$ guix package -S 17 -d 18
$ guix package -d 18 -S 17
does not the same thing. The '%actions' (roll-back, delete-generation,
switch-generation) are processed in reversed order as they appear on the
command-line -- because 'for-each' and 'assoc-ref'.
However, the transaction plan is always the same:
Therefore, I propose to split the 'for-each' on '%actions' (step0) into
fixed steps, such as the transaction always happens using this plan:
whatever the order in the command line.
On one hand, it reduces the "power" of combining '-S', '-d' and
'--roll-back'. On the other hand, it enforces commutativity which is
somehow what we want a transaction to be.
WDYT? I can come up with a patch. This initial issue had been reported
(Note that an issue about short-name with optional argument can also
happen and tracked by bug#50472 [2].)