fileset: perform membership test against set for status queries Previously, fileset functions operating on status items performed membership tests against a list of items. When there are thousands of items having a specific status, that test can be extremely slow. Changing the membership test to a set makes this operation substantially faster. On the mozilla-central repo: $ hg files -r d14cac631ecc 'set:added()' before: 28.120s after: 0.860s $ hg status --change d14cac631ecc --added 0.690s