Initial public release

backend/core/dependencies/_registry.py

@@ -0,0 +1,35 @@
+"""Singleton decorator and automatic cleanup registry for DI providers."""
+
+from __future__ import annotations
+
+from functools import lru_cache, wraps
+from typing import Callable, TypeVar
+
+F = TypeVar("F", bound=Callable)
+
+_singleton_registry: list[Callable] = []
+
+
+def singleton(fn: F) -> F:
+    """Wrap *fn* with ``@lru_cache(maxsize=1)`` and register it for automatic cleanup."""
+    cached = lru_cache(maxsize=1)(fn)
+    _singleton_registry.append(cached)
+
+    @wraps(fn)
+    def wrapper(*args, **kwargs):
+        return cached(*args, **kwargs)
+
+    # Expose cache_clear so callers can invalidate individual singletons
+    wrapper.cache_clear = cached.cache_clear  # type: ignore[attr-defined]
+    wrapper.cache_info = cached.cache_info  # type: ignore[attr-defined]
+    wrapper._cached = cached  # type: ignore[attr-defined]
+    _singleton_registry[-1] = wrapper  # replace with the wrapper so clear_all hits wrapper
+    return wrapper  # type: ignore[return-value]
+
+
+def clear_all_singletons() -> None:
+    """Call ``cache_clear()`` on every registered singleton provider."""
+    for fn in _singleton_registry:
+        cache_clear = getattr(fn, "cache_clear", None)
+        if callable(cache_clear):
+            cache_clear()