Normalise path separators in cache key

Summary:
Changelog:
* **[Experimental]**: `metro-file-map`: Normalize root-relative paths for cross-platform cache compatibility.

Reviewed By: GijsWeterings

Differential Revision: D46829313

fbshipit-source-id: 31f3cbbff66e0bd400b0d94432dccaa441aedf2e

packages/metro-file-map/src/crawlers/__tests__/watchman-test.js

@@ -13,7 +13,8 @@ import {AbortController} from 'node-abort-controller';
 const path = require('path');
 
 jest.mock('fb-watchman', () => {
-  const normalizePathSep = require('../../lib/normalizePathSep').default;
+  const normalizePathSeparatorsToSystem =
+    require('../../lib/normalizePathSeparatorsToSystem').default;
   const Client = jest.fn();
   const endedClients = new WeakSet();
   Client.prototype.command = jest.fn(function (args, callback) {
@@ -23,7 +24,9 @@ jest.mock('fb-watchman', () => {
         callback(new Error('Client has ended'));
         return;
       }
-      const path = args[1] ? normalizePathSep(args[1]) : undefined;
+      const path = args[1]
+        ? normalizePathSeparatorsToSystem(args[1])
+        : undefined;
       const response = mockResponse[args[0]][path];
       callback(null, response.next ? response.next().value : response);
     });

packages/metro-file-map/src/crawlers/watchman/index.js

@@ -21,7 +21,7 @@ import type {WatchmanQueryResponse, WatchmanWatchResponse} from 'fb-watchman';
 
 import H from '../../constants';
 import * as fastPath from '../../lib/fast_path';
-import normalizePathSep from '../../lib/normalizePathSep';
+import normalizePathSeparatorsToSystem from '../../lib/normalizePathSeparatorsToSystem';
 import {planQuery} from './planQuery';
 import invariant from 'invariant';
 import * as path from 'path';
@@ -291,7 +291,7 @@ module.exports = async function watchmanCrawl({
   perfLogger?.point('watchmanCrawl/processResults_start');
 
   for (const [watchRoot, response] of results) {
-    const fsRoot = normalizePathSep(watchRoot);
+    const fsRoot = normalizePathSeparatorsToSystem(watchRoot);
     const relativeFsRoot = fastPath.relative(rootDir, fsRoot);
     newClocks.set(
       relativeFsRoot,
@@ -302,7 +302,8 @@ module.exports = async function watchmanCrawl({
     );
 
     for (const fileData of response.files) {
-      const filePath = fsRoot + path.sep + normalizePathSep(fileData.name);
+      const filePath =
+        fsRoot + path.sep + normalizePathSeparatorsToSystem(fileData.name);
       const relativeFilePath = fastPath.relative(rootDir, filePath);
       const existingFileData = previousState.files.get(relativeFilePath);
 

packages/metro-file-map/src/index.js

@@ -45,7 +45,7 @@ import checkWatchmanCapabilities from './lib/checkWatchmanCapabilities';
 import deepCloneRawModuleMap from './lib/deepCloneRawModuleMap';
 import * as fastPath from './lib/fast_path';
 import getPlatformExtension from './lib/getPlatformExtension';
-import normalizePathSep from './lib/normalizePathSep';
+import normalizePathSeparatorsToSystem from './lib/normalizePathSeparatorsToSystem';
 import TreeFS from './lib/TreeFS';
 import HasteModuleMap from './ModuleMap';
 import {Watcher} from './Watcher';
@@ -866,7 +866,7 @@ export default class HasteMap extends EventEmitter {
     if (this._options.mocksPattern) {
       const absoluteFilePath = path.join(
         this._options.rootDir,
-        normalizePathSep(relativeFilePath),
+        normalizePathSeparatorsToSystem(relativeFilePath),
       );
       if (
         this._options.mocksPattern &&
@@ -951,7 +951,10 @@ export default class HasteMap extends EventEmitter {
         return;
       }
 
-      const absoluteFilePath = path.join(root, normalizePathSep(filePath));
+      const absoluteFilePath = path.join(
+        root,
+        normalizePathSeparatorsToSystem(filePath),
+      );
 
       // Ignore files (including symlinks) whose path matches ignorePattern
       // (we don't ignore node_modules in watch mode)

packages/metro-file-map/src/lib/__tests__/normalizePathSep-test.js → packages/metro-file-map/src/lib/__tests__/normalizePathSeparatorsToSystem-test.js

@@ -10,18 +10,24 @@
 
 'use strict';
 
-describe('normalizePathSep', () => {
+describe('normalizePathSeparatorsToSystem', () => {
   it('does nothing on posix', () => {
     jest.resetModules();
     jest.mock('path', () => jest.requireActual('path').posix);
-    const normalizePathSep = require('../normalizePathSep').default;
-    expect(normalizePathSep('foo/bar/baz.js')).toEqual('foo/bar/baz.js');
+    const normalizePathSeparatorsToSystem =
+      require('../normalizePathSeparatorsToSystem').default;
+    expect(normalizePathSeparatorsToSystem('foo/bar/baz.js')).toEqual(
+      'foo/bar/baz.js',
+    );
   });
 
   it('replace slashes on windows', () => {
     jest.resetModules();
     jest.mock('path', () => jest.requireActual('path').win32);
-    const normalizePathSep = require('../normalizePathSep').default;
-    expect(normalizePathSep('foo/bar/baz.js')).toEqual('foo\\bar\\baz.js');
+    const normalizePathSeparatorsToSystem =
+      require('../normalizePathSeparatorsToSystem').default;
+    expect(normalizePathSeparatorsToSystem('foo/bar/baz.js')).toEqual(
+      'foo\\bar\\baz.js',
+    );
   });
 });

packages/metro-file-map/src/lib/__tests__/rootRelativeCacheKeys-test.js

@@ -10,6 +10,8 @@
 
 import type {BuildParameters} from '../../flow-types';
 
+import typeof PathModule from 'path';
+
 import rootRelativeCacheKeys from '../rootRelativeCacheKeys';
 
 const buildParameters: BuildParameters = {
@@ -124,3 +126,31 @@ it('returns a distinct cache key for any change', () => {
     seen.set(configHash, i);
   }
 });
+
+describe('cross-platform cache keys', () => {
+  afterEach(() => {
+    jest.unmock('path');
+  });
+
+  it('returns the same cache key for Windows and POSIX path parameters', () => {
+    let mockPathModule;
+    jest.mock('path', () => mockPathModule);
+
+    jest.resetModules();
+    mockPathModule = jest.requireActual<PathModule>('path').posix;
+    const configHashPosix = require('../rootRelativeCacheKeys').default({
+      ...buildParameters,
+      rootDir: '/root',
+      roots: ['/root/a', '/b/c'],
+    }).relativeConfigHash;
+
+    jest.resetModules();
+    mockPathModule = jest.requireActual<PathModule>('path').win32;
+    const configHashWin32 = require('../rootRelativeCacheKeys').default({
+      ...buildParameters,
+      rootDir: 'c:\\root',
+      roots: ['c:\\root\\a', 'c:\\b\\c'],
+    }).relativeConfigHash;
+    expect(configHashWin32).toEqual(configHashPosix);
+  });
+});

packages/metro-file-map/src/lib/normalizePathSeparatorsToPosix.js

@@ -0,0 +1,21 @@
+/**
+ * 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
+ * @flow strict
+ */
+
+import * as path from 'path';
+
+let normalizePathSeparatorsToPosix: (string: string) => string;
+if (path.sep === '/') {
+  normalizePathSeparatorsToPosix = (filePath: string): string => filePath;
+} else {
+  normalizePathSeparatorsToPosix = (filePath: string): string =>
+    filePath.replace(/\\/g, '/');
+}
+
+export default normalizePathSeparatorsToPosix;

packages/metro-file-map/src/lib/normalizePathSep.js → packages/metro-file-map/src/lib/normalizePathSeparatorsToSystem.js

@@ -10,12 +10,12 @@
 
 import * as path from 'path';
 
-let normalizePathSep: (string: string) => string;
+let normalizePathSeparatorsToSystem: (string: string) => string;
 if (path.sep === '/') {
-  normalizePathSep = (filePath: string): string => filePath;
+  normalizePathSeparatorsToSystem = (filePath: string): string => filePath;
 } else {
-  normalizePathSep = (filePath: string): string =>
+  normalizePathSeparatorsToSystem = (filePath: string): string =>
     filePath.replace(/\//g, path.sep);
 }
 
-export default normalizePathSep;
+export default normalizePathSeparatorsToSystem;

packages/metro-file-map/src/lib/rootRelativeCacheKeys.js

@@ -12,6 +12,7 @@
 import type {BuildParameters} from '../flow-types';
 
 import * as fastPath from './fast_path';
+import normalizePathSeparatorsToPosix from './normalizePathSeparatorsToPosix';
 import {createHash} from 'crypto';
 
 function moduleCacheKey(modulePath: ?string) {
@@ -37,15 +38,17 @@ export default function rootRelativeCacheKeys(
   relativeConfigHash: string,
 } {
   const {rootDir, ...otherParameters} = buildParameters;
-  const rootDirHash = createHash('md5').update(rootDir).digest('hex');
+  const rootDirHash = createHash('md5')
+    .update(normalizePathSeparatorsToPosix(rootDir))
+    .digest('hex');
 
   const cacheComponents = Object.keys(otherParameters)
     .sort()
     .map(key => {
       switch (key) {
         case 'roots':
           return buildParameters[key].map(root =>
-            fastPath.relative(rootDir, root),
+            normalizePathSeparatorsToPosix(fastPath.relative(rootDir, root)),
           );
         case 'cacheBreaker':
         case 'extensions':