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gc: BOXED_PRIMITIVE_PAYLOADS is a rekeyed address-keyed table with no dead-key prune #8191
Description
BOXED_PRIMITIVE_PAYLOADS (crates/perry-runtime/src/builtins/formatting/boxed_primitives.rs) is keyed by an ObjectHeader address (register_boxed_primitive_payload, boxed_primitives.rs:98) and its key is rekeyed by scan_boxed_primitive_payload_roots_mut (boxed_primitives.rs:189, visit_metadata_usize_slot) — rewritten if the owner moved, deliberately not marked.
No death hook exists: the table is absent from gc::dead_owner's DEAD_KEY_PRUNES fan-out, and the file contains only the declaration, two reads and the scanner.
That is the #8040 shape — a rekeyed table whose dead key survives to the next cycle's rewrite_raw_addr, where recycled bytes can carry a coincidental GC_FLAG_FORWARDED. #8174 narrowed what can be followed out of such a header; it did not remove the dead key.
Fix: add a prune and wire it into DEAD_KEY_PRUNES (crates/perry-runtime/src/gc/dead_owner.rs), with a dead_owner_side_tables.rs case.
Declared as open_gap in scripts/gc_rekeyed_key_tables.json; closing this must delete that entry, or the gate fails on the stale exemption.
Activity
fix(gc): give the six unpruned rekeyed tables a death story (#8190-#8195
proggeramlug commentedon Aug 16, 2026
Fixed in #8196.
The #8174 registry gate enumerated every
visit_metadata_*rekey site and required a written verdict for each; this table had none, and rather than declare it an exemption the prune is wired in. Its entry inscripts/gc_rekeyed_key_tables.jsonnow names a registeredDEAD_KEY_PRUNESmember, andMAX_OPEN_GAPSis 0 — the manifest ships with no declared gaps at all.Covered by a pair of cases in
gc/tests/dead_owner_side_tables.rs: the prune fires (dead owner, one collection, the table observably shrinks) and its inverse (a rooted owner's entry survives).Independent evidence that these were real stale keys and not a theoretical hazard: with only #8174's forwarding-target discriminators in place and none of these prunes, the production Next App Route forced-evacuation workload logged 988
[gc-forwarding] refused_sourcesevents — stale forwarding headers reaching a rewrite walk. With the six prunes in, the same workload logs 0 across 458 copying minors and 182,977 copied objects.fix(gc): give the six unpruned rekeyed tables a death story (#8190-#8195
fix(gc): refuse a forwarding walk out of, or into, a non-object, and …