From fda507ac09e2940835af4d176becf7988e321deb Mon Sep 17 00:00:00 2001
From: Gustaf Dalemar <gustaf.dalemar@gmail.com>
Date: Wed, 10 May 2017 10:48:35 +0200
Subject: [PATCH] Changed the Node resolving to be more reliable, fixes some
 issues

Sometimes _resolveFilename will be called without parent.id being
present which would result in a crash with the previous logic. This
change addresses this and instead uses parent.paths[0] for the same
functionality.

This solves in particular some problems that have been seen when used
together with babel-plugin-lodash.
---
 docs/RocObject.md                   |  2 +-
 src/require/createResolveRequest.js |  4 ++--
 src/require/patchResolveFilename.js | 17 +++++++++++++++--
 3 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/docs/RocObject.md b/docs/RocObject.md
index 5014928..23370d8 100644
--- a/docs/RocObject.md
+++ b/docs/RocObject.md
@@ -149,7 +149,7 @@ __`request`__
 A string, the path that was requested.
 
 __`requestContext`__  
-A string, the location of the request. The path to the file that did the request.
+A string, the location of the request. The path to the directory from which the request was performed.
 
 #### `requires`
 Dependencies that are required and will be verified to exist by Roc.
diff --git a/src/require/createResolveRequest.js b/src/require/createResolveRequest.js
index 0b91173..9a3d7a2 100644
--- a/src/require/createResolveRequest.js
+++ b/src/require/createResolveRequest.js
@@ -30,8 +30,8 @@ export default function createResolveRequest(exports, directory, dependencyConte
     };
 
     const requestHelper = (request, context, fallback, identifier) => {
-        // If we got an empty request we want to let Node handle it
-        if (!request) {
+        // If we got an empty request or context we want to let Node handle it
+        if (!request || !context) {
             return { completedRequest: request };
         }
 
diff --git a/src/require/patchResolveFilename.js b/src/require/patchResolveFilename.js
index 92b775d..7cb3b93 100644
--- a/src/require/patchResolveFilename.js
+++ b/src/require/patchResolveFilename.js
@@ -1,4 +1,5 @@
 const Module = require('module');
+const path = require('path');
 
 const log = require('debug')('roc:core:require');
 
@@ -8,8 +9,20 @@ export default function patchResolveFilename(resolveRequest) {
     log('Initializing');
 
     Module._resolveFilename = function rocResolveFilename(request, parent) {
+        // Get the context for the request, the directory that the request is coming from.
+        // We are using "dirname" here to remove "node_modules" from the path that will be
+        // present given how Nodes algorithm works, with the first path being the directory
+        // from which the request was performed.
+        // Example: [/dir/that/did/the/request/node_modules, /dir/that/did/the/node_modules, ...]
+        const context = parent && parent.paths
+            ? path.dirname(parent.paths[0])
+            : undefined;
+
         try {
-            return originalResolveFilename.apply(this, [resolveRequest(request, parent.id), parent]);
+            return originalResolveFilename.apply(this, [
+                resolveRequest(request, context),
+                parent,
+            ]);
         } catch (_error) {
             /* We try again with fallback enabled.
              * This emulates kinda how NODE_PATH works in that we try again with another scope.
@@ -19,7 +32,7 @@ export default function patchResolveFilename(resolveRequest) {
              * extension is providing.
              */
             return originalResolveFilename.apply(this, [
-                resolveRequest(request, parent.id, { fallback: true }),
+                resolveRequest(request, context, { fallback: true }),
                 parent,
             ]);
         }