Re: frames vs. weak hash tables and garbage collection

[Joe Wells]

Has anyone else been able to reproduce this bug?

Joe

Joe Wells <jbw@macs.hw.ac.uk> writes:

> Thien-Thi Nguyen <ttn@gnuvola.org> writes:
>
>> () Joe Wells <jbw@macs.hw.ac.uk>
>> () Thu, 30 Aug 2007 02:27:32 +0100
>>
>>    ;; The only reference to the new frame is now the key in the hash
>>    ;; table.  Because of the weakness, this key should not keep the
>>    ;; frame alive.
>>
>> there's a lot of stuff going on w/ make-frame.
>>
>> try replacing `(make-frame)' with:
>>
>>   (x-create-frame-with-faces)
>>
>> here, i see that `reproduce-bug' returns nil.
>> what do you see?
>
> It doesn't help me to even replace make-frame with x-create-frame (the
> primitive used by x-create-frame-with-faces).
>
> Are you able to reproduce the bug at all with the code I originally
> sent?
>
> Thien-Thi Nguyen <ttn@gnuvola.org> writes:
>
>> another thing: one gc pass may not be enough.
>> i see (reproduce-bug) => nil only at:
>>
>> (dotimes (i N)
>>   (garbage-collect))
>>
>> where (< 1 N).  my emacs is tweaked, however (ymmv).
>
> Running garbage-collect 10 times makes no difference for me.
>
> Here is the code I am now using to reproduce the bug:
>
>   (defun reproduce-bug ()
>     (let ((ht (make-hash-table :weakness 'key)))
>       (let* (after-make-frame-functions
>              (x
>               (x-create-frame nil)
>               ;;(x-create-frame-with-faces)
>               ;;(make-frame)
>               ;;(get-buffer-create "xyzzy")
>               ))
>         (puthash x t ht)
>         (delete-frame x)
>         ;;(kill-buffer x)
>         )
>       ;; The only reference to the new frame is now the key in the hash
>       ;; table.  Because of the weakness, this key should not keep the
>       ;; frame alive.
>       (loop repeat 10 do (garbage-collect))
>       ;; The hash table should now be empty.
>       (let (l)
>         (maphash (lambda (k v) (push (cons k v) l)) ht)
>         l)))
>
> With the above definition, I still get (reproduce-bug) returning
> ((#<dead frame emacs@localhost.localdomain 0xa2ae808> . t)) instead of
> nil.
>
> -- 
> Joe