handle relative path in node_modules case, fix css-modules#161

Author: Long Ho

.editorconfig

@@ -0,0 +1,15 @@
+# http://editorconfig.org
+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[*.md]
+trim_trailing_whitespace = false
+
+[package.json]
+indent_size = 2

node_modules/cool-styles/bar.css

@@ -26,7 +26,8 @@ export default class FileSystemLoader {
     this.traces = {}
     this.importNr = 0
     this.core = new Core(plugins)
-    this.tokensByFile = {};
+    this.tokensByFile = {}
+    this.resolvedPaths = {}
   }
 
   fetch( _newPath, relativeTo, _trace ) {
@@ -40,9 +41,16 @@ export default class FileSystemLoader {
       // if the path is not relative or absolute, try to resolve it in node_modules
       if (newPath[0] !== '.' && newPath[0] !== '/') {
         try {
-          fileRelativePath = require.resolve(newPath);
+          fileRelativePath = require.resolve(newPath)
+          // Record the resolved path since this might be inside node_modules
+          this.resolvedPaths[rootRelativePath] = path.dirname(fileRelativePath)
         }
         catch (e) {}
+      } else {
+        // Relative path but might be relative to a node_modules module
+        if (this.resolvedPaths[relativeTo]) {
+          fileRelativePath = path.resolve(this.resolvedPaths[relativeTo], newPath)
+        }
       }
 
       const tokens = this.tokensByFile[fileRelativePath]

node_modules/cool-styles/foo.css

@@ -1,5 +1,12 @@
+._compose_node_module_cool_styles_bar__example2 {
+  color: black;
+}
 ._compose_node_module_cool_styles_foo__example {
   color: #F00;
 }
+._compose_node_module_cool_styles_foo__example3 {
+}
 ._compose_node_module_source__foo {
 }
+._compose_node_module_source__bar {
+}

src/file-system-loader.js

@@ -1,3 +1,4 @@
 {
-  "foo": "_compose_node_module_source__foo _compose_node_module_cool_styles_foo__example"
+  "foo": "_compose_node_module_source__foo _compose_node_module_cool_styles_foo__example",
+  "bar": "_compose_node_module_source__bar _compose_node_module_cool_styles_foo__example3 _compose_node_module_cool_styles_bar__example2"
 }

test/test-cases/compose-node-module/expected.css

@@ -1,3 +1,6 @@
 .foo {
   composes: example from "cool-styles/foo.css";
 }
+.bar {
+  composes: example3 from "cool-styles/foo.css";
+}