From 91fdb10abf4dd7c198ba57566c86e0601801193f Mon Sep 17 00:00:00 2001
From: Jean Lauliac <jeanlauliac@fb.com>
Date: Mon, 22 May 2017 11:30:47 -0700
Subject: [PATCH] packager: ResolutionRequest: empty module is special case

Summary: Because we don't want to test for `empty-module.ios.js`, etc. We know the module is supposed to be here. This simpler version makes it easier for me to switch the rest of the `loadAsFile` callsites to the "candidates" system to the "candidates" system.

Reviewed By: davidaurelio

Differential Revision: D5103816

fbshipit-source-id: 7e7d9be27573a1f33d562aeb850759e073fbc72f
---
 .../DependencyGraph/ResolutionRequest.js      | 25 +++++++++++--------
 1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/packages/metro-bundler/src/node-haste/DependencyGraph/ResolutionRequest.js b/packages/metro-bundler/src/node-haste/DependencyGraph/ResolutionRequest.js
index bf010ec9..c20150f6 100644
--- a/packages/metro-bundler/src/node-haste/DependencyGraph/ResolutionRequest.js
+++ b/packages/metro-bundler/src/node-haste/DependencyGraph/ResolutionRequest.js
@@ -481,11 +481,7 @@ class ResolutionRequest<TModule: Moduleish, TPackage: Packageish> {
       potentialModulePath,
     );
     if (realModuleName === false) {
-      return this._loadAsFileOrThrow(
-        ResolutionRequest.EMPTY_MODULE,
-        fromModule,
-        toModuleName,
-      );
+      return this._getEmptyModule(fromModule, toModuleName);
     }
 
     return tryResolveSync(
@@ -501,11 +497,7 @@ class ResolutionRequest<TModule: Moduleish, TPackage: Packageish> {
     const realModuleName = this._redirectRequire(fromModule, toModuleName);
     // exclude
     if (realModuleName === false) {
-      return this._loadAsFileOrThrow(
-        ResolutionRequest.EMPTY_MODULE,
-        fromModule,
-        toModuleName,
-      );
+      return this._getEmptyModule(fromModule, toModuleName);
     }
 
     if (isRelativeImport(realModuleName) || isAbsolutePath(realModuleName)) {
@@ -720,6 +712,19 @@ class ResolutionRequest<TModule: Moduleish, TPackage: Packageish> {
     return resolver.tryToResolveFileName(fileName) ? fileName : null;
   }
 
+  _getEmptyModule(fromModule: TModule, toModuleName: string): TModule {
+    const {moduleCache} = this._options;
+    const module = moduleCache.getModule(ResolutionRequest.EMPTY_MODULE);
+    if (module != null) {
+      return module;
+    }
+    throw new UnableToResolveError(
+      fromModule,
+      toModuleName,
+      "could not resolve `${ResolutionRequest.EMPTY_MODULE}'",
+    );
+  }
+
   _loadAsDir(
     potentialDirPath: string,
     fromModule: TModule,