[python] Add mock API tests for XML scenarios from PR #10063 and fix XML serialization bugs (WIP)

.chronus/changes/python-xml-test-cases-2026-3-19-22-47-48.md

@@ -0,0 +1,7 @@
+---
+changeKind: internal
+packages:
+  - "@typespec/http-client-python"
+---
+
+Add mock API test cases for XML scenarios introduced in https://github.com/microsoft/typespec/pull/10063, covering: renamed property, nested model, renamed nested model, wrapped primitive with custom item names, model array variants (wrapped/unwrapped/renamed), renamed attribute, namespace, and namespace-on-properties. Tests for unwrapped model array serialization and namespace handling are skipped pending generator bug fixes.

.gitignore

@@ -87,6 +87,7 @@ celerybeat-schedule
 /.env
 .env.local
 .venv
+.venv_test
 env/
 venv/
 ENV/

packages/http-client-python/generator/pygen/codegen/templates/model_base.py.jinja2

@@ -630,7 +630,11 @@ class Model(_MyMutableMapping):
                 for rf in self._attr_to_rest_field.values():
                     prop_meta = getattr(rf, "_xml", {})
                     xml_name = prop_meta.get("name", rf._rest_name)
-                    xml_ns = prop_meta.get("ns", model_meta.get("ns", None))
+                    xml_ns = prop_meta.get("ns") or prop_meta.get("namespace")
+                    # If the property has no namespace but the model uses a default namespace
+                    # (declared without a prefix), child elements inherit that namespace.
+                    if xml_ns is None and not model_meta.get("prefix"):
+                        xml_ns = model_meta.get("ns") or model_meta.get("namespace")
                     if xml_ns:
                         xml_name = "{" + xml_ns + "}" + xml_name
 
@@ -761,7 +765,9 @@ class Model(_MyMutableMapping):
             model_meta = getattr(cls, "_xml", {})
             prop_meta = getattr(discriminator, "_xml", {})
             xml_name = prop_meta.get("name", discriminator._rest_name)
-            xml_ns = prop_meta.get("ns", model_meta.get("ns", None))
+            xml_ns = prop_meta.get("ns") or prop_meta.get("namespace")
+            if xml_ns is None and not model_meta.get("prefix"):
+                xml_ns = model_meta.get("ns") or model_meta.get("namespace")
             if xml_ns:
                 xml_name = "{" + xml_ns + "}" + xml_name
 
@@ -1254,10 +1260,15 @@ def _get_element(
 
         # if prop is a model, then use the prop element directly, else generate a wrapper of model
         if wrapped_element is None:
+            # When serializing as an array item (parent_meta is set), check if the parent has an
+            # explicit itemsName. This ensures correct element names for unwrapped arrays (where
+            # the element tag is the property/items name, not the model type name).
+            _items_name = parent_meta.get("itemsName") if parent_meta is not None else None
+            element_name = _items_name if _items_name else (model_meta.get("name") or o.__class__.__name__)
             wrapped_element = _create_xml_element(
-                model_meta.get("name", o.__class__.__name__),
+                element_name,
                 model_meta.get("prefix"),
-                model_meta.get("ns"),
+                model_meta.get("ns") or model_meta.get("namespace"),
             )
 
         readonly_props = []
@@ -1279,7 +1290,9 @@ def _get_element(
                 # additional properties will not have rest field, use the wire name as xml name
                 prop_meta = {"name": k}
 
-            # if no ns for prop, use model's
+            # Propagate model namespace to properties only for old-style "ns"-keyed models.
+            # DPG-generated models use the "namespace" key and explicitly declare namespace on
+            # each property that needs it, so propagation is intentionally skipped for them.
             if prop_meta.get("ns") is None and model_meta.get("ns"):
                 prop_meta["ns"] = model_meta.get("ns")
                 prop_meta["prefix"] = model_meta.get("prefix")
@@ -1292,9 +1305,10 @@ def _get_element(
                 wrapped_element.text = _get_primitive_type_value(v)
             elif prop_meta.get("attribute", False):
                 xml_name = prop_meta.get("name", k)
-                if prop_meta.get("ns"):
-                    ET.register_namespace(prop_meta.get("prefix"), prop_meta.get("ns"))  # pyright: ignore
-                    xml_name = "{" + prop_meta.get("ns") + "}" + xml_name  # pyright: ignore
+                _attr_ns = prop_meta.get("ns") or prop_meta.get("namespace")
+                if _attr_ns:
+                    ET.register_namespace(prop_meta.get("prefix"), _attr_ns)  # pyright: ignore
+                    xml_name = "{" + _attr_ns + "}" + xml_name  # pyright: ignore
                 # attribute should be primitive type
                 wrapped_element.set(xml_name, _get_primitive_type_value(v))
             else:
@@ -1312,7 +1326,7 @@ def _get_element(
                     exclude_readonly,
                     {
                         "name": k,
-                        "ns": parent_meta.get("ns") if parent_meta else None,
+                        "ns": (parent_meta.get("ns") or parent_meta.get("namespace")) if parent_meta else None,
                         "prefix": parent_meta.get("prefix") if parent_meta else None,
                     },
                 )
@@ -1327,7 +1341,7 @@ def _get_element(
             {
                 "name": parent_meta.get("itemsName", parent_meta.get("name")),
                 "prefix": parent_meta.get("itemsPrefix", parent_meta.get("prefix")),
-                "ns": parent_meta.get("itemsNs", parent_meta.get("ns")),
+                "ns": parent_meta.get("itemsNs") or parent_meta.get("ns") or parent_meta.get("namespace"),
             },
         )
 
@@ -1340,7 +1354,7 @@ def _get_wrapped_element(
     meta: typing.Optional[dict[str, typing.Any]],
 ) -> ET.Element:
     wrapped_element = _create_xml_element(
-        meta.get("name") if meta else None, meta.get("prefix") if meta else None, meta.get("ns") if meta else None
+        meta.get("name") if meta else None, meta.get("prefix") if meta else None, (meta.get("ns") or meta.get("namespace")) if meta else None
     )
     if isinstance(v, (dict, list)):
         wrapped_element.extend(_get_element(v, exclude_readonly, meta))
@@ -1365,7 +1379,16 @@ def _create_xml_element(
   tag: typing.Any, prefix: typing.Optional[str] = None, ns: typing.Optional[str] = None
 ) -> ET.Element:
     if prefix and ns:
-        ET.register_namespace(prefix, ns)
+        try:
+            ET.register_namespace(prefix, ns)
+        except ValueError:
+            # Some prefixes (e.g. 'ns2') match Python's reserved 'ns\d+' pattern used for
+            # auto-generated prefixes, causing register_namespace to raise ValueError.
+            # Fall back to directly registering in the internal namespace map so the intended
+            # prefix is honoured when serialising to XML.
+            _ns_map = getattr(ET, "_namespace_map", None)
+            if _ns_map is not None:
+                _ns_map[ns] = prefix
     if ns:
         return ET.Element("{" + ns + "}" + tag)
     return ET.Element(tag)

packages/http-client-python/generator/test/generic_mock_api_tests/asynctests/test_payload_xml_async.py

@@ -7,12 +7,21 @@
 import pytest
 from payload.xml.aio import XmlClient
 from payload.xml.models import (
+    Author,
+    Book,
     SimpleModel,
     ModelWithSimpleArrays,
     ModelWithArrayOfModel,
     ModelWithAttributes,
     ModelWithUnwrappedArray,
+    ModelWithUnwrappedModelArray,
     ModelWithRenamedArrays,
+    ModelWithRenamedProperty,
+    ModelWithRenamedAttribute,
+    ModelWithRenamedNestedModel,
+    ModelWithRenamedWrappedModelArray,
+    ModelWithRenamedUnwrappedModelArray,
+    ModelWithRenamedWrappedAndItemModelArray,
     ModelWithOptionalField,
     ModelWithRenamedFields,
     ModelWithEmptyArray,
@@ -21,6 +30,10 @@
     ModelWithEncodedNames,
     ModelWithEnum,
     ModelWithDatetime,
+    ModelWithNamespace,
+    ModelWithNamespaceOnProperties,
+    ModelWithNestedModel,
+    ModelWithWrappedPrimitiveCustomItemNames,
 )
 
 
@@ -37,13 +50,27 @@ async def test_simple_model(client: XmlClient):
     await client.simple_model_value.put(model)
 
 
+@pytest.mark.asyncio
+async def test_model_with_renamed_property(client: XmlClient):
+    model = ModelWithRenamedProperty(title="foo", author="bar")
+    assert await client.model_with_renamed_property_value.get() == model
+    await client.model_with_renamed_property_value.put(model)
+
+
 @pytest.mark.asyncio
 async def test_model_with_simple_arrays(client: XmlClient):
     model = ModelWithSimpleArrays(colors=["red", "green", "blue"], counts=[1, 2])
     assert await client.model_with_simple_arrays_value.get() == model
     await client.model_with_simple_arrays_value.put(model)
 
 
+@pytest.mark.asyncio
+async def test_model_with_wrapped_primitive_custom_item_names(client: XmlClient):
+    model = ModelWithWrappedPrimitiveCustomItemNames(tags=["fiction", "classic"])
+    assert await client.model_with_wrapped_primitive_custom_item_names_value.get() == model
+    await client.model_with_wrapped_primitive_custom_item_names_value.put(model)
+
+
 @pytest.mark.asyncio
 async def test_model_with_array_of_model(client: XmlClient):
     model = ModelWithArrayOfModel(
@@ -56,13 +83,68 @@ async def test_model_with_array_of_model(client: XmlClient):
     await client.model_with_array_of_model_value.put(model)
 
 
+@pytest.mark.asyncio
+async def test_model_with_unwrapped_model_array(client: XmlClient):
+    model = ModelWithUnwrappedModelArray(
+        items_property=[
+            SimpleModel(name="foo", age=123),
+            SimpleModel(name="bar", age=456),
+        ]
+    )
+    assert await client.model_with_unwrapped_model_array_value.get() == model
+    await client.model_with_unwrapped_model_array_value.put(model)
+
+
+@pytest.mark.asyncio
+async def test_model_with_renamed_wrapped_model_array(client: XmlClient):
+    model = ModelWithRenamedWrappedModelArray(
+        items_property=[
+            SimpleModel(name="foo", age=123),
+            SimpleModel(name="bar", age=456),
+        ]
+    )
+    assert await client.model_with_renamed_wrapped_model_array_value.get() == model
+    await client.model_with_renamed_wrapped_model_array_value.put(model)
+
+
+@pytest.mark.asyncio
+async def test_model_with_renamed_unwrapped_model_array(client: XmlClient):
+    model = ModelWithRenamedUnwrappedModelArray(
+        items_property=[
+            SimpleModel(name="foo", age=123),
+            SimpleModel(name="bar", age=456),
+        ]
+    )
+    assert await client.model_with_renamed_unwrapped_model_array_value.get() == model
+    await client.model_with_renamed_unwrapped_model_array_value.put(model)
+
+
+@pytest.mark.asyncio
+async def test_model_with_renamed_wrapped_and_item_model_array(client: XmlClient):
+    model = ModelWithRenamedWrappedAndItemModelArray(
+        books=[
+            Book(title="The Great Gatsby"),
+            Book(title="Les Miserables"),
+        ]
+    )
+    assert await client.model_with_renamed_wrapped_and_item_model_array_value.get() == model
+    await client.model_with_renamed_wrapped_and_item_model_array_value.put(model)
+
+
 @pytest.mark.asyncio
 async def test_model_with_attributes(client: XmlClient):
     model = ModelWithAttributes(id1=123, id2="foo", enabled=True)
     assert await client.model_with_attributes_value.get() == model
     await client.model_with_attributes_value.put(model)
 
 
+@pytest.mark.asyncio
+async def test_model_with_renamed_attribute(client: XmlClient):
+    model = ModelWithRenamedAttribute(id=123, title="The Great Gatsby", author="F. Scott Fitzgerald")
+    assert await client.model_with_renamed_attribute_value.get() == model
+    await client.model_with_renamed_attribute_value.put(model)
+
+
 @pytest.mark.asyncio
 async def test_model_with_unwrapped_array(client: XmlClient):
     model = ModelWithUnwrappedArray(colors=["red", "green", "blue"], counts=[1, 2])
@@ -84,6 +166,20 @@ async def test_model_with_optional_field(client: XmlClient):
     await client.model_with_optional_field_value.put(model)
 
 
+@pytest.mark.asyncio
+async def test_model_with_nested_model(client: XmlClient):
+    model = ModelWithNestedModel(nested=SimpleModel(name="foo", age=123))
+    assert await client.model_with_nested_model_value.get() == model
+    await client.model_with_nested_model_value.put(model)
+
+
+@pytest.mark.asyncio
+async def test_model_with_renamed_nested_model(client: XmlClient):
+    model = ModelWithRenamedNestedModel(author=Author(name="foo"))
+    assert await client.model_with_renamed_nested_model_value.get() == model
+    await client.model_with_renamed_nested_model_value.put(model)
+
+
 @pytest.mark.asyncio
 async def test_model_with_renamed_fields(client: XmlClient):
     model = ModelWithRenamedFields(
@@ -141,6 +237,20 @@ async def test_model_with_datetime(client: XmlClient):
     await client.model_with_datetime_value.put(model)
 
 
+@pytest.mark.asyncio
+async def test_model_with_namespace(client: XmlClient):
+    model = ModelWithNamespace(id=123, title="The Great Gatsby")
+    assert await client.model_with_namespace_value.get() == model
+    await client.model_with_namespace_value.put(model)
+
+
+@pytest.mark.asyncio
+async def test_model_with_namespace_on_properties(client: XmlClient):
+    model = ModelWithNamespaceOnProperties(id=123, title="The Great Gatsby", author="F. Scott Fitzgerald")
+    assert await client.model_with_namespace_on_properties_value.get() == model
+    await client.model_with_namespace_on_properties_value.put(model)
+
+
 @pytest.mark.asyncio
 async def test_xml_error_value(client: XmlClient, core_library):
     with pytest.raises(core_library.exceptions.HttpResponseError) as ex: