Re: bizarre byte-compile issue, possibly due to EIEIO

[David Engster <deng@randomsample.de>]

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David Engster writes:
> Ted Zlatanov writes:
>> On Fri, 01 Apr 2011 15:29:38 -0500 Ted Zlatanov <tzz@lifelogs.com> wrote: 
>>
>> TZ> In other words, the registry.elc file is breaking the tests.  I can't
>
>> TZ> figure out what's wrong, but it seems EIEIO-related.  If I try to
>> TZ> edebug, that evaluates the problematic methods (e.g. `registry-lookup')
>> TZ> and then they don't exhibit the problem.
>>
>> TZ> Using "(eval-when-compile (require 'registry))" instead of 
>> TZ> "(require 'registry)" doesn't help.  All the registry.el ERT tests pass.
>
> I can't really explain anything, but maybe I can at least shift the
> blame. ;-)

> If I rewrite your registry-lookup function to use 'mapcar' instead of
> 'loop', the tests work as expected:

[...]

I tested a little bit more. I created a short test case which I attached
to this mail. Run it by doing

emacs --batch -L .  -l bc-test -f bc-test

If everything works, you should get

Method with mapcar: (("20" "foo 20") ("30" "foo 30") ("40" "foo 40"))
Method with loop: (("20" "foo 20") ("30" "foo 30") ("40" "foo 40"))

Here's what I observe:

* The 'mapcar' method always works.
* If you don't byte-compile, the 'loop' method will also work.
* If you byte-compile, the 'loop' method will fail with Emacs24 *before*
  the lexbind merge. After the lexbind merge, it works as expected.

Note that the :initform evaluation will not work with the EIEIO version
which ships with Emacs23. I remember some discussions regarding this
issue; it's probably best to use an explicit constructor. I included it
in the test case (you have to uncomment it). When using the class w/
constructor, you can also compile it under Emacs23, and the 'loop'
method will then also fail. The funny thing is that Emacs24 *after* the
lexbind merge cannot run that byte-compiled code from Emacs23; is that
to be expected?

-David


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