Bug 1394125

Summary:	dnf output makes it impossible to figure out what's causing a dependency issue with obsoleted packages
Product:	[Fedora] Fedora	Reporter:	Adam Williamson <awilliam>
Component:	dnf	Assignee:	rpm-software-management
Status:	CLOSED NOTABUG	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	high	Docs Contact:
Priority:	unspecified
Version:	24	CC:	mluscon, packaging-team-maint, pnemade, rpm-software-management, vmukhame
Target Milestone:	---
Target Release:	---
Hardware:	x86_64
OS:	Linux
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Fixed In Version:		Doc Type:	If docs needed, set a value
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Last Closed:	2016-11-11 07:45:32 UTC	Type:	Bug
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Description Adam Williamson 2016-11-11 06:24:01 UTC

Trying to upgrade my F24 laptop to F25, I get this *really helpful* output:

[root@xps13 adamw]# dnf system-upgrade download --releasever=25 --best --allowerasing
Private side repo                                                                     100 kB/s | 257  B     00:00    
Failed to synchronize cache for repo 'rpmfusion-free-updates', disabling.
Failed to synchronize cache for repo 'rpmfusion-nonfree-updates', disabling.
Error: package ghc-nats-0.2-3.fc24.x86_64 requires libHSarray-0.5.0.0-ghc7.8.4.so()(64bit), but none of the providers can be installed.
package rpm-python3-4.13.0-1.fc24.x86_64 requires rpm = 4.13.0-1.fc24, but none of the providers can be installed.
package rpm-python-4.13.0-1.fc24.x86_64 requires rpm = 4.13.0-1.fc24, but none of the providers can be installed

This tells me exactly nothing useful, because the real question is 'why does dnf think I still need rpm-python3 and rpm-python instead of the python2-rpm and python3-rpm packages that obsolete / provide them'?

But it doesn't tell me and I'm reduced to playing 'dnf remove bingo' to try and figure it out.

Comment 1 Adam Williamson 2016-11-11 07:45:32 UTC

hah, well, turns out it's relatively simple: the rpm I have installed on f24 is actually a higher NEVR than f25's rpm-python2 / rpm-python3 have obsoletes for...

hmm, not sure the error message could be much better in this situation, really.

Comment 2 Igor Gnatenko 2016-11-11 07:47:20 UTC

(In reply to Adam Williamson from comment #1)
> hah, well, turns out it's relatively simple: the rpm I have installed on f24
> is actually a higher NEVR than f25's rpm-python2 / rpm-python3 have
> obsoletes for...
> 
> hmm, not sure the error message could be much better in this situation,
> really.

in DNF 2.0 this is done.