\jJ ZdZddlmZddlZddlmZejeZd d Z dd Z dS)uBest-effort accessors for the single-writer stream fence (#65991). The fence itself lives on ``AIAgent`` (``_claim_stream_writer`` / ``_stream_writer_is_current`` in ``run_agent.py``), but the streaming code paths that use it live in *other* modules — ``chat_completion_helpers`` (chat / anthropic / bedrock) and ``codex_runtime`` (codex responses). Calling the fence directly as ``agent._claim_stream_writer()`` from those modules makes them hard-depend on the method being present on whatever object is passed in as ``agent``. That coupling is a latent crash: a partially-updated checkout (the streaming helper module newer than ``run_agent``), a hot-reloaded gateway, a duck-typed agent, or a test double without the method turns an *additive* safety net into a fatal ``AttributeError`` that aborts the whole turn. A cron job died exactly this way with ``'AIAgent' object has no attribute '_claim_stream_writer'``. The fence is only ever allowed to drop a *provably* superseded stream — never the sole legitimate writer. So when the guard is unavailable (or raises), the correct degradation is "no fence": keep streaming. These helpers make the claim/check best-effort to guarantee that. ) annotationsN)Anyagentrreturnintct|dd}t|rD t|S#t$rtddYnwxYwdS)aClaim the delta sink for the calling stream attempt, best-effort. Returns the agent's monotonic writer token when the fence is available, or ``0`` when the agent doesn't expose it (or the claim raised). A ``0`` token pairs with :func:`stream_writer_is_current` always returning ``True``, so a guard-less agent is simply never fenced instead of crashing the turn. _claim_stream_writerNz7stream single-writer: claim failed; proceeding unfencedTexc_infor)getattrcallabler Exceptionloggerdebug)rclaims @/home/thesage/.hermes/hermes-agent/agent/stream_single_writer.pyclaim_stream_writerrs E14 8 8E uuww<<     LLI        1s9&A"!A"tokenboolc|sdSt|dd}t|rE t||S#t$rtddYnwxYwdS)adTrue when ``token`` is still the active writer, best-effort. A falsy token (from a claim that no-oped) or an agent without the fence means we cannot prove supersession, so the stream is treated as current and never fenced. This preserves the single-writer invariant's one-way promise: only a demonstrably stale writer is ever stopped. T_stream_writer_is_currentNzBstream single-writer: is_current check failed; treating as currentr )r r rrrr)rr is_currents rstream_writer_is_currentr3s t ;TBBJ   5))** *    LLT        4s>&A'&A')rrrr)rrrrrr) __doc__ __future__rloggingtypingr getLogger__name__rrrrr"s,#"""""  8 $ $    (r!