view mercurial/__init__.py @ 18246:58ca19edc043

clfilter: add impactable filter

The `mutable` filter still have some chance to get invalidated. This will happen
when:

- you garbage collect hidden changeset,
- public phase is moved backward,
- something is changed in the filtering (this could be fixed)

So we introduce an even more stable filtering set: everything with a revision
number egal or higher than the first mutable changeset is filtered.

The only official use of this filter is for branchcache.