[armedbear-devel] Fwd: [Bug] Identically named gensymed coalesced into same object in fasl file

[Tobias C. Rittweiler]

Erik Huelsmann <ehuels at gmail.com> writes:

> Sent the response below to Tobias privately by accident.
>
> ---------- Forwarded message ----------
> From: Erik Huelsmann <ehuels at gmail.com>
> Date: Mon, Jan 11, 2010 at 11:40 PM
> Subject: Re: [armedbear-devel] [Bug] Identically named gensymed
> coalesced into same object in fasl file
> To: "Tobias C. Rittweiler" <tcr at freebits.de>
>
>
> Hi Tobias,
>
> Thanks for your report. This issue has long been in ABCL and it's not fixed yet.
>
> I have known about this problem for a while, but was kind of hoping it
> wouldn't show up in practice. I guess it did.
>
> This is what happens: when reading, the fasl loader creates an
> anonymous package in which it interns uninterned symbols. It "has" to
> do that, because ABCL doesn't store references to the actual unique
> objects everywhere; instead it stores the textual representation in
> some places. These symbols get coalesced by use of the anonymous
> package.
>
> So, generally the system of coalescing is something inherent to this
> idea. The idea is wrong enough for you to run into and get bitten by
> it.
>
> We'll have to come up with a better idea. Can you add the mail message
> below to our issue tracker?

It's tracked as 

  http://trac.common-lisp.net/armedbear/ticket/79

> BTW: Did you happen to find this issue by accident? How did you find it?

I wondered what 3.2.4.2.2 (``Two apparently uninterned symbols S and C
are similar if their names are similar.'') is supposed to mean. I came
up with that test case, and tried it on all implementations that I've
got installed.

I first thought that ABCL's behaviour is what the standard would
prescribe, even though I couldn't believe that to be true -- until I was
pointed out 3.2.4.1 by Bart Botta.

  -T.