[Python-Dev] PEP 397 (Python launcher for Windows) reference implementation

[Paul Moore]

On 5 July 2011 03:26, Nick Coghlan <ncoghlan at gmail.com> wrote:
> On Tue, Jul 5, 2011 at 12:12 PM, Mark Hammond <skippy.hammond at gmail.com> wrote:
>> If the launcher is such that we can unconditionally recommend its use, IMO
>> we should just install it with Python.  I'll go with the consensus though...
>
> I've installed other WIndows apps that create multiple add/remove
> programs entries from a single installer. I believe people are
> suggesting a similar thing here (i.e. have the launcher installed
> automatically when installing python, but create a separate add/remove
> entry so uninstallation leaves it behind unless removal is explicitly
> requested)

That's certainly what I was meaning.

I'm 100% in favour of Python 3.3 and later containing the installer as
part of the core Python installer. One download, one install. (And two
add/remove entries).

I'd like to see a standalone installer for users of Python 2.7/3.2 and
earlier. It's too useful a feature to not make it available for people
who haven't installed 3.3 yet. And I'd prefer it if that standalone
installer was hosted on python.org for visibility, rather than on
PyPI.

I'm not enough of an MSI expert to know if this can be implemented by
having a standalone MSI, and then "embedding" it in the Python 3.3
MSI. That was what I'd thought of, but Vinay's later email suggests it
might not be advisable:

> AFAICT, although you can embed an MSI inside another one, the practice
> of concurrent/nested installations is strongly discouraged by Microsoft -
> see http://goo.gl/FJx1S (Rule 20).
[...]
> So you could package Python and the launcher as separate MSIs (this would
> make sense so that you could restore associations to the launcher just by
> repairing its installation), but since nested MSIs are a no-no, that means
> installing via a bootstrapping .exe. This is a bigger change to our Windows
> packaging than some people might be comfortable with ...

Paul.