nx_sc_scope_gate.nx

nx_sc_scope_gate.nx -- the referee for LR2, structured concurrency: scoped spawn. SUBJECT: sc_scope_spawn and its scope verbs in runtime/nx_thread_pool.nx. WHY THIS GATE IS BUILT THE WAY IT IS. A concurrency gate is the easiest kind to write vacuously: if the child finishes before the parent looks, EVERY assertion passes and NOTHING about joining has been tested. So the join teeth here do not ask "did the children finish" -- that is true of a no-op join too. They ask three questions a no-op join cannot answer yes to: * were the children observably INSIDE their bodies, and observably NOT finished, at the instant the parent was about to join (the fixture is asserted to have REACHED the condition before any outcome is asserted); * did join return STRICTLY AFTER every child completed, proved by a shared monotonic sequence counter rather than by a millisecond clock that can tie; * did join BLOCK for at least the interval the children were measured holding. A no-op join returns in microseconds while the children hold for witness-hold-ms, so the third tooth alone separates them, and the second proves the ordering exactly. NO FIXTURE FILES. This gate builds its whole fixture at RUNTIME out of mmapped words and pool tasks, so it shares no path with any production beat and needs no /tmp scratch directory to create or clean up. EVERY THRESHOLD IS A CONF ROW (knowledge/sc_scope.conf). The two exceptions are the join guard and the join spin, which carry NO row on purpose because they are DERIVED from nx_pool_wait -- and one of the teeth below proves the conf really does not carry them, so the derivation cannot be quietly unpinned. expect_exit: 0 license_tier: ORIGINAL lineage_id: sc_scope_gate_v1