From ddfd36a50d9c2b6e165c05ef51a154d379a411b4 Mon Sep 17 00:00:00 2001
From: Ti Chi Robot <ti-community-prow-bot@tidb.io>
Date: Fri, 18 Aug 2023 15:17:01 +0800
Subject: [PATCH] parser: reset `lexer.identifierDot` correctly when reusing
 parsers (#45903) (#45909)

close pingcap/tidb#45898
---
 parser/lexer.go       |  1 +
 parser/parser_test.go | 12 ++++++++++++
 2 files changed, 13 insertions(+)

diff --git a/parser/lexer.go b/parser/lexer.go
index 0a172abfda027..caf289cfefd81 100644
--- a/parser/lexer.go
+++ b/parser/lexer.go
@@ -98,6 +98,7 @@ func (s *Scanner) reset(sql string) {
 	s.stmtStartPos = 0
 	s.inBangComment = false
 	s.lastKeyword = 0
+	s.identifierDot = false
 }
 
 func (s *Scanner) stmtText() string {
diff --git a/parser/parser_test.go b/parser/parser_test.go
index 4706ef1f196d1..2b052ca422884 100644
--- a/parser/parser_test.go
+++ b/parser/parser_test.go
@@ -7192,3 +7192,15 @@ func TestTTLTableOption(t *testing.T) {
 
 	RunTest(t, table, false)
 }
+
+func TestIssue45898(t *testing.T) {
+	p := parser.New()
+	p.ParseSQL("a.")
+	stmts, _, err := p.ParseSQL("select count(1) from t")
+	require.NoError(t, err)
+	var sb strings.Builder
+	restoreCtx := NewRestoreCtx(DefaultRestoreFlags, &sb)
+	sb.Reset()
+	stmts[0].Restore(restoreCtx)
+	require.Equal(t, "SELECT COUNT(1) FROM `t`", sb.String())
+}