[Python] Fix for optional properties in flatten model to keep compatibility (#3271)

* Update dependencies

* Add changelog .chronus/changes/auto-microsoft-python-fix-optional-properties-2025-11-3-16-16-35.md

* Update dependencies (2025-12-03 09:28:16)

* Regenerate for typespec-python (2025-12-03 09:33:26)

---------

Co-authored-by: AutoPrFromHttpClientPython <AutoPrFromHttpClientPython>

Author: msyyc

.chronus/changes/auto-microsoft-python-fix-optional-properties-2025-11-3-16-16-35.md

@@ -0,0 +1,8 @@
+---
+changeKind: fix
+packages:
+  - "@autorest/python"
+  - "@azure-tools/typespec-python"
+---
+
+Fix for optional properties in flatten model to keep compatibility

packages/autorest.python/package.json

@@ -29,7 +29,7 @@
   },
   "homepage": "https://github.com/Azure/autorest.python/blob/main/README.md",
   "dependencies": {
-    "@typespec/http-client-python": "https://artprodcus3.artifacts.visualstudio.com/A0fb41ef4-5012-48a9-bf39-4ee3de03ee35/29ec6040-b234-4e31-b139-33dc4287b756/_apis/artifact/cGlwZWxpbmVhcnRpZmFjdDovL2F6dXJlLXNkay9wcm9qZWN0SWQvMjllYzYwNDAtYjIzNC00ZTMxLWIxMzktMzNkYzQyODdiNzU2L2J1aWxkSWQvNTYyNzAzNy9hcnRpZmFjdE5hbWUvYnVpbGRfYXJ0aWZhY3RzX3B5dGhvbg2/content?format=file&subPath=%2Fpackages%2Ftypespec-http-client-python-0.21.0.tgz",
+    "@typespec/http-client-python": "https://artprodcus3.artifacts.visualstudio.com/A0fb41ef4-5012-48a9-bf39-4ee3de03ee35/29ec6040-b234-4e31-b139-33dc4287b756/_apis/artifact/cGlwZWxpbmVhcnRpZmFjdDovL2F6dXJlLXNkay9wcm9qZWN0SWQvMjllYzYwNDAtYjIzNC00ZTMxLWIxMzktMzNkYzQyODdiNzU2L2J1aWxkSWQvNTYzMTg5My9hcnRpZmFjdE5hbWUvYnVpbGRfYXJ0aWZhY3RzX3B5dGhvbg2/content?format=file&subPath=%2Fpackages%2Ftypespec-http-client-python-0.21.0.tgz",
     "@autorest/system-requirements": "~1.0.2",
     "fs-extra": "~11.2.0",
     "tsx": "~4.19.1"

packages/typespec-python/package.json

@@ -67,7 +67,7 @@
     "js-yaml": "~4.1.0",
     "semver": "~7.6.2",
     "tsx": "~4.19.1",
-    "@typespec/http-client-python": "https://artprodcus3.artifacts.visualstudio.com/A0fb41ef4-5012-48a9-bf39-4ee3de03ee35/29ec6040-b234-4e31-b139-33dc4287b756/_apis/artifact/cGlwZWxpbmVhcnRpZmFjdDovL2F6dXJlLXNkay9wcm9qZWN0SWQvMjllYzYwNDAtYjIzNC00ZTMxLWIxMzktMzNkYzQyODdiNzU2L2J1aWxkSWQvNTYyNzAzNy9hcnRpZmFjdE5hbWUvYnVpbGRfYXJ0aWZhY3RzX3B5dGhvbg2/content?format=file&subPath=%2Fpackages%2Ftypespec-http-client-python-0.21.0.tgz",
+    "@typespec/http-client-python": "https://artprodcus3.artifacts.visualstudio.com/A0fb41ef4-5012-48a9-bf39-4ee3de03ee35/29ec6040-b234-4e31-b139-33dc4287b756/_apis/artifact/cGlwZWxpbmVhcnRpZmFjdDovL2F6dXJlLXNkay9wcm9qZWN0SWQvMjllYzYwNDAtYjIzNC00ZTMxLWIxMzktMzNkYzQyODdiNzU2L2J1aWxkSWQvNTYzMTg5My9hcnRpZmFjdE5hbWUvYnVpbGRfYXJ0aWZhY3RzX3B5dGhvbg2/content?format=file&subPath=%2Fpackages%2Ftypespec-http-client-python-0.21.0.tgz",
     "fs-extra": "~11.2.0"
   },
   "devDependencies": {

packages/typespec-python/test/azure/generated/authentication-api-key/authentication/apikey/_utils/model_base.py

@@ -998,7 +998,11 @@ def __init__(
 
     @property
     def _class_type(self) -> typing.Any:
-        return getattr(self._type, "args", [None])[0]
+        result = getattr(self._type, "args", [None])[0]
+        # type may be wrapped by nested functools.partial so we need to check for that
+        if isinstance(result, functools.partial):
+            return getattr(result, "args", [None])[0]
+        return result
 
     @property
     def _rest_name(self) -> str:

packages/typespec-python/test/azure/generated/authentication-http-custom/authentication/http/custom/_utils/model_base.py

@@ -998,7 +998,11 @@ def __init__(
 
     @property
     def _class_type(self) -> typing.Any:
-        return getattr(self._type, "args", [None])[0]
+        result = getattr(self._type, "args", [None])[0]
+        # type may be wrapped by nested functools.partial so we need to check for that
+        if isinstance(result, functools.partial):
+            return getattr(result, "args", [None])[0]
+        return result
 
     @property
     def _rest_name(self) -> str:

packages/typespec-python/test/azure/generated/authentication-oauth2/authentication/oauth2/_utils/model_base.py

@@ -998,7 +998,11 @@ def __init__(
 
     @property
     def _class_type(self) -> typing.Any:
-        return getattr(self._type, "args", [None])[0]
+        result = getattr(self._type, "args", [None])[0]
+        # type may be wrapped by nested functools.partial so we need to check for that
+        if isinstance(result, functools.partial):
+            return getattr(result, "args", [None])[0]
+        return result
 
     @property
     def _rest_name(self) -> str:

packages/typespec-python/test/azure/generated/authentication-union/authentication/union/_utils/model_base.py

@@ -998,7 +998,11 @@ def __init__(
 
     @property
     def _class_type(self) -> typing.Any:
-        return getattr(self._type, "args", [None])[0]
+        result = getattr(self._type, "args", [None])[0]
+        # type may be wrapped by nested functools.partial so we need to check for that
+        if isinstance(result, functools.partial):
+            return getattr(result, "args", [None])[0]
+        return result
 
     @property
     def _rest_name(self) -> str:

packages/typespec-python/test/azure/generated/azure-client-generator-core-access/specs/azure/clientgenerator/core/access/_utils/model_base.py

@@ -998,7 +998,11 @@ def __init__(
 
     @property
     def _class_type(self) -> typing.Any:
-        return getattr(self._type, "args", [None])[0]
+        result = getattr(self._type, "args", [None])[0]
+        # type may be wrapped by nested functools.partial so we need to check for that
+        if isinstance(result, functools.partial):
+            return getattr(result, "args", [None])[0]
+        return result
 
     @property
     def _rest_name(self) -> str:

packages/typespec-python/test/azure/generated/azure-client-generator-core-alternate-type/specs/azure/clientgenerator/core/alternatetype/_utils/model_base.py

@@ -1012,7 +1012,11 @@ def __init__(
 
     @property
     def _class_type(self) -> typing.Any:
-        return getattr(self._type, "args", [None])[0]
+        result = getattr(self._type, "args", [None])[0]
+        # type may be wrapped by nested functools.partial so we need to check for that
+        if isinstance(result, functools.partial):
+            return getattr(result, "args", [None])[0]
+        return result
 
     @property
     def _rest_name(self) -> str:

packages/typespec-python/test/azure/generated/azure-client-generator-core-api-version-header/client/alternateapiversion/service/header/_utils/model_base.py

@@ -998,7 +998,11 @@ def __init__(
 
     @property
     def _class_type(self) -> typing.Any:
-        return getattr(self._type, "args", [None])[0]
+        result = getattr(self._type, "args", [None])[0]
+        # type may be wrapped by nested functools.partial so we need to check for that
+        if isinstance(result, functools.partial):
+            return getattr(result, "args", [None])[0]
+        return result
 
     @property
     def _rest_name(self) -> str: