fix: reparent governance backend failures under GatewayUnavailableError (issue #7)

A fail-closed limiter or breaker backend means the scope cannot emit a
single request, which is exactly scope-level unavailability. But the error
sat directly under PolyGatewayError, so a caller writing only
`except GatewayUnavailableError` dropped it into the catch-all branch:
Redis blips once and a backlog of tasks burns its business failure budget
into the dead letter queue, over a fault a restart would clear.

Three gate paths leak to callers rather than being absorbed by
_record_quietly (try_acquire, try_enter, progress_age_s); each is now
pinned by a test, since none of them had one before.

The two unknown-source sites move to SourceNotConfiguredError instead of
following along. They report a misconfigured source name, not an outage,
and letting them into the retryable family would be the mirror of the bug
being fixed here: the task would retry forever and never surface.

src/polygateway/backends/memory/limiter.py

@@ -15,7 +15,7 @@ import time
 import uuid
 from typing import TYPE_CHECKING
 
-from polygateway.errors import GovernanceBackendError
+from polygateway.errors import SourceNotConfiguredError
 from polygateway.types import GlobalLimits, SourceConfig, SourceStats
 
 if TYPE_CHECKING:
@@ -89,7 +89,7 @@ class InMemoryLimiter:
     def _cfg(self, source_key: str) -> SourceConfig:
         cfg = self._sources.get(source_key)
         if cfg is None:
-            raise GovernanceBackendError(f"未知源 {source_key!r}(scope={self._scope})")
+            raise SourceNotConfiguredError(f"未知源 {source_key!r}(scope={self._scope})")
         return cfg
 
     def _window(self) -> int:

src/polygateway/backends/redis/breaker.py

@@ -367,7 +367,7 @@ class RedisGate:
                 keys=[self._key(source_name)], args=[owner, self._probe_ttl_ms]
             )
         except RedisError as exc:
-            raise GovernanceBackendError(f"熔断后端 try_enter 失败: {exc}") from exc
+            raise GovernanceBackendError(f"熔断后端 try_enter 失败: {exc}", scope=self._scope) from exc
         return self._decision(source_name, result)
 
     async def record_success(
@@ -385,7 +385,7 @@ class RedisGate:
         try:
             result = await self._success_lua(keys=[self._key(entry.source_name)], args=args)
         except RedisError as exc:
-            raise GovernanceBackendError(f"熔断后端 record_success 失败: {exc}") from exc
+            raise GovernanceBackendError(f"熔断后端 record_success 失败: {exc}", scope=self._scope) from exc
         return self._update(result)
 
     async def record_failure(
@@ -407,7 +407,7 @@ class RedisGate:
         try:
             result = await self._failure_lua(keys=[self._key(entry.source_name)], args=args)
         except RedisError as exc:
-            raise GovernanceBackendError(f"熔断后端 record_failure 失败: {exc}") from exc
+            raise GovernanceBackendError(f"熔断后端 record_failure 失败: {exc}", scope=self._scope) from exc
         return self._update(result)
 
     async def release_probe(self, entry: GateDecision) -> GateUpdate:
@@ -419,7 +419,7 @@ class RedisGate:
                 keys=[self._key(entry.source_name)], args=[entry.epoch, entry.probe_owner]
             )
         except RedisError as exc:
-            raise GovernanceBackendError(f"熔断后端 release_probe 失败: {exc}") from exc
+            raise GovernanceBackendError(f"熔断后端 release_probe 失败: {exc}", scope=self._scope) from exc
         return self._update(result)
 
     async def retry_after_s(self, sources: tuple[str, ...]) -> float:
@@ -429,7 +429,7 @@ class RedisGate:
         try:
             result = await self._retry_after_lua(keys=[self._key(s) for s in sources])
         except RedisError as exc:
-            raise GovernanceBackendError(f"熔断后端 retry_after_s 失败: {exc}") from exc
+            raise GovernanceBackendError(f"熔断后端 retry_after_s 失败: {exc}", scope=self._scope) from exc
         return int(result) / 1000.0
 
     async def aclose(self) -> None:

src/polygateway/backends/redis/limiter.py

@@ -22,7 +22,7 @@ from typing import TYPE_CHECKING
 from loguru import logger
 from redis.exceptions import RedisError
 
-from polygateway.errors import GovernanceBackendError
+from polygateway.errors import GovernanceBackendError, SourceNotConfiguredError
 from polygateway.types import GlobalLimits, SourceConfig, SourceStats
 
 if TYPE_CHECKING:
@@ -195,7 +195,7 @@ class RedisLimiter:
     def _cfg(self, source_key: str) -> SourceConfig:
         cfg = self._sources.get(source_key)
         if cfg is None:
-            raise GovernanceBackendError(f"未知源 {source_key!r}(scope={self._scope})")
+            raise SourceNotConfiguredError(f"未知源 {source_key!r}(scope={self._scope})")
         return cfg
 
     def _lease_keys(self, source_key: str) -> tuple[str, str]:
@@ -247,7 +247,7 @@ class RedisLimiter:
                 ],
             )
         except RedisError as exc:
-            raise GovernanceBackendError(f"限流后端 try_acquire 失败: {exc}") from exc
+            raise GovernanceBackendError(f"限流后端 try_acquire 失败: {exc}", scope=self._scope) from exc
         if ok != 1:
             return None
         return _RedisPermit(self, source_key, lease_id, est_tokens, window)
@@ -265,14 +265,14 @@ class RedisLimiter:
         try:
             await self._release_lua(keys=[gl, sl], args=[lease_id])
         except RedisError as exc:
-            raise GovernanceBackendError(f"限流后端 release 失败: {exc}") from exc
+            raise GovernanceBackendError(f"限流后端 release 失败: {exc}", scope=self._scope) from exc
 
     async def _settle_tpm(self, source_key: str, delta: int, window: int) -> None:
         wk = self._window_keys(source_key, window)
         try:
             await self._settle_lua(keys=[wk["g_tpm"], wk["s_tpm"]], args=[delta, _WINDOW_TTL_S])
         except RedisError as exc:
-            raise GovernanceBackendError(f"限流后端 settle 失败: {exc}") from exc
+            raise GovernanceBackendError(f"限流后端 settle 失败: {exc}", scope=self._scope) from exc
 
     async def source_stats(self, source_key: str) -> SourceStats:
         """当前窗口快照;读侧 clamp ≥0(展示口径,存储保留负值)。"""
@@ -283,7 +283,7 @@ class RedisLimiter:
             wk = self._window_keys(source_key, window)
             res = await self._stats_lua(keys=[sl, wk["s_rpm"], wk["s_tpm"]])
         except RedisError as exc:
-            raise GovernanceBackendError(f"限流后端 source_stats 失败: {exc}") from exc
+            raise GovernanceBackendError(f"限流后端 source_stats 失败: {exc}", scope=self._scope) from exc
         return SourceStats(
             inflight=int(res[0]),
             rpm_used=max(0, int(res[1])),
@@ -295,14 +295,14 @@ class RedisLimiter:
         try:
             await self._progress_mark_lua(keys=[self._progress_key()], args=[_PROGRESS_TTL_S])
         except RedisError as exc:
-            raise GovernanceBackendError(f"限流后端 mark_progress 失败: {exc}") from exc
+            raise GovernanceBackendError(f"限流后端 mark_progress 失败: {exc}", scope=self._scope) from exc
 
     async def progress_age_s(self) -> float:
         """距上次全局成功的秒数;仅键缺失(-1)= 从未进展 → inf(CHS limiter.py:208)。"""
         try:
             res = await self._progress_age_lua(keys=[self._progress_key()])
         except RedisError as exc:
-            raise GovernanceBackendError(f"限流后端 progress_age_s 失败: {exc}") from exc
+            raise GovernanceBackendError(f"限流后端 progress_age_s 失败: {exc}", scope=self._scope) from exc
         return float("inf") if int(res) == -1 else int(res) / 1000.0
 
     async def aclose(self) -> None:

src/polygateway/embedding.py

@@ -120,8 +120,8 @@ class EmbeddingClient:
         # 否则遥测会记录一个从未发出的采样参数(issue #4 决策 G)
         self._sources = strip_unsupported_extra_body(list(sources), path="embedding")
         self._selector = selector
-        self._quota = QuotaGate(limiter)
-        self._breaker = BreakerGate(breaker)
+        self._quota = QuotaGate(limiter, scope=self._scope)
+        self._breaker = BreakerGate(breaker, scope=self._scope)
         self._transport = transport
         self._retry = retry
         self._bp = backpressure

src/polygateway/errors.py

@@ -150,5 +150,29 @@ class SourceNotConfiguredError(PolyGatewayError):
     """
 
 
-class GovernanceBackendError(PolyGatewayError):
-    """限流/熔断状态后端自身故障: 必须报错而非放行(防击穿网关,降级方向铁律)。"""
+class GovernanceBackendError(GatewayUnavailableError):
+    """限流/熔断状态后端自身故障: 必须报错而非放行(防击穿网关,降级方向铁律)。
+
+    继承 `GatewayUnavailableError`(issue #7): fail-closed 意味着整个 scope 一个
+    请求都发不出去,语义上即 scope 级不可用。此前它是 `PolyGatewayError` 的直接
+    子类,只写 `except GatewayUnavailableError` 的调用方接不住,后果是"Redis 抖
+    一下 → 积压任务消耗业务失败预算 → 进死信",而那是运维重启即可恢复的故障。
+    """
+
+    def __init__(
+        self,
+        message: str,
+        *,
+        scope: str,
+        retry_after_s: float = GOVERNANCE_BACKEND_RETRY_AFTER_S,
+        source_name: str | None = None,
+    ) -> None:
+        super().__init__(
+            scope=scope,
+            reason="governance_backend_down",
+            retry_after_s=retry_after_s,
+            source_name=source_name,
+        )
+        # 父类会把 message 覆写为 "{scope} 网关暂时不可用: {reason}",而各构造点
+        # 携带的诊断串(如"限流后端 try_acquire 失败: ...")是排障主线索,必须保住
+        self.args = (message,)

src/polygateway/middleware/breaker.py

@@ -14,8 +14,10 @@ if TYPE_CHECKING:
 class BreakerGate:
     """RetryMW 面向熔断后端的唯一入口;包装一切后端异常。"""
 
-    def __init__(self, gate: ProviderGate) -> None:
+    def __init__(self, gate: ProviderGate, *, scope: str) -> None:
         self._gate = gate
+        # 后端故障即 scope 级不可用,异常须携 scope 供调用方定位(issue #7 §3.3)
+        self._scope = scope
 
     async def try_enter(self, source: SourceConfig, owner: str) -> GateDecision:
         try:
@@ -23,7 +25,7 @@ class BreakerGate:
         except GovernanceBackendError:
             raise
         except Exception as exc:
-            raise GovernanceBackendError(f"熔断后端故障(try_enter): {exc}") from exc
+            raise GovernanceBackendError(f"熔断后端故障(try_enter): {exc}", scope=self._scope) from exc
 
     async def record_success(
         self, entry: GateDecision, *, count_attempt: bool = True
@@ -33,7 +35,7 @@ class BreakerGate:
         except GovernanceBackendError:
             raise
         except Exception as exc:
-            raise GovernanceBackendError(f"熔断后端故障(record_success): {exc}") from exc
+            raise GovernanceBackendError(f"熔断后端故障(record_success): {exc}", scope=self._scope) from exc
 
     async def record_failure(
         self, entry: GateDecision, reason: str, force_open: bool
@@ -43,7 +45,7 @@ class BreakerGate:
         except GovernanceBackendError:
             raise
         except Exception as exc:
-            raise GovernanceBackendError(f"熔断后端故障(record_failure): {exc}") from exc
+            raise GovernanceBackendError(f"熔断后端故障(record_failure): {exc}", scope=self._scope) from exc
 
     async def release_probe(self, entry: GateDecision) -> GateUpdate:
         try:
@@ -51,7 +53,7 @@ class BreakerGate:
         except GovernanceBackendError:
             raise
         except Exception as exc:
-            raise GovernanceBackendError(f"熔断后端故障(release_probe): {exc}") from exc
+            raise GovernanceBackendError(f"熔断后端故障(release_probe): {exc}", scope=self._scope) from exc
 
     async def retry_after_s(self, sources: tuple[str, ...]) -> float:
         try:
@@ -59,4 +61,4 @@ class BreakerGate:
         except GovernanceBackendError:
             raise
         except Exception as exc:
-            raise GovernanceBackendError(f"熔断后端故障(retry_after_s): {exc}") from exc
+            raise GovernanceBackendError(f"熔断后端故障(retry_after_s): {exc}", scope=self._scope) from exc

src/polygateway/middleware/ratelimit.py

@@ -18,8 +18,10 @@ if TYPE_CHECKING:
 class QuotaGate:
     """RetryMW 面向限流后端的唯一入口;包装一切后端异常。"""
 
-    def __init__(self, limiter: RateLimiter) -> None:
+    def __init__(self, limiter: RateLimiter, *, scope: str) -> None:
         self._limiter = limiter
+        # 后端故障即 scope 级不可用,异常须携 scope 供调用方定位(issue #7 §3.3)
+        self._scope = scope
 
     async def try_acquire(self, source: SourceConfig) -> Permit | None:
         try:
@@ -27,7 +29,7 @@ class QuotaGate:
         except GovernanceBackendError:
             raise
         except Exception as exc:
-            raise GovernanceBackendError(f"限流后端故障(try_acquire): {exc}") from exc
+            raise GovernanceBackendError(f"限流后端故障(try_acquire): {exc}", scope=self._scope) from exc
 
     async def stats(self, source: SourceConfig) -> SourceStats:
         try:
@@ -35,7 +37,7 @@ class QuotaGate:
         except GovernanceBackendError:
             raise
         except Exception as exc:
-            raise GovernanceBackendError(f"限流后端故障(source_stats): {exc}") from exc
+            raise GovernanceBackendError(f"限流后端故障(source_stats): {exc}", scope=self._scope) from exc
 
     async def mark_progress(self) -> None:
         try:
@@ -43,7 +45,7 @@ class QuotaGate:
         except GovernanceBackendError:
             raise
         except Exception as exc:
-            raise GovernanceBackendError(f"限流后端故障(mark_progress): {exc}") from exc
+            raise GovernanceBackendError(f"限流后端故障(mark_progress): {exc}", scope=self._scope) from exc
 
     async def progress_age_s(self) -> float:
         try:
@@ -51,4 +53,4 @@ class QuotaGate:
         except GovernanceBackendError:
             raise
         except Exception as exc:
-            raise GovernanceBackendError(f"限流后端故障(progress_age_s): {exc}") from exc
+            raise GovernanceBackendError(f"限流后端故障(progress_age_s): {exc}", scope=self._scope) from exc

src/polygateway/middleware/retry.py

@@ -183,8 +183,8 @@ class RetryMW:
         self._scope = scope
         self._sources = list(sources)
         self._selector = selector
-        self._quota = QuotaGate(limiter)
-        self._breaker = BreakerGate(gate)
+        self._quota = QuotaGate(limiter, scope=self._scope)
+        self._breaker = BreakerGate(gate, scope=self._scope)
         self._transport = transport
         self._retry = retry
         self._bp = backpressure

src/polygateway/ocr.py

@@ -119,8 +119,8 @@ class OcrClient:
         self._sources = strip_unsupported_extra_body(list(sources), path="OCR")
         self._selector = selector
         self._feed_health = isinstance(selector, OutcomeAwareSelector)
-        self._quota = QuotaGate(limiter)
-        self._breaker = BreakerGate(breaker)
+        self._quota = QuotaGate(limiter, scope=self._scope)
+        self._breaker = BreakerGate(breaker, scope=self._scope)
         self._transport = transport
         self._retry = retry
         self._bp = backpressure

tests/integration/test_redis_cross_connection.py

@@ -16,7 +16,11 @@ import pytest
 from polygateway.backends.redis.breaker import RedisGate
 from polygateway.backends.redis.limiter import RedisLimiter
 from polygateway.client import GatewayClient
-from polygateway.errors import AllSourcesExhausted, GovernanceBackendError
+from polygateway.errors import (
+    AllSourcesExhausted,
+    GatewayUnavailableError,
+    GovernanceBackendError,
+)
 from polygateway.sources import RoundRobinSelector
 from polygateway.types import (
     BackpressurePolicy,
@@ -225,7 +229,11 @@ async def test_cancel_in_flight_releases_lease(clients):
 
 
 async def test_redis_down_admission_fails_closed():
-    """Redis 不可达 → 准入侧抛 GovernanceBackendError,绝不放行(库铁律)。"""
+    """Redis 不可达 → 准入侧报错绝不放行(库铁律),且以 scope 级形态到达调用方。
+
+    issue #7: 调用方只写 `except GatewayUnavailableError` 就该覆盖后端故障——
+    真实 Redis 掉线是这条链路唯一的端到端证据,故断言收紧到 scope 级语义。
+    """
     import redis.asyncio as aioredis
 
     dead = aioredis.from_url(
@@ -240,9 +248,12 @@ async def test_redis_down_admission_fails_closed():
             lease_ttl_s=30.0,
         )
         gate = RedisGate(config=_CFG, redis=dead, scope="t-dead")
-        with pytest.raises(GovernanceBackendError):
-            await limiter.try_acquire("s1", 0)
-        with pytest.raises(GovernanceBackendError):
-            await gate.try_enter("s1", "w")
+        for call in (limiter.try_acquire("s1", 0), gate.try_enter("s1", "w")):
+            with pytest.raises(GatewayUnavailableError) as ei:
+                await call
+            assert isinstance(ei.value, GovernanceBackendError)
+            assert ei.value.reason == "governance_backend_down"
+            assert ei.value.scope == "t-dead"
+            assert ei.value.retry_after_s > 0
     finally:
         await dead.aclose()

tests/unit/test_backpressure.py

@@ -11,7 +11,13 @@ import pytest
 
 from polygateway.backends.memory.breaker import InMemoryGate
 from polygateway.backends.memory.limiter import InMemoryLimiter
-from polygateway.errors import AllSourcesExhausted, GovernanceBackendError, TransientError
+from polygateway.errors import (
+    AllSourcesExhausted,
+    GatewayUnavailableError,
+    GovernanceBackendError,
+    SourceNotConfiguredError,
+    TransientError,
+)
 from polygateway.middleware.retry import RetryMW, backoff_delay
 from polygateway.sources import RoundRobinSelector, SourceCooldownMemo
 from polygateway.types import (
@@ -173,17 +179,17 @@ class TestStallQuadrants:
 
 class _GateSuccessBroken(InMemoryGate):
     async def record_success(self, entry):
-        raise GovernanceBackendError("redis 抖动")
+        raise GovernanceBackendError("redis 抖动", scope="llm")
 
 
 class _GateFailureBroken(InMemoryGate):
     async def record_failure(self, entry, reason, force_open):
-        raise GovernanceBackendError("redis 抖动")
+        raise GovernanceBackendError("redis 抖动", scope="llm")
 
 
 class _LimiterProgressBroken(InMemoryLimiter):
     async def mark_progress(self):
-        raise GovernanceBackendError("redis 抖动")
+        raise GovernanceBackendError("redis 抖动", scope="llm")
 
 
 class TestAccountingDegradation:
@@ -252,6 +258,71 @@ class TestQuotaGateProgressAge:
             async def progress_age_s(self):
                 raise OSError("down")
 
-        assert await QuotaGate(_L()).progress_age_s() == 12.5
+        assert await QuotaGate(_L(), scope="llm").progress_age_s() == 12.5
         with pytest.raises(GovernanceBackendError):
-            await QuotaGate(_Broken()).progress_age_s()
+            await QuotaGate(_Broken(), scope="llm").progress_age_s()
+
+
+class TestUnknownSourceIsAssemblyDefect:
+    """未知源 = 限流后端的源名单与治理循环对不上,是装配缺陷不是后端故障。
+
+    两个后端行为必须一致(Redis 版对应用例在 `test_redis_key_layout.py::
+    TestConversions::test_unknown_source_rejected`);内存版此前无覆盖,
+    该分支从未被测过(issue #7 §3.4)。
+    """
+
+    def test_memory_limiter_rejects_unknown_source(self):
+        limiter = InMemoryLimiter(
+            scope="llm", sources={"s1": make_source("s1")}, global_limits=_NO_GLOBAL
+        )
+        with pytest.raises(SourceNotConfiguredError) as ei:
+            limiter._cfg("nope")
+        # 关键: 若归入 scope 级家族,配置写错的任务会永远延期重投、永不进死信
+        assert not isinstance(ei.value, GatewayUnavailableError)
+
+
+class TestGateFailuresReachCallersAsScopeLevel:
+    """三条闸门泄漏路径必须以 scope 级不可用的形态到达调用方(issue #7)。
+
+    记账路径由 `_record_quietly` 降级为 warning,但闸门路径没有那层包裹,会一路
+    抛给调用方。只写 `except GatewayUnavailableError` 的调用方此前接不住,后果
+    是 Redis 抖一下就让积压任务烧掉业务失败预算进死信——而那是运维重启即可恢复
+    的故障。三条路径逐一钉住,防止将来任何一条被漏掉。
+    """
+
+    async def test_try_acquire_failure_is_scope_level(self):
+        from polygateway.middleware.ratelimit import QuotaGate
+
+        class _Broken:
+            async def try_acquire(self, name, est):
+                raise OSError("down")
+
+        with pytest.raises(GatewayUnavailableError) as ei:
+            await QuotaGate(_Broken(), scope="LLM").try_acquire(make_source("s1"))
+        assert ei.value.scope == "llm"
+        assert ei.value.reason == "governance_backend_down"
+        assert ei.value.retry_after_s > 0  # 0 会让积压任务零延迟冲击已挂的后端
+
+    async def test_try_enter_failure_is_scope_level(self):
+        from polygateway.middleware.breaker import BreakerGate
+
+        class _Broken:
+            async def try_enter(self, name, owner):
+                raise OSError("down")
+
+        with pytest.raises(GatewayUnavailableError) as ei:
+            await BreakerGate(_Broken(), scope="LLM").try_enter(make_source("s1"), "owner")
+        assert ei.value.scope == "llm"
+        assert ei.value.reason == "governance_backend_down"
+
+    async def test_progress_age_failure_is_scope_level(self):
+        from polygateway.middleware.ratelimit import QuotaGate
+
+        class _Broken:
+            async def progress_age_s(self):
+                raise OSError("down")
+
+        with pytest.raises(GatewayUnavailableError) as ei:
+            await QuotaGate(_Broken(), scope="LLM").progress_age_s()
+        assert ei.value.scope == "llm"
+        assert ei.value.reason == "governance_backend_down"

tests/unit/test_errors.py

@@ -89,10 +89,27 @@ class TestGatewayUnavailable:
 class TestBackendFailure:
     def test_governance_backend_error_is_not_transient(self):
         """限流/熔断后端故障必须报错不放行,且不落入可重试分类。"""
-        exc = GovernanceBackendError("redis down")
+        exc = GovernanceBackendError("redis down", scope="llm")
         assert isinstance(exc, PolyGatewayError)
         assert not isinstance(exc, TransientError)
 
+    def test_is_scope_level_unavailability(self):
+        """fail-closed 时整个 scope 一个请求都发不出去,调用方一条 except 应覆盖(issue #7)。"""
+        exc = GovernanceBackendError("限流后端 try_acquire 失败: boom", scope="LLM")
+        assert isinstance(exc, GatewayUnavailableError)
+        assert exc.reason == "governance_backend_down"
+        assert exc.scope == "llm"  # 与既有 scope 级异常同款: 归一化小写
+        assert exc.retry_after_s == GOVERNANCE_BACKEND_RETRY_AFTER_S
+
+    def test_diagnostic_message_survives_reparenting(self):
+        """父类把 message 覆写为模板串,而各构造点的诊断串是排障主线索(§3.5)。"""
+        exc = GovernanceBackendError("熔断后端 try_enter 失败: boom", scope="llm")
+        assert str(exc) == "熔断后端 try_enter 失败: boom"
+
+    def test_retry_after_overridable(self):
+        exc = GovernanceBackendError("redis down", scope="llm", retry_after_s=30.0)
+        assert exc.retry_after_s == 30.0
+
 
 class TestSourceNotConfigured:
     """装配缺陷有意留在 scope 级家族之外(issue #7 §3.4,Q1 人类拍板)。"""

tests/unit/test_redis_key_layout.py

@@ -68,10 +68,13 @@ class TestConversions:
             _limiter(lease_ttl_s=0)
 
     def test_unknown_source_rejected(self):
-        from polygateway.errors import GovernanceBackendError
+        """未知源是装配缺陷,不是后端故障(issue #7 §3.4)。"""
+        from polygateway.errors import GatewayUnavailableError, SourceNotConfiguredError
 
-        with pytest.raises(GovernanceBackendError):
+        with pytest.raises(SourceNotConfiguredError) as ei:
             _limiter()._cfg("nope")
+        # 关键: 若归入 scope 级家族,配置写错的任务会永远延期重投、永不进死信
+        assert not isinstance(ei.value, GatewayUnavailableError)
 
 
 class TestLuaFidelity: