On Wed, 21 Jun 2000, Dr Wes Munsil wrote:
> Let me run an error scenario by you concerning this patch and a possible
> interaction with Java static variables.
>
> Scenario: A Java static object is returned to a Tcl script by some TclBlend
> call, represented by the command name java0x4 (say). Much time passes--many
> more objects are created, there are no more Tcl references to the Java
> object, and its command name goes away. Finally, the same Java static object
> is returned again, by the same TclBlend call.
>
> Since we are not doing the decrRefCount on finalize (it's commented out),
> dispose() was never called, and the Java object is still in the reflect table
> with the command name java0x4; so this is returned to the Tcl script, which
> no longer recognizes the name java0x4. An "invalid command name" error
> results.
Could you create a small script and a .java file that reproduces this
error? I would love to have some good refcounting tests so that
we can be sure any ref counting changes that are made really work.
> Is this possible? I am seeing something that behaves very much this way, and
> this is my lame attempt to diagnose it.
Yes, this is not just possible but highly likely. The patch I send you
was just a quick hack to avoid a deadlock. From your note, I assume
that it does in fact avoid the deadlock, which proves that it
was the GC thread running the finalizer method on the CObject class
that was causing the deadlock in the first place. To really
fix the problem correctly, we need to do a rather large redesign
of the ref counting system for Tcl objects used with Tcl Blend.
So the good news is we know there is a problem and we know what
the problem is, the bad news is that it is going to take
time to fix it properly. While we are at it, we should also
drop the ref counting stuff from Jacl where it makes sense.
The code shared between Jacl and Tcl Blend will need to use
ref counts because Tcl Blend needs them.
Mo DeJong
Red Hat
----------------------------------------------------------------
The TclJava mailing list is sponsored by Scriptics Corporation.
To subscribe: send mail to [EMAIL PROTECTED]
with the word SUBSCRIBE as the subject.
To unsubscribe: send mail to [EMAIL PROTECTED]
with the word UNSUBSCRIBE as the subject.
To send to the list, send email to '[EMAIL PROTECTED]'.
An archive is available at http://www.mail-archive.com/tcljava@scriptics.com
