cloning with and without explicit use of keyword_arguments model/scenario doesnt provide the same results

[OFR-IIASA]

When explicitily using the keyword arguments model/scenario, and only when the model name is kept the same as in the scenario to be cloned (scenario: base - in the example below), then the clone command makes a a copy and assigns this the base scenario name "base" scenario instead of making a copy and assigning the copied scenario the "new scenario name".

import message_ix
import ixmp
mp = ixmp.Platform(dbtype='HSQLDB')
base = message_ix.Scenario(mp, 'Westeros Electrified', 'baseline', cache=True)

__
2018-11-26 10:33:35,663 INFO at.ac.iiasa.ixmp.objects.Scenario:215 - loading default Scenario 'Westeros Electrified|baseline' (version: 7, runid: 86)...
2018-11-26 10:33:35,744 INFO at.ac.iiasa.ixmp.objects.Scenario:241 - done loading Scenario from the database!
2018-11-26 10:33:35,744 INFO at.ac.iiasa.ixmp.objects.MsgScenario:457 - spatial and temporal disaggregation maps assignment
2018-11-26 10:33:35,760 INFO at.ac.iiasa.ixmp.objects.MsgScenario:573 - period mapping assignment
2018-11-26 10:33:35,760 INFO at.ac.iiasa.ixmp.objects.MsgScenario:599 - duration period assignment
2018-11-26 10:33:35,760 INFO at.ac.iiasa.ixmp.objects.Scenario:1826 - committing changes of Scenario 'Westeros Electrified|baseline' to the database (runid: 86)...
2018-11-26 10:33:35,856 INFO at.ac.iiasa.ixmp.objects.Scenario:601 - done updating Scenario 'Westeros Electrified|baseline' to the database (runid: 86, version: 7)!
2018-11-26 10:33:35,856 INFO at.ac.iiasa.ixmp.objects.MsgScenario:457 - spatial and temporal disaggregation maps assignment
2018-11-26 10:33:35,872 INFO at.ac.iiasa.ixmp.objects.MsgScenario:573 - period mapping assignment
2018-11-26 10:33:35,872 INFO at.ac.iiasa.ixmp.objects.MsgScenario:599 - duration period assignment
__

With the explicit use of keyword arguments yields the following
scen = base.clone(model='Westeros Electrified', scenario='baseline_1',)
--> the base scenario is cloned and assigned a new version
__
2018-11-26 10:33:35,948 INFO at.ac.iiasa.ixmp.objects.Scenario:215 - loading default Scenario 'Westeros Electrified|baseline' (version: 0, runid: 86)...
2018-11-26 10:33:35,963 INFO at.ac.iiasa.ixmp.objects.Scenario:241 - done loading Scenario from the database!
2018-11-26 10:33:35,963 INFO at.ac.iiasa.ixmp.objects.Scenario:1896 - saving Scenario 'Westeros Electrified|baseline' to database (runid: 111)...
2018-11-26 10:33:36,087 INFO at.ac.iiasa.ixmp.objects.Scenario:604 - done saving Scenario 'Westeros Electrified|baseline' to the database (runid: 111, version: 10)
__

withOUT the explicit use of keyword arguments yields the following
scen = base.clone('Westeros Electrified', 'baseline_2',)
--> the base scenario is cloned with a new scenario name and assigned a new version
__
2018-11-26 10:33:36,109 INFO at.ac.iiasa.ixmp.objects.Scenario:215 - loading default Scenario 'Westeros Electrified|baseline_2' (version: 0, runid: 86)...
2018-11-26 10:33:36,125 INFO at.ac.iiasa.ixmp.objects.Scenario:241 - done loading Scenario from the database!
2018-11-26 10:33:36,125 INFO at.ac.iiasa.ixmp.objects.Scenario:1896 - saving Scenario 'Westeros Electrified|baseline_2' to database (runid: 112)...
2018-11-26 10:33:36,217 INFO at.ac.iiasa.ixmp.objects.Scenario:604 - done saving Scenario 'Westeros Electrified|baseline_2' to the database (runid: 112, version: 4)!
__

[gidden]

Hi oliver - yes, this is indeed caused by #129. We allow additional kwargs so your scenario kwarg is not getting picked up. Would you mind making a PR which changes scen to scenario in the clone function? In that PR, we would also want to deprecate scen similar to how keep_sol is deprecated.