fixes #64: invalid less should throw CSSSyntaxError (#66)

Author: shellscape

lib/less-parser.js

@@ -143,7 +143,7 @@ export default class LessParser extends Parser {
         let bracket = null;
         const brackets = [];
         const start = this.pos;
-        
+
         // we need pass "()" as spaces
         // However we can override method Parser.loop, but it seems less maintainable
         if (this.tokens[start][0] === 'brackets') {
@@ -213,7 +213,8 @@ export default class LessParser extends Parser {
             this.unclosedBracket(bracket);
         }
 
-        if (end) {
+        // dont process an end of rule if there's only one token and it's unknown (#64)
+        if (end && this.tokens.length > 1) {
             const foundEndOfRule = this.processEndOfRule({
                 start,
                 params,

test/postcss.spec.js

@@ -1,12 +1,13 @@
 // chai uses expressions for validation
 /* eslint no-unused-expressions: 0 */
 
+import CssSyntaxError from 'postcss/lib/css-syntax-error';
 import {expect} from 'chai';
 import lessSyntax from '../lib/less-syntax';
 import postcss from 'postcss';
 
 describe('#postcss', () => {
-    it('can process LESS syntax', (done) => {
+    it('should process LESS syntax', (done) => {
         const lessText = 'a { b {} }';
 
         postcss()
@@ -19,8 +20,8 @@ describe('#postcss', () => {
                 done();
             }).catch(done);
     });
-    
-    it('can parse LESS mixins as at rules', (done) => {
+
+    it('should parse LESS mixins as at rules', (done) => {
         const lessText = '.foo (@bar; @baz...) { border: @{baz}; }';
 
         postcss()
@@ -33,4 +34,15 @@ describe('#postcss', () => {
                 done();
             }).catch(done);
     });
-});
+
+    it('should not parse invalid LESS (#64)', (done) => {
+        const lessText = '.foo';
+
+        postcss()
+            .process(lessText, {syntax: lessSyntax})
+            .catch((err) => {
+                expect(err).to.be.an.instanceof(CssSyntaxError);
+                done();
+            });
+    });
+});