Description of problem:

DNF is annoyingly broken in terms of reuse of already downloaded packages -
i.e. today my rawhide upgrade:

# dnf upgrade
....
Delta RPMs reduced 905.0 MB of updates to 617.4 MB (31.1% saved)
Running transaction check
Transaction check succeeded.
Running transaction test
Error: Transaction check error:
  file /usr/include/phonon/Phonon from install of phonon-devel-4.8.3-4.fc23.x86_64 conflicts with file from package phonon-devel-4.8.3-2.fc23.x86_64

Error Summary
-------------

So executing again:

# dnf upgrade --exclude phonon*
Last metadata expiration check performed 0:25:32 ago on Thu May 21 13:57:56 2015.
Dependencies resolved.
...
[DRPM] dialog-1.2-13.20150225.fc23_1.2-14.20150513.fc23.x86_64.drpm: done                                                              
[DRPM] control-center-3.16.1-1.fc23_3.16.2-1.fc23.x86_64.drpm: done                                                                    
stax2-api-3.1.4-2.fc23.noarch: Checksum of the delta-rebuilt RPM failed
thunderbird-31.6.0-1.fc22.x86_64: Delta RPM rebuild failed
(1/2): stax2-api-3.1.4-2.fc23.noarch.rpm                                                                559 kB/s | 155 kB     00:00    
(2/2): thunderbird-31.6.0-1.fc22.x86_64.rpm                                                             1.5 MB/s |  52 MB     00:35    
----------------------------------------------------------------------------------------------------------------------------------------
Total                                                                                                   932 kB/s | 606 MB     11:05     
Delta RPMs reduced 904.7 MB of updates to 617.1 MB (31.1% saved)
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
  Upgrading   : glibc-common-2.21.90-13.fc23.x86_64            
....


So my Internet connection wasted ~600MB!

And it happens very often with dnf - I guess whevener I rerun dnf with different option all already downloaded (and DRPM rebuilded) packages gets lots??

Maybe this issue is dup of  bug  1218415  ?
But yum surely was not losing downloaded and not installed packages so easily.
So as dnf pretends to be yum replacement - it should be at least as good as yum here.

Version-Release number of selected component (if applicable):
dnf-1.0.0-1.fc23.noarch

How reproducible:


Steps to Reproduce:
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Actual results:


Expected results:


Additional info: