Re: [gentoo-user] update fails, but I don't see why [PROGRESS]

[n952162 <n952162@web.de>]

On 12/30/20 9:35 AM, Arve Barsnes wrote:
> On Wed, 30 Dec 2020 at 08:46, n952162 <n952162@web.de> wrote:
>> Well, yes, the current version, indeed requires python3_8.  The version
>> that was installed on my system, however, to be updated, listed
>> python3_7 in the PYTHON_TARGETS section.  That was the only difference
>> between the two packages in the collision.  It apparently disqualified
>> the update with a slot conflict.
> I tried walking you through the massive output from portage on one of
> these conflicts last week, was it helpful? The point either way, was
> that the slot conflict is not setuptools itself, but further down the
> dependency chain, where some package is unable to update to python
> 3.8, and it's dragging its dependencies back with it.
>
> Regards,
> Arve
>

I spent hours studying your analysis, and then I thought it was a simple
transitive-closure problem.  I wrote a script that would take an emerge
log  and turn it into vectors and do a TC on those, but it didn't work. 
For one thing, I got tangled up in the issue of whether the "scheduled
for merge" or the "installed" section was relevant.  Then I noticed that
in most (but not all) cases, the problem centered around a single
package that had multiple, slightly different (mostly in the
PYTHON_TARGETS variable) specs. At first, I thought that there was
always just one such conflict package, all the other having a single new
depender, rather than multiple.  But I think now, that was a red herring.

In your analysis, I didn't see that you made a distinction between
"scheduled for emerge" and "installed" dependers.  When using all
potential dependers, I just wasn't able to following any chain to a
useful conclusion.  Perhaps it's there and just requires more thought.

Anyway, my blanket --depclean kind of put a stop to that direction.