generatorset: implement __nonzero__ This is necessary to become a real smartset.

spanset: use base implementation for __add__

spanset: use base implementation for __sub__

spanset: use base implementation for __and__

spanset: use base implementation for filter

filteredset: use base implementation for filter

filteredset: use base implementation for __add__

filteredset: use base implementation for __sub__

filteredset: use base implementation for __and__

abstractsmartset: add default implementation for __sub__

abstractsmartset: add default implementation for __add__

abstractsmartset: add default implementation for __and__

abstractsmartset: add default implementation for filter

lazyset: rename the class to filteredset All smartsets try to be lazy. The purpose of this class is to apply a filter on another set. So we rename the class (and all its occurences) to `filteredset`.

lazyset: add order awareness to the class Just a bit of extra code makes the lazyset aware of order. This renders orderedlazyset useless. At some point, the `subset` will become responsible for this ordering logic. But we are not there yet because the various objects used as subsets are not good enough.

lazyset: remove min/max This is now handled by abstractsmartset.

baseset: remove min/max methods This is now handled by the base class.

abstractsmartset: add a default implementation for min and max This default implementation takes advantage of the fast iterator if available.

lazyset: drop now useless ascending/descending definition

lazyset: inherit the fastasc and fastdesc method from subset When the filtered subset has such methods, we can use them. It is implemented as properties to be able to quickly return None if no corresponding fastasc exists on the subset.

lazyset: split the iteration logic from the condition filtering logic So that the filter can be reused by `fastasc` or `fastdesc`.

spanset: do a single range check in __contains__ Now that `start <= end` is always true, we can simplify this function.

spanset: enforce the order lazily to gain `fastasc` and `fastdesc` methods Instead of having the direction of iteration enforced through the ordering of `start` and `end` attributes of spanset, we encode the iteration direction in an explicit attribute and always store start < end. The logic for sort and reverse has to be updated. The __iter__ is now based on the newly introduced `fastasc` and `fastdesc` methods. This will allow other code simplifications in the future.

abstractsmartset: document the `fastasc` and `fastdesc` attributes/methods See the in-line documentation for details. (This is the beginning of a massive overhaul of revset).

spanset: remove ascending/descending implementation We can rely on their implementation in abstractsmartset.

baseset: remove ascending/descending redefinition We can rely on the abstractsmartset implementation.

abstractsmartset: default implementation for `ascending` and `descending` These two methods are actually silly aliases for `sort()` and `sort(reverse=True)`. So we get that aliasing at the abstractsmartset level. We will slowly phase out all the custom implementations and eventually remove any mentions of it from the code.

revert: bring back usage of `subset & ps` in `parents` Changeset 95af98616aa7 switched the order of the operand of the "&" computation to work around an issue from repo-wide spanset. The need for a workaround has been alleviated by the introduction of `fullreposet`. So we restore it to normal. The benchmark shows no significant changes as expected. We also revert the bogus test change introduced by 95af98616aa7. The order is actually important.

color: update docstring for debug option 964dd1c491ca updated the format for the --color=debug option. This updates the documentation to match this new format.

color: document the possibility to colourise tabs in diffs This is a no-op change that simply suggests that tabs can be colourised, but defaults to no colour effects for tabs. This complements cset c343557a8442. Like the similar effects for phases from f8e2aebbb24c, we set the default effects to '' instead of None, so that this is a true noop change. Otherwise, the diff.tab effect would override (i.e. neutralise) the effect of the surrounding label.