I found 2 problems on remove python2-foo packages

[Sérgio Basto]

Hi, 
These removed python2 packages are breaking upgrade path 

1- when you remove python2-foo , you should add to main package
Obsoletes: python2-foo 

2- IMHO you should just remove python2-foo only on latest branches,
please don't forget epel7 case, so please add something like : 
%if 0%{?fedora} >= 30 
%endif 

Thanks,
-- 
Sérgio M. B.

[Nico Kadel-Garcia]

On Mon, Jun 3, 2019 at 10:51 AM Sérgio Basto <sergio(a)serjux.com&gt; wrote:
>  Hi,
>  These removed python2 packages are breaking upgrade path
>
>  1- when you remove python2-foo , you should add to main package
>  Obsoletes: python2-foo 
If I may suggest, *absolutely not*. "Obsoletes: python2-foo"
specifically means that it includes and provides "python2-foo"
functionality, and "python3-foo" packages *do not* provide this. There
are a very few tools that put things in "/usr/bin" for typical use,
such as the "rpm" package itself which might benefit from such
options. But I think it's quite dangerous to replace them willy-nilly
due to compatibility for old packages which would have their
requirements replaced with something quite incompatible without
notification.

>  2- IMHO you should just remove python2-foo only on latest branches,
>  please don't forget epel7 case, so please add something like :
>  %if 0%{?fedora} >= 30
>  %endif 
Much too late for this release, I think. And dangerous for third party
python modules that have not been upgraded to python3 to break them
without notice. I think it would be much safer, if desired to force
migration, to use this:

    %global pypi_name foo

    %if 0%{?fedora} >= 30 || 0%{?rhel} >= 8
    Conflicts: python2-%{pypi_name} >= %{verson}-%{release}
    %endif

This would avoid touching older versions of the python2-foo modules
for compatibility with old packages, and block ongoing updates until
the older modules can be replaced. There are a potential few conflicts
that drop binaries in "/usr/bin/foo", tools such as "awscli". Those
might need review on a case by case basis, but they often have a
package without "python2-" in the name, and don't face the same
"python2/python3-" package split issue.

Does this make sense to you

[Sérgio Basto]

On Tue, 2019-06-04 at 03:25 -0400, Nico Kadel-Garcia wrote:
>  If I may suggest, *absolutely not*. "Obsoletes:
> python2-foo"
>  specifically means that it includes and provides "python2-foo"
>  functionality, 
No , on update just force remove of python2-foo , doesn't provide it .
instead dnf broken dep, python2-foo requires foo=n when foo=n+1 .

I remembered and as Leigh wrote : "The python2-foo removed packages be
added to the fedora-obsoletes package." 

but not all python2-foo packages are in fedora-obsoletes and we also
may not install fedora-obsoletes package ...

Best regards,
-- 
Sérgio M. B.

[Neal Gompa]

On Tue, Jun 4, 2019 at 3:26 AM Nico Kadel-Garcia <nkadel(a)gmail.com&gt; wrote:
>  On Mon, Jun 3, 2019 at 10:51 AM Sérgio Basto <sergio(a)serjux.com&gt; wrote:
>  >
>  > Hi,
>  > These removed python2 packages are breaking upgrade path
>  >
>  > 1- when you remove python2-foo , you should add to main package
>  > Obsoletes: python2-foo
>
>  If I may suggest, *absolutely not*. "Obsoletes: python2-foo"
>  specifically means that it includes and provides "python2-foo"
>  functionality, and "python3-foo" packages *do not* provide this. There
>  are a very few tools that put things in "/usr/bin" for typical use,
>  such as the "rpm" package itself which might benefit from such
>  options. But I think it's quite dangerous to replace them willy-nilly
>  due to compatibility for old packages which would have their
>  requirements replaced with something quite incompatible without
>  notification.
>  
I think you misunderstand here. Obsoletes does not specifically
indicate it is equivalent. It is saying that you're replacing it. You
will still get a broken dep chain if something Requires something that
was obsoleted.

It is absolutely the correct strategy to do Obsoletes (without Provides) here.

-- 
真実はいつも一つ！/ Always, there's only one truth!

[Nico Kadel-Garcia]

On Tue, Jun 4, 2019 at 7:57 AM Neal Gompa <ngompa13(a)gmail.com&gt; wrote:
>  On Tue, Jun 4, 2019 at 3:26 AM Nico Kadel-Garcia <nkadel(a)gmail.com&gt; wrote:
>  >
>  > On Mon, Jun 3, 2019 at 10:51 AM Sérgio Basto <sergio(a)serjux.com&gt; wrote:
>  > >
>  > > Hi,
>  > > These removed python2 packages are breaking upgrade path
>  > >
>  > > 1- when you remove python2-foo , you should add to main package
>  > > Obsoletes: python2-foo
>  >
>  > If I may suggest, *absolutely not*. "Obsoletes: python2-foo"
>  > specifically means that it includes and provides "python2-foo"
>  > functionality, and "python3-foo" packages *do not* provide this. There
>  > are a very few tools that put things in "/usr/bin" for typical use,
>  > such as the "rpm" package itself which might benefit from such
>  > options. But I think it's quite dangerous to replace them willy-nilly
>  > due to compatibility for old packages which would have their
>  > requirements replaced with something quite incompatible without
>  > notification.
>  >
>
>  I think you misunderstand here. Obsoletes does not specifically
>  indicate it is equivalent. It is saying that you're replacing it. You
>  will still get a broken dep chain if something Requires something that
>  was obsoleted.
>
>  It is absolutely the correct strategy to do Obsoletes (without Provides) here. 
I double checked and see your point. I still think it's dangerous due
to undetected dependency chains, but not as dangerous as I thought.

[Leigh Scott]

The python2-foo removed packages be added to the fedora-obsoletes package.