tree c7dc0b91b505d730ca1a6c141ee6c97eed895cf2
parent b5e7cedd00abd8e48ec670bbe845b4f009912974
author Dave Borowitz <dborowitz@google.com> 1551811503 -0800
committer Luca Milanesio <luca.milanesio@gmail.com> 1668803994 +0000

Add an index-safe predicate that matches all changes

Iad564dd47 was problematic in the error case because it returned
Predicate.not(Predicate.any()). The "any" predicate is not an index
predicate, which produces at least two problems:

* When used in a with another non-index predicate, it
  might throw "no ChangeDataSource" from AndSource/OrSource.
* More dangerously, when combined with an index predicate, it is used as
  a post-filtering predicate. A post-filtering predicate that matches no
  results means it gets applied to every change in the index before
  returning an empty set, which is bad.

Instead, reuse a handy existing index predicate that is designed to
return no results efficiently from the index:
ChangeStatusPredicate.NONE. Expose this from a more general location,
ChangeIndexPredicate#none().

Release-Notes: skip
Change-Id: Ic9a7e277070cff7768ec91c1972cf8e9f6deacb1
(cherry picked from commit d9679cdb605b8a10977e1fc821f57dd5749b1dd5)