DRAFT: MCOL-6432 Fix ASan-detected memory leaks on the ColumnStore DDL path

[mariadb-VasilyKozhukhovskiy]

No description provided.

[gemini-code-assist]

Code Review

This pull request updates dbcon/mysql/ha_mcs_ddl.cpp to use modern C++ memory management. Specifically, it replaces a raw pointer rowgroup::RowGroup* with a std::unique_ptr<rowgroup::RowGroup> and utilizes std::make_unique for instantiation, ensuring safer memory handling. There are no review comments, and we have no additional feedback to provide.

[mariadb-VasilyKozhukhovskiy]

/gemini review

[gemini-code-assist]

Code Review

This pull request improves memory management by cleaning up allocated members in the AtaRenameColumn destructor and replacing a raw pointer with std::unique_ptr in ha_mcs_ddl.cpp. The review feedback suggests utilizing a range-based for loop in the destructor of AtaRenameColumn for cleaner C++ code, and wrapping constraint_list in a std::unique_ptr to guarantee exception safety during assignment.

[gemini-code-assist]

Using a range-based for loop instead of an explicit iterator makes the code more concise, readable, and idiomatic in modern C++.

  for (auto* constraint : fConstraints)
  {
    delete constraint;
  }

[gemini-code-assist]

If fConstraints = *constraint_list; throws an exception (such as std::bad_alloc during container copy), the delete constraint_list; statement will be bypassed, resulting in a memory leak of the constraint_list container. Wrapping the raw pointer in a std::unique_ptr immediately ensures exception-safe cleanup.

    {
      std::unique_ptr<ColumnConstraintList> auto_delete(constraint_list);
      fConstraints = *auto_delete;
    }