Adjusted fix for OverZealous#13 to only error if tasks are duplicated…

… in parallel, rather than in a series.

index.js

@@ -4,11 +4,11 @@
 
 var colors = require('chalk');
 
-function verifyTaskSets(gulp, taskSets, skipArrays, foundTasks) {
+function verifyTaskSets(gulp, taskSets, skipArrays) {
 	if(taskSets.length === 0) {
 		throw new Error('No tasks were provided to run-sequence');
 	}
-	foundTasks = foundTasks || {};
+	var foundTasks = {};
 	taskSets.forEach(function(t) {
 		var isTask = typeof t === "string",
 			isArray = !skipArrays && Array.isArray(t);
@@ -18,7 +18,7 @@ function verifyTaskSets(gulp, taskSets, skipArrays, foundTasks) {
 		if(isTask && !gulp.hasTask(t)) {
 			throw new Error("Task "+t+" is not configured as a task on gulp.  If this is a submodule, you may need to use require('run-sequence').use(gulp).");
 		}
-		if(isTask) {
+		if(skipArrays && isTask) {
 			if(foundTasks[t]) {
 				throw new Error("Task "+t+" is listed more than once. This is probably a typo.");
 			}

test/main.js

@@ -151,6 +151,32 @@ describe('runSequence', function() {
 		});
 	});
 
+	describe('Duplicate Tasks', function() {
+		it('should not error if a task is duplicated across tasks-lists', function() {
+			(function() {
+				runSequence(['task1', 'task2'], ['task3', 'task1']);
+			}).should.not.throw();
+			task1.counter.should.eql(4);
+			task2.counter.should.eql(2);
+			task3.counter.should.eql(3);
+		});
+
+		it('should not error if a task is duplicated serially', function() {
+			(function() {
+				runSequence('task1', 'task2', 'task1');
+			}).should.not.throw();
+			task1.counter.should.eql(3);
+			task2.counter.should.eql(2);
+		});
+
+		it('should error if a task is duplicated within a parallel array', function() {
+			(function() {
+				runSequence(['task1', 'task1'], 'task2');
+			}).should.throw(/more than once/i);
+			shouldNotRunAnything();
+		});
+	});
+
 	function shouldNotRunAnything() {
 		task1.counter.should.eql(-1);
 		task2.counter.should.eql(-1);
@@ -203,20 +229,6 @@ describe('runSequence', function() {
 			}).should.throw(/not configured/i);
 			shouldNotRunAnything();
 		});
-
-		it('should error if a task is duplicated', function() {
-			(function() {
-				runSequence(['task1', 'task1'], 'task2');
-			}).should.throw(/more than once/i);
-			shouldNotRunAnything();
-		});
-
-		it('should error if a task is duplicated across tasks-lists', function() {
-			(function() {
-				runSequence(['task1', 'task2'], 'task1');
-			}).should.throw(/more than once/i);
-			shouldNotRunAnything();
-		});
 	});
 
 });