I've been trying to debug a dnfdragora crash:

https://bugzilla.redhat.com/show_bug.cgi?id=1624652

If I got it right, what's basically going on is that a transaction progress callback is using 'action' values that aren't defined in the callback API. The callback API includes these package actions:

PKG_DOWNGRADE = dnf.transaction.PKG_DOWNGRADE  # :api
PKG_INSTALL = dnf.transaction.PKG_INSTALL  # :api
PKG_OBSOLETE = dnf.transaction.PKG_OBSOLETE  # :api
PKG_REINSTALL = dnf.transaction.PKG_REINSTALL  # :api
PKG_REMOVE = dnf.transaction.PKG_ERASE  # :api
PKG_UPGRADE = dnf.transaction.PKG_UPGRADE  # :api

PKG_CLEANUP = dnf.transaction.PKG_CLEANUP  # :api
PKG_VERIFY = dnf.transaction.PKG_VERIFY  # :api
PKG_SCRIPTLET = dnf.transaction.PKG_SCRIPTLET  # :api

the values for those are, respectively:

2
1
4
9
8
6
101
102
103

but in the traceback of the dnfdragora bug, we catch the value '7' showing up for the action:

Local variables in innermost frame:
self: <dnfdragora.dnf_backend.DnfRootBackend object at 0x7fda65f7f320>
package: 'texlive-xetex,7,20180414,19.fc29,x86_64,@System'
action: 7
te_current: 0
te_total: 28
ts_current: 119
ts_total: 232
num: ' ( 119/232 )'
name: 'texlive-xetex-7:20180414-19.fc29.x86_64'

If we look in dnf.transaction, we see some *other* package action constants which aren't in the callback API:

PKG_DOWNGRADE = libdnf.transaction.TransactionItemAction_DOWNGRADE
PKG_DOWNGRADED = libdnf.transaction.TransactionItemAction_DOWNGRADED
PKG_INSTALL = libdnf.transaction.TransactionItemAction_INSTALL
PKG_OBSOLETE = libdnf.transaction.TransactionItemAction_OBSOLETE
PKG_OBSOLETED = libdnf.transaction.TransactionItemAction_OBSOLETED
PKG_REINSTALL = libdnf.transaction.TransactionItemAction_REINSTALL
PKG_REINSTALLED = libdnf.transaction.TransactionItemAction_REINSTALLED
PKG_REMOVE = libdnf.transaction.TransactionItemAction_REMOVE
PKG_UPGRADE = libdnf.transaction.TransactionItemAction_UPGRADE
PKG_UPGRADED = libdnf.transaction.TransactionItemAction_UPGRADED

if we poke those, we find that '7' is actually PKG_UPGRADED:

>>> print(dnf.transaction.PKG_UPGRADED)
7

so it seems that we're getting a progress callback for the action 'upgraded', but that action isn't in the callback API. That seems wrong.

I think the commit that caused this was the one that refactored the progress callbacks to use libdnf as part of the near-removal (only an API-fulfilling stub remains, now) of dnf.transaction, this one:

https://github.com/rpm-software-management/dnf/commit/8198019c0