fix(binding-mcp): settle a still-establishing toolkit client on reset/abort - #2427
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…/abort An mcp(client)-backed session's south connections toward each routed toolkit are established eagerly and in parallel; the north-facing session's own accept is deferred until every one of them settles (either by opening successfully or by being told to settle explicitly). McpLifecycleClient's onClientAbort/onClientReset only told the session to settle when hydration was in progress AND this client had never opened -- any other combination propagated the abort/reset to the session. That condition had no else branch, so exactly that one case did neither: a hydration session's still-establishing toolkit resetting or aborting left the session waiting on a settlement that would now never arrive, wedging the whole hydration attempt indefinitely. Both handlers now call settleLifecycle for that case instead of doing nothing, letting the session proceed without that toolkit; the existing per-kind retry/backoff already re-attempts it once the session is no longer blocked. A caller's own (non-hydration) session and an already-established toolkit's later failure keep propagating exactly as before. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01W7N8Z9vABdU8pVPGthRodY
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Description
An
mcp(client)-backed session's south connections toward each routed toolkit are established eagerly and in parallel; the north-facing session's own accept is deferred until every one of them settles (either by opening successfully or by being told to settle explicitly).McpLifecycleClient'sonClientAbort/onClientResetonly told the session to settle when hydration was in progress and this client had never opened -- any other combination propagated the abort/reset to the session. That condition had noelsebranch, so exactly that one case did neither: a hydration session's still-establishing toolkit resetting or aborting left the session waiting on a settlement that would now never arrive, wedging the whole hydration attempt indefinitely.Both handlers now call
settleLifecyclefor that case instead of doing nothing, letting the session proceed without that toolkit; the existing per-kind retry/backoff already re-attempts it once the session is no longer blocked. A caller's own (non-hydration) session and an already-established toolkit's later failure keep propagating exactly as before.Validated end-to-end against a two-node cluster with a hydration-backed cache: reproduced the wedge (a node became unresponsive to every new session once a toolkit reset mid-establishment), confirmed the fix resolves it (hydration completes and the node stays responsive across repeated fresh restarts), and confirmed
initializeresponses and per-kind cache recovery are unaffected for every other case../mvnw -pl runtime/binding-mcp -am testpasses (178 tests, 0 failures/errors).Fixes # (issue)
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