[issue33081] multiprocessing Queue leaks a file descriptor associated with the pipe writer

[Henrique Andrade]

Henrique Andrade <hcma at unscrambl.com> added the comment:

Your comparison is not correct.

RAII in C++ ensures that, on object destruction, resources that have been
acquired will be closed and deallocated.

The closest analogy in Python is the use of a context manager, which, btw,
a Queue does not provide.

Indeed, such a design (with a context manager) would have been cleaner
because, on exit, both pipes would have been closed and file descriptors
would not hang around.

And, yes, that is what I'd prefer too - but one can't have everything. :)

With the current design, which is more akin to Java, one is exposed to the
vagaries of the garbage collector. Note that, even in Java,
try-with-resources and the auto-closeable interface would also take care of
this. In fact, most the Java classes that require external resources have
migrated to this model.

For these reasons, I think the design could be substantially improved
(i.e., with a context manager or with the provision of a method that really
terminates the queue, so resources are properly closed immediately).

On Sun, Mar 18, 2018 at 1:12 PM, Pablo Galindo Salgado <
report at bugs.python.org> wrote:

>
> Pablo Galindo Salgado <pablogsal at gmail.com> added the comment:
>
> >"I want to terminate the queue and make sure that no resources are leaked.
>
> Then you don't need to do anything special, those will be cleared on
> object destruction. This is not an unusual pattern even in other languages.
> For example, RAII in C++ is one of the most used patterns for acquiring
> resources and that works cleaning those resources on object destruction.
>
> ----------
>
> _______________________________________
> Python tracker <report at bugs.python.org>
> <https://bugs.python.org/issue33081>
> _______________________________________
>

-- 

Henrique Andrade | +1-530-426-2123 | hcma at unscrambl.com |
https://unscrambl.com

----------

_______________________________________
Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue33081>
_______________________________________