Letting SourceNotConfiguredError through the gate wrappers opened a hole
the recheck caught: _record_quietly only degrades GovernanceBackendError,
so an assembly defect raised from the accounting side would now escape and
destroy a response from a call that had already genuinely succeeded. That
inverts the exact invariant _record_quietly exists to hold.
Widening _record_quietly is the right fix rather than narrowing the
wrappers, because that layer degrades by what the path is (accounting, the
call is already done) rather than by which error type shows up. Narrowing
would have left 4 of 9 wrapper methods as exceptions to a rule nobody can
remember.
No backend raises it from an accounting method today, so this is a
guardrail for whoever adds source-name validation to a breaker backend.
The stub that first reported this green was wrong: its record_success
lacked count_attempt, so it raised TypeError and the wrapper relabeled it.
Fixed signature, then the test failed as it should have.
Also finishes the three-to-five leak path correction across the four
remaining spots, including the wiki summary card that indexes this design.
Independent verification caught that the split shipped in the previous
commit did not actually hold on the only path production uses. The gate
wrappers re-raise GovernanceBackendError but nothing else, so
SourceNotConfiguredError fell into the following `except Exception` and
came back out as a governance_backend_down failure with retry_after_s=5.0.
A misconfigured source name would still retry forever and never surface.
The existing tests missed it because both of them call the private _cfg()
directly, one layer below the wrapper the governance loops actually go
through. The regression test goes through QuotaGate.
telemetry.py has to widen its terminal catch in the same commit: once the
wrapper stops relabeling the error, it is no longer a GovernanceBackendError,
and it is raised before any attempt exists, so the path would have recorded
no telemetry at all.
Also corrects the leak path count from three to five. QuotaGate.stats and
BreakerGate.retry_after_s are not wrapped by _record_quietly either.
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.
iomgaa