Improve typing and invariant checks for CaseListService

src/open_inwoner/cms/cases/views/cases.py

@@ -1,4 +1,5 @@
 import logging
+from typing import Sequence
 
 from django.urls import reverse
 from django.utils.functional import cached_property
@@ -69,8 +70,8 @@ def get_context_data(self, **kwargs):
         context["filter_form_enabled"] = config.zaken_filter_enabled
 
         # update ctx with open submissions and cases (possibly fitered)
-        open_submissions: list[UniformCase] = case_service.get_submissions()
-        preprocessed_cases: list[UniformCase] = case_service.get_cases()
+        open_submissions: Sequence[UniformCase] = case_service.get_submissions()
+        preprocessed_cases: Sequence[UniformCase] = case_service.get_cases()
 
         if config.zaken_filter_enabled:
             case_status_frequencies = case_service.get_case_status_frequencies()

src/open_inwoner/cms/cases/views/services.py

@@ -17,7 +17,6 @@
     ZaakTypeStatusTypeConfig,
     ZGWApiGroupConfig,
 )
-from open_inwoner.openzaak.types import UniformCase
 from open_inwoner.openzaak.utils import get_user_fetch_parameters, is_zaak_visible
 
 logger = logging.getLogger(__name__)
@@ -30,12 +29,12 @@ class CaseFilterFormOption(enum.Enum):
 
 
 @dataclass(frozen=True)
-class ZaakWithApiGroup(UniformCase):
+class ZaakWithApiGroup:
     zaak: Zaak
     api_group: ZGWApiGroupConfig
 
     @property
-    def identification(self):
+    def identification(self) -> str:
         return self.zaak.url
 
     def process_data(self) -> dict:
@@ -48,7 +47,7 @@ class SubmissionWithApiGroup:
     api_group: ZGWApiGroupConfig
 
     @property
-    def identifier(self):
+    def identification(self) -> str:
         return self.submission.url
 
     def process_data(self) -> dict:
@@ -87,12 +86,15 @@ def __init__(self, request: HttpRequest):
 
     def get_submissions_for_api_group(
         self, group: ZGWApiGroupConfig
-    ) -> list[UniformCase]:
+    ) -> list[OpenSubmission]:
+        if not group.forms_client:
+            raise ValueError(f"{group} has no `forms_client`")
+
         return group.forms_client.fetch_open_submissions(
             **get_user_fetch_parameters(self.request, check_rsin=False)
         )
 
-    def get_submissions(self):
+    def get_submissions(self) -> list[SubmissionWithApiGroup]:
         all_api_groups = list(
             ZGWApiGroupConfig.objects.exclude(form_service__isnull=True)
         )
@@ -103,7 +105,7 @@ def get_submissions(self):
                 for group in all_api_groups
             ]
 
-            subs_with_api_group = []
+            subs_with_api_group: list[SubmissionWithApiGroup] = []
             for task in concurrent.futures.as_completed(futures):
                 try:
                     group_for_task = all_api_groups[futures.index(task)]