Avoid using DerivedElement with known elements for mixed wildcards

docs/examples.rst

@@ -11,12 +11,21 @@ Code Generation
     examples/docstrings
     examples/xml-modeling
     examples/json-modeling
-    examples/pycode-serializer
     examples/dtd-modeling
     examples/compound-fields
     examples/dataclasses-features
 
 
+Data Binding
+============
+
+.. toctree::
+    :maxdepth: 1
+
+    examples/pycode-serializer
+    examples/working-with-wildcards
+
+
 Advance Topics
 ==============
 

docs/faq/how-to-work-with-wildcard-fields.rst → docs/examples/working-with-wildcards.rst

@@ -1,5 +1,7 @@
-How to work with wildcard fields?
-==================================
+======================
+Working with wildcards
+======================
+
 
 One of the xml schema traits is to support any extensions with wildcards.
 
@@ -39,6 +41,9 @@ The generator will roughly create this class for you.
     ...      )
 
 
+Generics
+========
+
 xsdata comes with two generic models that are used during parsing and you can also use
 to generate any custom xml element.
 
@@ -87,3 +92,63 @@ to generate any custom xml element.
       </bar>
     </MetadataType>
     <BLANKLINE>
+
+
+Mixed content
+=============
+
+For mixed content with known choices you can skip wrapping your instances with a
+generic model. During data binding xsdata will try first to match one of the qualified
+choices.
+
+.. doctest::
+
+    >>> @dataclass
+    ... class Beta:
+    ...     class Meta:
+    ...         name = "beta"
+    ...
+    >>> @dataclass
+    ... class Alpha:
+    ...     class Meta:
+    ...         name = "alpha"
+    ...
+    >>> @dataclass
+    ... class Doc:
+    ...     class Meta:
+    ...         name = "doc"
+    ...
+    ...     content: List[object] = field(
+    ...         default_factory=list,
+    ...         metadata={
+    ...             "type": "Wildcard",
+    ...             "namespace": "##any",
+    ...             "mixed": True,
+    ...             "choices": (
+    ...                 {
+    ...                     "name": "a",
+    ...                     "type": Alpha,
+    ...                     "namespace": "",
+    ...                 },
+    ...                 {
+    ...                     "name": "b",
+    ...                     "type": Beta,
+    ...                     "namespace": "",
+    ...                 },
+    ...             ),
+    ...         }
+    ...     )
+    ...
+    >>> obj = Doc(
+    ...     content=[
+    ...         Alpha(),
+    ...         Beta(),
+    ...     ]
+    ... )
+    ...
+    >>> print(serializer.render(obj))
+    <doc>
+      <a/>
+      <b/>
+    </doc>
+    <BLANKLINE>

tests/fixtures/models.py

@@ -166,7 +166,14 @@ class Meta:
 
     content: List[object] = field(
         default_factory=list,
-        metadata=dict(type="Wildcard", namespace="##any", mixed=True),
+        metadata=dict(
+            type="Wildcard",
+            namespace="##any",
+            mixed=True,
+            choices=(
+                dict(name="span", type=Span),
+            ),
+        )
     )
 
 

tests/formats/dataclass/parsers/nodes/test_element.py

@@ -266,26 +266,38 @@ def test_bind_wild_list_var(self):
         self.assertEqual(expected, params)
 
     def test_prepare_generic_value(self):
-        actual = self.node.prepare_generic_value(None, 1)
+        var = XmlVarFactory.create(
+            index=2,
+            xml_type=XmlType.WILDCARD,
+            qname="a",
+            types=(object,),
+            elements={"known": XmlVarFactory.create()},
+        )
+
+        actual = self.node.prepare_generic_value(None, 1, var)
         self.assertEqual(1, actual)
 
-        actual = self.node.prepare_generic_value("a", 1)
+        actual = self.node.prepare_generic_value("a", 1, var)
         expected = AnyElement(qname="a", text="1")
         self.assertEqual(expected, actual)
 
-        actual = self.node.prepare_generic_value("a", "foo")
+        actual = self.node.prepare_generic_value("a", "foo", var)
         expected = AnyElement(qname="a", text="foo")
         self.assertEqual(expected, actual)
 
         fixture = make_dataclass("Fixture", [("content", str)])
-        actual = self.node.prepare_generic_value("a", fixture("foo"))
+        actual = self.node.prepare_generic_value("a", fixture("foo"), var)
         expected = DerivedElement(qname="a", value=fixture("foo"), type="Fixture")
         self.assertEqual(expected, actual)
 
-        actual = self.node.prepare_generic_value("a", expected)
+        fixture = make_dataclass("Fixture", [("content", str)])
+        actual = self.node.prepare_generic_value("known", fixture("foo"), var)
+        self.assertEqual(fixture("foo"), actual)
+
+        actual = self.node.prepare_generic_value("a", expected, var)
         self.assertIs(expected, actual)
 
-        actual = self.node.prepare_generic_value("Fixture", fixture("foo"))
+        actual = self.node.prepare_generic_value("Fixture", fixture("foo"), var)
         expected = DerivedElement(qname="Fixture", value=fixture("foo"))
         self.assertEqual(expected, actual)
 

xsdata/formats/dataclass/parsers/nodes/element.py

@@ -214,7 +214,7 @@ def bind_wild_var(self, params: Dict, var: XmlVar, qname: str, value: Any) -> bo
         generic instance add the current value as a child object.
         """
 
-        value = self.prepare_generic_value(qname, value)
+        value = self.prepare_generic_value(qname, value, var)
 
         if var.list_element:
             items = params.get(var.name)
@@ -240,11 +240,14 @@ def bind_mixed_objects(self, params: Dict, var: XmlVar, objects: List):
 
         pos = self.position
         params[var.name] = [
-            self.prepare_generic_value(qname, value) for qname, value in objects[pos:]
+            self.prepare_generic_value(qname, value, var)
+            for qname, value in objects[pos:]
         ]
         del objects[pos:]
 
-    def prepare_generic_value(self, qname: Optional[str], value: Any) -> Any:
+    def prepare_generic_value(
+        self, qname: Optional[str], value: Any, var: XmlVar
+    ) -> Any:
         """Prepare parsed value before binding to a wildcard field."""
 
         if qname:
@@ -253,7 +256,9 @@ def prepare_generic_value(self, qname: Optional[str], value: Any) -> Any:
 
             if not self.context.class_type.is_model(value):
                 value = any_factory(qname=qname, text=converter.serialize(value))
-            elif not isinstance(value, (any_factory, derived_factory)):
+            elif not isinstance(
+                value, (any_factory, derived_factory)
+            ) and not var.find_choice(qname):
                 meta = self.context.fetch(type(value))
                 xsi_type = namespaces.real_xsi_type(qname, meta.target_qname)
                 value = derived_factory(qname=qname, value=value, type=xsi_type)

xsdata/formats/dataclass/serializers/xml.py

@@ -118,11 +118,15 @@ def write_dataclass(
         yield XmlWriterEvent.END, qname
 
     def write_xsi_type(self, value: Any, var: XmlVar, namespace: NoneStr) -> Generator:
-        """Produce an events stream from a dataclass for the given var with
-        with xsi abstract type check for non wildcards."""
+        """Produce an events stream from a dataclass for the given var with xsi
+        abstract type check for non wildcards."""
 
         if var.is_wildcard:
-            yield from self.write_dataclass(value, namespace)
+            choice = var.find_value_choice(value, True)
+            if choice:
+                yield from self.write_value(value, choice, namespace)
+            else:
+                yield from self.write_dataclass(value, namespace)
         else:
             xsi_type = self.xsi_type(var, value, namespace)
             yield from self.write_dataclass(