melib/imap: fix LOGINDISABLED support

LOGINDISABLED disables the LOGIN command, not authenticating in general;
doh! 🤦🤦🤦🤦

Signed-off-by: Manos Pitsidianakis <manos@pitsidianak.is>

melib/src/imap/connection.rs

@@ -380,15 +380,6 @@ impl ImapStream {
                 &server_conf.server_hostname
             ))
             .set_kind(ErrorKind::ProtocolNotSupported));
-        } else if capabilities
-            .iter()
-            .any(|cap| cap.eq_ignore_ascii_case(b"LOGINDISABLED"))
-        {
-            return Err(Error::new(format!(
-                "Could not connect to {}: server does not accept logins [LOGINDISABLED]",
-                &server_conf.server_hostname
-            ))
-            .set_kind(ErrorKind::Authentication));
         }
 
         (uid_store.event_consumer)(
@@ -452,6 +443,17 @@ impl ImapStream {
                 ret.send_literal(b"c2lyaGM=").await?;
             }
             _ => {
+                if capabilities
+                    .iter()
+                    .any(|cap| cap.eq_ignore_ascii_case(b"LOGINDISABLED"))
+                {
+                    return Err(Error::new(format!(
+                        "Could not connect to {}: server does not accept the LOGIN command \
+                         [LOGINDISABLED]",
+                        &server_conf.server_hostname
+                    ))
+                    .set_kind(ErrorKind::Authentication));
+                }
                 let username = AString::try_from(server_conf.server_username.as_str())
                     .chain_err_kind(ErrorKind::Bug)?;
                 let password = AString::try_from(server_conf.server_password.as_str())

melib/src/imap/mod.rs

@@ -309,6 +309,23 @@ impl MailBackend for ImapType {
                             };
                         }
                     }
+                    "LOGINDISABLED" => {
+                        if !(oauth2 || auth_anonymous) {
+                            *status = MailBackendExtensionStatus::Enabled {
+                                comment: Some(
+                                    "Use of LOGIN command is the default for given user \
+                                     configuration, but server rejects its use",
+                                ),
+                            };
+                        } else {
+                            *status = MailBackendExtensionStatus::Supported {
+                                comment: Some(
+                                    "Current user authentication is not performed with the LOGIN \
+                                     command",
+                                ),
+                            };
+                        }
+                    }
                     _ => {
                         if SUPPORTED_CAPABILITIES
                             .iter()