Mark Snowflake connection form Proxy Port field optional (#65444)

Author: nikhilcss97

providers/snowflake/src/airflow/providers/snowflake/hooks/snowflake.py

@@ -138,6 +138,7 @@ def get_connection_form_widgets(cls) -> dict[str, Any]:
         )
         from flask_babel import lazy_gettext
         from wtforms import BooleanField, IntegerField, PasswordField, StringField
+        from wtforms.validators import Optional
 
         return {
             "account": StringField(lazy_gettext("Account"), widget=BS3TextFieldWidget()),
@@ -153,7 +154,11 @@ def get_connection_form_widgets(cls) -> dict[str, Any]:
                 label=lazy_gettext("Insecure mode"), description="Turns off OCSP certificate checks"
             ),
             "proxy_host": StringField(lazy_gettext("Proxy Host"), widget=BS3TextFieldWidget()),
-            "proxy_port": IntegerField(lazy_gettext("Proxy Port")),
+            "proxy_port": IntegerField(
+                lazy_gettext("Proxy Port"),
+                widget=BS3TextFieldWidget(),
+                validators=[Optional()],
+            ),
             "proxy_user": StringField(lazy_gettext("Proxy User"), widget=BS3TextFieldWidget()),
             "proxy_password": PasswordField(lazy_gettext("Proxy Password"), widget=BS3PasswordFieldWidget()),
         }

providers/snowflake/tests/unit/snowflake/hooks/test_snowflake.py

@@ -1787,3 +1787,37 @@ def test_get_sqlalchemy_engine_with_proxy(self):
             # Check that the URI doesn't contain proxy params
             called_uri = mock_create_engine.call_args[0][0]
             assert "proxy_host" not in str(called_uri)
+
+    def test_get_connection_form_widgets_proxy_port_is_optional(self):
+        """Proxy Port is an IntegerField and must remain optional.
+
+        Regression test for the Snowflake connection form silently rejecting
+        save when `Proxy Port` is left blank. `IntegerField` fails WTForms
+        validation on empty input by default, so `Optional()` is required to
+        preserve the documented optional semantics.
+        """
+        pytest.importorskip("flask_appbuilder")
+        pytest.importorskip("flask_babel")
+        Form = pytest.importorskip("wtforms").Form
+        Optional = pytest.importorskip("wtforms.validators").Optional
+        MultiDict = pytest.importorskip("werkzeug.datastructures").MultiDict
+
+        widgets = SnowflakeHook.get_connection_form_widgets()
+        assert "proxy_port" in widgets
+
+        proxy_port_field = widgets["proxy_port"]
+        assert any(isinstance(v, Optional) for v in proxy_port_field.kwargs.get("validators", []))
+
+        form_cls = type("_SnowflakeConnForm", (Form,), dict(widgets))
+
+        empty_form = form_cls(MultiDict([("proxy_port", "")]))
+        assert empty_form.validate() is True, empty_form.errors
+        assert empty_form.proxy_port.data is None
+
+        populated_form = form_cls(MultiDict([("proxy_port", "8080")]))
+        assert populated_form.validate() is True, populated_form.errors
+        assert populated_form.proxy_port.data == 8080
+
+        invalid_form = form_cls(MultiDict([("proxy_port", "not-an-int")]))
+        assert invalid_form.validate() is False
+        assert "proxy_port" in invalid_form.errors