Prioritize SCA-required responses over generic init errors

Author: mo22

fints/client.py

@@ -1273,6 +1273,21 @@ def __init__(self, bank_identifier, user_id, pin, server, customer_id=None, tan_
         self._bootstrap_mode = True
         super().__init__(bank_identifier=bank_identifier, user_id=user_id, customer_id=customer_id, *args, **kwargs)
 
+    def process_response_message(self, dialog, message: FinTSInstituteMessage, internal_send=True):
+        previous_sca_required_response = getattr(self, "_processing_sca_required_response", False)
+        self._processing_sca_required_response = self._message_has_sca_required_response(message)
+        try:
+            return super().process_response_message(dialog, message, internal_send=internal_send)
+        finally:
+            self._processing_sca_required_response = previous_sca_required_response
+
+    def _message_has_sca_required_response(self, message):
+        for seg in list(message.find_segments(HIRMG2)) + list(message.find_segments(HIRMS2)):
+            for response in seg.responses:
+                if response.code == '9075':
+                    return True
+        return False
+
     def _new_dialog(self, lazy_init=False):
         if self.pin is None:
             enc = None
@@ -1601,7 +1616,16 @@ def _process_response(self, dialog, segment, response):
             raise FinTSClientError("Error during dialog initialization, could not fetch BPD. Please check that you "
                                    "passed the correct bank identifier to the HBCI URL of the correct bank.")
 
-        if ((not dialog.open and response.code.startswith('9')) and not self._bootstrap_mode)  or response.code in ('9340', '9910', '9930', '9931', '9942'):
+        sca_required_in_message = getattr(self, "_processing_sca_required_response", False)
+        if (
+            (
+                not dialog.open
+                and response.code.startswith('9')
+                and not self._bootstrap_mode
+                and not sca_required_in_message
+            )
+            or response.code in ('9340', '9910', '9930', '9931', '9942')
+        ):
             # Assume all 9xxx errors in a not-yet-open dialog refer to the PIN or authentication
             # During a dialog also listen for the following codes which may explicitly indicate an
             # incorrect pin: 9340, 9910, 9930, 9931, 9942

tests/test_client.py

@@ -1,5 +1,6 @@
 from fints.client import FinTS3PinTanClient, TransactionResponse, NeedTANResponse, ResponseStatus, NeedRetryResponse
-from fints.exceptions import FinTSClientPINError, FinTSClientTemporaryAuthError
+from fints.exceptions import FinTSClientPINError, FinTSClientTemporaryAuthError, FinTSSCARequiredError
+from fints.parser import FinTS3Parser
 from decimal import Decimal
 import pytest
 
@@ -73,6 +74,27 @@ def test_pin_locked(fints_server):
         str(client.pin)
 
 
+def test_sca_required_takes_precedence_over_unopened_dialog_error(fints_server):
+    client = FinTS3PinTanClient(
+        '12345678',
+        'test1',
+        '1234',
+        fints_server,
+        product_id="TEST-123", product_version="1.2.3",
+    )
+    client._bootstrap_mode = False
+    dialog = type("Dialog", (), {"open": False})()
+    message = FinTS3Parser().parse_message(
+        b"HIRMG:3:2+9050::Nachricht enthaelt Fehler.'"
+        b"HIRMS:4:2:3+9075::Starke Kundenauthentifizierung notwendig.'"
+    )
+
+    with pytest.raises(FinTSSCARequiredError):
+        client.process_response_message(dialog, message)
+
+    assert not client.pin.blocked
+
+
 def test_resume(fints_client, fints_server):
     with fints_client:
         system_id = fints_client.system_id