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

worker: flush ui buffers before running the worker a91c6275 introduces flushing ui buffers after a worker finished. If the ui was not flushed before the worker was started, fork will copy the existing buffers to the worker. This causes messages issued before the worker started to be written to the terminal for each worker. We are now flushing the ui before we start a worker and add an appropriate test which will fail before this patch.