From 03590c1bc87c98c121ee902701f6017d9df9e56f Mon Sep 17 00:00:00 2001
From: Ti Chi Robot <ti-community-prow-bot@tidb.io>
Date: Mon, 14 Aug 2023 18:02:00 +0800
Subject: [PATCH] parser: reset `lexer.identifierDot` correctly when reusing
 parsers (#45903) (#45908)

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 659fc14dd9235..37b952efdbc79 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 85e62987e96ec..3e96ace30f832 100644
--- a/parser/parser_test.go
+++ b/parser/parser_test.go
@@ -6722,3 +6722,15 @@ func TestNonTransactionalDelete(t *testing.T) {
 
 	RunTest(t, cases, 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())
+}