ignore: only read an ignore file once

ignore: refactor ignore into two functions This prepares us for eventually being able to hash the list of patterns in use.

clfilter: fix `nodemap` usage in `getbundle` With the current implementation, `changelog.nodemap` is not filtered. So some filtered changeset in common are not filtered by `n in nodemap`. This leads to crash lower in the stack when the bundle generation try to access those node on a filtered changelog.

test: fix truncated comment in test The push is made to ensure repository are related. The comment in the initial changeset got truncated somehow.

clfilter: ensure context raise RepoLookupError when the revision is filtered Currently the code path of `changectx(filteredrepo, rev)` call `filteredrepo.changelog.node(rev)`. When `rev` is filtered this raise an unhandled `IndexError`. This case now raise a `RepoLookupError` as other error case do.

revlog: remove incancestors since it is no longer used

transplant: replace incancestors uses with ancestors

revlog.ancestors: add support for including revs This is in preparation for an upcoming refactoring. This also fixes a bug in incancestors, where if an element of revs was an ancestor of another it would be generated twice.

perf: add command to test performance of membership in ancestor set The new command, perfancestorset, takes an argument denoting which revset to test the membership of. Currently this runs through all the ancestors and converts them into a set. The primary purpose of having this is to compare this approach, currently used in several places, against the upcoming lazy approach.

ancestor: move missingancestors doctest out into a separate file This is in preparation for upcoming patches which will reuse the same graph for tests.