Feature or enhancement

Proposal:

Currently, the multiprocessing.heap module validates requested memory sizes in two different places:

• Heap.malloc()
• BufferWrapper.__init__()

Both duplicate the same logic:

if size < 0:
    raise ValueError("Size {0:n} out of range".format(size))
if sys.maxsize <= size:
    raise OverflowError("Size {0:n} too large".format(size))

Proposed Change

Move this logic into a private static method (Heap._validate_size).

Benefits

• Removes duplication and ensures consistency.
• Improves maintainability (future changes affect only one place).
• Binds sys.maxsize at definition time (_maxsize=sys.maxsize) to avoid repeated global lookups.

Impact

• No behavior changes. This change does not alter functionality or the external API of multiprocessing. It only removes duplication and ensures future modifications to size validation remain consistent.
• Existing multiprocessing tests already cover these code paths.

Has this already been discussed elsewhere?

This is a minor feature, which does not need previous discussion elsewhere

Links to previous discussion of this feature:

No response

Linked PRs

• gh-137928: Centralize size validation in multiprocessing.heap #137929