Discard byte order mark (fix #962)

caddyfile/lexer.go

@@ -26,9 +26,20 @@ type (
 )
 
 // load prepares the lexer to scan an input for tokens.
+// It discards any leading byte order mark.
 func (l *lexer) load(input io.Reader) error {
 	l.reader = bufio.NewReader(input)
 	l.line = 1
+
+	// discard byte order mark, if present
+	firstCh, _, err := l.reader.ReadRune()
+	if err == nil && firstCh != 0xFEFF {
+		err := l.reader.UnreadRune()
+		if err != nil {
+			return err
+		}
+	}
+
 	return nil
 }
 

caddyfile/lexer_test.go

@@ -128,6 +128,12 @@ func TestLexer(t *testing.T) {
 				{Line: 2, Text: "characters"},
 			},
 		},
+		{
+			input: "\xEF\xBB\xBF:8080", // test with leading byte order mark
+			expected: []Token{
+				{Line: 1, Text: ":8080"},
+			},
+		},
 	}
 
 	for i, testCase := range testCases {