Fix start-to-close timeout failure caused by short heatbeat timeout#1300
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- start_to_close_timeout < heartbeat_timeout - neither timeout
chris-olszewski
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May 28, 2026
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Haven't fully reviewed, but pretty concerned about the integration test being flakey.
chris-olszewski
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May 28, 2026
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LGTM, very minor suggestions
Co-authored-by: Chris Olszewski <chrisdolszewski@gmail.com>
Co-authored-by: Chris Olszewski <chrisdolszewski@gmail.com>
Co-authored-by: Chris Olszewski <chrisdolszewski@gmail.com>
Co-authored-by: Chris Olszewski <chrisdolszewski@gmail.com>
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When an activity has both startToCloseTimeout and heartbeatTimeout set, and heartbeatTimeout < startToCloseTimeout, the Core SDK's local timeout timer never fires because successful heartbeats keep resetting it. The activity runs indefinitely on the worker even after the server has timed it out.
The previous implementation simply ignored the start_to_close timeout when the heartbeat timeout was shorter, which would work if the heartbeat timeout was not reset after each heartbeat ack. Instead, the heartbeat acks kept the activity alive long after the server had hit the start-to-close timeout. The workflow correctly resolved with a timeout, but the activity kept running and occupying a worker task slot.
The fix is to run both timeouts together -- the one-time start_to_close timeout and the infinitely resettable heartbeat timeout.
Tests: 3 unit, 1 integration.
Fixes #1188