[core] add tests and fix backcompat functions

sdk/core/azure-core/CHANGELOG.md

@@ -1,12 +1,10 @@
 # Release History
 
-## 1.36.1 (Unreleased)
+## 1.37.0 (2025-12-08)
 
 ### Features Added
 
-### Breaking Changes
-
-### Bugs Fixed
+- Added `get_backcompat_attr_name` to `azure.core.serialization`. `get_backcompat_attr_name` gets the backcompat name of an attribute using backcompat attribute access.  #44084
 
 ### Other Changes
 

sdk/core/azure-core/azure/core/_version.py

@@ -9,4 +9,4 @@
 # regenerated.
 # --------------------------------------------------------------------------
 
-VERSION = "1.36.1"
+VERSION = "1.37.0"

sdk/core/azure-core/azure/core/serialization.py

@@ -4,6 +4,7 @@
 # Licensed under the MIT License. See License.txt in the project root for
 # license information.
 # --------------------------------------------------------------------------
+# pylint: disable=protected-access
 import base64
 from functools import partial
 from json import JSONEncoder
@@ -19,6 +20,7 @@
     "as_attribute_dict",
     "attribute_list",
     "TypeHandlerRegistry",
+    "get_backcompat_attr_name",
 ]
 TZ_UTC = timezone.utc
 
@@ -317,7 +319,7 @@ def _is_readonly(p: Any) -> bool:
     :rtype: bool
     """
     try:
-        return p._visibility == ["read"]  # pylint: disable=protected-access
+        return p._visibility == ["read"]
     except AttributeError:
         return False
 
@@ -332,6 +334,20 @@ def _as_attribute_dict_value(v: Any, *, exclude_readonly: bool = False) -> Any:
     return as_attribute_dict(v, exclude_readonly=exclude_readonly) if is_generated_model(v) else v
 
 
+def _get_backcompat_name(rest_field: Any, default_attr_name: str) -> str:
+    """Get the backcompat name for an attribute.
+
+    :param any rest_field: The rest field to get the backcompat name from.
+    :param str default_attr_name: The default attribute name to use if no backcompat name
+    :return: The backcompat name.
+    :rtype: str
+    """
+    try:
+        return rest_field._original_tsp_name or default_attr_name
+    except AttributeError:
+        return default_attr_name
+
+
 def _get_flattened_attribute(obj: Any) -> Optional[str]:
     """Get the name of the flattened attribute in a generated TypeSpec model if one exists.
 
@@ -348,11 +364,9 @@ def _get_flattened_attribute(obj: Any) -> Optional[str]:
     if flattened_items is None:
         return None
 
-    for k, v in obj._attr_to_rest_field.items():  # pylint: disable=protected-access
+    for k, v in obj._attr_to_rest_field.items():
         try:
-            if set(v._class_type._attr_to_rest_field.keys()).intersection(  # pylint: disable=protected-access
-                set(flattened_items)
-            ):
+            if set(v._class_type._attr_to_rest_field.keys()).intersection(set(flattened_items)):
                 return k
         except AttributeError:
             # if the attribute does not have _class_type, it is not a typespec generated model
@@ -372,12 +386,12 @@ def attribute_list(obj: Any) -> List[str]:
         raise TypeError("Object is not a generated SDK model.")
     if hasattr(obj, "_attribute_map"):
         # msrest model
-        return list(obj._attribute_map.keys())  # pylint: disable=protected-access
+        return list(obj._attribute_map.keys())
     flattened_attribute = _get_flattened_attribute(obj)
     retval: List[str] = []
-    for attr_name, rest_field in obj._attr_to_rest_field.items():  # pylint: disable=protected-access
+    for attr_name, rest_field in obj._attr_to_rest_field.items():
         if flattened_attribute == attr_name:
-            retval.extend(attribute_list(rest_field._class_type))  # pylint: disable=protected-access
+            retval.extend(attribute_list(rest_field._class_type))
         else:
             retval.append(attr_name)
     return retval
@@ -410,16 +424,16 @@ def as_attribute_dict(obj: Any, *, exclude_readonly: bool = False) -> Dict[str,
         # create a reverse mapping from rest field name to attribute name
         rest_to_attr = {}
         flattened_attribute = _get_flattened_attribute(obj)
-        for attr_name, rest_field in obj._attr_to_rest_field.items():  # pylint: disable=protected-access
+        for attr_name, rest_field in obj._attr_to_rest_field.items():
 
             if exclude_readonly and _is_readonly(rest_field):
                 # if we're excluding readonly properties, we need to track them
-                readonly_props.add(rest_field._rest_name)  # pylint: disable=protected-access
+                readonly_props.add(rest_field._rest_name)
             if flattened_attribute == attr_name:
-                for fk, fv in rest_field._class_type._attr_to_rest_field.items():  # pylint: disable=protected-access
-                    rest_to_attr[fv._rest_name] = fk  # pylint: disable=protected-access
+                for fk, fv in rest_field._class_type._attr_to_rest_field.items():
+                    rest_to_attr[fv._rest_name] = fk
             else:
-                rest_to_attr[rest_field._rest_name] = attr_name  # pylint: disable=protected-access
+                rest_to_attr[rest_field._rest_name] = attr_name
         for k, v in obj.items():
             if exclude_readonly and k in readonly_props:  # pyright: ignore
                 continue
@@ -429,10 +443,8 @@ def as_attribute_dict(obj: Any, *, exclude_readonly: bool = False) -> Dict[str,
             else:
                 is_multipart_file_input = False
                 try:
-                    is_multipart_file_input = next(  # pylint: disable=protected-access
-                        rf
-                        for rf in obj._attr_to_rest_field.values()  # pylint: disable=protected-access
-                        if rf._rest_name == k  # pylint: disable=protected-access
+                    is_multipart_file_input = next(
+                        rf for rf in obj._attr_to_rest_field.values() if rf._rest_name == k
                     )._is_multipart_file_input
                 except StopIteration:
                     pass
@@ -444,3 +456,36 @@ def as_attribute_dict(obj: Any, *, exclude_readonly: bool = False) -> Dict[str,
     except AttributeError as exc:
         # not a typespec generated model
         raise TypeError("Object must be a generated model instance.") from exc
+
+
+def get_backcompat_attr_name(model: Any, attr_name: str) -> str:
+    """Get the backcompat attribute name for a given attribute.
+
+    This function takes an attribute name and returns the backcompat name (original TSP name)
+    if one exists, otherwise returns the attribute name itself.
+
+    :param any model: The model instance.
+    :param str attr_name: The attribute name to get the backcompat name for.
+    :return: The backcompat attribute name (original TSP name) or the attribute name itself.
+    :rtype: str
+    """
+    if not is_generated_model(model):
+        raise TypeError("Object must be a generated model instance.")
+
+    # Check if attr_name exists in the model's attributes
+    flattened_attribute = _get_flattened_attribute(model)
+    for field_attr_name, rest_field in model._attr_to_rest_field.items():
+        # Check if this is the attribute we're looking for
+        if field_attr_name == attr_name:
+            # Return the original TSP name if it exists, otherwise the attribute name
+            return _get_backcompat_name(rest_field, attr_name)
+
+        # If this is a flattened attribute, check inside it
+        if flattened_attribute == field_attr_name:
+            for fk, fv in rest_field._class_type._attr_to_rest_field.items():
+                if fk == attr_name:
+                    # Return the original TSP name for this flattened property
+                    return _get_backcompat_name(fv, fk)
+
+    # If not found in the model, just return the attribute name as-is
+    return attr_name

sdk/core/azure-core/tests/specs_sdk/modeltypes/modeltypes/_utils/model_base.py

@@ -654,6 +654,10 @@ def __new__(cls, *args: typing.Any, **kwargs: typing.Any) -> Self:
                 if not rf._rest_name_input:
                     rf._rest_name_input = attr
             cls._attr_to_rest_field: typing.Dict[str, _RestField] = dict(attr_to_rest_field.items())
+            cls._backcompat_attr_to_rest_field: typing.Dict[str, _RestField] = {
+                Model._get_backcompat_attribute_name(cls._attr_to_rest_field, attr): rf
+                for attr, rf in cls._attr_to_rest_field.items()
+            }
             cls._calculated.add(f"{cls.__module__}.{cls.__qualname__}")
 
         return super().__new__(cls)
@@ -663,6 +667,16 @@ def __init_subclass__(cls, discriminator: typing.Optional[str] = None) -> None:
             if hasattr(base, "__mapping__"):
                 base.__mapping__[discriminator or cls.__name__] = cls  # type: ignore
 
+    @classmethod
+    def _get_backcompat_attribute_name(cls, _attr_to_rest_field: typing.Dict[str, "_RestField"], attr_name: str) -> str:
+        rest_field = _attr_to_rest_field.get(attr_name)  # pylint: disable=protected-access
+        if rest_field is None:
+            return attr_name
+        original_tsp_name = getattr(rest_field, "_original_tsp_name", None)  # pylint: disable=protected-access
+        if original_tsp_name:
+            return original_tsp_name
+        return attr_name
+
     @classmethod
     def _get_discriminator(cls, exist_discriminators) -> typing.Optional["_RestField"]:
         for v in cls.__dict__.values():
@@ -998,6 +1012,7 @@ def __init__(
         format: typing.Optional[str] = None,
         is_multipart_file_input: bool = False,
         xml: typing.Optional[typing.Dict[str, typing.Any]] = None,
+        original_tsp_name: typing.Optional[str] = None,
     ):
         self._type = type
         self._rest_name_input = name
@@ -1009,6 +1024,7 @@ def __init__(
         self._format = format
         self._is_multipart_file_input = is_multipart_file_input
         self._xml = xml if xml is not None else {}
+        self._original_tsp_name = original_tsp_name
 
     @property
     def _class_type(self) -> typing.Any:
@@ -1060,6 +1076,7 @@ def rest_field(
     format: typing.Optional[str] = None,
     is_multipart_file_input: bool = False,
     xml: typing.Optional[typing.Dict[str, typing.Any]] = None,
+    original_tsp_name: typing.Optional[str] = None,
 ) -> typing.Any:
     return _RestField(
         name=name,
@@ -1069,6 +1086,7 @@ def rest_field(
         format=format,
         is_multipart_file_input=is_multipart_file_input,
         xml=xml,
+        original_tsp_name=original_tsp_name,
     )