🥅 Add SASL::AuthenticationIncomplete

lib/net/imap.rb

@@ -1266,7 +1266,7 @@ def authenticate(mechanism, *creds, sasl_ir: true, **props, &callback)
       end
       if authenticator.respond_to?(:done?) && !authenticator.done?
         logout!
-        raise SASL::AuthenticationFailed, "authentication ended prematurely"
+        raise SASL::AuthenticationIncomplete, result
       end
       @capabilities = capabilities_from_resp_code result
       result

lib/net/imap/sasl.rb

@@ -114,6 +114,18 @@ module SASL
       # messages has not passed integrity checks.
       AuthenticationFailed = Class.new(Error)
 
+      # Indicates that authentication cannot proceed because one of the server's
+      # ended authentication prematurely.
+      class AuthenticationIncomplete < AuthenticationFailed
+        # The success response from the server
+        attr_reader :response
+
+        def initialize(response, message = "authentication ended prematurely")
+          super(message)
+          @response = response
+        end
+      end
+
       # autoloading to avoid loading all of the regexps when they aren't used.
       sasl_stringprep_rb = File.expand_path("sasl/stringprep", __dir__)
       autoload :StringPrep,          sasl_stringprep_rb

test/net/imap/test_imap.rb

@@ -966,7 +966,7 @@ def test_id
         server.state.authenticate(server.config.user)
         cmd.done_ok
       end
-      assert_raise(Net::IMAP::SASL::AuthenticationFailed) do
+      assert_raise(Net::IMAP::SASL::AuthenticationIncomplete) do
         imap.authenticate("DIGEST-MD5", "test_user", "test-password",
                           warn_deprecation: false)
       end