tests/test-issue619.t

peer: make ui an attribute

With abc interfaces, instance attributes could not satisfy
@abc.abstractproperty requirements because interface conformance
was tested at type creation time. When we created the abc
peer interfaces, we had to make "ui" a @property to satisfy
abc.

Now that peer interfaces are using zope.interface and there is no
import time validation (but there are tests validating instances
conform to the interface), we can go back to using regular object
attributes.

Differential Revision: https://phab.mercurial-scm.org/D3069

https://bz.mercurial-scm.org/619

  $ hg init
  $ echo a > a
  $ hg ci -Ama
  adding a

  $ echo b > b
  $ hg branch b
  marked working directory as branch b
  (branches are permanent and global, did you want a bookmark?)
  $ hg ci -Amb
  adding b

  $ hg co -C 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

Fast-forward:

  $ hg merge b
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci -Ammerge

Bogus fast-forward should fail:

  $ hg merge b
  abort: merging with a working directory ancestor has no effect
  [255]

Even with strange revset (issue4465)

  $ hg merge ::.
  abort: merging with a working directory ancestor has no effect
  [255]