Make sourcemap source paths relative to file.base; fixes #92.

index.js

@@ -42,15 +42,24 @@ module.exports = function (options) {
       opts.includePaths = [fileDir];
     }
 
-    opts.success = function (css, map) {
-      var sourceMap;
-      if (typeof opts.onSuccess === 'function') opts.onSuccess(css, map);
+    opts.success = function (css, sourceMap) {
+      if (typeof opts.onSuccess === 'function') opts.onSuccess(css, sourceMap);
 
-      if (map) {
+      if (sourceMap) {
         // hack to remove the already added sourceMappingURL from libsass
         css = css.replace(/\/\*#\s*sourceMappingURL\=.*\*\//, '');
 
-        applySourceMap(file, map);
+        // libsass gives us sources' paths relative to file;
+        // gulp-sourcemaps needs sources' paths relative to file.base;
+        // so alter the sources' paths to please gulp-sourcemaps.
+        sourceMap = JSON.parse(sourceMap);
+        sourceMap.sources = sourceMap.sources.map(function(source) {
+          var abs = path.resolve(path.dirname(file.path), source);
+          return path.relative(file.base, abs);
+        });
+        sourceMap = JSON.stringify(sourceMap);
+
+        applySourceMap(file, sourceMap);
       }
 
       file.path      = ext(file.path, '.css');

test/scss/includes/_cats.scss

@@ -1,2 +1,6 @@
 $blue: #3bbfce;
-$margin: 16px;
+$margin: 16px;
+
+body {
+	background: pink;
+}

test/scss/subdir/multilevelimport.scss

@@ -0,0 +1 @@
+@import "../inheritance";

test/test.js

@@ -4,6 +4,7 @@ var gutil = require('gulp-util');
 var fs = require('fs');
 var path = require('path');
 var test = require('tape');
+var sourcemap = require('source-map');
 
 function createVinyl(sassFileName, contents) {
   var base = path.join(__dirname, 'scss');
@@ -106,4 +107,37 @@ test('call custom error callback when opts.onError is given', function (t) {
     new Buffer('body { font \'Comic Sans\'; }'));
 
   stream.write(errorFile);
-});
+});
+
+test('sourcemaps', function (t) {
+  var sassFile = createVinyl('subdir/multilevelimport.scss');
+
+  // Pretend sourcemap.init() happened by mimicking
+  // the object it would create.
+  sassFile.sourceMap = {
+    version: 3,
+    file: 'scss/subdir/multilevelimport.scss',
+    names: [],
+    mappings: '',
+    sources: [ 'scss/subdir/multilevelimport.scss' ],
+    sourcesContent: [ '@import "../inheritance";\n' ]
+  };
+
+  // Expected sources are relative to file.base
+  var expectedSources = [
+    'includes/_cats.scss',
+    'inheritance.scss'
+  ];
+
+  var stream = gsass();
+
+  stream.on('data', function (cssFile) {
+    t.deepEqual(
+      cssFile.sourceMap.sources,
+      expectedSources,
+      'sourcemap paths are relative to file.base'
+    );
+    t.end();
+  });
+  stream.write(sassFile);
+});