Geometry race condition fix

* fixes race condition for geometry conflict and parcel calculation
* harmonizes empty geometries from None/MultiPolygonEmpty to MultiPolygonEmpty

konova/forms/geometry_form.py

@@ -63,6 +63,7 @@ class SimpleGeomForm(BaseForm):
         geom = self.data["geom"]
         if geom is None or len(geom) == 0:
             # empty geometry is a valid geometry
+            self.cleaned_data["geom"] = MultiPolygon(srid=DEFAULT_SRID_RLP).ewkt
             return is_valid
         geom = json.loads(geom)
 
@@ -106,6 +107,8 @@ class SimpleGeomForm(BaseForm):
                 return is_valid
 
             features.append(polygon)
+
+        # Unionize all geometry features into one new MultiPolygon
         form_geom = MultiPolygon(srid=DEFAULT_SRID_RLP)
         for feature in features:
             form_geom = form_geom.union(feature)

konova/models/geometry.py

@@ -116,6 +116,11 @@ class Geometry(BaseResource):
 
         """
         from konova.models import Parcel, District, ParcelIntersection, Municipal, ParcelGroup
+
+        if self.geom.empty:
+            # Nothing to do
+            return
+
         parcel_fetcher = ParcelWFSFetcher(
             geometry_id=self.id,
         )

konova/templates/konova/includes/parcels/parcels.html

@@ -17,11 +17,17 @@
             </div>
         </div>
         <div class="card-body">
+            {% if geom_form.instance.geometry %}
             <div hx-trigger="load, every 5s" hx-get="{% url 'geometry-parcels' geom_form.instance.geometry.id %}">
                 <div class="row justify-content-center">
                     <span class="spinner-border rlp-r-inv" role="status"></span>
                 </div>
             </div>
+            {% else %}
+            <div class="alert alert-danger">
+                {% translate 'No geometry entry found on database. Please contact an admin!' %}
+            </div>
+            {% endif %}
         </div>
     </div>
 </div>

konova/views/geometry.py

@@ -32,16 +32,16 @@ def get_geom_parcels(request: HttpRequest, id: str):
     parcels = geom.get_underlying_parcels()
     geos_geom = geom.geom
 
-    parcels_are_currently_calculated = geos_geom is not None and geos_geom.area > 0 and len(parcels) == 0
+    geometry_exists = not geos_geom.empty
+    parcels_are_currently_calculated = geometry_exists and geos_geom.area > 0 and len(parcels) == 0
     parcels_available = len(parcels) > 0
-    no_geometry_given = geos_geom is None
 
     if parcels_are_currently_calculated:
         # Parcels are being calculated right now. Change the status code, so polling stays active for fetching
         # resutls after the calculation
         status_code = 200
 
-    if parcels_available or no_geometry_given:
+    if parcels_available or not geometry_exists:
         parcels = parcels.order_by("-municipal", "flr", "flrstck_zhlr", "flrstck_nnr")
         municipals = parcels.order_by("municipal").distinct("municipal").values("municipal__id")
         municipals = Municipal.objects.filter(id__in=municipals)