[Asdf-devel] Need to do uiop:setup-temporary-directory in image built with uiop

[Faré]

On Tue, Jun 17, 2014 at 4:33 PM, Robert P. Goldman <rpgoldman at sift.info> wrote:
>> It is probably a bug that there isn't a uiop/stream:clear-temporary-directory
>> that gets registered via uiop/configuration:register-clear-configuration-hook
>> in uiop/configuration. I can do it, though I'd rather someone else do it.
>
> I can do this, but I need some help understanding what's going on here.
>  The following is a little circular:
>
>   (defun clear-configuration ()
>     "Call the functions in *CLEAR-CONFIGURATION-HOOK*"
>
> What is the configuration?  ASDF has at least two configurations: the
> configuration of source locations and the configuration of output-file
> translations.  Is this one of those, or something else?  I'm a bit
> confused because uiop/configuration.lisp looks like it provides a
> *general* utility for configuring things.  And TEMPORARY-FILE is
> something that is yet another aspect of configuration, outside both of
> these.
>
clear-configuration is the function you call
when configuration files may have been modified and
you want to invalidate any current configuration loaded from them.
All it does is call the functions in the *clear-configuration-hook*,
so you can extend what "the configuration" means.
UIOP itself has none (so far), but ASDF has configuration for
source-registry and output-translations.
clear-configuration is itself registered as an image-dump-hook,
so when you save an image, you don't get configuration
from whichever user, process, machine dumped the image.

I'm not completely sure whether you should
(register-configuration-hook 'clear-temporary-directory)
or more directly
(register-image-dump-hook 'clear-temporary-directory)

Since default-temporary-directory (at least for now)
doesn't consult any configuration file, only an environment variable,
that is unlikely to change during execution,
an image-dump-hook is probably all you need.
It's a subtle difference in the intent of future possible modifications.

> I assume that when I understand this, I'll be able to understand how to
> test it.
Testing this functionality involves dumping an image
while TMPDIR is something and running it while it is something else.
Sigh. Could be done in test-program.script, I suppose.

>> That said, even with that hook function defined and registered,
>> you still need to explicitly (call-image-dump-hook)
>> before you dump an image using implementation-specific tools, and
>> you need to (call-image-restore-hook) when you restart.
>>

>>> I'd encourage you to do that, and CC me when you submit the bugreport to
>>> Franz.
>>>
>> I don't believe there's any Franz bug.
>> It's a bug in how UIOP is not used properly.
>> These hooks probably need to be documented better, too.
>
> I don't agree.  If a lisp implementation ships with ASDF, and a lisp
> image dumping facility, then to the maximum extent possible the lisp
> image dumping facility should not require additional work on the user's
> part.  Also, it's likely to make the implementation maintainers happier
> if they don't have to get complaints from users about cryptic errors
> from the combination of these two features.
>
Well, so far UIOP is defined as a layer on top of what the
implementation provides
and not the other way around. That said, it might be great if the documentation
for these implementations would remind the users that if they use
these functions
while building their software with ASDF (or similar software),
they may want to explicitly  (uiop:call-image-dump-hook) and
(uiop:call-image-restore-hook) (or the equivalent for their software).

> Suggestion: if there are bits of configuration that can leak out of ASDF
> and UIOP across image dumpings, let's try to document them, and make a
> note for implementers that they may wish to appropriately modify their
> image-dumping facilities to behave properly with their ASDF without
> requiring additional user actions.
>
If there's a leak, it's probably a bug, to be fixed with
an appropriate image-dump-hook.

> If worst comes to worst, and the implementors don't feel like handling
> this, the documentation will be useful to the ASDF user who has to
> handle it him or herself.
>
> Follow-up question: is it getting to be time to add a separate manual
> for UIOP?
>
That would be great. I was kind of hoping for one of the many automatic
documentation generators to be used based on the many docstrings.
There are just too many functions to hope to maintain the documentation
outside of said docstrings and other source comments.

—♯ƒ • François-René ÐVB Rideau •Reflection&Cybernethics• http://fare.tunes.org
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