sel_key_cmp_fn compared keys with memcmp on the whole sel_node_key_t
struct, including the 4-byte padding between type and op1. The stack-
allocated search key in gc_sweep_select_nodes can have different padding
bytes than the heap-allocated copy stored by key_add, causing key_del
to miss the entry and leave a dangling pointer in the CSE intern table.
Replace memcmp with field-by-field comparison on type, op1, op2.
Also fix GC sweep tests that asserted pointer inequality after re-intern:
calloc may lawfully reuse the freed address, so pointer inequality does
not reliably indicate a successful sweep. Track the swept node's
node_id before freeing and assert the re-interned node gets a fresh id.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
- Add gc_clear_marks(): iterates intern table and zeroes all gc_mark bits
- Rename static gc_mark_tree → public gc_mark_select_tree (no attribute((unused)))
- Remove Phase 6 guard (live_jobs != NULL early return) from gc_sweep_select_nodes
- Remove the mark-clear loop from gc_sweep_select_nodes; add (void) casts for now-unused params
- Declare gc_clear_marks and gc_mark_select_tree in resreq.h with protocol comment
- Add TDD test test_gc_clear_marks_exported verifying the exported primitives
- Prefix all existing gc_sweep_select_nodes(NULL, 0) call sites in test_select.c with gc_clear_marks()
