SearchFieldDataType.Collection not visible to static type checkers (requires # type: ignore at every call site)

Library: azure-search-documents
Version: 12.1.0b1 (observed after upgrading from 11.7.0b2)
Python: 3.13

What we ran into

After upgrading azure-search-documents to 12.1.0b1, our static type checker started flagging every use of SearchFieldDataType.Collection(...) as a call on a non-callable. We build vector/collection fields the way the SDK docstrings recommend, e.g.:

SearchField(
    name="embedding",
    type=SearchFieldDataType.Collection(SearchFieldDataType.Single),
    ...
)

To keep our type-check gate green we had to add a suppression at every call site (8 across our codebase). Since Collection(Edm.Single) is the standard way to declare vector fields, this affects essentially anyone doing vector search, so we wanted to raise it rather than just silently suppress.

Why it seems to happen

SearchFieldDataType is defined in _enums.py as a plain enum with no Collection member. Collection is instead added at runtime in models/_patch.py:

SearchFieldDataType.Collection = staticmethod(_collection_helper)  # type: ignore[attr-defined]

Because the attribute only exists at runtime, static analyzers (we hit this with ty, but I'd expect mypy/pyright to behave the same since the symbol isn't present at type-check time) can't see it as callable — they model SearchFieldDataType.Collection as an enum member and report the call as call-non-callable / not-callable. The SDK already suppresses the same underlying issue internally on the monkey-patch line.

Possible directions (deferring to your judgment)

I'm not sure what the intended pattern is here, so a few options that would each remove the need for downstream suppressions — whichever fits your codegen/_patch conventions best:

• There's already a module-level def Collection(typ: Any) -> str in _patch.py that isn't in __all__. Exporting it would let callers use a fully-typed Collection(...) helper.
• Or add a typed @staticmethod declaration for Collection on the enum class so the runtime patch is visible to type checkers.
• Or document the officially-supported, type-safe way to construct a collection field type, if one already exists that we've missed.

Happy to provide a minimal repro or test a proposed fix.