CLI: Only read stdin if there were no files supplied and not in tty mode.

lib/cli.js

@@ -64,7 +64,7 @@ module.exports = function(program) {
         return returnArgs;
     }
 
-    if (args.length === 0 && process.stdin.isTTY) {
+    if (!args.length && process.stdin.isTTY) {
         console.error('No input files specified. Try option --help for usage information.');
         defer.reject(1);
 
@@ -106,8 +106,12 @@ module.exports = function(program) {
     checker.registerDefaultRules();
     checker.configure(config);
 
-    if (! process.stdin.isTTY) {
-        // Handle usage like cat myfile.js | jscs
+    // Handle usage like 'cat myfile.js | jscs' or 'jscs -''
+    var usedDash = args[args.length - 1] === '-';
+    if (!args.length || usedDash) {
+        // So the dash doesn't register as a file
+        if (usedDash) { args.length--; }
+
         process.stdin.setEncoding('utf8');
 
         process.stdin.on('data', function(chunk) {

test/cli.js

@@ -208,7 +208,7 @@ describe('modules/cli', function() {
             });
         });
 
-        it('should should accept empty input being piped', function(done) {
+        it('should accept empty input being piped', function(done) {
             // 'cat myEmptyFile.js | jscs' should report a successful run
             rAfter();
 
@@ -233,6 +233,34 @@ describe('modules/cli', function() {
                 done();
             });
         });
+
+        it('should not accept piped input if files were specified (#563)', function() {
+            var checker = require('../lib/checker');
+            var spy = sinon.spy(checker.prototype, 'checkPath');
+
+            var result = cli({
+                args: [__dirname + '/data/cli/success.js']
+            });
+
+            return result.promise.always(function() {
+                assert(spy.called);
+                checker.prototype.checkPath.restore();
+                rAfter();
+            });
+        });
+
+        it('should check stdin if - was supplied as the last argument (#563)', function() {
+            var spy = sinon.spy(process.stdin, 'on');
+
+            var result = cli({
+                args: [__dirname + '/data/cli/success.js', '-']
+            });
+
+            return result.promise.always(function() {
+                assert(spy.called);
+                rAfter();
+            });
+        });
     });
 
     describe('reporter option', function() {