From 8d991c45e189e78bbac4f586f6a45f4a0b817511 Mon Sep 17 00:00:00 2001
From: nick evans <nicholas.evans@gmail.com>
Date: Sat, 14 Oct 2023 14:03:27 -0400
Subject: [PATCH] Delegate checking auth args to the authenticator

Each authenticator has different parameters, so argument validation must
be delegated to the authenticator classes.
---
 lib/net/smtp.rb               | 26 +++++++-------------------
 lib/net/smtp/authenticator.rb | 17 +++++++++++++++++
 2 files changed, 24 insertions(+), 19 deletions(-)

diff --git a/lib/net/smtp.rb b/lib/net/smtp.rb
index 145f897..e359566 100644
--- a/lib/net/smtp.rb
+++ b/lib/net/smtp.rb
@@ -633,10 +633,7 @@ def tcp_socket(address, port)
 
     def do_start(helo_domain, user, secret, authtype)
       raise IOError, 'SMTP session already started' if @started
-      if user or secret
-        check_auth_method(authtype || DEFAULT_AUTH_TYPE)
-        check_auth_args user, secret
-      end
+      check_auth_args authtype, user, secret
       s = Timeout.timeout(@open_timeout, Net::OpenTimeout) do
         tcp_socket(@address, @port)
       end
@@ -832,27 +829,18 @@ def open_message_stream(from_addr, *to_addrs, &block)   # :yield: stream
     DEFAULT_AUTH_TYPE = :plain
 
     def authenticate(user, secret, authtype = DEFAULT_AUTH_TYPE)
-      check_auth_method authtype
-      check_auth_args user, secret
+      check_auth_args authtype, user, secret
       authenticator = Authenticator.auth_class(authtype).new(self)
       authenticator.auth(user, secret)
     end
 
     private
 
-    def check_auth_method(type)
-      unless Authenticator.auth_class(type)
-        raise ArgumentError, "wrong authentication type #{type}"
-      end
-    end
-
-    def check_auth_args(user, secret, authtype = DEFAULT_AUTH_TYPE)
-      unless user
-        raise ArgumentError, 'SMTP-AUTH requested but missing user name'
-      end
-      unless secret
-        raise ArgumentError, 'SMTP-AUTH requested but missing secret phrase'
-      end
+    def check_auth_args(type, *args, **kwargs)
+      return unless type || args.any? || kwargs.any?
+      Authenticator.check_auth_type_args(
+        type || DEFAULT_AUTH_TYPE, *args, **kwargs
+      )
     end
 
     #
diff --git a/lib/net/smtp/authenticator.rb b/lib/net/smtp/authenticator.rb
index 75350f0..98aaf75 100644
--- a/lib/net/smtp/authenticator.rb
+++ b/lib/net/smtp/authenticator.rb
@@ -13,6 +13,23 @@ def self.auth_class(type)
         Authenticator.auth_classes[type.intern]
       end
 
+      def self.check_auth_type_args(authtype, user, secret, type: nil, **auth)
+        return unless user || secret || auth.any? || authtype || type
+        klass = auth_class(type || authtype || DEFAULT_AUTH_TYPE) or
+          raise ArgumentError, "wrong authentication type #{type}"
+        klass.check_args(user, secret, **auth)
+      end
+
+      def self.check_args(user_arg = nil, secret_arg = nil,
+                          *, **)
+        unless user_arg
+          raise ArgumentError, 'SMTP-AUTH requested but missing user name'
+        end
+        unless secret_arg
+          raise ArgumentError, 'SMTP-AUTH requested but missing secret phrase'
+        end
+      end
+
       attr_reader :smtp
 
       def initialize(smtp)