bug#9900: Using a guardian on a value in a weak hash

[Ian Price]

Hi guilers,

If I 'guard' a value, and store it in a weak-key hashtable, then it
doesn't appear in the guardian even after it is removed from the
weak-hash by a garbage collection. Note, this only happens in a
_script_, and will work fine in a REPL (you should only need two GCs,
one for the weak hash, and one for the now free value).
e.g.


(define guardian (make-guardian))
(define finalizer-table (make-weak-key-hash-table))

(let ((f (lambda () (display "test\n"))))
  (guardian f)
  (hashq-set! finalizer-table (cons #f #f) f)
  #f)

(write finalizer-table)
(newline)

(gc)(gc)(gc)(gc)(gc)(gc)(gc)(gc)(gc)(gc)(gc)(gc)

(write finalizer-table)
(newline)

(write (guardian))
(newline)


will produce the output


address@hidden guile]$ guile -s /tmp/gcbug.scm 
#<weak−key−hash−table 1/31>
#<weak−key−hash−table 0/31>
#f
address@hidden guile]$ 

-- 
Ian Price

"Programming is like pinball. The reward for doing it well is
the opportunity to do it again" - from "The Wizardy Compiled"