[issue15368] bytecode generation is not deterministic

[Meador Inge]

Meador Inge <meadori at gmail.com> added the comment:

On Mon, Jul 16, 2012 at 8:11 AM, Brett Cannon <report at bugs.python.org> wrote:

> I might come to regret asking this, but so what? Is this actually causing you issues,
> or are you literally just finding "this behavior surprising" and that's it?

I noticed it in the context of working on issue15352.  There are still
a few issue in the
build system where 'importlib.h' isn't regenerated when it needs to be
(e.g. when
the marshaling code is changed).  When investigating that issue I noticed that
trivial changes (e.g. `touch _bootstrap.py`) can cause differences in
'importlib.h'.
Those differences are mainly due to the cell and free var indexes being
reordered.

Since the bytecode generation isn't deterministic, there can be some noisy diffs
in your working copy when mucking around with the files related to the frozen
importlib.  Thus if we ever wanted to just always generate importlib.h because
we can't be sure which changed source files should cause importlib.h to be
regenerated, then the non-determinism would be a real annoyance.

That is the only concrete issue I currently am aware of.  This issue may not
actually be worth addressing, but I felt it was worthy of discussion.

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue15368>
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