[data] Fix type hint for config parameter in build_processor

[ArchishmanSengupta]

Description

The public engine config classes (vLLMEngineProcessorConfig, SGLangEngineProcessorConfig,
HttpRequestProcessorConfig, ServeDeploymentProcessorConfig) only inherited from their
internal base classes, not from the public ProcessorConfig wrapper. This made them sibling
types of ProcessorConfig in the static type system, so type checkers (pyright, mypy, IDE
linters) flagged valid calls like build_processor(config=vLLMEngineProcessorConfig(...)) as
type errors, even though they work correctly at runtime.

This adds ProcessorConfig as a secondary base class to each public config class. Since they
already inherit from internal classes that derive from the same _ProcessorConfig base, this
forms a valid diamond and correctly establishes them as subclasses of the public
ProcessorConfig. build_processor keeps its clean public config: ProcessorConfig type hint.
No internal types are leaked into the public API and no runtime behavior changes.

Related issues

Fixes #57981

Additional information

Verified with pyright — the repro from the issue and all config types now produce 0 type errors.

[gemini-code-assist]

Code Review

This pull request updates the type hint of the config parameter in the public build_processor function from ProcessorConfig to the internal _ProcessorConfig. The reviewer advises against exposing internal classes in the public API and suggests keeping the public ProcessorConfig type hint by utilizing multiple inheritance on the configuration classes.

Important

The consumer version of Gemini Code Assist on GitHub is being sunset. Starting June 18, 2026, new organization installations will be blocked, and all code review activity will officially cease on July 17, 2026.
For more details on the timeline and next steps, please review the Help Documentation.

[gemini-code-assist]

Exposing the internal/private class _ProcessorConfig in the public API signature of build_processor is not ideal, as it leaks internal implementation details to users and static analysis tools.

Instead of changing the type hint of build_processor to _ProcessorConfig, a cleaner and more idiomatic approach is to make the public config classes inherit from the public ProcessorConfig class as well. Since they already inherit from their respective internal classes (which inherit from _ProcessorConfig), adding ProcessorConfig as a secondary base class forms a valid diamond inheritance and correctly establishes them as subclasses of ProcessorConfig in the type system.

For example:

class HttpRequestProcessorConfig(_HttpRequestProcessorConfig, ProcessorConfig):
    pass

class vLLMEngineProcessorConfig(_vLLMEngineProcessorConfig, ProcessorConfig):
    pass

This allows build_processor to keep its clean, public type hint.

Suggested change

	config: _ProcessorConfig,
	config: ProcessorConfig,