remove_nullable can be called on const column

Author: starocean999

be/src/vec/columns/column_const.h

@@ -185,7 +185,7 @@ class ColumnConst final : public COWHelper<IColumn, ColumnConst> {
         return false;
     }
 
-    bool is_nullable() const override { return data->is_nullable(); }
+    //    bool is_nullable() const override { return is_column_nullable(*data); }
     bool only_null() const override { return data->is_null_at(0); }
     bool is_numeric() const override { return data->is_numeric(); }
     bool is_fixed_and_contiguous() const override { return data->is_fixed_and_contiguous(); }

be/src/vec/exec/join/vhash_join_node.cpp

@@ -1175,7 +1175,7 @@ void HashJoinNode::_prepare_probe_block() {
     // remove add nullmap of probe columns
     for (auto index : _probe_column_convert_to_null) {
         auto& column_type = _probe_block.safe_get_by_position(index);
-        DCHECK(column_type.column->is_nullable());
+        DCHECK(column_type.column->is_nullable() || is_column_const(*(column_type.column.get())));
         DCHECK(column_type.type->is_nullable());
 
         column_type.column = remove_nullable(column_type.column);