ensureFreshMerkleProofPath coalesces concurrent callers onto a single
in-flight refetch future and awaited it directly. Chronos propagates
cancellation into the awaited future, so one caller being cancelled
(e.g. a publish retry whose RlnRefreshRetryTimeout fired mid-refetch)
cancelled the shared future under every coalesced caller — and threw
away an eth_call that may have been about to complete.
Await the in-flight future via join() instead: cancelling a caller only
detaches its callback. The refetch always runs to completion, coalesced
callers keep waiting, and even when every caller times out the cache
still gets populated in the background so the next publish fast-paths
instead of paying the RPC round-trip again.
Detaching is safe because doRefresh cannot fail with an unhandled
exception: the eth_call wrappers catch CatchableError and return
Result, and failures surface to callers through fetchOk / an empty
cache exactly as before.
Adds a test cancelling the initiating caller mid-refetch and asserting
the shared future survives and the coalesced caller completes with a
populated cache.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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