Key-weak hash tables are never cleaned automatically, not even in a
secondary GC daemon; unless you call HASH-TABLE/CLEAN! or cause them
to be rehashed, broken entries will retain their data (but not their
keys) strongly.
(let ((a (make-eq-hash-table))
(b (make-eq-hash-table)))
(let ((p (list 'p))
(q (list 'q))
(r (list 'r)))
(hash-table/put! a p q)
(hash-table/put! b q r))
(gc-flip)
(list (hash-table/datum-list a)
(hash-table/datum-list b)))
;Value: (() ((r)))
The manual doesn't claim that *associations* are deleted from weak
hash tables if their keys are reclaimed -- it says only that the hash
table holds its keys weakly --, but this is not the behaviour I expect
for an object called a `weak hash table'. Does this behaviour worry
anyone else?
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