[asdf-devel] bug in new ASDF

[Robert Goldman]

Robert Goldman wrote:
> Robert Goldman wrote:
>> I see the following when I try to load an asdf system now:
>>
>> Error loading #P"/Users/rpg/clinit.cl":
>> While searching for system `asdf-context`: `(MERGE-PATHNAMES systems/
>> /Users/rpg/lisp/asdf-install-systems/)`
>> evaluated to `/Users/rpg/lisp/asdf-install-systems/systems/` which is
>> not a directory.
>>
>> The problem with this error is that, in fact, that IS a directory:
>>
>> CL-USER(2): (probe-file "/Users/rpg/lisp/asdf-install-systems/systems/")
>> #P"/Users/rpg/lisp/asdf-install-systems/systems/"
>>
>> I'm looking in sysdef-central-registry-search and the logic seems to be
>> completely borked.  It looks for a system definition and, if it doesn't
>> find one, it assumes that the directory name is bad.  I believe the
>> logic should be:
>>
>> 1.  Look at the directory and ensure that it exists.
>>
>> 2.  If it does not exist, push it onto the bad list
>>
>> 3.  Else merge in the system name and look for the system definition.
>>
>> The current logic merges in the system name first, so misdiagnoses.
>>
>> [I will now proceed to wrestle with git, which I am coming to loathe
>> with a consuming hatred, in order to attempt to verify that my diagnosis
>> is correct, and then send a patch.  More soon.]
>>
> 
> OK, I /have/ misdiagnosed this.  The logic seems actually busted in
> directory-pathname-p.  The problem is that, at least on allegro, you can
> get a valid directory pathname whose name component is neither NIL, nor
> :unspecific, but "" (the empty string).
> 
> This seems like a place where wrestling with CL pathnames is very
> unpleasant....  What I'd really like to do here is resolve the pathname
> and just ask the bloody OS if this is a directory or not, instead of do
> these kind of seemingly random flailings with the pathname object:
> 
> (defun directory-pathname-p (pathname)
>   (and (member (pathname-name pathname) (list nil :unspecific))
>        (member (pathname-type pathname) (list nil :unspecific))))
> 
> This will now have to be
> 
> (member (pathname-name pathname) (list nil "" :unspecific) :test 'equal)
> 
> which seems like it's metastasizing complexity...

Yet worse.  On the #lisp IRC antifuchs and Xach point out more possible
problems:

antifuchs:  actually, a :name component of "." with :type
nil/:unspecific would make sense in posix

Xach:  antifuchs: or :name nil and :type "" :-)

This suggests that fixing directory-pathname-p may be sufficiently
horrible that we should back out this attempted helpfulness.

The only alternative seems to me to be to figure out a way to ask the OS
whether a file name denotes a directory, which seems like such an
expensive thing that we may not want ASDF to do it inside an inner loop
like sysdef-central-registry-search.

Every time I look deeply into CL pathnames I regret them more....