some implementations of cp can't create hardlinks

  $ cat > cp.py <<EOF

  > from mercurial import util

  > import sys

  > util.copyfiles(sys.argv[1], sys.argv[2], hardlink=True)

  > EOF

Test hardlinking outside hg:

  $ mkdir x

  $ echo foo > x/a

  $ python cp.py x y

  $ echo bar >> y/a

No diff if hardlink:

  $ diff x/a y/a

Test mq hardlinking:

  $ echo "[extensions]" >> $HGRCPATH

  $ echo "mq=" >> $HGRCPATH

  $ hg init a

  $ cd a

  $ hg qimport -n foo - << EOF

  > # HG changeset patch

  > # Date 1 0

  > diff -r 2588a8b53d66 a

  > --- /dev/null	Thu Jan 01 00:00:00 1970 +0000

  > +++ b/a	Wed Jul 23 15:54:29 2008 +0200

  > @@ -0,0 +1,1 @@

  > +a

  > EOF

  adding foo to series file

  $ hg qpush

  applying foo

  now at: foo

  $ cd ..

  $ python cp.py a b

  $ cd b

  $ hg qimport -n bar - << EOF

  > # HG changeset patch

  > # Date 2 0

  > diff -r 2588a8b53d66 a

  > --- /dev/null	Thu Jan 01 00:00:00 1970 +0000

  > +++ b/b	Wed Jul 23 15:54:29 2008 +0200

  > @@ -0,0 +1,1 @@

  > +b

  > EOF

  adding bar to series file

  $ hg qpush

  applying bar

  now at: bar

  $ cat .hg/patches/status

  430ed4828a74fa4047bc816a25500f7472ab4bfe:foo

  4e7abb4840c46a910f6d7b4d3c3fc7e5209e684c:bar

  $ cat .hg/patches/series

  foo

  bar

  $ cat ../a/.hg/patches/status

  430ed4828a74fa4047bc816a25500f7472ab4bfe:foo

  $ cat ../a/.hg/patches/series

  foo

Test tags hardlinking:

  $ hg qdel -r qbase:qtip

  patch foo finalized without changeset message

  patch bar finalized without changeset message

  $ hg tag -l lfoo

  $ hg tag foo

  $ cd ..

  $ python cp.py b c

  $ cd c

  $ hg tag -l -r 0 lbar

  $ hg tag -r 0 bar

  $ cat .hgtags

  4e7abb4840c46a910f6d7b4d3c3fc7e5209e684c foo

  430ed4828a74fa4047bc816a25500f7472ab4bfe bar

  $ cat .hg/localtags

  4e7abb4840c46a910f6d7b4d3c3fc7e5209e684c lfoo

  430ed4828a74fa4047bc816a25500f7472ab4bfe lbar

  $ cat ../b/.hgtags

  4e7abb4840c46a910f6d7b4d3c3fc7e5209e684c foo

  $ cat ../b/.hg/localtags

  4e7abb4840c46a910f6d7b4d3c3fc7e5209e684c lfoo