tests/test-revlog.t

urlutil: add a `get_clone_path` function

We add a new function with a semantic focussed on `clone` operation (so without
an existing repository). I am not certain the return type is the best, but this
is what we need for now. Once all caller are migrated we might start thinking
about that the API should be. For now that will do.

Differential Revision: https://phab.mercurial-scm.org/D10401

  $ hg init empty-repo
  $ cd empty-repo

Flags on revlog version 0 are rejected

  >>> with open('.hg/store/00changelog.i', 'wb') as fh:
  ...     fh.write(b'\x00\x01\x00\x00') and None

  $ hg log
  abort: unknown flags (0x01) in version 0 revlog 00changelog.i
  [50]

Unknown flags on revlog version 1 are rejected

  >>> with open('.hg/store/00changelog.i', 'wb') as fh:
  ...     fh.write(b'\x00\x04\x00\x01') and None

  $ hg log
  abort: unknown flags (0x04) in version 1 revlog 00changelog.i
  [50]

Unknown version is rejected

  >>> with open('.hg/store/00changelog.i', 'wb') as fh:
  ...     fh.write(b'\x00\x00\xbe\xef') and None

  $ hg log
  abort: unknown version (48879) in revlog 00changelog.i
  [50]

  $ cd ..

Test for CVE-2016-3630

  $ hg init

  >>> import codecs
  >>> open("a.i", "wb").write(codecs.decode(codecs.decode(
  ... b"""eJxjYGZgZIAAYQYGxhgom+k/FMx8YKx9ZUaKSOyqo4cnuKb8mbqHV5cBCVTMWb1Cwqkhe4Gsg9AD
  ... Joa3dYtcYYYBAQ8Qr4OqZAYRICPTSr5WKd/42rV36d+8/VmrNpv7NP1jQAXrQE4BqQUARngwVA==""",
  ... "base64"), "zlib")) and None

  $ hg debugrevlogindex a.i
     rev linkrev nodeid       p1           p2
       0       2 99e0332bd498 000000000000 000000000000
       1       3 6674f57a23d8 99e0332bd498 000000000000

  >>> from mercurial import revlog, vfs
  >>> tvfs = vfs.vfs(b'.')
  >>> tvfs.options = {b'revlogv1': True}
  >>> rl = revlog.revlog(tvfs, b'a.i')
  >>> rl.revision(1)
  mpatchError(*'patch cannot be decoded'*) (glob)