Files
DECNET/decnet/ttp/impl/_state.py
anti e7531ee756 refactor(ttp): extract RuleIndex from RuleEngine
E.3.9.0 prerequisite for the per-source lifters (E.3.9-E.3.13). The
dispatch index, install/evict/apply_change atomic-swap protocol, and
state-modulation helpers (is_active / apply_ceiling) move out of
rule_engine.py into _rule_index.py and _state.py. RuleEngine wraps a
RuleIndex; back-compat shims preserve _by_kind / _by_rule / _install
attribute access for tests poking at the dispatch internals.

Lifters in E.3.9-E.3.12 will each hold their own RuleIndex, watching
the same RuleStore via subscribe_changes() fan-out. Hot-reload
semantics (disable / clip / TTL via set_state API) now reach
lifter-bound rules through the same atomic-swap path the engine uses,
not a future composite-rebuild compromise.
2026-05-01 20:09:18 -04:00

56 lines
2.0 KiB
Python

"""Shared state-modulation helpers for rule consumers.
Both :class:`~decnet.ttp.impl.rule_engine.RuleEngine` and the per-source
lifters (E.3.9 onward) read :class:`~decnet.ttp.store.base.RuleState`
the same way: skip on ``disabled``, defense-in-depth re-check
``expires_at``, clamp confidence on ``clipped``. Single source of truth
so a future change to the state contract lands in one place.
"""
from __future__ import annotations
from datetime import datetime, timezone
from typing import TYPE_CHECKING
if TYPE_CHECKING:
from decnet.ttp.store.base import RuleState
def is_active(state: "RuleState") -> bool:
"""Return ``True`` iff a rule with this state is allowed to fire.
``disabled`` rules never fire. ``clipped`` rules still fire — the
clip caps emitted confidence, doesn't suppress the emit. Expired
states act as ``disabled`` even though the store auto-reverts; the
re-check here is defense-in-depth against a racing read between
expiry and the store's revert pass.
"""
if state.state == "disabled":
return False
if state.expires_at is not None:
expires = state.expires_at
if expires.tzinfo is None:
expires = expires.replace(tzinfo=timezone.utc)
if expires < datetime.now(tz=timezone.utc):
return False
return True
def apply_ceiling(base: float, state: "RuleState") -> float:
"""Apply the operator's confidence ceiling, downward only.
A ``clipped`` state with ``confidence_max < 1.0`` clamps the emitted
confidence to ``min(base, base * ceiling)``. Any other state is a
no-op. The clamp is downward by construction — operator clips can
never raise a rule's confidence above its YAML-declared base, per
TTP_TAGGING.md §"Confidence model".
"""
if state.state != "clipped":
return base
ceiling = state.confidence_max
if ceiling is None or ceiling >= 1.0:
return base
return min(base, base * ceiling)
__all__ = ["is_active", "apply_ceiling"]