5 ms·

defer (/using/with) all require the programmer to remember, and write, O(use site) times, the code to release the resource. RAII destructors, on the other hand

defer (/using/with) all require the programmer to remember, and write, O(use site) times, the code to release the resource. RAII destructors, on the other hand, do not permit the coder (at the use site of the type) to forget, as the destructor is invoked automatically when the variable goes out of scope. In my time reviewing Python (also GC, "with" provides a similar functionality), this is a very common error.

pjmlp 5y ago
Apparently you missed my go vet reference on purpose, just make all of us aware of it not being the same. Same applies to using on .NET, where forgetting to call using on an IDisposable type can trigger a compiler error, via Roslyn plugins. Also seem to be unaware how closure based RAII works on FP languages. RAII isn't triggered on heap allocated objects unless smart pointers are used everywhere. Python doesn't have a static analysis tool for with, nor does it support value types with stack allocation. Not all GC languages were born equal.
- nemetroid 5y ago
  > RAII isn't triggered on heap allocated objects unless smart pointers are used everywhere. It's triggered unless you have memory leaks.
  - pjmlp 5y ago
    So it isn't.
    - nemetroid 5y ago
      Correct, but except in very special cases, memory leaks are themselves considered bugs. Using memory leaks as an example of RAII not always working is, in my mind, similar to saying Rust doesn't prevent memory errors since it has the "unsafe" keyword.
      - pjmlp 5y ago
        Except when using system code you might have to pack pointers in OS IPC structures which don't map into smart pointers. Similar to forgetting memory in Rust, and then there is no miracle RAII.
        nemetroid 5y ago
        Yes, if you're not using RAII, RAII doesn't work.