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From: Ricardo Wurmus <rekado@elephly.net>
To: Marius Bakke <mbakke@fastmail.com>
Cc: 22533@debbugs.gnu.org
Subject: bug#22533: Python bytecode reproducibility
Date: Sat, 03 Mar 2018 23:37:29 +0100	[thread overview]
Message-ID: <87606c23bq.fsf@elephly.net> (raw)
In-Reply-To: <87bmqfu44s.fsf@fastmail.com>

Hi Guix,

Marius Bakke <mbakke@fastmail.com> writes:

> It would be great to revive this longstanding bug!

Indeed.

Here’s another attempt.  As far as I understand, the timestamp in the
pyc files only affects the header.

Up until Python 3.6 (incl) the header looks like this:

  magic | timestamp | size

Since Python 3.7 the header may either contain a timestamp or a hash:

  magic | 00000000000000000000000000000000 | timestamp | size
  magic | 00000000000000000000000000000001 | hash      | size

This means we likely won’t have this problem any more with Python 3.7.
For Python 3.6 I guess we could add a final build phase that overwrites
the timestamp in the *binary*.  This needs to happen before any of the
compiled files are wrapped up in a wheel.

Should we just wait for Python 3.7 which is expected to be released in
June 2018?  We’d still have to deal with this problem in Python 2,
though.

Is it a bad idea to override the timestamps in the generated binaries?
I think that we could avoid the recency check then, which was an
obstacle to resetting the timestamps of the source files.

--
Ricardo

GPG: BCA6 89B6 3655 3801 C3C6  2150 197A 5888 235F ACAC
https://elephly.net

  reply	other threads:[~2018-03-03 22:38 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-02  5:15 bug#22533: Non-determinism in python-3 ".pyc" bytecode Leo Famulari
2016-02-02  8:54 ` Leo Famulari
2016-02-02 20:41 ` Ludovic Courtès
2016-02-04 23:17   ` Leo Famulari
2016-03-29 23:11     ` Cyril Roelandt
2016-03-29 23:13     ` Cyril Roelandt
2016-04-06  8:29       ` Ludovic Courtès
2017-05-26 13:41 ` bug#22533: Python bytecode reproducibility Marius Bakke
2018-03-03 22:37   ` Ricardo Wurmus [this message]
2018-03-04  9:21     ` Gábor Boskovits
2018-03-04 12:46       ` Ricardo Wurmus
2018-03-04 15:30         ` Gábor Boskovits
2018-03-04 19:18         ` Ricardo Wurmus
2018-03-05  0:02           ` Ricardo Wurmus
2018-03-05  0:05             ` Ricardo Wurmus
2018-03-05 15:36               ` Gábor Boskovits
2018-03-05 20:33                 ` Gábor Boskovits
2018-03-05 21:46                   ` Ricardo Wurmus
2018-03-05 22:02               ` Ricardo Wurmus
2018-03-05 22:06             ` Ricardo Wurmus
2018-03-05 23:21           ` Marius Bakke
2018-03-06 13:28             ` Ricardo Wurmus
2018-03-06 14:43               ` Ricardo Wurmus
2018-03-06 14:57                 ` Gábor Boskovits
2018-03-08 10:39           ` Gábor Boskovits
2019-01-14 13:40             ` Ricardo Wurmus
2019-02-03 21:22               ` Ricardo Wurmus
2019-02-04 22:39                 ` Ludovic Courtès
2018-03-05  9:25     ` Ludovic Courtès

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