mypy plugin added.

.coveragerc

@@ -0,0 +1,3 @@
+[run]
+omit =
+    pydantic_xml/mypy.py

pydantic_xml/model.py

@@ -162,23 +162,42 @@ def __init__(
             utils.register_nsmap(nsmap)
 
 
-def attr(name: Optional[str] = None, ns: Optional[str] = None, **kwargs: Any) -> Any:
+_Unset: Any = pdc.PydanticUndefined
+
+
+def attr(
+        name: Optional[str] = None,
+        ns: Optional[str] = None,
+        *,
+        default: Any = pdc.PydanticUndefined,
+        default_factory: Optional[Callable[[], Any]] = _Unset,
+        **kwargs: Any,
+) -> Any:
     """
     Marks a pydantic field as an xml attribute.
 
     :param name: attribute name
     :param ns: attribute xml namespace
+    :param default: the default value of the field.
+    :param default_factory: the factory function used to construct the default for the field.
     :param kwargs: pydantic field arguments. See :py:class:`pydantic.Field`
     """
 
-    return XmlEntityInfo(EntityLocation.ATTRIBUTE, path=name, ns=ns, **kwargs)
+    return XmlEntityInfo(
+        EntityLocation.ATTRIBUTE,
+        path=name, ns=ns, default=default, default_factory=default_factory,
+        **kwargs,
+    )
 
 
 def element(
         tag: Optional[str] = None,
         ns: Optional[str] = None,
         nsmap: Optional[NsMap] = None,
         nillable: bool = False,
+        *,
+        default: Any = pdc.PydanticUndefined,
+        default_factory: Optional[Callable[[], Any]] = _Unset,
         **kwargs: Any,
 ) -> Any:
     """
@@ -188,17 +207,26 @@ def element(
     :param ns: element xml namespace
     :param nsmap: element xml namespace map
     :param nillable: is element nillable. See https://www.w3.org/TR/xmlschema-1/#xsi_nil.
+    :param default: the default value of the field.
+    :param default_factory: the factory function used to construct the default for the field.
     :param kwargs: pydantic field arguments. See :py:class:`pydantic.Field`
     """
 
-    return XmlEntityInfo(EntityLocation.ELEMENT, path=tag, ns=ns, nsmap=nsmap, nillable=nillable, **kwargs)
+    return XmlEntityInfo(
+        EntityLocation.ELEMENT,
+        path=tag, ns=ns, nsmap=nsmap, nillable=nillable, default=default, default_factory=default_factory,
+        **kwargs,
+    )
 
 
 def wrapped(
         path: str,
         entity: Optional[pd.fields.FieldInfo] = None,
         ns: Optional[str] = None,
         nsmap: Optional[NsMap] = None,
+        *,
+        default: Any = pdc.PydanticUndefined,
+        default_factory: Optional[Callable[[], Any]] = _Unset,
         **kwargs: Any,
 ) -> Any:
     """
@@ -208,10 +236,16 @@ def wrapped(
     :param path: entity path
     :param ns: element xml namespace
     :param nsmap: element xml namespace map
+    :param default: the default value of the field.
+    :param default_factory: the factory function used to construct the default for the field.
     :param kwargs: pydantic field arguments. See :py:class:`pydantic.Field`
     """
 
-    return XmlEntityInfo(EntityLocation.WRAPPED, path=path, ns=ns, nsmap=nsmap, wrapped=entity, **kwargs)
+    return XmlEntityInfo(
+        EntityLocation.WRAPPED,
+        path=path, ns=ns, nsmap=nsmap, wrapped=entity, default=default, default_factory=default_factory,
+        **kwargs,
+    )
 
 
 class XmlModelMeta(ModelMetaclass):

pydantic_xml/mypy.py

@@ -0,0 +1,96 @@
+from typing import Callable, Optional, Tuple, Union
+
+from mypy import nodes
+from mypy.plugin import ClassDefContext, FunctionContext, Plugin, Type
+from pydantic.mypy import PydanticModelTransformer, PydanticPlugin
+
+ATTR_FULLNAME = 'pydantic_xml.model.attr'
+ELEMENT_FULLNAME = 'pydantic_xml.model.element'
+WRAPPED_FULLNAME = 'pydantic_xml.model.wrapped'
+ENTITIES_FULLNAME = (ATTR_FULLNAME, ELEMENT_FULLNAME, WRAPPED_FULLNAME)
+
+
+def plugin(version: str) -> type[Plugin]:
+    return PydanticXmlPlugin
+
+
+class PydanticXmlPlugin(PydanticPlugin):
+    def get_function_hook(self, fullname: str) -> Optional[Callable[[FunctionContext], Type]]:
+        sym = self.lookup_fully_qualified(fullname)
+        if sym and sym.fullname == ATTR_FULLNAME:
+            return self._attribute_callback
+        elif sym and sym.fullname == ELEMENT_FULLNAME:
+            return self._element_callback
+        elif sym and sym.fullname == WRAPPED_FULLNAME:
+            return self._wrapped_callback
+
+        return super().get_function_hook(fullname)
+
+    def _attribute_callback(self, ctx: FunctionContext) -> Type:
+        return super()._pydantic_field_callback(self._pop_first_args(ctx, 2))
+
+    def _element_callback(self, ctx: FunctionContext) -> Type:
+        return super()._pydantic_field_callback(self._pop_first_args(ctx, 4))
+
+    def _wrapped_callback(self, ctx: FunctionContext) -> Type:
+        return super()._pydantic_field_callback(self._pop_first_args(ctx, 4))
+
+    def _pop_first_args(self, ctx: FunctionContext, num: int) -> FunctionContext:
+        return FunctionContext(
+            arg_types=ctx.arg_types[num:],
+            arg_kinds=ctx.arg_kinds[num:],
+            callee_arg_names=ctx.callee_arg_names[num:],
+            arg_names=ctx.arg_names[num:],
+            default_return_type=ctx.default_return_type,
+            args=ctx.args[num:],
+            context=ctx.context,
+            api=ctx.api,
+        )
+
+    def _pydantic_model_class_maker_callback(self, ctx: ClassDefContext) -> bool:
+        transformer = PydanticXmlModelTransformer(ctx.cls, ctx.reason, ctx.api, self.plugin_config)
+        return transformer.transform()
+
+
+class PydanticXmlModelTransformer(PydanticModelTransformer):
+    @staticmethod
+    def get_has_default(stmt: nodes.AssignmentStmt) -> bool:
+        expr = stmt.rvalue
+        if isinstance(expr, nodes.TempNode):
+            return False
+
+        if (
+            isinstance(expr, nodes.CallExpr) and
+            isinstance(expr.callee, nodes.RefExpr) and
+            expr.callee.fullname in ENTITIES_FULLNAME
+        ):
+            for arg, name in zip(expr.args, expr.arg_names):
+                if name == 'default':
+                    return arg.__class__ is not nodes.EllipsisExpr
+                if name == 'default_factory':
+                    return not (isinstance(arg, nodes.NameExpr) and arg.fullname == 'builtins.None')
+
+            return False
+
+        return PydanticModelTransformer.get_has_default(stmt)
+
+    @staticmethod
+    def get_alias_info(stmt: nodes.AssignmentStmt) -> Tuple[Union[str, None], bool]:
+        expr = stmt.rvalue
+        if isinstance(expr, nodes.TempNode):
+            return None, False
+
+        if (
+            isinstance(expr, nodes.CallExpr) and
+            isinstance(expr.callee, nodes.RefExpr) and
+            expr.callee.fullname in ENTITIES_FULLNAME
+        ):
+            for arg, arg_name in zip(expr.args, expr.arg_names):
+                if arg_name != 'alias':
+                    continue
+                if isinstance(arg, nodes.StrExpr):
+                    return arg.value, False
+                else:
+                    return None, True
+
+        return PydanticModelTransformer.get_alias_info(stmt)