Fix list type annotations when model property is named "list"

[Copilot]

Fix list type annotations when model property is named "list"

This PR fixes a syntax error that occurs when a model property is named "list", preventing TypeError: '_RestField' object is not subscriptable errors in generated Python code.

Changes

• Add has_property_named_list property to CodeModel class (similar to has_operation_named_list)
• Update ListType.type_annotation() to use "List" instead of "list" when property named "list" exists in models
• Add type alias definition in DpgModelSerializer.imports() (List = list) when needed
• Address code review feedback (improve test structure, fix spacing)
• Pass security checks (0 alerts)
• Add changelog entry

Summary

When a model has a property named "list", the generated code now uses a type alias List = list and references it as List[...] instead of list[...] to avoid naming conflicts. This follows the same pattern as the existing fix for operations named "list".

Files changed:

• code_model.py: Added has_property_named_list property
• list_type.py: Updated type annotation logic to handle property name conflicts
• model_serializer.py: Added type alias definition when needed
• .chronus/changes/copilot-fix-list-property-name-2025-12-22-05-33-41.md: Added changelog entry

The fix ensures backward compatibility and only applies the workaround when necessary.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>List type annotations leads to syntax error</issue_title>
<issue_description>I used the latest Python TypeSpec emitter on this tsplocation:

directory: specification/purview/data-plane/datamap
commit: 0c932f4a1e126784161397209484678f3adda2f6
repo: Azure/azure-rest-api-specs
additionalDirectories: 

I get annotation using list, so the code is not valid:

azure/purview/datamap/__init__.py:15: in <module>
    from ._client import DataMapClient  # type: ignore
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
azure/purview/datamap/_client.py:19: in <module>
    from .operations import (
azure/purview/datamap/operations/__init__.py:15: in <module>
    from ._operations import EntityOperations  # type: ignore
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
azure/purview/datamap/operations/_operations.py:30: in <module>
    from .. import models as _models
azure/purview/datamap/models/__init__.py:16: in <module>
    from ._models import (  # type: ignore
azure/purview/datamap/models/_models.py:496: in <module>
    class AtlasClassifications(_Model):
azure/purview/datamap/models/_models.py:514: in AtlasClassifications
    list: Optional[list[Any]] = rest_field(visibility=["read", "create", "update", "delete", "query"])
                   ^^^^^^^^^
E   TypeError: '_RestField' object is not subscriptable

Either we import "from future import annotation", or we use List. I think I prefer to import future annotations, since it's more oriented to the future.

I'm using Python 3.12.3, so totally recent runtime.</issue_description>

<agent_instructions>We ever fixed a similar bug that an operation is named "list"

typespec/packages/http-client-python/generator/pygen/codegen/models/list_type.py

Lines 44 to 46 in dd8b601

	# if there is a function named `list` we have to make sure there's no conflict with the built-in `list`
	list_type = "List" if self.code_model.has_operation_named_list and kwargs.get("is_operation_file") else "list"
	return f"{list_type}[{self.element_type.type_annotation(**kwargs)}]"

. And this issue is about model property so we could add similar logic to fix it.</agent_instructions>

Comments on the Issue (you are @copilot in this section)

@msyyc We ever fixed a similar bug that an operation is named "list" https://github.com/microsoft/typespec/blob/dd8b60156738aeb9ce4c854805b7a15afdd4108f/packages/http-client-python/generator/pygen/codegen/models/list_type.py#L44-L46. And this issue is about model property so we could add similar logic to fix it.

• Fixes List type annotations leads to syntax error #9248

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commit: 52305cf

[github-actions]

All changed packages have been documented.

• ✅ @typespec/http-client-python

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@typespec/http-client-python - fix ✏️

Fix syntax error when model property is named "list" by using type alias to avoid naming conflicts