tests/test-copy2.out

convert: fix mercurial_sink.putcommit

Changeset 4ebc8693ce72 added some code to putcommit to avoid creating a
revision that touches no files, but this can break regular conversions
from some repositories:

- conceptually, since we're converting a repo, we should try to make
  the new hg repo as similar as possible to the original repo - we
  should create a new changeset, even if the original revision didn't
  touch any files (maybe the commit message had some important bit);

- even if a "regular" revision that doesn't touch any file may seem
  weird (and maybe even broken), it's completely legitimate for a merge
  revision to not touch any file, and, if we just skip it, the
  converted repo will end up with wrong history and possibly an extra
  head.

  As an example, say the crew and main hg repos are sync'ed.  Somebody
  sends an important patch to the mailing list.  Matt quickly applies
  and pushes it.  But at the same time somebody also applies it to crew
  and pushes it.  Suppose the commit message ended up being a bit
  different (say, there was a typo and somebody didn't fix it) or that
  the date ended up being different (because of different patch-applying
  scripts): the changeset hashes will be different, but the manifests
  will be the same.

  Since both changesets were pushed to public repos, it's hard to recall
  them.  If both are merged, the manifest from the resulting merge
  revision will have the exact same contents as its parents - i.e. the
  merge revision really doesn't touch any file at all.

To keep the file filtering stuff "working", the generic code was changed
to skip empty revisions if we're filtering the repo, fixing a bug in the
process (we want parents[0] instead of tip).

# should fail - foo is not managed
foo: not copying - file is not managed
abort: no files to copy
? foo
# dry-run; print a warning that this is not a real copy; foo is added
foo has not been committed yet, so no copy data will be stored for bar.
A foo
# should print a warning that this is not a real copy; bar is added
foo has not been committed yet, so no copy data will be stored for bar.
A bar
# should print a warning that this is not a real copy; foo is added
bar has not been committed yet, so no copy data will be stored for foo.
A foo
# dry-run; should show that foo is clean
C foo
# should show copy
A bar
  foo
# shouldn't show copy
# should match
   rev    offset  length   base linkrev nodeid       p1           p2
     0         0       5      0       0 2ed2a3912a0b 000000000000 000000000000
bar renamed from foo:2ed2a3912a0b24502043eae84ee4b279c18b90dd
# should not be renamed
bar not renamed
# should show copy
M bar
  foo
# should show no parents for tip
   rev    offset  length   base linkrev nodeid       p1           p2
     0         0      69      0       1 6ca237634e1f 000000000000 000000000000
     1        69       6      1       2 7a1ff8e75f5b 6ca237634e1f 000000000000
     2        75      82      1       3 243dfe60f3d9 000000000000 000000000000
# should match
   rev    offset  length   base linkrev nodeid       p1           p2
     0         0       5      0       0 2ed2a3912a0b 000000000000 000000000000
     1         5       7      1       2 dd12c926cf16 2ed2a3912a0b 000000000000
bar renamed from foo:dd12c926cf165e3eb4cf87b084955cb617221c17
# should show no copies
# copy --after on an added file
A baz
  bar
# foo was clean:
C foo
# but it's considered modified after a copy --after --force
M foo
  bar