Created attachment 1149106 [details]
original of the error messages

Description of problem:
DNF shows error message when there is some problem while resolving the dependencies for installed packages. When the command is invoked with multiple packages and there is an issue with resolving dependencies, the latest command argument is marked as the one that caused the problem even if that is not the case. Together with the fact, that dnf only reports one direct dependency as unable to install, this leads to completely useless error message.

Detailed description at the end of the report. The issue was found on a system that has had lingering package from updates-testing while installing with updates-testing disabled. I will use this case to provide a reproducer.

Version-Release number of selected component (if applicable):
dnf-1.1.8-1.fc23.noarch

How reproducible:
always

Steps to Reproduce:
1. Have a system or repository in a state that causes problem in a dependency chain of one of the installed packages
2. Install this package as one of multiple packages in one command (not the last one)
3. Error message blames wrong package

Actual results:
The package that was passed as the last command line argument is blamed.

Expected results:
The correct package is reported as the one introducing the problem


Additional info:
Runs of commands I used. I will comment inside:

[root@vm-161 ~]# dnf install freeipa-server-dns freeipa-server-trust-ad python-ipatests
Last metadata expiration check: 0:03:31 ago on Wed Apr 20 14:24:04 2016.
Error: package python2-ipatests-4.3.90-20160420120628Zjenkins1git0e1cceb.fc23.noarch requires python2-ipalib = 4.3.90-20160420120628Zjenkins1git0e1cceb.fc23, but none of the providers can be installed
(try to add '--allowerasing' to command line to replace conflicting packages)

### python-ipatests is blamed here, in next command, the dependencies are resolved

[root@vm-161 ~]# dnf install python-ipatests
Last metadata expiration check: 0:03:45 ago on Wed Apr 20 14:24:04 2016.
Dependencies resolved.
===============================================================================================================================================================================================
 Package                                      Arch                          Version                                                                 Repository                            Size
===============================================================================================================================================================================================
Installing:
 freeipa-client-common                        noarch                        4.3.90-20160420120628Zjenkins1git0e1cceb.fc23                           freeipa-local                         29 k
 freeipa-common                               noarch                        4.3.90-20160420120628Zjenkins1git0e1cceb.fc23                           freeipa-local                        288 k
 keyutils                                     x86_64                        1.5.9-7.fc23                                                            fedora                                60 k
 ldns                                         x86_64                        1.6.17-16.fc23                                                          fedora                               151 k
 ldns-utils                                   x86_64                        1.6.17-16.fc23                                                          fedora                               187 k
 python-coverage                              x86_64                        4.0.3-1.fc23                                                            updates                              224 k
 python-nose                                  noarch                        1.3.7-4.fc23                                                            fedora                               280 k
 python-paste                                 noarch                        1.7.5.1-12.20111221hg1498.fc23                                          fedora                               871 k
 python-tempita                               noarch                        0.5.1-9.fc23                                                            fedora                                37 k
 python2-ipalib                               noarch                        4.3.90-20160420120628Zjenkins1git0e1cceb.fc23                           freeipa-local                        1.1 M
 python2-ipatests                             noarch                        4.3.90-20160420120628Zjenkins1git0e1cceb.fc23                           freeipa-local                        783 k

Transaction Summary
===============================================================================================================================================================================================
Install  11 Packages

Total size: 3.9 M
Total download size: 1.8 M
Installed size: 19 M
Is this ok [y/N]: 
Operation aborted.

[root@vm-161 ~]# dnf install freeipa-server-dns freeipa-server-trust-ad python-ipatests
Last metadata expiration check: 0:17:51 ago on Wed Apr 20 14:24:04 2016.
Error: package python2-ipatests-4.3.90-20160420120628Zjenkins1git0e1cceb.fc23.noarch requires python2-ipalib = 4.3.90-20160420120628Zjenkins1git0e1cceb.fc23, but none of the providers can be installed
(try to add '--allowerasing' to command line to replace conflicting packages)

[root@vm-161 ~]# dnf install freeipa-server-dns freeipa-server-trust-ad
Last metadata expiration check: 0:18:12 ago on Wed Apr 20 14:24:04 2016.
Error: package freeipa-server-trust-ad-4.2.4-1.fc23.x86_64 requires freeipa-server = 4.2.4-1.fc23, but none of the providers can be installed
(try to add '--allowerasing' to command line to replace conflicting packages)

### Again, the latest argument is blamed

[root@vm-161 ~]# dnf install freeipa-server-dns
Last metadata expiration check: 0:18:21 ago on Wed Apr 20 14:24:04 2016.
Error: package freeipa-server-dns-4.2.4-1.fc23.x86_64 requires freeipa-server = 4.2.4-1.fc23, but none of the providers can be installed
(try to add '--allowerasing' to command line to replace conflicting packages)

[root@vm-161 ~]# dnf install freeipa-server
Last metadata expiration check: 0:18:28 ago on Wed Apr 20 14:24:04 2016.
Error: package freeipa-server-4.2.2-1.fc23.x86_64 requires pki-kra >= 10.2.6, but none of the providers can be installed
(try to add '--allowerasing' to command line to replace conflicting packages)

[root@vm-161 ~]# dnf install pki-kra
Last metadata expiration check: 0:18:57 ago on Wed Apr 20 14:24:04 2016.
Error: package pki-kra-10.2.6-16.fc23.noarch requires pki-server = 10.2.6-16.fc23, but none of the providers can be installed
(try to add '--allowerasing' to command line to replace conflicting packages)

[root@vm-161 ~]# dnf install pki-server
Last metadata expiration check: 0:19:06 ago on Wed Apr 20 14:24:04 2016.
Error: package pki-server-10.2.6-7.fc23.noarch requires pki-base = 10.2.6-7.fc23, but none of the providers can be installed
(try to add '--allowerasing' to command line to replace conflicting packages)

### Here pki-base is identified as the real origin of the issue

[root@vm-161 ~]# dnf install pki-base
Last metadata expiration check: 0:19:16 ago on Wed Apr 20 14:24:04 2016.
Package pki-base-10.2.6-18.fc23.noarch is already installed, skipping.
Dependencies resolved.
Nothing to do.
Complete!