view tests/test-debugrename.t @ 33377:5d63e5f40bea

revset: define successors revset

This revset returns all successors, including transit nodes and the source
nodes (to be consistent with existing revsets like "ancestors").

To filter out transit nodes, use `successors(X)-obsolete()`.
To filter out divergent case, use `successors(X)-divergent()-obsolete()`.

The revset could be useful to define rebase destination, like:
`max(successors(BASE)-divergent()-obsolete())`. The `max` is to deal with
splits.

There are other implementations where `successors` returns just one level of
successors, and `allsuccessors` returns everything. I think `successors`
returning all successors by default is more user friendly. We have seen
cases in production where people use 1-level `successors` while they really
want `allsuccessors`. So it seems better to just have one single revset
returning all successors by default to avoid user errors.

In the future we might want to add `depth` keyword argument to it and for
other revsets like `ancestors` etc. Or even build some flexible indexing
syntax [1] to satisfy people having the depth limit requirement.

[1]: https://www.mercurial-scm.org/pipermail/mercurial-devel/2017-July/101140.html

  $ hg init
  $ echo a > a
  $ hg ci -Am t
  adding a

  $ hg mv a b
  $ hg ci -Am t1
  $ hg debugrename b
  b renamed from a:b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3

  $ hg mv b a
  $ hg ci -Am t2
  $ hg debugrename a
  a renamed from b:37d9b5d994eab34eda9c16b195ace52c7b129980

  $ hg debugrename --rev 1 b
  b renamed from a:b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3