[CP] regexp use const pattern uncorrectly in non-static engine

src/sql/code_generator/ob_expr_generator_impl.cpp

@@ -597,7 +597,9 @@ inline int ObExprGeneratorImpl::visit_regex_expr(ObOpRawExpr& expr, ObExprRegexp
     } else {
       // The value && pattern are const, it is calculated in pre_calculate
       regexp_op->set_value_is_const(value_expr->has_flag(IS_CONST) || value_expr->has_flag(IS_CONST_EXPR));
-      regexp_op->set_pattern_is_const(pattern_expr->has_flag(IS_CONST) || pattern_expr->has_flag(IS_CONST_EXPR));
+      if (!pattern_expr->has_flag(CNT_EXEC_PARAM)) {
+        regexp_op->set_pattern_is_const(pattern_expr->has_flag(IS_CONST) || pattern_expr->has_flag(IS_CONST_EXPR));
+      }
     }
   }
   return ret;

tools/deploy/mysql_test/test_suite/expr/r/mysql/func_regexp.result

@@ -6287,3 +6287,18 @@ insert into t values ('');
 select c1 regexp 'ddd' from t;
 c1 regexp 'ddd'
 0
+drop table if exists t1, t2;
+create table t1(c1 int, c2 varchar(10));
+insert into t1 values(1, '1');
+create table t2(c1 int);
+insert into t2 values(1), (2);
+select t2.*, (select t1.c1 from t1 where t1.c2 REGEXP t2.c1 limit 1 ) from t2;
+c1	(select t1.c1 from t1 where t1.c2 REGEXP t2.c1 limit 1 )
+1	1
+2	NULL
+select t2.*, (select t1.c1 from t1 where t1.c2 REGEXP t2.c1+1-1 limit 1 ) from t2;
+c1	(select t1.c1 from t1 where t1.c2 REGEXP t2.c1+1-1 limit 1 )
+1	1
+2	NULL
+drop table t1;
+drop table t2;

tools/deploy/mysql_test/test_suite/expr/t/func_regexp.test

@@ -442,3 +442,20 @@ drop table if exists t;
 create table t (c1 char(20));
 insert into t values ('');
 select c1 regexp 'ddd' from t;
+
+##bug:https://work.aone.alibaba-inc.com/issue/43976234
+
+--disable_warnings
+drop table if exists t1, t2;
+--enable_warnings
+
+create table t1(c1 int, c2 varchar(10));
+insert into t1 values(1, '1');
+create table t2(c1 int);
+insert into t2 values(1), (2);
+
+select t2.*, (select t1.c1 from t1 where t1.c2 REGEXP t2.c1 limit 1 ) from t2;
+select t2.*, (select t1.c1 from t1 where t1.c2 REGEXP t2.c1+1-1 limit 1 ) from t2;
+
+drop table t1;
+drop table t2;
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