Improve source map support

lib/loader.js

@@ -27,7 +27,7 @@ function sassLoader(content) {
     const resourcePath = this.resourcePath;
 
     function addNormalizedDependency(file) {
-        // node-sass returns UNIX-style paths
+        // node-sass returns POSIX paths
         self.dependency(path.normalize(file));
     }
 
@@ -57,8 +57,12 @@ function sassLoader(content) {
             result.map.file = resourcePath;
             // The first source is 'stdin' according to libsass because we've used the data input
             // Now let's override that value with the correct relative path
-            result.map.sources[0] = path.relative(self.options.context, resourcePath);
-            result.map.sourceRoot = path.relative(self.options.context, process.cwd());
+            result.map.sources[0] = path.basename(resourcePath);
+            result.map.sourceRoot = path.dirname(resourcePath);
+            // node-sass returns POSIX paths, that's why we need to transform them back to native paths.
+            // This fixes an error on windows where the source-map module cannot resolve the source maps.
+            // @see https://github.com/jtangelder/sass-loader/issues/366#issuecomment-279460722
+            result.map.sources = result.map.sources.map(path.normalize);
         } else {
             result.map = null;
         }

package.json

@@ -6,10 +6,10 @@
   "scripts": {
     "create-spec": "node test/tools/runCreateSpec.js",
     "pretest": "node test/tools/runCreateSpec.js",
-    "test": "mocha -R spec",
+    "test": "mocha -R spec -t 10000",
     "posttest": "eslint --fix lib test",
     "test-bootstrap-sass": "webpack-dev-server --config test/bootstrapSass/webpack.config.js --content-base ./test/bootstrapSass",
-    "test-source-map": "webpack-dev-server --config test/sourceMap/webpack.config.js --content-base ./test/sourceMap",
+    "test-source-map": "webpack-dev-server --config test/sourceMap/webpack.config.js --content-base ./test/sourceMap --inline",
     "test-watch": "webpack --config test/watch/webpack.config.js",
     "test-extract-text": "webpack --config test/extractText/webpack.config.js",
     "test-hmr": "webpack-dev-server --config test/hmr/webpack.config.js --content-base ./test/hmr --hot --inline"

test/index.test.js

@@ -113,7 +113,7 @@ describe("sass-loader", () => {
                             ]
                         }]
                     }
-                }, (err) => err ? reject(err) : resolve());
+                }, err => err ? reject(err) : resolve());
             })
                 .then(() => {
                     const expectedCss = readCss("scss", "imports");
@@ -137,6 +137,34 @@ describe("sass-loader", () => {
                 })
         );
     });
+    describe("source maps", () => {
+        it("should compile without errors", () =>
+            new Promise((resolve, reject) => {
+                runWebpack({
+                    entry: path.join(__dirname, "scss", "imports.scss"),
+                    // We know that setting a custom context can confuse webpack when resolving source maps
+                    context: path.join(__dirname, "scss"),
+                    output: {
+                        filename: "bundle.source-maps.compile-without-errors.js"
+                    },
+                    devtool: "source-map",
+                    module: {
+                        rules: [{
+                            test: /\.scss$/,
+                            use: [
+                                { loader: "css-loader", options: {
+                                    sourceMap: true
+                                } },
+                                { loader: pathToSassLoader, options: {
+                                    sourceMap: true
+                                } }
+                            ]
+                        }]
+                    }
+                }, err => err ? reject(err) : resolve());
+            })
+        );
+    });
     describe("errors", () => {
         it("should throw an error in synchronous loader environments", () => {
             try {
@@ -209,8 +237,8 @@ function runWebpack(baseConfig, done) {
 
     webpack(webpackConfig, (webpackErr, stats) => {
         const err = webpackErr ||
-            (stats.hasErrors && stats.compilation.errors[0]) ||
-            (stats.hasWarnings && stats.compilation.warnings[0]);
+            (stats.hasErrors() && stats.compilation.errors[0]) ||
+            (stats.hasWarnings() && stats.compilation.warnings[0]);
 
         done(err || null);
     });

test/scss/imports.scss

@@ -13,3 +13,7 @@
 @import "~animate.css/animate";
 /* @import url(http://example.com/something/from/the/interwebs); */
 @import url(http://example.com/something/from/the/interwebs);
+/* scoped import @import "language"; */
+.scoped-import {
+    @import "language";
+}

test/sourceMap/index.html

@@ -3,9 +3,9 @@
 <head>
     <title></title>
     <meta charset="utf-8"/>
-    <script async src="/bundle.sourcemap.js"></script>
+    <script async src="/bundle.js"></script>
 </head>
-<body>
+<body class="scoped-import">
     <h1 class="another-scss-module box">Open the developer tools, dude!</h1>
 </body>
 </html>

test/sourceMap/webpack.config.js

@@ -4,10 +4,9 @@ const path = require("path");
 const sassLoader = require.resolve("../../lib/loader");
 
 module.exports = {
-    entry: path.resolve(__dirname, "./entry.js"),
+    entry: path.resolve(__dirname, "..", "scss", "imports.scss"),
     output: {
-        path: path.resolve(__dirname, "../output"),
-        filename: "bundle.sourceMap.js"
+        filename: "bundle.js"
     },
     devtool: "source-map",
     module: {