Fix error plumbing

lib/index.js

@@ -4,13 +4,28 @@ var stream = require("stream");
 var combiner = require("stream-combiner2");
 var plumber = require("gulp-plumber");
 var namedLog = require("gulp-named-log");
+var util = require("util");
 
 module.exports = function (name, streams) {
 	var options = arguments.length <= 2 || arguments[2] === undefined ? {} : arguments[2];
 
 	var logger = namedLog(name, options.logger);
 
-	var streamList = [plumber(logger.error)].concat(streams).concat([logger.stream()]);
+	var streamList = streams.concat([logger.stream()]);
 
-	return combiner.obj(streamList);
+	/* We need to patch in the `pipe` handler manually, as this monkeypatch doesn't
+  * carry over to Duplex streams that are created by `stream-combiner2`. The
+  * `stream-combiner2` library will take care of re-emitting the errors on the
+  * combined stream, so we don't need `gulp-plumber` in our actual pipeline.
+  */
+	var plumberStream = plumber(function (err) {
+		logger.error(err.toString());
+		/* Ensure that the task finishes, so as to not break `gulp.watch`. */
+		this.emit("end");
+	});
+	var combinedStream = combiner.obj(streamList);
+
+	plumberStream.pipe(combinedStream);
+
+	return combinedStream;
 };

src/index.js

@@ -4,15 +4,28 @@ const stream = require("stream");
 const combiner = require("stream-combiner2");
 const plumber = require("gulp-plumber");
 const namedLog = require("gulp-named-log");
+const util = require("util");
 
 module.exports = function(name, streams, options = {}) {
 	let logger = namedLog(name, options.logger);
 
-	let streamList = [
-		plumber(logger.error)
-	].concat(streams).concat([
+	let streamList = streams.concat([
 		logger.stream()
 	]);
 
-	return combiner.obj(streamList)
+	/* We need to patch in the `pipe` handler manually, as this monkeypatch doesn't
+	 * carry over to Duplex streams that are created by `stream-combiner2`. The
+	 * `stream-combiner2` library will take care of re-emitting the errors on the
+	 * combined stream, so we don't need `gulp-plumber` in our actual pipeline.
+	 */
+	let plumberStream = plumber(function(err) {
+		logger.error(err.toString());
+		/* Ensure that the task finishes, so as to not break `gulp.watch`. */
+		this.emit("end");
+	});
+	let combinedStream = combiner.obj(streamList);
+
+	plumberStream.pipe(combinedStream);
+
+	return combinedStream;
 }