrcsDir: String?,
-    val android: ModelCodegenConfigAndroid?
+    val android: ModelCodegenConfigAndroid?,
+    val includesGeneratedCode: Boolean?,
 )

packages/react-native/scripts/codegen/generate-artifacts-executor.js

@@ -41,6 +41,10 @@ const REACT_NATIVE = 'react-native';
 
 // HELPERS
 
+function pkgJsonIncludesGeneratedCode(pkgJson) {
+  return pkgJson.codegenConfig && pkgJson.codegenConfig.includesGeneratedCode;
+}
+
 function isReactNativeCoreLibrary(libraryName) {
   return libraryName in CORE_LIBRARIES_WITH_OUTPUT_FOLDER;
 }
@@ -195,7 +199,12 @@ function computeOutputPath(projectRoot, baseOutputPath, pkgJson) {
       baseOutputPath = projectRoot;
     }
   }
-  return path.join(baseOutputPath, 'build', 'generated', 'ios');
+  if (pkgJsonIncludesGeneratedCode(pkgJson)) {
+    // Don't create nested directories for libraries to make importing generated headers easier.
+    return baseOutputPath;
+  } else {
+    return path.join(baseOutputPath, 'build', 'generated', 'ios');
+  }
 }
 
 function generateSchemaInfo(library) {
@@ -260,6 +269,16 @@ function needsThirdPartyComponentProvider(schemaInfo) {
   return !isReactNativeCoreLibrary(schemaInfo.library.config.name);
 }
 
+function mustGenerateNativeCode(includeLibraryPath, schemaInfo) {
+  // If library's 'codegenConfig' sets 'includesGeneratedCode' to 'true',
+  // then we assume that native code is shipped with the library,
+  // and we don't need to generate it.
+  return (
+    schemaInfo.library.libraryPath === includeLibraryPath ||
+    !schemaInfo.library.config.includesGeneratedCode
+  );
+}
+
 function createComponentProvider(schemas) {
   console.log('\n\n>>>>> Creating component provider');
   const outputDir = path.join(
@@ -281,10 +300,12 @@ function createComponentProvider(schemas) {
 }
 
 function findCodegenEnabledLibraries(pkgJson, projectRoot) {
-  return [
-    ...findExternalLibraries(pkgJson),
-    ...findProjectRootLibraries(pkgJson, projectRoot),
-  ];
+  const projectLibraries = findProjectRootLibraries(pkgJson, projectRoot);
+  if (pkgJsonIncludesGeneratedCode(pkgJson)) {
+    return projectLibraries;
+  } else {
+    return [...projectLibraries, ...findExternalLibraries(pkgJson)];
+  }
 }
 
 // It removes all the empty files and empty folders
@@ -355,12 +376,19 @@ function execute(projectRoot, baseOutputPath) {
     const outputPath = computeOutputPath(projectRoot, baseOutputPath, pkgJson);
 
     const schemaInfos = generateSchemaInfos(libraries);
-    generateNativeCode(outputPath, schemaInfos);
+    generateNativeCode(
+      outputPath,
+      schemaInfos.filter(schemaInfo =>
+        mustGenerateNativeCode(projectRoot, schemaInfo),
+      ),
+    );
 
-    const schemas = schemaInfos
-      .filter(needsThirdPartyComponentProvider)
-      .map(schemaInfo => schemaInfo.schema);
-    createComponentProvider(schemas);
+    if (!pkgJsonIncludesGeneratedCode(pkgJson)) {
+      const schemas = schemaInfos
+        .filter(needsThirdPartyComponentProvider)
+        .map(schemaInfo => schemaInfo.schema);
+      createComponentProvider(schemas);
+    }
     cleanupEmptyFilesAndFolders(outputPath);
   } catch (err) {
     console.error(err);