Don't allow 0 as valid form value for required rating field (baserow#5084)

Author: stribny

backend/src/baserow/contrib/database/fields/field_types.py

@@ -910,16 +910,29 @@ def prepare_value_for_db(self, instance, value):
         return value
 
     def get_serializer_field(self, instance, **kwargs):
-        return serializers.IntegerField(
-            **{
-                "required": False,
-                "allow_null": False,
-                "min_value": 0,
-                "default": 0,
-                "max_value": instance.max_value,
-                **kwargs,
-            }
-        )
+        required = kwargs.get("required", False)
+        field_kwargs = {
+            "required": False,
+            "allow_null": False,
+            "min_value": 0,
+            "default": 0,
+            "max_value": instance.max_value,
+            **kwargs,
+        }
+        if required:
+            field_kwargs.pop("default", None)
+            validators = field_kwargs.get("validators", [])
+            validators.append(self._rating_required_validator)
+            field_kwargs["validators"] = validators
+        return serializers.IntegerField(**field_kwargs)
+
+    @staticmethod
+    def _rating_required_validator(value):
+        if value == 0:
+            raise ValidationError(
+                "This field is required.",
+                code="required",
+            )
 
     def force_same_type_alter_column(self, from_field, to_field):
         """

backend/tests/baserow/contrib/database/api/views/form/test_form_view_views.py

@@ -2995,6 +2995,89 @@ def test_submit_form_view_for_required_number_field_with_0(api_client, data_fixt
     }
 
 
+@pytest.mark.django_db
+def test_submit_form_view_for_required_rating_field_with_0(api_client, data_fixture):
+    user, token = data_fixture.create_user_and_token()
+    table = data_fixture.create_database_table(user=user)
+    form = data_fixture.create_form_view(
+        table=table,
+        submit_action_message="Test",
+        submit_action_redirect_url="https://baserow.io",
+    )
+    rating_field = data_fixture.create_rating_field(table=table)
+    data_fixture.create_form_view_field_option(
+        form, rating_field, required=True, enabled=True, order=2
+    )
+
+    url = reverse("api:database:views:form:submit", kwargs={"slug": form.slug})
+
+    # Submitting 0 should fail because 0 means "no rating" for a required rating field
+    response = api_client.post(
+        url,
+        {f"field_{rating_field.id}": 0},
+        format="json",
+        HTTP_AUTHORIZATION=f"JWT {token}",
+    )
+    assert response.status_code == HTTP_400_BAD_REQUEST
+    response_json = response.json()
+    assert response_json["detail"][f"field_{rating_field.id}"][0]["code"] == "required"
+
+    # Submitting a valid rating should succeed
+    response = api_client.post(
+        url,
+        {f"field_{rating_field.id}": 3},
+        format="json",
+        HTTP_AUTHORIZATION=f"JWT {token}",
+    )
+    assert response.status_code == HTTP_200_OK
+    response_json = response.json()
+    assert response_json == {
+        "row_id": AnyInt(),
+        "submit_action": "MESSAGE",
+        "submit_action_message": "Test",
+        "submit_action_redirect_url": "https://baserow.io",
+    }
+
+
+@pytest.mark.django_db
+def test_submit_form_view_for_non_required_rating_field_with_0(
+    api_client, data_fixture
+):
+    """
+    Submitting 0 should succeed when the rating field is not required.
+    """
+
+    user, token = data_fixture.create_user_and_token()
+    table = data_fixture.create_database_table(user=user)
+    form = data_fixture.create_form_view(
+        table=table,
+        submit_action_message="Test",
+        submit_action_redirect_url="https://baserow.io",
+    )
+    rating_field = data_fixture.create_rating_field(table=table)
+    data_fixture.create_form_view_field_option(
+        form, rating_field, required=False, enabled=True, order=2
+    )
+
+    url = reverse("api:database:views:form:submit", kwargs={"slug": form.slug})
+
+    response = api_client.post(
+        url,
+        {f"field_{rating_field.id}": 0},
+        format="json",
+        HTTP_AUTHORIZATION=f"JWT {token}",
+    )
+
+    assert response.status_code == HTTP_200_OK
+    response_json = response.json()
+    assert response_json == {
+        "row_id": AnyInt(),
+        "submit_action": "MESSAGE",
+        "submit_action_message": "Test",
+        "submit_action_redirect_url": "https://baserow.io",
+    }
+
+
 @pytest.mark.django_db
 def test_upload_file_view(api_client, data_fixture, tmpdir):
     user, token = data_fixture.create_user_and_token(

changelog/entries/unreleased/bug/4985_rating_field_0.json

@@ -0,0 +1,9 @@
+{
+    "type": "bug",
+    "message": "Rating field now doesn't accept 0 as a valid value in form views when the field is required",
+    "issue_origin": "github",
+    "issue_number": 4985,
+    "domain": "database",
+    "bullet_points": [],
+    "created_at": "2026-03-30"
+}

web-frontend/modules/database/components/row/RowEditFieldRating.vue

@@ -10,6 +10,9 @@
         @update="update"
       />
     </div>
+    <div v-show="touched && !isValid()" class="error">
+      {{ getError() }}
+    </div>
   </div>
 </template>
 

web-frontend/modules/database/fieldTypes.js

@@ -1994,6 +1994,13 @@ export class RatingFieldType extends FieldType {
     return 0
   }
 
+  isEmpty(field, value) {
+    if (value === 0) {
+      return true
+    }
+    return super.isEmpty(field, value)
+  }
+
   canUpsert() {
     return true
   }