Implements the PnP resolver into Metro

Reviewed By: pvdz

Differential Revision: D13097265

fbshipit-source-id: ee2daed2256843448bc2e070c394800fee829790

packages/metro-config/src/__tests__/__snapshots__/loadConfig-test.js.snap

@@ -10,6 +10,7 @@ Object {
   "reporter": null,
   "resetCache": false,
   "resolver": Object {
+    "allowPnp": true,
     "assetExts": Array [
       "bmp",
       "gif",
@@ -132,6 +133,7 @@ Object {
   "reporter": null,
   "resetCache": false,
   "resolver": Object {
+    "allowPnp": true,
     "assetExts": Array [
       "bmp",
       "gif",

packages/metro-config/src/configTypes.flow.js

@@ -67,6 +67,7 @@ export type Middleware = (
 ) => mixed;
 
 export type OldConfigT = {
+  allowPnp: boolean,
   assetRegistryPath: string,
   cacheStores: Array<CacheStore<TransformResult<>>>,
   cacheVersion: string,
@@ -102,6 +103,7 @@ export type OldConfigT = {
 };
 
 type ResolverConfigT = {|
+  allowPnp: boolean,
   assetExts: $ReadOnlyArray<string>,
   blacklistRE: RegExp,
   extraNodeModules: {[name: string]: string},

packages/metro-config/src/convertConfig.js

@@ -44,6 +44,7 @@ async function convertOldToNew({
   reporter = new TerminalReporter(new Terminal(process.stdout)),
 }: PublicMetroOptions): Promise<ConfigT> {
   const {
+    allowPnp,
     getBlacklistRE,
     cacheStores,
     createModuleIdFactory,
@@ -97,6 +98,7 @@ async function convertOldToNew({
 
   return {
     resolver: {
+      allowPnp,
       assetExts,
       platforms,
       providesModuleNodeModules,

packages/metro-config/src/defaults/index.js

@@ -32,6 +32,7 @@ import type {ConfigT} from '../configTypes.flow';
 
 const getDefaultValues = (projectRoot: ?string): ConfigT => ({
   resolver: {
+    allowPnp: true,
     assetExts,
     platforms,
     sourceExts,

packages/metro-config/src/oldConfig.js

@@ -23,6 +23,7 @@ const {FileStore} = require('metro-cache');
 import type {OldConfigT as ConfigT} from './configTypes.flow.js';
 
 const DEFAULT = ({
+  allowPnp: true,
   assetRegistryPath: 'missing-asset-registry-path',
   enhanceMiddleware: middleware => middleware,
   extraNodeModules: {},

packages/metro-resolver/src/__tests__/index-test.js

@@ -54,6 +54,7 @@ const CONTEXT: ResolutionContext = (() => {
   );
   return {
     allowHaste: true,
+    allowPnp: false,
     doesFileExist: filePath => fileSet.has(filePath),
     extraNodeModules: null,
     getPackageMainPath: dirPath => path.join(path.dirname(dirPath), 'main'),

packages/metro-resolver/src/makePnpResolver.js

@@ -0,0 +1,88 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ * @format
+ */
+
+'use strict';
+
+// $FlowFixMe it exists!
+const Module = require('module');
+
+const path = require('path');
+
+import type {ResolutionContext} from './types';
+
+const builtinModules = new Set(
+  // $FlowFixMe "process.binding" exists
+  Module.builtinModules || Object.keys(process.binding('natives')),
+);
+
+module.exports = (pnp: any) => (
+  context: ResolutionContext,
+  request: string,
+  platform: string | null,
+) => {
+  // We don't support builtin modules, so we force pnp to resolve those
+  // modules as regular npm packages by appending a `/` character
+  if (builtinModules.has(request)) {
+    request += '/';
+  }
+
+  const unqualifiedPath = pnp.resolveToUnqualified(
+    request,
+    context.originModulePath,
+  );
+
+  const baseExtensions = context.sourceExts.map(extension => `.${extension}`);
+  let finalExtensions = [...baseExtensions];
+
+  if (context.preferNativePlatform) {
+    finalExtensions = [
+      ...baseExtensions.map(extension => `.native${extension}`),
+      ...finalExtensions,
+    ];
+  }
+
+  if (platform) {
+    // We must keep a const reference to make Flow happy
+    const p = platform;
+
+    finalExtensions = [
+      ...baseExtensions.map(extension => `.${p}${extension}`),
+      ...finalExtensions,
+    ];
+  }
+
+  try {
+    return {
+      type: 'sourceFile',
+      filePath: pnp.resolveUnqualified(unqualifiedPath, {
+        extensions: finalExtensions,
+      }),
+    };
+  } catch (error) {
+    // Only catch the error if it was caused by the resolution process
+    if (error.code !== 'QUALIFIED_PATH_RESOLUTION_FAILED') {
+      throw error;
+    }
+
+    const dirname = path.dirname(unqualifiedPath);
+    const basename = path.basename(unqualifiedPath);
+
+    const assetResolutions = context.resolveAsset(dirname, basename, platform);
+
+    if (assetResolutions) {
+      return {
+        type: 'assetFiles',
+        filePaths: assetResolutions.map<string>(name => `${dirname}/${name}`),
+      };
+    } else {
+      throw error;
+    }
+  }
+};

packages/metro-resolver/src/resolve.js

@@ -16,6 +16,7 @@ const InvalidPackageError = require('./InvalidPackageError');
 
 const formatFileCandidates = require('./formatFileCandidates');
 const isAbsolutePath = require('absolute-path');
+const makePnpResolver = require('./makePnpResolver');
 const path = require('path');
 
 import type {
@@ -39,8 +40,16 @@ function resolve(
   moduleName: string,
   platform: string | null,
 ): Resolution {
+  let resolveRequest = context.resolveRequest;
+
+  if (!resolveRequest && context.allowPnp && process.versions.pnp) {
+    // $FlowFixMe `pnpapi` is a builtin under PnP environments
+    const pnp = require('pnpapi');
+    resolveRequest = makePnpResolver(pnp);
+  }
+
   if (
-    !context.resolveRequest &&
+    !resolveRequest &&
     (isRelativeImport(moduleName) || isAbsolutePath(moduleName))
   ) {
     return resolveModulePath(context, moduleName, platform);
@@ -59,7 +68,7 @@ function resolve(
     isRelativeImport(realModuleName) || isAbsolutePath(realModuleName);
 
   // We disable the direct file loading to let the custom resolvers deal with it
-  if (!context.resolveRequest && isDirectImport) {
+  if (!resolveRequest && isDirectImport) {
     // derive absolute path /.../node_modules/originModuleDir/realModuleName
     const fromModuleParentIdx =
       originModulePath.lastIndexOf('node_modules' + path.sep) + 13;
@@ -82,13 +91,9 @@ function resolve(
     }
   }
 
-  if (context.resolveRequest) {
+  if (resolveRequest) {
     try {
-      const resolution = context.resolveRequest(
-        context,
-        realModuleName,
-        platform,
-      );
+      const resolution = resolveRequest(context, realModuleName, platform);
       if (resolution) {
         return resolution;
       }

packages/metro-resolver/src/types.js

@@ -107,6 +107,7 @@ export type ModulePathContext = FileOrDirContext & {
 
 export type ResolutionContext = ModulePathContext &
   HasteContext & {
+    allowPnp: boolean,
     allowHaste: boolean,
     extraNodeModules: ?{[string]: string},
     originModulePath: string,

packages/metro/src/ModuleGraph/node-haste/node-haste.js

@@ -32,6 +32,7 @@ import type {Extensions, Path} from './node-haste.flow';
 import type {CustomResolver} from 'metro-resolver';
 
 type ResolveOptions = {|
+  allowPnp: boolean,
   assetExts: Extensions,
   extraNodeModules: {[id: string]: string},
   mainFields: $ReadOnlyArray<string>,
@@ -107,6 +108,7 @@ const createModuleMap = ({files, helpers, moduleCache, sourceExts}) => {
 
 exports.createResolveFn = function(options: ResolveOptions): ResolveFn {
   const {
+    allowPnp,
     assetExts,
     extraNodeModules,
     transformedFiles,
@@ -140,6 +142,7 @@ exports.createResolveFn = function(options: ResolveOptions): ResolveFn {
     platforms,
   });
   const moduleResolver = new ModuleResolver({
+    allowPnp,
     dirExists: filePath => hasteFS.dirExists(filePath),
     doesFileExist: filePath => hasteFS.exists(filePath),
     extraNodeModules,

packages/metro/src/node-haste/DependencyGraph.js

@@ -143,6 +143,7 @@ class DependencyGraph extends EventEmitter {
 
   _createModuleResolver() {
     this._moduleResolver = new ModuleResolver({
+      allowPnp: this._config.resolver.allowPnp,
       dirExists: filePath => {
         try {
           return fs.lstatSync(filePath).isDirectory();

packages/metro/src/node-haste/DependencyGraph/ModuleResolution.js

@@ -53,6 +53,7 @@ export type ModuleishCache<TModule, TPackage> = {
 };
 
 type Options<TModule, TPackage> = {|
+  +allowPnp: boolean,
   +dirExists: DirExistsFn,
   +doesFileExist: DoesFileExist,
   +extraNodeModules: ?Object,