MDEV-22837 JSON_ARRAYAGG and JSON_OBJECTAGG treat JSON arguments as text.

Item_field::is_json_value() implemented.

mysql-test/main/func_json.result

@@ -1320,6 +1320,13 @@ Warnings:
 Warning	1260	Row 1 was cut by JSON_ARRAYAGG()
 drop table t1;
 SET group_concat_max_len= default;
+create table t1 (col1 json);
+insert into t1 values('{"color":"red", "size":1}' );
+insert into t1 values('{"color":"blue", "size":2}' );
+select JSON_ARRAYAGG(col1) from t1;
+JSON_ARRAYAGG(col1)
+[{"color":"red", "size":1},{"color":"blue", "size":2}]
+drop table t1;
 #
 # End of 10.5 tests
 #

mysql-test/main/func_json.test

@@ -820,6 +820,12 @@ select json_arrayagg(a) from t1;
 drop table t1;
 SET group_concat_max_len= default;
 
+create table t1 (col1 json);
+insert into t1 values('{"color":"red", "size":1}' );
+insert into t1 values('{"color":"blue", "size":2}' );
+select JSON_ARRAYAGG(col1) from t1;
+drop table t1;
+
 --echo #
 --echo # End of 10.5 tests
 --echo #

sql/item.cc

@@ -3052,6 +3052,17 @@ Item_field::Item_field(THD *thd, Item_field *item)
 }
 
 
+bool Item_field::is_json_type()
+{
+  if (!field->check_constraint ||
+      field->check_constraint->expr->type() != FUNC_ITEM)
+    return FALSE;
+
+  Item_func *f= (Item_func *) field->check_constraint->expr;
+  return f->functype() == Item_func::JSON_VALID_FUNC;
+}
+
+
 void Item_field::set_field(Field *field_par)
 {
   field=result_field=field_par;			// for easy coding with fields

sql/item.h

@@ -3389,6 +3389,7 @@ class Item_field :public Item_ident,
   my_decimal *val_decimal_result(my_decimal *);
   bool val_bool_result();
   bool is_null_result();
+  bool is_json_type();
   bool send(Protocol *protocol, st_value *buffer);
   Load_data_outvar *get_load_data_outvar()
   {

sql/item_func.h

@@ -76,7 +76,7 @@ class Item_func :public Item_func_or_sum,
                   SUSERVAR_FUNC, GUSERVAR_FUNC, COLLATE_FUNC,
                   EXTRACT_FUNC, CHAR_TYPECAST_FUNC, FUNC_SP, UDF_FUNC,
                   NEG_FUNC, GSYSVAR_FUNC, IN_OPTIMIZER_FUNC, DYNCOL_FUNC,
-                  JSON_EXTRACT_FUNC,
+                  JSON_EXTRACT_FUNC, JSON_VALID_FUNC,
                   CASE_SEARCHED_FUNC, // Used by ColumnStore/Spider
                   CASE_SIMPLE_FUNC    // Used by ColumnStore/spider
                 };

sql/item_jsonfunc.h

@@ -91,6 +91,7 @@ class Item_func_json_valid: public Item_bool_func
   }
   Item *get_copy(THD *thd)
   { return get_item_copy<Item_func_json_valid>(thd, this); }
+  enum Functype functype() const   { return JSON_VALID_FUNC; }
 };