tests/test-issue1089.t

phabricator: add --blocker argument to phabsend to specify blocking reviewers

The way to signal to Conduit that a reviewer is considered blocking is just to
wrap their PHID in "blocking()" when including it in the list of PHIDs passed
to `reviewers.add`.

arc doesn't have a --blocker, instead one is supposed to append a '!' to the
end of reviewer names (I think reviewers are usually added in an editor rather
than the command line, where '!'s can be more hazardous).

moz-phab (Mozilla's arcanist wrapper) does have a --blocker argument, and being
explicit like this is also more discoverable. Even `arc diff`'s help doesn't
seem to mention the reviewer! syntax.

Differential Revision: https://phab.mercurial-scm.org/D6512

https://bz.mercurial-scm.org/1089

  $ hg init
  $ mkdir a
  $ echo a > a/b
  $ hg ci -Am m
  adding a/b

  $ hg rm a
  removing a/b
  $ hg ci -m m a

  $ mkdir a b
  $ echo a > a/b
  $ hg ci -Am m
  adding a/b

  $ hg rm a
  removing a/b
  $ cd b

Relative delete:

  $ hg ci -m m ../a

  $ cd ..