[asdf-devel] One failure on ASDF on Allegro/Windows

Felix Lange fjl at twurst.com
Tue Feb 25 21:40:32 UTC 2014

Sorry for hijacking this discussion.

Why are system names case sensitive at all?
Wouldn't it be more sane to just make them case-insensitive?

It is more complicated to perform case-insensitive file search
on a case-sensitive filesystem, of course.

On 25 Feb 2014, at 19:40, Faré wrote:

> On Tue, Feb 25, 2014 at 1:19 PM, Robert P. Goldman 
> <rpgoldman at sift.info> wrote:
>> Faré wrote:
>>> I recommend we just let the user choose between PATHNAME-EQUAL and
>>> PATHNAME-EQUALP, or some such.
>> The only question about this would be whether this is visible to the
>> user or not?
> I'd rather the user be in control.
>> Looking into ASDF we find the following calls to PATHNAME-EQUAL:
>> * BINARY-OP calls PATHNAME-EQUAL to see if it will inadvertently
>> overwrite the system .asd file
>> * Under ECL and MKCL, when building a bundle, we use pushnew with
>> PATHNAME-EQUAL; if this is wrong, and PATHNAME-EQUALP is right, then 
>> we
>> could get duplicates in the bundle
>> * FIND-SYSTEM calls PATHNAME-EQUAL to see if the system definition
>> source file has been changed.  A false positive here will cause
>> unnecessary reloads.
>> * SAME-PACKAGE-SYSTEM-P uses PATHNAME-EQUAL to check and see if two
>> package-systems are the same.
>> I don't see how these problems can be resolved by punting to the 
>> user:
>> the user doesn't have access to this level of control.
> For FIND-SYSTEM and SAME-PACKAGE-SYSTEM-P, remember that
> these happen within the context of a same configuration.
> foo.asd will be searched for system "foo", and "Foo.asd" for system 
> "Foo".
> To ASDF, these are different systems (NB: symbols are downcased),
> so it's OK for PATHNAME-EQUAL to distinguish them.
> Then, if the directories are case-sensitive unequal, but 
> case-sensitive equal,
> that means that you found one file in the first one in configuration 
> order,
> and the other file in the second one in configuration order,
> which is proof enough that they are different files.
> And if configuration changed and case with it, that's also a good
> reason to reload.
> Remains the bundle issues. The first one is avoiding to overwrite a 
> .asd file;
> the second is trying to avoid having the uiop library twice in the
> archive. Both would require
> quite some custom asdf methods to have the asd file (respectively uiop
> library) as output-files
> of some user system yet with a case-tweaked pathname. Yes, it's
> possible to do it wrong,
> but the user has to try hard for it, at which point I think it's OK to
> concede defeat.
>> While I agree that a heuristic for deciding whether pathnames are
>> case-sensitive is not ideal, I don't see an alternative to supplying 
>> one.
> I suspect that committing myself to a mental institution might be a
> sane alternative to trying to supply a heuristic for case-sensitivity
> of a filesystem without using CFFI.
>> But perhaps there's a different way out?  At any rate, we'd have to
>> figure out how to handle the above cases.
> You're right of course that handling those cases right is important,
> but I believe they are already handled as right as can be. Trying to
> double-guess the user based on a flaky case-sensitive heuristic is
> only the recipe for debugging madness either for you or for the poor
> user who'll be double-guessed wrong.
> —♯ƒ • François-René ÐVB Rideau •Reflection&Cybernethics• 
> http://fare.tunes.org
> If you could ask a unique question to a computer during a Turing test,
> what would you ask?
>      — Douglas Hofstadter, Metamagical Themas

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