openpgp: Improve cert canonicalization.

  - Previously, a bad self-signature was mistakenly classified as
    third-party-signature by the hash-prefix heuristic.  For example,
    a missing primary key binding signature on a self-signature causes
    the verification to fail, but the hash-prefix heuristic (which
    does not consider the missing primary key binding signature)
    attributes it to the subkey as a third-party-signature.

  - Use issuer information to distinguish between self-signatures and
    third-party-signatures, then use this information to limit the
    sorting heuristic to the corresponding buckets.

1 files changed, 2 insertions, 1 deletions

diff --git a/openpgp/src/packet_pile.rs b/openpgp/src/packet_pile.rs
index cebf4ab2..5cebda45 100644
--- a/openpgp/src/packet_pile.rs
+++ b/openpgp/src/packet_pile.rs
@@ -83,8 +83,9 @@ use crate::parse::Cookie;
 /// }
 ///
 /// let cert = Cert::try_from(pp)?;
-/// if let CouldBe(_) = cert.revocation_status(policy, None) {
+/// if let NotAsFarAsWeKnow = cert.revocation_status(policy, None) {
 ///     // revocation signature is broken and the key is not definitely revoked
+///     assert_eq!(cert.bad_signatures().len(), 1);
 /// }
 /// # else {
 /// #   unreachable!();