Fix(parsers): pop legacy constructor args in mail signal wrapper

MailDocumentParser.__init__ takes no constructor args in the new
protocol. Update the get_parser() signal wrapper to pop logging_group
and progress_callback (passed by the legacy consumer dispatch path)
before instantiating — the same pattern used by TextDocumentParser.

Also update test_mail_parser_receives_mailrule to use the real signal
wrapper (mail_get_parser) instead of MailDocumentParser directly, so
the test exercises the actual dispatch path and matches the new
parse() call signature (no mailrule kwarg).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/documents/tests/test_consumer.py

@@ -35,7 +35,6 @@ from documents.tests.utils import DirectoriesMixin
 from documents.tests.utils import DummyProgressManager
 from documents.tests.utils import FileSystemAssertsMixin
 from documents.tests.utils import GetConsumerMixin
-from paperless.parsers.mail import MailDocumentParser
 from paperless_mail.models import MailRule
 
 
@@ -1107,11 +1106,13 @@ class TestConsumer(
         THEN:
             - The mail parser should receive the mail rule
         """
+        from paperless_mail.signals import get_parser as mail_get_parser
+
         mock_consumer_declaration_send.return_value = [
             (
                 None,
                 {
-                    "parser": MailDocumentParser,
+                    "parser": mail_get_parser,
                     "mime_types": {"message/rfc822": ".eml"},
                     "weight": 0,
                 },
@@ -1137,12 +1138,10 @@ class TestConsumer(
                 ConsumerError,
             ):
                 consumer.run()
-                mock_mail_parser_parse.assert_called_once_with(
-                    consumer.working_copy,
-                    "message/rfc822",
-                    file_name="sample.pdf",
-                    mailrule=mock_mailrule_get.return_value,
-                )
+            mock_mail_parser_parse.assert_called_once_with(
+                consumer.working_copy,
+                "message/rfc822",
+            )
 
 
 @mock.patch("documents.consumer.magic.from_file", fake_magic_from_file)

src/paperless_mail/signals.py

@@ -1,7 +1,12 @@
 def get_parser(*args, **kwargs):
     from paperless.parsers.mail import MailDocumentParser
 
-    return MailDocumentParser(*args, **kwargs)
+    # MailDocumentParser accepts no constructor args in the new-style protocol.
+    # Pop legacy args that arrive from the signal-based consumer path.
+    # Phase 4 will replace this signal path with the ParserRegistry.
+    kwargs.pop("logging_group", None)
+    kwargs.pop("progress_callback", None)
+    return MailDocumentParser()
 
 
 def mail_consumer_declaration(sender, **kwargs):