OpencodeExecutor and MimocodeExecutor rotated to the next account only on
HTTP 429. A network exception (timeout, connection refused/reset) on one
account instead propagated out of execute() and failed the whole request,
even when other accounts remained available.
Both executors now rotate on a network exception only when the failed
account has its own dedicated proxy (account.proxy !== null) — a dead
proxy is genuinely account-scoped, so rotating away from it is safe.
Accounts sharing the default egress (no proxy configured) trigger the
same cooldown and are skipped for the rest of the request once the shared
egress is known down, but a later account with its own dedicated proxy is
still tried normally — a throw on a proxy-less account no longer strands
a proxied account further in the rotation. This behavior is gated behind
NETWORK_ROTATION_SHARED_EGRESS_GUARD (Feature Flag, default on); disabled,
it reproduces the immediate-propagation behavior this fix started from.
The shared rotation mechanics (pickAccount/markCooldown/markSuccess) are
extracted into executors/accountRotation.ts, used by both executors —
they had independently implemented the same round-robin+cooldown
skeleton. This also fixes an identical, pre-existing bug in
MimocodeExecutor that predates this PR: its catch block called
markCooldown unconditionally on any throw, with no proxy check and no
warn log (a silent exception swallow on a path that influences the
result).
The cooldown formula for both the proxy and shared-egress cases reuses
the repo's already-established "transient, not clearly attributable"
constants (errorConfig.ts TRANSIENT_COOLDOWN_MS/COOLDOWN_MS.transientMax,
already used by accountFallback.ts for network-error classification)
instead of introducing a separate value.
MimocodeExecutor's network-error 502 body also now goes through
buildErrorBody()/sanitizeErrorMessage() instead of embedding the raw
caught error message directly (Hard Rule #12), matching the sanitization
already used on its #2101 malformed-request path.
Validated by TDD (Hard Rule #18): tests/unit/account-rotation.test.ts
covers the shared module directly; opencode-proxy-rotation-4954.test.ts
and mimocode-executor.test.ts cover the proxy-configured rotation path,
the mixed-fleet case, the shared-egress single-network-call case, and the
NETWORK_ROTATION_SHARED_EGRESS_GUARD-disabled legacy path, for each
executor. tsc, lint, and the provider golden-path gates
(check:provider-consistency, check:provider-assets,
provider-translate-path-golden.test.ts) are clean on all touched files.
Co-authored-by: Max <maxmad64@gmail.com>
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