subrepo/svn: fix checked out rev number retrieval (issue2968) The initial version was to take the "Revision" field from svn info. It works but produces false positive when parent paths are being moved or unrelated changes are being committed, causing it to change while the svn checkout itself remains the same. To avoid spurious commit, we took "Revision" and "Last Changed Rev" for general comparison and kept the latter to answer "what is your revision?" question. This is better but fails when the subrepo path exists at "Revision" but not at "Last Changed Rev". This patch adds a check for this, and returns "Revision" if the path does not exist. We try to avoid doing this as much as possible at it implies an extra, *remote* call.

  $ hg init repo
  $ cd repo

  $ touch foo
  $ hg ci -Am 'add foo'
  adding foo

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

this should be stored as a delta against rev 0

  $ echo foo bar baz > foo
  $ hg ci -Am 'add foo again'
  adding foo
  created new head

  $ hg debugindex foo
     rev    offset  length   base linkrev nodeid       p1           p2
       0         0       0      0       0 b80de5d13875 000000000000 000000000000
       1         0      24      0       1 0376abec49b8 000000000000 000000000000