revset: gratuitous code move in '_children' As 'cs' is empty as the time of the conditional, we can just return an empty 'baseset' and create the variable later.

revset: mark spots that should use 'smartset.min()' Using smartset's min will be significantly faster when the input set can provided an optimised answer. I do not have time to fix all of them but I'm marking the spot.

revset: mark the place where we are combining sets in the wrong direction We should always combine with subset as the left operand (to preserve the order). I do not have time to fix all of them so I'm just marking the spot.

revset: point out wrong behavior in fullreposet I cannot fix all issues in revset because I've got other things to do, but let's write down all the brokenness to help other people reading and fixing.