Revert packager randomization revert

packager/react-packager/src/DependencyResolver/DependencyGraph/HasteMap.js

@@ -8,8 +8,9 @@
  */
 'use strict';
 
+const chalk = require('chalk');
 const path = require('path');
-const getPontentialPlatformExt = require('../../lib/getPlatformExtension');
+const getPlatformExtension = require('../../lib/getPlatformExtension');
 
 class HasteMap {
   constructor({ fastfs, moduleCache, helpers }) {
@@ -17,6 +18,7 @@ class HasteMap {
     this._moduleCache = moduleCache;
     this._helpers = helpers;
     this._map = Object.create(null);
+    this._warnedAbout = Object.create(null);
   }
 
   build() {
@@ -35,6 +37,9 @@ class HasteMap {
 
   processFileChange(type, absPath) {
     return Promise.resolve().then(() => {
+      // Rewarn after file changes.
+      this._warnedAbout = Object.create(null);
+
       /*eslint no-labels: 0 */
       if (type === 'delete' || type === 'change') {
         loop: for (let name in this._map) {
@@ -64,19 +69,39 @@ class HasteMap {
   }
 
   getModule(name, platform = null) {
-    if (this._map[name]) {
-      const modules = this._map[name];
-      if (platform != null) {
-        for (let i = 0; i < modules.length; i++) {
-          if (getPontentialPlatformExt(modules[i].path) === platform) {
-            return modules[i];
-          }
+    if (!this._map[name]) {
+      return null;
+    }
+
+    const modules = this._map[name];
+    if (platform != null) {
+      for (let i = 0; i < modules.length; i++) {
+        if (getPlatformExtension(modules[i].path) === platform) {
+          return modules[i];
         }
       }
 
-      return modules[0];
+      if (modules.length > 1) {
+        if (!this._warnedAbout[name]) {
+          this._warnedAbout[name] = true;
+          console.warn(
+            chalk.yellow(
+              '\nWARNING: Found multiple haste modules or packages ' +
+              'with the name `%s`. Please fix this by adding it to ' +
+              'the blacklist or deleting the modules keeping only one.\n' +
+              'One of the following modules will be selected at random:\n%s\n'
+            ),
+            name,
+            modules.map(m => m.path).join('\n'),
+          );
+        }
+
+        const randomIndex = Math.floor(Math.random() * modules.length);
+        return modules[randomIndex];
+      }
     }
-    return null;
+
+    return modules[0];
   }
 
   _processHasteModule(file) {

packager/react-packager/src/DependencyResolver/DependencyGraph/ResolutionRequest.js

@@ -252,6 +252,11 @@ class ResolutionRequest {
   _loadAsFile(potentialModulePath) {
     return Promise.resolve().then(() => {
       if (this._helpers.isAssetFile(potentialModulePath)) {
+        const dirname = path.dirname(potentialModulePath);
+        if (!this._fastfs.dirExists(dirname)) {
+          throw new UnableToResolveError(`Directory ${dirname} doesn't exist`);
+        }
+
         const {name, type} = getAssetDataFromName(potentialModulePath);
 
         let pattern = '^' + name + '(@[\\d\\.]+x)?';
@@ -263,7 +268,7 @@ class ResolutionRequest {
         // We arbitrarly grab the first one, because scale selection
         // will happen somewhere
         const [assetFile] = this._fastfs.matches(
-          path.dirname(potentialModulePath),
+          dirname,
           new RegExp(pattern)
         );
 

packager/react-packager/src/lib/getPlatformExtension.js

@@ -10,7 +10,7 @@
 
 const path = require('path');
 
-const SUPPORTED_PLATFORM_EXTS = ['android', 'ios'];
+const SUPPORTED_PLATFORM_EXTS = ['android', 'ios', 'web'];
 
 const re = new RegExp(
   '[^\\.]+\\.(' + SUPPORTED_PLATFORM_EXTS.join('|') + ')\\.\\w+$'