fix: source map sources and file paths

README.md

@@ -294,21 +294,6 @@ They are not enabled by default because they expose a runtime overhead and incre
 }
 ```
 
-#### Opting out of legacy source maps behavior
-
-To receive source maps as URLs relative to `loader.resourcePath`, set the `legacySourceMaps` option to `false`.
-
-
-```javascript
-{
-  loader: 'css-loader',
-  options: {
-    legacySourceMaps: false,
-    sourceMap: true
-  }
-}
-```
-
 ### `camelCase`
 
 By default, the exported JSON keys mirror the class names. If you want to camelize class names (useful in JS), pass the query parameter `camelCase` to css-loader.

lib/loader.js

@@ -54,32 +54,26 @@ module.exports = function(content, map) {
 		map = null;
 	}
 
-	if (query.legacySourceMaps !== false) {
-		processCssFrom = loaderUtils.getRemainingRequest(this).split("!").pop();
-		processCssTo = loaderUtils.getCurrentRequest(this).split("!").pop();
-	} else {
-
-		/**
-		 * > To ensure that PostCSS generates source maps and displays better syntax
-		 * > errors, runners must specify the from and to options. If your runner
-		 * > does not handle writing to disk (for example, a gulp transform), you
-		 * > should set both options to point to the same file
-		 * @see postcss [PostCSS Runner Guidelines]{@link https://github.com/postcss/postcss/blob/master/docs/guidelines/runner.md#21-set-from-and-to-processing-options}
-		 *
-		 * `css-loader` isn't responsible for writing the map, so it doesn't have to
-		 * worry about updating the map with a transformation that changes locations
-		 * (suchs as map.file or map.sources).
-		 *
-		 * Changing the file extension counts as changing the location because it
-		 * changes the path.
-		 *
-		 * PostCSS's `from` and `to` arguments are only concerned with the file
-		 * system. They don't know about, care about, or understand the webpack
-		 * loader's current request or remaining request.
-		 */
-		processCssFrom = processFrom(this.resourcePath, map);
-		processCssTo = processCssFrom;
-	}
+	/**
+	 * > To ensure that PostCSS generates source maps and displays better syntax
+	 * > errors, runners must specify the from and to options. If your runner
+	 * > does not handle writing to disk (for example, a gulp transform), you
+	 * > should set both options to point to the same file
+	 * @see postcss [PostCSS Runner Guidelines]{@link https://github.com/postcss/postcss/blob/master/docs/guidelines/runner.md#21-set-from-and-to-processing-options}
+	 *
+	 * `css-loader` isn't responsible for writing the map, so it doesn't have to
+	 * worry about updating the map with a transformation that changes locations
+	 * (suchs as map.file or map.sources).
+	 *
+	 * Changing the file extension counts as changing the location because it
+	 * changes the path.
+	 *
+	 * PostCSS's `from` and `to` arguments are only concerned with the file
+	 * system. They don't know about, care about, or understand the webpack
+	 * loader's current request or remaining request.
+	 */
+	processCssFrom = processFrom(this.resourcePath, map);
+	processCssTo = processCssFrom;
 
 	processCss(content, map, {
 		mode: moduleMode ? "local" : "global",
@@ -160,15 +154,6 @@ module.exports = function(content, map) {
 		if(sourceMap && result.map) {
 			// add a SourceMap
 			map = result.map;
-			if (query.legacySourceMaps !== false) {
-				if(map.sources) {
-					map.sources = map.sources.map(function(source) {
-						return source.split("!").pop().replace(/\\/g, '/');
-					}, this);
-					map.sourceRoot = "";
-				}
-				map.file = map.file.split("!").pop().replace(/\\/g, '/');
-			}
 			map = JSON.stringify(map);
 			moduleJs = "exports.push([module.id, " + cssAsString + ", \"\", " + map + "]);";
 		} else {

lib/processCss.js

@@ -179,16 +179,8 @@ module.exports = function processCss(inputSource, inputMap, options, callback) {
 		parserPlugin(parserOptions)
 	]);
 
-	var postCssFrom;
-	if (options.query.legacySourceMaps !== false) {
-		// we need a prefix to avoid path rewriting of PostCSS
-		postCssFrom = "/css-loader!" + options.from;
-	} else {
-		postCssFrom = options.from;
-	}
-
 	pipeline.process(inputSource, {
-		from: postCssFrom,
+		from: options.from,
 		to: options.to,
 		map: options.sourceMap ? {
 			prev: inputMap,