Merge 'cp_405852314724db75147aea7bee4be0e2bb24a900_cnch-dev' into 'cnch-dev'

fix(clickhousech@m-3000759214):fix json function parse  lc null return value

See merge request: !25198

src/Functions/FunctionsJSON.h

@@ -114,7 +114,7 @@ public:
                 throw Exception{"The first argument of function " + String(Name::name) + " should be a string containing JSON, illegal type: " + first_column.type->getName(),
                                 ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT};
             
-            const ColumnPtr & arg_json = recursiveAssumeNotNullable(first_column.column);
+            const ColumnPtr & arg_json = recursiveAssumeNotNullable(recursiveRemoveLowCardinality(first_column.column));
             const auto * col_json_const = typeid_cast<const ColumnConst *>(arg_json.get());
             const auto * col_json_string
                 = typeid_cast<const ColumnString *>(col_json_const ? col_json_const->getDataColumnPtr().get() : arg_json.get());
@@ -510,9 +510,11 @@ public:
     String getName() const override { return Name::name; }
     bool useDefaultImplementationForNulls() const override { return false; }
     bool useDefaultImplementationForConstants() const override { return true; }
+    // bool useDefaultImplementationForLowCardinalityColumns()  const override { return false; }
 
     ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, size_t input_rows_count) const override
     {
+        NullPresence lc_null_presence = getNullPresense(arguments);
         if (null_presence.has_null_constant)
             return result_type->createColumnConstWithDefaultValue(input_rows_count);
 
@@ -520,6 +522,10 @@ public:
         auto temporary_result = Derived::run(temp_arguments, json_return_type, input_rows_count);
         if (null_presence.has_nullable)
             return wrapInNullable(temporary_result, arguments, result_type, input_rows_count);
+
+        if (lc_null_presence.has_nullable)
+            return wrapInNullable(temporary_result, arguments, result_type, input_rows_count);
+
         return temporary_result;
     }
 
@@ -750,6 +756,7 @@ public:
     bool isVariadic() const override { return true; }
     size_t getNumberOfArguments() const override { return 0; }
     bool useDefaultImplementationForNulls() const override { return false; }
+    // bool useDefaultImplementationForLowCardinalityColumns()  const override { return false; }
 
     FunctionBasePtr build(const ColumnsWithTypeAndName & arguments) const override
     {
@@ -763,6 +770,8 @@ public:
 
         const auto & first_column = arguments[0];
         auto first_type_base = removeNullable(removeLowCardinality(first_column.type));
+        auto first_type_is_lc_null = first_column.type->isLowCardinalityNullable();
+        auto first_type_is_lc = WhichDataType(first_column.type).isLowCardinality();
 
         bool is_string = isString(first_type_base);
         bool is_object = isObject(first_type_base);
@@ -783,6 +792,10 @@ public:
             return_type = makeNullable(std::make_shared<DataTypeNothing>());
         else if (null_presence.has_nullable)
             return_type = makeNullable(json_return_type);
+        else if (first_type_is_lc_null)
+            return_type = std::make_shared<DataTypeLowCardinality>(makeNullable(json_return_type));
+        else if (first_type_is_lc)
+            return_type = std::make_shared<DataTypeLowCardinality>(json_return_type);
         else
             return_type = json_return_type;
 

tests/queries/4_cnch_stateless/12294_function_get_json_object.reference

@@ -6,6 +6,8 @@ abc
 [{"ac":"abc","xz":"xz"},{"def":"def"}]
 100
 100
+\N
+\N
 {"a":"b"}	2017-08-31 18:36:48
 -1	1504193808
 ["a","c"]	1504193808

tests/queries/4_cnch_stateless/12294_function_get_json_object.sql

@@ -8,6 +8,9 @@ SELECT JSONExtractRaw('{"n_s" : [{"ac":"abc","xz":"xz"}, {"def":"def"}], "n_i" :
 select get_json_object('{"a":100}'::Nullable(String), '$.a');
 select get_json_object('{"a":100}'::LowCardinality(Nullable(String)), '$.a');
 
+select get_json_object(null::Nullable(String), '$.a');
+select get_json_object(null::LowCardinality(Nullable(String)), '$.a');
+
 DROP TABLE IF EXISTS test;
 CREATE TABLE test(a Nullable(String)) ENGINE = CnchMergeTree ORDER BY tuple() PARTITION BY tuple();
 SELECT get_json_object('{"test": "test"}', a) FROM test;