fix validation

Author: svenseeberg

opendrift_leeway_webgui/leeway/forms.py

@@ -7,7 +7,14 @@
 from django.contrib.auth import get_user_model
 from django.contrib.auth.forms import UserCreationForm
 from django.core.exceptions import ValidationError
-from django.forms import ChoiceField, DecimalField, ModelForm, Select, TextInput
+from django.forms import (
+    ChoiceField,
+    DecimalField,
+    FloatField,
+    ModelForm,
+    Select,
+    TextInput,
+)
 
 from .models import LeewaySimulation, Webhook
 
@@ -43,6 +50,12 @@ class LeewaySimulationForm(ModelForm):
     decimal value in the ``clean_latitude`` / ``clean_longitude`` methods.
     """
 
+    # Override model FloatFields as not-required so that returning None from
+    # clean_latitude / clean_longitude (when a sub-field already reported an
+    # error) does not produce a duplicate "This field is required." message.
+    latitude = FloatField(required=False)
+    longitude = FloatField(required=False)
+
     #: Direction choices for latitude
     LAT_DIR_CHOICES = [("N", "N"), ("S", "S")]
     #: Direction choices for longitude