From a169b601b403c7650e513fff94a32046e877d8bb Mon Sep 17 00:00:00 2001
From: Ti Chi Robot <ti-community-prow-bot@tidb.io>
Date: Fri, 8 Dec 2023 22:33:16 +0800
Subject: [PATCH] planner: fix a panic during column pruning (#47883) (#48809)

close pingcap/tidb#47331
---
 executor/test/BUILD.bazel         | 15 +++++++
 executor/test/explain_test.go     | 71 +++++++++++++++++++++++++++++++
 executor/test/main_test.go        | 30 +++++++++++++
 planner/core/rule_join_reorder.go |  3 +-
 4 files changed, 118 insertions(+), 1 deletion(-)
 create mode 100644 executor/test/BUILD.bazel
 create mode 100644 executor/test/explain_test.go
 create mode 100644 executor/test/main_test.go

diff --git a/executor/test/BUILD.bazel b/executor/test/BUILD.bazel
new file mode 100644
index 0000000000000..0d0c1f1a307ec
--- /dev/null
+++ b/executor/test/BUILD.bazel
@@ -0,0 +1,15 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_test")
+
+go_test(
+    name = "test_test",
+    timeout = "short",
+    srcs = [
+        "explain_test.go",
+        "main_test.go",
+    ],
+    flaky = True,
+    deps = [
+        "//testkit",
+        "@org_uber_go_goleak//:goleak",
+    ],
+)
diff --git a/executor/test/explain_test.go b/executor/test/explain_test.go
new file mode 100644
index 0000000000000..743218844440c
--- /dev/null
+++ b/executor/test/explain_test.go
@@ -0,0 +1,71 @@
+// Copyright 2023 PingCAP, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package explain
+
+import (
+	"testing"
+
+	"github.com/pingcap/tidb/testkit"
+)
+
+func TestIssue47331(t *testing.T) {
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("use test")
+	tk.MustExec("drop table if exists t1")
+	tk.MustExec(`create table t1(
+		id1 varchar(2) DEFAULT '00',
+		id2 varchar(30) NOT NULL,
+		id3 datetime DEFAULT NULL,
+		id4 varchar(100) NOT NULL DEFAULT 'ecifdata',
+		id5 datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
+		id6 int(11) DEFAULT NULL,
+		id7 int(11) DEFAULT NULL,
+		UNIQUE KEY UI_id2 (id2),
+		KEY ix_id1 (id1)
+	)`)
+	tk.MustExec("drop table if exists t2")
+	tk.MustExec(`create table t2(
+		id10 varchar(40) NOT NULL,
+		id2 varchar(30) NOT NULL,
+		KEY IX_id2 (id2),
+		PRIMARY KEY (id10)
+	)`)
+	tk.MustExec("drop table if exists t3")
+	tk.MustExec(`create table t3(
+		id20 varchar(40) DEFAULT NULL,
+		UNIQUE KEY IX_id20 (id20)
+	)`)
+	tk.MustExec(`
+		explain
+		UPDATE t1 a
+		SET a.id1 = '04',
+			a.id3 = CURRENT_TIMESTAMP,
+			a.id4 = SUBSTRING_INDEX(USER(), '@', 1),
+			a.id5 = CURRENT_TIMESTAMP
+		WHERE a.id1 = '03'
+			AND a.id6 - IFNULL(a.id7, 0) =
+				(
+					SELECT COUNT(1)
+					FROM t2 b, t3 c
+					WHERE b.id10 = c.id20
+						AND b.id2 = a.id2
+						AND b.id2 in (
+							SELECT rn.id2
+							FROM t1 rn
+							WHERE rn.id1 = '03'
+						)
+				);
+	`)
+}
diff --git a/executor/test/main_test.go b/executor/test/main_test.go
new file mode 100644
index 0000000000000..365c88b4af771
--- /dev/null
+++ b/executor/test/main_test.go
@@ -0,0 +1,30 @@
+// Copyright 2022 PingCAP, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package explain
+
+import (
+	"testing"
+
+	"go.uber.org/goleak"
+)
+
+func TestMain(m *testing.M) {
+	opts := []goleak.Option{
+		goleak.IgnoreTopFunction("github.com/golang/glog.(*loggingT).flushDaemon"),
+		goleak.IgnoreTopFunction("github.com/lestrrat-go/httprc.runFetchWorker"),
+		goleak.IgnoreTopFunction("github.com/tikv/client-go/v2/txnkv/transaction.keepAlive"),
+	}
+	goleak.VerifyTestMain(m, opts...)
+}
diff --git a/planner/core/rule_join_reorder.go b/planner/core/rule_join_reorder.go
index 5bdecb4bfe753..7c25ef91d0063 100644
--- a/planner/core/rule_join_reorder.go
+++ b/planner/core/rule_join_reorder.go
@@ -311,7 +311,8 @@ func (s *joinReOrderSolver) optimizeRecursive(ctx sessionctx.Context, p LogicalP
 			proj := LogicalProjection{
 				Exprs: expression.Column2Exprs(originalSchema.Columns),
 			}.Init(p.SCtx(), p.SelectBlockOffset())
-			proj.SetSchema(originalSchema)
+			// Clone the schema here, because the schema may be changed by column pruning rules.
+			proj.SetSchema(originalSchema.Clone())
 			proj.SetChildren(p)
 			p = proj
 		}