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Subject: Re: Uninstall python 2.7 fails - alternative dependencies
To: cygwin@cygwin.com
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Message-ID: <e98658b6-f2d4-8774-6d65-d2153e86b42a@gmail.com>
Date: Tue, 2 Mar 2021 21:45:55 +0100
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From: Marco Atzeri via Cygwin <cygwin@cygwin.com>
Reply-To: Marco Atzeri <marco.atzeri@gmail.com>
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On 02.03.2021 18:32, Doug Henderson via Cygwin wrote:
> I attempted to remove all packages related to Python 2.7 from my
> cygwin installation.
> 
> I am unable to remove four packages.
> 
> python2
> python27
> python27-pip
> python27-setuptools

Question:
you can not remove because they are cross dependent or because they
are pulled by other packages ?

> There are over 500 packages that require python2 and over 700 packages
> which depend2 on python2.

much less

$ cygcheck-dep -S -q -n python2| wc -w
124

$ cygcheck-dep -S -q -n python27| wc -w
145

and most are python2-* or python27-* packages

> There are also around 90 packages that refer to both python2 and
> python3 packages. I have many of these packages installed. I suspect
> that at least some of these actually require either python2 or
> python3, but do not require both.

are you sure ? May be you are counting different releases ?
Usually they should pull only one version of python.

> To assist in supporting this kind of requirement, is there a way to
> create a package whose requirements are resolved by either of several
> other packages?

Not that I am aware

> For instance, could we have a package e.g. python-alternatives, that
> when required is satisfied by either python2 or python3. This
> mechanism might be useful for dealing with any set of packages that
> work with the alternatives system.
> 
> Thanks for your consideration,
> Doug
> 
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