From 915d1c8c92c01c118dc469b0a05467cf9b9c7ced Mon Sep 17 00:00:00 2001
From: winkyao <golangwink@gmail.com>
Date: Mon, 18 Jun 2018 15:02:36 +0800
Subject: [PATCH] parser: allow comments end with multi asterisk (#6847)

---
 parser/lexer.go       | 14 +++++++++++---
 parser/parser_test.go |  6 ++++++
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/parser/lexer.go b/parser/lexer.go
index c82d3bbb574bb..70ff48c7fa368 100644
--- a/parser/lexer.go
+++ b/parser/lexer.go
@@ -335,16 +335,24 @@ func startWithSlash(s *Scanner) (tok int, pos Pos, lit string) {
 	ch0 := s.r.peek()
 	if ch0 == '*' {
 		s.r.inc()
+		startWithAsterisk := false
 		for {
 			ch0 = s.r.readByte()
+			if startWithAsterisk && ch0 == '/' {
+				// Meets */, means comment end.
+				break
+			} else if ch0 == '*' {
+				startWithAsterisk = true
+			} else {
+				startWithAsterisk = false
+			}
+
 			if ch0 == unicode.ReplacementChar && s.r.eof() {
 				// unclosed comment
 				s.errs = append(s.errs, ParseErrorWith(s.r.data(&pos), s.r.p.Line))
 				return
 			}
-			if ch0 == '*' && s.r.readByte() == '/' {
-				break
-			}
+
 		}
 
 		comment := s.r.data(&pos)
diff --git a/parser/parser_test.go b/parser/parser_test.go
index a0548895ae859..ce06c0a8fa39f 100644
--- a/parser/parser_test.go
+++ b/parser/parser_test.go
@@ -462,6 +462,12 @@ func (s *testParserSuite) TestDMLStmt(c *C) {
 
 		{`ANALYZE TABLE t`, true},
 
+		// for comments
+		{`/** 20180417 **/ show databases;`, true},
+		{`/* 20180417 **/ show databases;`, true},
+		{`/** 20180417 */ show databases;`, true},
+		{`/** 20180417 ******/ show databases;`, true},
+
 		// for Binlog stmt
 		{`BINLOG '
 BxSFVw8JAAAA8QAAAPUAAAAAAAQANS41LjQ0LU1hcmlhREItbG9nAAAAAAAAAAAAAAAAAAAAAAAA