fix(responses): invalidate changed options safely

src/govoplan_poll/backend/capabilities.py

@@ -31,6 +31,7 @@ from govoplan_poll.backend.service import (
     create_poll_invitation,
     decide_poll,
     get_poll,
+    get_poll_response_for_respondents,
     list_poll_responses,
     open_poll,
     poll_result_summary_by_id,
@@ -291,6 +292,27 @@ class SqlPollSchedulingProvider(PollSchedulingProvider):
             raise PollCapabilityError(str(exc)) from exc
         return tuple(_response_ref(response) for response in responses)
 
+    def get_response(
+        self,
+        session: object,
+        *,
+        tenant_id: str,
+        poll_id: str,
+        respondent_ids: Sequence[str],
+        invitation_id: str | None = None,
+    ) -> PollResponseRef | None:
+        try:
+            response = get_poll_response_for_respondents(
+                session,
+                tenant_id=tenant_id,
+                poll_id=poll_id,
+                respondent_ids=tuple(respondent_ids),
+                invitation_id=invitation_id,
+            )
+        except PollError as exc:
+            raise PollCapabilityError(str(exc)) from exc
+        return _response_ref(response) if response is not None else None
+
     @staticmethod
     def _transition(callback, session: object, *, tenant_id: str, poll_id: str) -> PollRef:
         try:

src/govoplan_poll/backend/service.py

@@ -732,6 +732,44 @@ def _lock_poll_for_response(session: Session, *, tenant_id: str, poll_id: str) -
     return poll
 
 
+def get_poll_response_for_respondents(
+    session: Session,
+    *,
+    tenant_id: str,
+    poll_id: str,
+    respondent_ids: tuple[str, ...],
+    invitation_id: str | None = None,
+) -> PollResponse | None:
+    """Resolve a response from server-trusted respondent identities."""
+
+    get_poll(session, tenant_id=tenant_id, poll_id=poll_id)
+    ids = tuple(dict.fromkeys(value for value in respondent_ids if value))
+    if ids:
+        response = (
+            session.query(PollResponse)
+            .filter(
+                PollResponse.tenant_id == tenant_id,
+                PollResponse.poll_id == poll_id,
+                PollResponse.respondent_id.in_(ids),
+                PollResponse.deleted_at.is_(None),
+            )
+            .order_by(PollResponse.submitted_at.desc(), PollResponse.id.desc())
+            .first()
+        )
+        if response is not None:
+            return response
+    if invitation_id is None:
+        return None
+    return next(
+        (
+            response
+            for response in reversed(list_poll_responses(session, tenant_id=tenant_id, poll_id=poll_id))
+            if (response.metadata_ or {}).get("invitation_id") == invitation_id
+        ),
+        None,
+    )
+
+
 def update_poll_option(
     session: Session,
     *,
@@ -793,6 +831,8 @@ def update_poll_option(
         .with_for_update()
         .all()
     )
+    if responses and not poll.allow_response_update:
+        raise PollError("Poll options cannot be edited after responses when response updates are disabled")
     option.label = label
     option.description = description
     option.value = normalized_value
@@ -805,6 +845,8 @@ def update_poll_option(
         ]
         if retained_answers != (response.answers or []):
             response.answers = retained_answers
+            if not retained_answers:
+                response.deleted_at = _now()
     session.flush()
     return option