revset: fixed sorting issue with spanset When a spanset was being sorted it didn't take into account it's current state (ascending or descending) and it reversed itself everytime the reverse parameter was True. This is not yet used but it will be as soon as the sort revset is changed to directly use the structures sort method.

tests: added tests to test sort revset This tests are intended to test sort in many different cases where it could fail when using the new structures

revset: added __nonzero__ method to spanset class Implemented it in a lazy way, just look for the first non-filtered revision and return True if there's any revision at all.

require: provide a link to a wiki page in addition of suggesting upgrade The wiki page is intended to describe several solution to the requirement issue. Some of those solutions does not involve upgrading mercurial. That is very useful for people that can't easily upgrade they Mercurial in some place.

revset: optimized sort method in lazyset class We are taking advantage of the smartset classes sort method when it exists and converting the set to a baseset otherwise.

revset: improve head revset performance Previously the head() revset would iterate over every item in the subset and check if it was a head. Since the subset is often the entire repo, this was slow on large repos. Now we iterate over each item in the head list and check if it's in the subset, which results in much less work. hg log -r 'head()' on a large repo: Before: 0.95s After: 0.28s

revset: added ascending attribute to addset class In case both collections are in an ascending/descending order then we will be able to iterate them lazily while keeping the order.