execution_graph: invalidate readers on host writes#85
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waywardmonkeys merged 1 commit intoMay 31, 2026
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Treat host write access events as dirty marks so graph runs that previously read the same resource key are scheduled after a writer mutates that key. Keep write events in access logs, handle the deps-only fast path the same way, and add a regression covering a writer node invalidating a prior host-state reader. Clarify the host access docs that reads and writes must share the same resource key namespace to interact.
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* execution_graph: stop a node's own writes from re-triggering it #85 made host writes mark the written key dirty so prior readers are invalidated. But a node that both reads and writes the same key then invalidated *itself*: the read made its output depend on the key, the write re-dirtied it, and the node re-ran on every run_all() forever (observed run_count 1, 2, 3, ... with no external change). Track the keys a node writes during a run and exclude them from its own dependency set (reads ∖ writes). The write still marks the key dirty, so other nodes that read it are still invalidated; only the writer's self-trigger is removed, so a read-modify-write node now reaches a fixpoint. Also ignore host writes to graph-owned Input keys: they intern to the same id as a node's input binding, so honoring them would let the self-write filter strip a real graph-input dependency and leave the node stale after invalidate_input. Hosts only own the HostState/OpaqueHost namespaces. Adds regression tests for both cases. * fmt & typos * execution_graph: don't let ignored Input writes satisfy strict-deps Host writes to graph-owned Input keys are ignored (mark_tape_key_dirty returns None), but the access sinks still bumped the strict-deps counter before that rejection. As a result a host call whose only action was ctx.record_write(ResourceKeyRef::Input(..)) advanced the counter and passed strict-deps, even though the graph recorded no dependency, no invalidation, and no access-log entry — weakening the mode's guarantee that every host call reports something usable. Move the counter increment inside the accepted-write branch in both CollectingAccessSink::write and DepsOnlyAccessSink::write, so only accepted (HostState/OpaqueHost) writes count as access events. Reads are unchanged; non-strict mode still silently ignores Input writes (it never reads the counter), while strict mode now rejects a call whose only event is an ignored write. Adds a regression test asserting StrictDepsViolation for a host call that only writes an Input key.
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Treat host write access events as dirty marks so graph runs that previously read the same resource key are scheduled after a writer mutates that key.
Keep write events in access logs, handle the deps-only fast path the same way, and add a regression covering a writer node invalidating a prior host-state reader. Clarify the host access docs that reads and writes must share the same resource key namespace to interact.