deprecation

Emit a deprecation warning with caller-controlled stack attribution.

langchain_core.warn_deprecated formats a standard message but hardcodes stacklevel=4 in its internal warnings.warn call. That value targets a decorator-wrapped frame layout; when called directly from a deprecated method's body the warning is attributed one frame too high (above the user's call site). This wrapper captures the formatted upstream warning and re-emits it with an explicit stacklevel, so the warning points at the user's call site.

Reset the @deprecated decorator's dedupe flag for testing.

The langchain_core @deprecated decorator emits each warning at most once per process via a closure-bound warned flag. Tests that assert per-call emission must reset that flag between cases — otherwise the assertions become reorder-sensitive (notably under pytest -n auto).

Accepts decorated functions, methods, and property objects (in which case the fget closure is reset). Targets without the expected warned freevar are silently skipped, so passing non-decorated callables is safe.