drpcpool: close connections returned to a closed pool#60
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Pool.Close only sees the connections currently idle in the cache. Connections that are checked out serving an in-flight Invoke or NewStream live outside the cache and are returned later via Put. Because the pool had no closed state, such a late Put re-inserted the connection and armed a fresh expiration timer, resurrecting the pool and leaking the connection (and its manager goroutines) until the timer fired. This is reachable on shutdown: long-lived streams (e.g. rangefeeds) hold their connection checked out, so Close cannot reach them. When the stream context is later canceled, the connection is handed back via Put and lingers well past the point the pool was closed. Mark the pool closed under the lock in Close, and have Put close the connection immediately instead of caching it once the pool is closed. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
suj-krishnan
approved these changes
Jun 10, 2026
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Pool.Close only sees the connections currently idle in the cache. Connections that are checked out serving an in-flight Invoke or NewStream live outside the cache and are returned later via Put. Because the pool had no closed state, such a late Put re-inserted the connection and armed a fresh expiration timer, resurrecting the pool and leaking the connection (and its manager goroutines) until the timer fired.
This is reachable on shutdown: long-lived streams (e.g. rangefeeds) hold their connection checked out, so Close cannot reach them. When the stream context is later canceled, the connection is handed back via Put and lingers well past the point the pool was closed.
Mark the pool closed under the lock in Close, and have Put close the connection immediately instead of caching it once the pool is closed.