Unable to open key for editing on revoked key

With the latest git head of monkeysign, signing one or many UIDs of a key fails with this error (debug mode):

[...]
Sign all identities? [y/N] y
Really sign key? [y/N] y
command: ['gpg', '--command-fd', '0', '--with-fingerprint', '--list-options', 'show-sig-subpackets,show-uid-validity,show-unusable-uids,show-unusable-subkeys,show-keyring,show-sig-expire', '--status-fd', '2', '--quiet', '--batch', '--fixed-list-mode', '--no-tty', '--with-colons', '--use-agent', '--local-user', 'USER_KEY_FP', '--secret-keyring', '/path/to/.gnupg/secring.gpg', '--homedir', '/tmp/pygpg-tnXQJY', '--sign-key', 'CLIENT_KEY_FP']
FOUND: [GNUPG:] GET_BOOL keyedit.sign_all.okay
FOUND: [GNUPG:] GOT_IT
SKIPPED: [GNUPG:] GET_BOOL sign_uid.revoke_okay
deleting the temporary keyring /tmp/pygpg-tnXQJY
Traceback (most recent call last):
  File "/usr/local/bin/monkeysign", line 41, in <module>
    u.main()
  File "/usr/local/lib/python2.7/dist-packages/monkeysign/cli.py", line 69, in main
    self.sign_key()
  File "/usr/local/lib/python2.7/dist-packages/monkeysign/ui.py", line 296, in sign_key
    if not self.tmpkeyring.sign_key(pattern, alluids):
  File "/usr/local/lib/python2.7/dist-packages/monkeysign/gpg.py", line 464, in sign_key
    raise GpgRuntimeError(self.context.returncode, _('unable to open key for editing: %s') % self.context.stderr.decode('utf-8'))
monkeysign.gpg.GpgRuntimeError: [Errno 0] unable to open key for editing:

Commit id of master branch: 2f922f4a

Note that it's the same exact error by signing only one UID of the key that is not revoked.

(from redmine: created on 2013-10-06)