ocaml/opam — pull request #1279 by AltGr (2014-03-27 13:38:03+00:00)
Title: Fail rather than do nonsense when external solver returns a bogus answer

OpamClient.preprocess_request has not been performed in that case, and that
can lead the internal heuristic to remove every package unrelated to the
request. It would sure be better to retry cleanly, but for now this is
strictly better, and anyway this shouldn't happen.