expression: don't cast collation for in expression is the new collation is disabled (#52812)

pkg/planner/core/expression_rewriter.go

@@ -1751,6 +1751,13 @@ 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');