Stop rolling back reminders/SEPA mails after a successful send

The previous fix reverted the reminder to "draft" on any failure after
mark_reminder_sent, including failures that happened after the mail had
already been handed to send_via_smtp or appended to an IMAP folder. That
made a successful send followed by a Sent-folder-copy or archive-move
failure look like nothing was sent, inviting a duplicate send/fee booking
on retry -- the same "sent" flag needs to be preserved once delivery is
no longer reversible, per follow-up review.

reminder_mail.generate_and_send_reminder_mail and
sepa_mail.generate_debit_mails now track whether the mail actually left
the building (SMTP accepted / IMAP append succeeded / local file written)
separately from the later archiving step:
- Failure before that point: reminder_mail reverts to draft (unchanged);
  sepa_mail now records a warning and continues with the remaining
  debits instead of aborting the whole batch.
- Failure after that point (Sent-copy append, moving the archive file
  into place): the reminder stays "sent" / the debit stays in the
  batch's results, an event is still logged for traceability (with an
  archive_error note and no document reference), and the caller gets a
  clear error to follow up on manually -- no rollback, no silent loss of
  the fact that the mail already went out.

tests/test_reminder_mail.py

@@ -301,3 +301,72 @@ def test_reminder_mail_local_write_failure_reverts_sent_status(tmp_path, monkeyp
 
     data = repository.get_contributions(member.member_id)
     assert data.reminders[0]["status"] == "draft"
+
+
+def test_reminder_mail_archiving_failure_after_smtp_success_does_not_revert(tmp_path, monkeypatch):
+    import ccma.services.reminder_mail as reminder_mail_module
+
+    repository, member = _overdue_claim_repository(tmp_path / "store")
+    member.email = "reminder@example.org"
+    repository.save_member(member)
+    repository.save_email_settings(
+        delivery_mode="send",
+        smtp_host="mail.example.org",
+        smtp_port=587,
+        smtp_security="none",
+        smtp_username="",
+        smtp_password="",
+        imap_host="",
+        imap_port=993,
+        imap_security="ssl",
+        imap_username="",
+        imap_password="",
+        imap_drafts_folder="",
+    )
+    reminder = repository.create_reminder_draft(
+        member.member_id,
+        "claim-1",
+        level=1,
+        name="Zahlungserinnerung",
+        payment_deadline_days=14,
+        items=[{"description": "Mahngebühr", "amount": "5.00"}],
+    )
+
+    @contextmanager
+    def _fake_smtp_session(settings):
+        yield "smtp-client"
+
+    monkeypatch.setattr(reminder_mail_module, "smtp_session", _fake_smtp_session)
+    monkeypatch.setattr(reminder_mail_module, "send_via_smtp", lambda client, content: None)
+
+    real_replace = reminder_mail_module.os.replace
+
+    def _flaky_replace(src, dst):
+        # Only the final archive move (into the "Mahnungen" folder) should fail --
+        # the mail has already been handed to send_via_smtp by that point.
+        if str(dst).endswith(".eml") and "Mahnungen" in str(dst):
+            raise OSError("disk full")
+        return real_replace(src, dst)
+
+    monkeypatch.setattr(reminder_mail_module.os, "replace", _flaky_replace)
+
+    with pytest.raises(RepositoryError, match="zugestellt"):
+        generate_and_send_reminder_mail(
+            repository,
+            member.member_id,
+            "claim-1",
+            reminder["reminder_id"],
+            delivery_mode="send",
+            sender_name="Verwaltung C3MA",
+            sender_email="verwaltung@example.org",
+            signature="Der Vorstand",
+        )
+
+    data = repository.get_contributions(member.member_id)
+    stored_reminder = data.reminders[0]
+    assert stored_reminder["status"] == "sent", "mail was already sent -- must not be un-sent"
+    assert stored_reminder.get("fee_item_ids")
+    events = repository.get_events(member.member_id)
+    assert events[-1].event_type == "reminder_email_sent"
+    assert events[-1].data["archive_error"]
+    assert "document" not in events[-1].references

tests/test_sepa.py

@@ -388,3 +388,194 @@ def test_generated_mail_send_mode_copies_to_sent_folder_reusing_one_imap_connect
     assert len(imap_connections) == 1, "one IMAP connection should be reused for the whole batch"
     assert ensured == ["INBOX.Gesendet"]
     assert appended == [("imap-client", "INBOX.Gesendet", r"(\Seen)")] * 2
+
+
+def test_generated_mail_archiving_failure_after_smtp_success_keeps_batch_going(tmp_path, monkeypatch):
+    import ccma.services.sepa_mail as sepa_mail_module
+
+    repository, ada = _repository(tmp_path)
+    second = repository.create_member(first_name="Grace", last_name="Hopper", member_number="C3-43")
+    second.status = "active"
+    second.email = "grace@example.org"
+    second.account_holder = "Grace Hopper"
+    second.iban = "DE89370400440532013000"
+    second.bic = "COBADEFFXXX"
+    second.mandate_reference = "MANDAT-43"
+    second.mandate_signed_at = "2025-01-10"
+    second.mandate_active = True
+    repository.save_member(second)
+    repository.save_contributions(
+        second.member_id,
+        ContributionData(
+            claims=[
+                {
+                    "claim_id": "due",
+                    "title": "Mitgliedsbeitrag 2026",
+                    "amount": "150.00",
+                    "due_date": "2026-01-31",
+                    "status": "open",
+                }
+            ]
+        ),
+    )
+    organization = repository.get_configuration()["organization"]
+    organization.update(
+        {
+            "name": "Chaos Computer Club Mannheim e.V.",
+            "email": "verwaltung@example.org",
+            "iban": "DE89370400440532013000",
+            "bic": "COBADEFFXXX",
+            "creditor_id": "DE98ZZZ09999999999",
+        }
+    )
+    repository.save_organization(organization)
+    repository.save_email_settings(
+        delivery_mode="send",
+        smtp_host="mail.example.org",
+        smtp_port=587,
+        smtp_security="none",
+        smtp_username="",
+        smtp_password="",
+        imap_host="",
+        imap_port=993,
+        imap_security="ssl",
+        imap_username="",
+        imap_password="",
+        imap_drafts_folder="",
+    )
+    debits, _warnings = pending_direct_debits(repository, due_until=date(2026, 12, 31))
+    assert len(debits) == 2
+
+    monkeypatch.setattr(
+        sepa_mail_module, "smtp_session", contextmanager(lambda settings: iter(["smtp-client"]))
+    )
+    sent = []
+    monkeypatch.setattr(sepa_mail_module, "send_via_smtp", lambda client, content: sent.append(content))
+
+    from pathlib import Path
+
+    original_write_bytes = Path.write_bytes
+
+    def _flaky_write_bytes(self, data):
+        if "documents" in str(self) and "C3-43" in self.name:
+            raise OSError("disk full")
+        return original_write_bytes(self, data)
+
+    monkeypatch.setattr(Path, "write_bytes", _flaky_write_bytes)
+
+    generated, warnings = generate_debit_mails(
+        repository,
+        debits,
+        collection_date=date(2026, 8, 3),
+        delivery_mode="send",
+        sender_name="Verwaltung C3MA",
+        sender_email="verwaltung@example.org",
+        signature="Der Vorstand",
+    )
+
+    # Both mails were handed to SMTP -- a broken archive write for one of them must
+    # not swallow the other, nor pretend the failing one was never sent.
+    assert len(sent) == 2
+    assert len(generated) == 2
+    assert len(warnings) == 1
+    assert "C3-43" in warnings[0] or "Grace" in warnings[0]
+
+    failing = next(g for g in generated if g.member_id == second.member_id)
+    assert not failing.archive_path.is_file()
+    succeeding = next(g for g in generated if g.member_id == ada.member_id)
+    assert succeeding.archive_path.is_file()
+
+    grace_event = repository.get_events(second.member_id)[-1]
+    assert grace_event.event_type == "sepa_notification_generated"
+    assert grace_event.data["archive_error"]
+    assert "document" not in grace_event.references
+    ada_event = repository.get_events(ada.member_id)[-1]
+    assert "document" in ada_event.references
+
+
+def test_generated_mail_smtp_failure_for_one_debit_does_not_abort_the_batch(tmp_path, monkeypatch):
+    import ccma.services.sepa_mail as sepa_mail_module
+    from ccma.storage.repository import RepositoryError
+
+    repository, ada = _repository(tmp_path)
+    second = repository.create_member(first_name="Grace", last_name="Hopper", member_number="C3-43")
+    second.status = "active"
+    second.email = "grace@example.org"
+    second.account_holder = "Grace Hopper"
+    second.iban = "DE89370400440532013000"
+    second.bic = "COBADEFFXXX"
+    second.mandate_reference = "MANDAT-43"
+    second.mandate_signed_at = "2025-01-10"
+    second.mandate_active = True
+    repository.save_member(second)
+    repository.save_contributions(
+        second.member_id,
+        ContributionData(
+            claims=[
+                {
+                    "claim_id": "due",
+                    "title": "Mitgliedsbeitrag 2026",
+                    "amount": "150.00",
+                    "due_date": "2026-01-31",
+                    "status": "open",
+                }
+            ]
+        ),
+    )
+    organization = repository.get_configuration()["organization"]
+    organization.update(
+        {
+            "name": "Chaos Computer Club Mannheim e.V.",
+            "email": "verwaltung@example.org",
+            "iban": "DE89370400440532013000",
+            "bic": "COBADEFFXXX",
+            "creditor_id": "DE98ZZZ09999999999",
+        }
+    )
+    repository.save_organization(organization)
+    repository.save_email_settings(
+        delivery_mode="send",
+        smtp_host="mail.example.org",
+        smtp_port=587,
+        smtp_security="none",
+        smtp_username="",
+        smtp_password="",
+        imap_host="",
+        imap_port=993,
+        imap_security="ssl",
+        imap_username="",
+        imap_password="",
+        imap_drafts_folder="",
+    )
+    debits, _warnings = pending_direct_debits(repository, due_until=date(2026, 12, 31))
+    assert len(debits) == 2
+
+    monkeypatch.setattr(
+        sepa_mail_module, "smtp_session", contextmanager(lambda settings: iter(["smtp-client"]))
+    )
+    sent = []
+
+    def _flaky_send(client, content):
+        if b"ada@example.org" in content:
+            raise RepositoryError("E-Mail konnte nicht versandt werden: connection reset")
+        sent.append(content)
+
+    monkeypatch.setattr(sepa_mail_module, "send_via_smtp", _flaky_send)
+
+    generated, warnings = generate_debit_mails(
+        repository,
+        debits,
+        collection_date=date(2026, 8, 3),
+        delivery_mode="send",
+        sender_name="Verwaltung C3MA",
+        sender_email="verwaltung@example.org",
+        signature="Der Vorstand",
+    )
+
+    assert len(sent) == 1
+    assert len(generated) == 1
+    assert generated[0].member_id == second.member_id
+    assert len(warnings) == 1
+    assert "connection reset" in warnings[0]
+    ada_events = repository.get_events(ada.member_id)
+    assert all(event.event_type != "sepa_notification_generated" for event in ada_events)