expression: don't cast collation for in expression is the new collati…

…on is disabled (#52812) (#53054)

close #52772

pkg/planner/core/expression_rewriter.go

@@ -1743,6 +1743,13 @@ func (er *expressionRewriter) castCollationForIn(colLen int, elemCnt int, stkLen
 	if colLen != 1 {
 		return
 	}
+	if !collate.NewCollationEnabled() {
+		// See https://github.com/pingcap/tidb/issues/52772
+		// This function will apply CoercibilityExplicit to the casted expression, but some checks(during ColumnSubstituteImpl) is missed when the new
+		// collation is disabled, then lead to panic.
+		// To work around this issue, we can skip the function, it should be good since the collation is disabled.
+		return
+	}
 	for i := stkLen - elemCnt; i < stkLen; i++ {
 		// todo: consider refining the code and reusing expression.BuildCollationFunction here
 		if er.ctxStack[i].GetType().EvalType() == types.ETString {

tests/integrationtest/r/collation_misc_disabled.result

@@ -125,3 +125,16 @@ insert into t values ("1", "a    ", "a");
 select /*+USE_INDEX(t, idx)*/ * from t;
 id	a	b
 1	a    	a
+drop table if exists t1;
+drop table if exists t2;
+create table t1(code varchar(32)) CHARSET=utf8 COLLATE=utf8_general_ci;
+create table t2(code varchar(32)) CHARSET=utf8 COLLATE=utf8_bin;
+desc format=brief select * from t1 join t2 on t1.code=t2.code and t1.code in ('1') and t2.code in ('1');
+id	estRows	task	access object	operator info
+HashJoin	12.50	root		inner join, equal:[eq(cd_test_utf8mb4_0900_bin.t1.code, cd_test_utf8mb4_0900_bin.t2.code)]
+├─TableReader(Build)	10.00	root		data:Selection
+│ └─Selection	10.00	cop[tikv]		eq(cd_test_utf8mb4_0900_bin.t2.code, "1"), not(isnull(cd_test_utf8mb4_0900_bin.t2.code))
+│   └─TableFullScan	10000.00	cop[tikv]	table:t2	keep order:false, stats:pseudo
+└─TableReader(Probe)	10.00	root		data:Selection
+  └─Selection	10.00	cop[tikv]		eq(cd_test_utf8mb4_0900_bin.t1.code, "1"), not(isnull(cd_test_utf8mb4_0900_bin.t1.code))
+    └─TableFullScan	10000.00	cop[tikv]	table:t1	keep order:false, stats:pseudo

tests/integrationtest/r/collation_misc_enabled.result

@@ -142,3 +142,17 @@ insert into t values ("1", "a    ", "a");
 select /*+USE_INDEX(t, idx)*/ * from t;
 id	a	b
 1	a    	a
+drop table if exists t1;
+drop table if exists t2;
+create table t1(code varchar(32)) CHARSET=utf8 COLLATE=utf8_general_ci;
+create table t2(code varchar(32)) CHARSET=utf8 COLLATE=utf8_bin;
+desc format=brief select * from t1 join t2 on t1.code=t2.code and t1.code in ('1') and t2.code in ('1');
+id	estRows	task	access object	operator info
+Projection	80000.00	root		cd_test_utf8mb4_0900_bin.t1.code, cd_test_utf8mb4_0900_bin.t2.code
+└─HashJoin	80000.00	root		CARTESIAN inner join
+  ├─TableReader(Build)	10.00	root		data:Selection
+  │ └─Selection	10.00	cop[tikv]		eq(cd_test_utf8mb4_0900_bin.t2.code, "1")
+  │   └─TableFullScan	10000.00	cop[tikv]	table:t2	keep order:false, stats:pseudo
+  └─TableReader(Probe)	8000.00	root		data:Selection
+    └─Selection	8000.00	cop[tikv]		eq(cd_test_utf8mb4_0900_bin.t1.code, "1")
+      └─TableFullScan	10000.00	cop[tikv]	table:t1	keep order:false, stats:pseudo

tests/integrationtest/t/collation_misc.test

@@ -89,3 +89,10 @@ use cd_test_utf8mb4_0900_bin;
 create table t (id varchar(255) primary key clustered, a varchar(255) collate utf8mb4_0900_bin, b varchar(255) collate utf8mb4_bin, key idx(a, b));
 insert into t values ("1", "a    ", "a");
 select /*+USE_INDEX(t, idx)*/ * from t;
+
+# issue 52772
+drop table if exists t1;
+drop table if exists t2;
+create table t1(code varchar(32)) CHARSET=utf8 COLLATE=utf8_general_ci;
+create table t2(code varchar(32)) CHARSET=utf8 COLLATE=utf8_bin;
+desc format=brief select * from t1 join t2 on t1.code=t2.code and t1.code in ('1') and t2.code in ('1');