fix(backend): allow negative numbers in rollup field filter input (baserow#5429)

* fix(backend): include number_negative in rollup field response (baserow#3925)

The rollup field's API response was missing the `number_negative` key
because `RollupFieldType.serializer_field_names` was built from
`BASEROW_FORMULA_TYPE_ALLOWED_FIELDS`, which does not include it (unlike
`BASEROW_FORMULA_TYPE_SERIALIZER_FIELD_NAMES` used by `LookupFieldType`).

As a result, the frontend filter input's `isValidChar` check
(`numberField.js`) silently dropped the `-` keypress, making it
impossible to type negative numbers when filtering a rollup field.

Add `number_negative` explicitly to Rollup's serializer field list and
overrides as a read-only boolean defaulting to True. Formula-backed
number fields never enforce a 'no negatives' restriction, so the default
is always correct, and `read_only=True` keeps the write API unchanged.

* fix(backend): align Rollup field similar to lookup

Author: alamin-br

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

@@ -6229,13 +6229,22 @@ class RollupFieldType(FormulaFieldType):
         "target_field_id",
         "rollup_function",
     ]
-    serializer_field_names = BASEROW_FORMULA_TYPE_ALLOWED_FIELDS + [
+    request_serializer_field_names = (
+        BASEROW_FORMULA_TYPE_REQUEST_SERIALIZER_FIELD_NAMES
+        + [
+            "through_field_id",
+            "target_field_id",
+            "rollup_function",
+            "formula_type",
+        ]
+    )
+    serializer_field_names = BASEROW_FORMULA_TYPE_SERIALIZER_FIELD_NAMES + [
         "through_field_id",
         "target_field_id",
         "rollup_function",
         "formula_type",
     ]
-    serializer_field_overrides = {
+    request_serializer_field_overrides = {
         "through_field_id": serializers.IntegerField(
             required=False,
             allow_null=True,
@@ -6252,14 +6261,6 @@ class RollupFieldType(FormulaFieldType):
         "nullable": serializers.BooleanField(required=False, read_only=True),
     }
 
-    @property
-    def request_serializer_field_names(self):
-        return self.serializer_field_names
-
-    @property
-    def request_serializer_field_overrides(self):
-        return self.serializer_field_overrides
-
     def before_create(
         self, table, primary, allowed_field_values, order, user, field_kwargs
     ):

backend/tests/baserow/contrib/database/field/test_rollup_field_type.py

@@ -736,3 +736,41 @@ def test_remove_dependent_count_rollup_field_through_field(
     test_field.refresh_from_db()
     assert test_field.through_field_id is None
     assert test_field.error == "references the deleted or unknown field "
+
+
+@pytest.mark.django_db
+def test_rollup_field_api_response_includes_number_negative(data_fixture, api_client):
+    user, token = data_fixture.create_user_and_token()
+    table = data_fixture.create_database_table(user=user)
+    table2 = data_fixture.create_database_table(user=user, database=table.database)
+    data_fixture.create_text_field(name="tableprimary", table=table, primary=True)
+    data_fixture.create_text_field(name="table2primary", table=table2, primary=True)
+    rolled_up_field = data_fixture.create_number_field(
+        name="number", table=table2, number_negative=True
+    )
+    link_row_field = FieldHandler().create_field(
+        user,
+        table,
+        "link_row",
+        name="linkrowfield",
+        link_row_table=table2,
+    )
+    rollup_field = FieldHandler().create_field(
+        user,
+        table,
+        "rollup",
+        name="rollup_field",
+        through_field_id=link_row_field.id,
+        target_field_id=rolled_up_field.id,
+        rollup_function="sum",
+    )
+
+    response = api_client.get(
+        reverse("api:database:fields:item", kwargs={"field_id": rollup_field.id}),
+        format="json",
+        HTTP_AUTHORIZATION=f"JWT {token}",
+    )
+    assert response.status_code == HTTP_200_OK
+    response_json = response.json()
+    assert response_json["type"] == "rollup"
+    assert response_json["number_negative"] is True

changelog/entries/unreleased/bug/lets_you_type_negative_numbers_when_filtering_by_rollup.json

@@ -0,0 +1,9 @@
+{
+  "type": "bug",
+  "message": "Lets you type negative numbers when filtering by rollup field",
+  "issue_origin": "github",
+  "issue_number": 3925,
+  "domain": "database",
+  "bullet_points": [],
+  "created_at": "2026-05-28"
+}