tests/test-issue842.t

revert: handle subrepos missing in the given --rev

The list of subrepos to revert is currently based on the given --rev, so there
is currently no way for this to fail.  Using the --rev context is wrong though,
because if the subrepo doesn't exist in --rev, it is skipped, so it won't be
changed.  This change makes it so that the revert aborts, which is what happens
if a plain file is reverted to -1.  Finding matches based on --rev is also
inconsistent with evaluating files against the working directory (5b85a5bc5bbb).

This change is made now, so as to not cause breakage when the context is
switched in an upcoming patch.

http://mercurial.selenic.com/bts/issue842

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

  $ hg up -r0000
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ echo bar > a

Should issue new head warning:

  $ hg ci -Amb
  adding a
  created new head

  $ hg up -r0000
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ echo stuffy > a

Should not issue new head warning:

  $ hg ci -q -Amc

  $ hg up -r0000
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ echo crap > a
  $ hg branch testing
  marked working directory as branch testing
  (branches are permanent and global, did you want a bookmark?)

Should not issue warning:

  $ hg ci -q -Amd