localrepo: introduce a `_quick_access_changeid` property Having faster access to `null` is cute… but limited. We want to speedup access to more useful revision, like `.`. We start with turning the fast path for `null` into something more generic. Differential Revision: https://phab.mercurial-scm.org/D7488

changectx: use unfiltered changelog to access parents of unfiltered revs If a revision is not filtered, we know that its parents are not either. So we can take a shortcut. This shortcut avoid the computation of all filtered revs in some cases. Differential Revision: https://phab.mercurial-scm.org/D7487

locarepo: also fastpath `nullid` lookup in __getitem__ We already use that fastpath for `"null"` and `nullrev`, using it for `nullid` is similar. Differential Revision: https://phab.mercurial-scm.org/D7486

repoview: add more tests to track operation not supposed to trigger filtering This test is useful to confirm we removed filtering trigger and to prevent it to come back without us noticing. The commands tested in the test were initially introduced one by one. However, on Martin von Zweigbergk request, we are adding them all at once. Differential Revision: https://phab.mercurial-scm.org/D7514

localrepo: mark nullrev has never filtered All repository have a null, and it cannot be filtered. Differential Revision: https://phab.mercurial-scm.org/D7484

changectx: add a "maybe filtered" filtered attribute There are changeset that we know not to be filtered (eg: `null`). In this case, we could access some information without triggering changelog filtering. We add an attribute to changectx that track this property. Differential Revision: https://phab.mercurial-scm.org/D7483

repoview: add a test that access actual changeset data of `null` Ideally, we would not trigger filtering here. However some work needs to happens first. Differential Revision: https://phab.mercurial-scm.org/D7482

localrepo: recognize trivial "null" queries in `anyrev` Bypassing the revset logic for trivial "null" queries means we can avoid to trigger the filtering logic in some cases. Differential Revision: https://phab.mercurial-scm.org/D7481

localrepo: also fastpath `nullrev` in __getitem__ As explained earlier, nullrev will exist in all repository, we do not need any special checking. Differential Revision: https://phab.mercurial-scm.org/D7480

repoview: add a test to track operation not supposed to trigger filtering This test will be useful to confirm we removed filtering trigger and to prevent it to come back without us noticing. Differential Revision: https://phab.mercurial-scm.org/D7479