refactor(api): type _error_to_stream_response with ErrorStreamResponseDict TypedDict

[aviu16]

Part of #32863 (api/core/app/apps/base_app_generate_response_converter.py)

Summary

• Define ErrorStreamResponseDict TypedDict for the _error_to_stream_response return type
• Replace dict[str, Any] return annotation and data variable annotation with the new TypedDict

Why this change

_error_to_stream_response returns a fixed 3-key dict (code, message, status) for every code path. The bare dict[str, Any] hides this contract from the stream response serializer and callers in the chat/completion pipelines.

Changes

• api/core/app/apps/base_app_generate_response_converter.py: Define ErrorStreamResponseDict, annotate _error_to_stream_response return type and data local variable

[github-actions]

Pyrefly Diff

base → PR

--- /tmp/pyrefly_base.txt	2026-04-12 03:37:02.855638893 +0000
+++ /tmp/pyrefly_pr.txt	2026-04-12 03:36:54.467662901 +0000
@@ -14,6 +14,20 @@
   --> controllers/console/setup.py:65:2
 ERROR Object of class `MissingRouter` has no attribute `get` [missing-attribute]
   --> controllers/console/version.py:30:2
+ERROR No matching overload found for function `typing.MutableMapping.update` called with arguments: (ErrorStreamResponseDict) [no-matching-overload]
+  --> core/app/apps/agent_chat/generate_response_converter.py:82:38
+ERROR No matching overload found for function `typing.MutableMapping.update` called with arguments: (ErrorStreamResponseDict) [no-matching-overload]
+   --> core/app/apps/agent_chat/generate_response_converter.py:118:38
+ERROR `dict[str, Any]` is not assignable to variable `data` with type `ErrorStreamResponseDict | None` [bad-assignment]
+   --> core/app/apps/base_app_generate_response_converter.py:139:24
+ERROR No matching overload found for function `typing.MutableMapping.update` called with arguments: (ErrorStreamResponseDict) [no-matching-overload]
+  --> core/app/apps/chat/generate_response_converter.py:82:38
+ERROR No matching overload found for function `typing.MutableMapping.update` called with arguments: (ErrorStreamResponseDict) [no-matching-overload]
+   --> core/app/apps/chat/generate_response_converter.py:118:38
+ERROR No matching overload found for function `typing.MutableMapping.update` called with arguments: (ErrorStreamResponseDict) [no-matching-overload]
+  --> core/app/apps/completion/generate_response_converter.py:80:38
+ERROR No matching overload found for function `typing.MutableMapping.update` called with arguments: (ErrorStreamResponseDict) [no-matching-overload]
+   --> core/app/apps/completion/generate_response_converter.py:117:38
 ERROR Class member `EasyUIBasedGenerateTaskPipeline._application_generate_entity` overrides parent class `BasedGenerateTaskPipeline` in an inconsistent manner [bad-override]
   --> core/app/task_pipeline/easy_ui_based_generate_task_pipeline.py:75:5
 ERROR `+=` is not supported between `list[PromptMessageContentUnionTypes]` and `str` [unsupported-operation]

[Copilot]

Pull request overview

This PR refactors _error_to_stream_response in the API app response conversion layer to make its return type explicit via a dedicated TypedDict, improving type safety for downstream stream response serialization/callers.

Changes:

• Introduces ErrorStreamResponseDict TypedDict to describe the error stream payload shape.
• Updates _error_to_stream_response return type (and a local variable) from dict[str, Any] to ErrorStreamResponseDict.

Comments suppressed due to low confidence (1)

api/core/app/apps/base_app_generate_response_converter.py:140

• data is annotated as ErrorStreamResponseDict, but error_responses values are plain dict[str, Any] and several entries omit the required message key. With basedpyright, assigning v to data and later mutating it via setdefault will not type-check against a total TypedDict. Consider typing error_responses with a (partial) TypedDict (e.g., message as NotRequired) and constructing a new ErrorStreamResponseDict that always includes code, status, and a computed message before returning (instead of setdefault).

        data: ErrorStreamResponseDict | None = None
        for k, v in error_responses.items():
            if isinstance(e, k):
                data = v

---

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