From 2bec70bf7d53bb4e5431c1ddeda8600cf8b5328f Mon Sep 17 00:00:00 2001
From: Marc Horowitz <mhorowitz@fb.com>
Date: Mon, 20 Mar 2017 12:56:30 -0700
Subject: [PATCH] Don't swallow the error if a module require fails

Reviewed By: davidaurelio

Differential Revision: D4733269

fbshipit-source-id: 2cca14c023b148b62cf24f204cdb355f8d2f3590
---
 packages/metro-bundler/src/Resolver/polyfills/require.js | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/packages/metro-bundler/src/Resolver/polyfills/require.js b/packages/metro-bundler/src/Resolver/polyfills/require.js
index 655d762a..3c1f0b24 100644
--- a/packages/metro-bundler/src/Resolver/polyfills/require.js
+++ b/packages/metro-bundler/src/Resolver/polyfills/require.js
@@ -38,6 +38,7 @@ type ModuleDefinition = {|
   exports: Exports,
   factory: FactoryFn,
   hasError: boolean,
+  error?: any,
   hot?: HotModuleReloadingData,
   isInitialized: boolean,
   verboseName?: string,
@@ -138,7 +139,7 @@ function loadModuleImplementation(moduleId, module) {
   }
 
   if (module.hasError) {
-    throw moduleThrewError(moduleId);
+    throw moduleThrewError(moduleId, module.error);
   }
 
   // `require` calls int  the require polyfill itself are not analyzed and
@@ -185,6 +186,7 @@ function loadModuleImplementation(moduleId, module) {
     return (module.exports = moduleObject.exports);
   } catch (e) {
     module.hasError = true;
+    module.error = e;
     module.isInitialized = false;
     module.exports = undefined;
     throw e;
@@ -201,9 +203,9 @@ function unknownModuleError(id) {
   return Error(message);
 }
 
-function moduleThrewError(id) {
+function moduleThrewError(id, error: any) {
   const displayName = __DEV__ && modules[id] && modules[id].verboseName || id;
-  return Error('Requiring module "' + displayName + '", which threw an exception.');
+  return Error('Requiring module "' + displayName + '", which threw an exception: ' + error);
 }
 
 if (__DEV__) {