The per-space single-writer lock — Redis CAS leader lock (SET NX PX, DEL-CAS and
PEXPIRE-CAS Lua), the in-process mutex, the per-process instanceId and the
heartbeat — lived inline in GitSyncOrchestrator. Extract it into a dedicated
@Injectable() SpaceLockService exposing one narrow surface, withSpaceLock(spaceId,
fn), so the lock is the orchestrator's only Redis-lock touch-point and is testable
in isolation. The orchestrator now injects SpaceLockService and both consumers
(runOnce, ingestExternalPush) go through spaceLock.withSpaceLock — behavior
unchanged (same sentinel returns, same 503-on-lock-held contract). Orchestrator
drops 591→472 lines.
Adds space-lock.service.spec.ts asserting the lock SEMANTICS against a fake Redis
(the test-coverage warning from the review): the SET NX/PX args, the DEL-CAS and
PEXPIRE-CAS Lua + ARGV[1]=instanceId, plus the lock-held / in-progress / throw-
still-releases paths. The orchestrator spec is unchanged in count and stays green
(it now builds the real SpaceLockService over its mock Redis).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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