Handle dynamic columns in typed paths

src/Columns/ColumnObject.cpp

@@ -1211,6 +1211,16 @@ void ColumnObject::takeDynamicStructureFromSourceColumns(const DB::Columns & sou
         }
         column->takeDynamicStructureFromSourceColumns(dynamic_path_source_columns);
     }
+
+    /// Typed paths also can contain types with dynamic structure.
+    for (auto & [path, column] : typed_paths)
+    {
+        Columns typed_path_source_columns;
+        typed_path_source_columns.reserve(source_columns.size());
+        for (const auto & source_column : source_columns)
+            typed_path_source_columns.push_back(assert_cast<const ColumnObject &>(*source_column).typed_paths.at(path));
+        column->takeDynamicStructureFromSourceColumns(typed_path_source_columns);
+    }
 }
 
 size_t ColumnObject::findPathLowerBoundInSharedData(StringRef path, const ColumnString & shared_data_paths, size_t start, size_t end)

tests/queries/0_stateless/03214_json_typed_dynamic_path.reference

@@ -0,0 +1,4 @@
+{"a":"42"}
+{"a":["1","2","3"]}
+{"a":"42"}
+{"a":["1","2","3"]}

tests/queries/0_stateless/03214_json_typed_dynamic_path.sql

@@ -0,0 +1,17 @@
+-- Tags: no-fasttest
+
+set allow_experimental_json_type = 1;
+drop table if exists test;
+create table test (json JSON(a Dynamic)) engine=MergeTree order by tuple() settings min_rows_for_wide_part=1, min_bytes_for_wide_part=1;
+insert into test select '{"a" : 42}';
+insert into test select '{"a" : [1, 2, 3]}';
+optimize table test;
+select * from test order by toString(json);
+drop table test;
+
+create table test (json JSON(a Dynamic)) engine=MergeTree order by tuple() settings min_rows_for_wide_part=10000000, min_bytes_for_wide_part=10000000;
+insert into test select '{"a" : 42}';
+insert into test select '{"a" : [1, 2, 3]}';
+optimize table test;
+select * from test order by toString(json);
+drop table test;