Bugfix: zero length vendor at rules

Author: tdewolff

css/parse.go

@@ -196,7 +196,7 @@ func (p *Parser) parseAtRule() GrammarType {
 	atRuleName := p.data
 	if len(atRuleName) > 0 && atRuleName[1] == '-' {
 		if i := bytes.IndexByte(atRuleName[2:], '-'); i != -1 {
-			atRuleName = atRuleName[i+3:] // skip vendor specific prefix
+			atRuleName = atRuleName[i+2:] // skip vendor specific prefix
 		}
 	}
 	atRule := ToHash(atRuleName[1:])

css/parse_test.go

@@ -129,6 +129,9 @@ func TestParser(t *testing.T) {
 	assertParse(t, true, ".class [c=y]{}", ".class [c=y]{}")                                                       // tdewolff/minify#16
 	assertParse(t, true, "table{font-family:Verdana}", "table{font-family:Verdana;}")                              // tdewolff/minify#22
 
+	// go-fuzz
+	assertParse(t, true, "@-webkit-", "@-webkit-;")
+
 	assert.Equal(t, "Error", ErrorGrammar.String())
 	assert.Equal(t, "AtRule", AtRuleGrammar.String())
 	assert.Equal(t, "BeginAtRule", BeginAtRuleGrammar.String())