[Python-Dev] 3.5 release schedule PEP

Steve Dower Steve.Dower at microsoft.com
Wed Sep 24 04:14:45 CEST 2014

"This new compiler has the incredibly awesome feature of being forwards compatible
right? Like in 10 years stuff compiled with a newer compiler will still work?"

That's the promise at least :)

All the macros that leaked implementation details (like file descriptors) are now isolated so if they change it won't break existing applications. It'll still be possible for newer compiler versions to break them, but the design now obviously discourages it. There's also an official guarantee, so if it is broken in future it'll be treated as a bug. As much as I'd love to make solid promises, I can only pass on the promises that were made to me.

But yes, we should have forward compatibility with later MSVC versions, which will help avoid the situation where it's hard to get hold of the right compiler...

Top-posted from my Windows Phone
From: Donald Stufft<mailto:donald at stufft.io>
Sent: ‎9/‎23/‎2014 18:50
To: Nick Coghlan<mailto:ncoghlan at gmail.com>
Cc: Steve Dower<mailto:Steve.Dower at microsoft.com>; python-dev at python.org<mailto:python-dev at python.org>
Subject: Re: [Python-Dev] 3.5 release schedule PEP

On Sep 23, 2014, at 9:48 PM, Nick Coghlan <ncoghlan at gmail.com<mailto:ncoghlan at gmail.com>> wrote:

On 24 September 2014 03:05, Steve Dower <Steve.Dower at microsoft.com<mailto:Steve.Dower at microsoft.com>> wrote:
Larry Hastings wrote:

On 09/19/2014 03:31 PM, Barry Warsaw wrote:
I think we need a Python 3.5 Release Schedule PEP.

Just checked it in as PEP 478.  It should show up here in a few minutes:

Key facts:
. Beta 1 is May 24th 2015, about a month after the end of the PyCon US 2015 sprints.
. Final release is September 13, 2015, just over a year from now.


Martin is no longer producing the Windows installers - that task has been handed to me. I'm planning to have a rewritten installer (also in the same repo) that should be easier to modify and maintain, as well as being able to produce alternative packages (such as a Python 3.5 or stdlib merge module, for example), though that doesn't necessarily need to go into the PEP.

I'm also considering/experimenting with installing into "Program Files" by default, but I suspect that isn't going to work out yet.

I'd like to move the Windows versions onto the next release of VC (currently "VC 14" until the branding team figures out what to call it). There isn't a promised RTM date for VC 14 yet, so it looks like the best available compiler by Beta 1 will be a "Go Live" RC. (The "Go Live" marking basically means "we think this is ready for use, but expect a round of minor updates/fixes soon - the compiler is least likely to be updated, my guess is that it'll be Visual Studio UI mostly).

I personally don't have any qualms about using the RC compiler for Beta 1, and Beta 2 will almost certainly use VC 14 RTM, but I know when I proposed this topic that some people were concerned about having the final version available for Python 3.5 Beta.

So far I've been building regularly with internal versions of VC and haven't been hitting any major issues with Python (OpenSSL has some issues, but I've been filing bugs on both sides so they should be worked out soon enough). My work is at http://hg.python.org/sandbox/steve.dower (branch: VC14) for anyone interested.

For the alphas, I'm contemplating producing two builds (VC 10 and VC 14), but I obviously want to settle on one or the other by Beta. Last time we discussed it, there was strong support for changing compiler, but I have a better idea of the timeline now and it's tighter than I thought...

Thoughts, anyone?

It's ultimately up to Larry as RM, but I'd personally favour targeting
the newer compiler and runtime, even with the slight risk of
potentially needing to slip our schedule. There's also a fair amount
of wiggle room between the first beta and the first release candidate.


Nick Coghlan   |   ncoghlan at gmail.com<mailto:ncoghlan at gmail.com>   |   Brisbane, Australia
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This new compiler has the incredibly awesome feature of being forwards compatible
right? Like in 10 years stuff compiled with a newer compiler will still work?

Donald Stufft
PGP: 7C6B 7C5D 5E2B 6356 A926 F04F 6E3C BCE9 3372 DCFA

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