tests/test-merge4.t

bookmarks: allow pushkey if new equals current

Previously a bookmark pushkey would be rejected if the specified 'old' value
didn't match the servers 'current' value. This change allows this situation, as
long as the 'current' server value equals the 'new' pushkey value already.

We are trying to write a hook that forces a server bookmark to move forward,
using a changegroup hook. If the user also pushed the bookmark, they would get
an error, since they computed their pushkey (old,new) pair before the server
moved the bookmark. Long term, bundle2 will let us do this more smartly, but
this change seems reasonable for now.

  $ hg init
  $ echo This is file a1 > a
  $ hg add a
  $ hg commit -m "commit #0"
  $ echo This is file b1 > b
  $ hg add b
  $ hg commit -m "commit #1"
  $ hg update 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo This is file c1 > c
  $ hg add c
  $ hg commit -m "commit #2"
  created new head
  $ hg merge 1
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ rm b
  $ echo This is file c22 > c

Test hg behaves when committing with a missing file added by a merge

  $ hg commit -m "commit #3"
  abort: cannot commit merge with missing files
  [255]