Fixed tricky bug with renamed file

index.js

@@ -64,8 +64,8 @@ function createPipeline(options) {
 	// each `transform` entry must be a function that returns a transform stream
 	if (options.transform) {
 		var t = Array.isArray(options.transform) ? options.transform : [options.transform];
-		t.forEach(function(streamFactory) {
-			output = output.pipe(streamFactory(options));
+		t.forEach(function(factory) {
+			output = output.pipe(factory(options));
 		});
 	}
 

lib/stream.js

@@ -6,6 +6,7 @@
 var through = require('through2');
 var postcss = require('postcss');
 var readContents = require('./read-contents');
+var File = require('vinyl');
 
 /**
  * Returns a transformaton stream that applies content transformations from
@@ -16,8 +17,11 @@ var readContents = require('./read-contents');
  * is ready 
  */
 module.exports = function(file, transform) {
+	// XXX this is very important: clone file before actual processing starts.
+	// Otherwise, when transformation process starts the actual file might 
+	// be renamed which may lead to invalid results
+	var f = cloneFile(file);
 	return readContents(function(contents, callback) {
-		var f = file.clone();
 		f.contents = contents;
 		f.stringify = stringify;
 		try {
@@ -32,6 +36,7 @@ module.exports = function(file, transform) {
 		.once('finish', function() {
 			// write transformed tree as file content
 			self.push(f.css ? new Buffer(f.stringify()) : f.contents);
+			f = null;
 			callback();
 		})
 		.end(f);
@@ -40,4 +45,16 @@ module.exports = function(file, transform) {
 
 function stringify() {
 	return this.css.toResult().toString();
+}
+
+function cloneFile(file) {
+	// do not use `file.clone()` here: if content is stream the original
+	// reader stream will be paused because of absent cloned stream consumer
+	return new File({
+		cwd: file.cwd,
+		base: file.base,
+		stat: null,
+		history: file.history.slice(),
+		contents: null
+	});
 }

package.json

@@ -14,6 +14,7 @@
     "graceful-fs": "^3.0.8",
     "postcss": "^4.1.12",
     "through2": "^2.0.0",
+    "vinyl": "^0.5.1",
     "xtend": "^4.0.0"
   },
   "devDependencies": {