Empty entries in $GUILE_LOAD_PATH

Empty entries in $GUILE_LOAD_PATH

[Ludovic Courtès]

Hello!

Try something like:

  $ GUILE_LOAD_PATH=/foo/bar: make check

… and see the LALR tests fail with:

  ERROR: In procedure primitive-load-path: Unable to find file "home/ludo/src/guile/test-suite/lalr/common-test.scm" in load path

(These tests use ‘load’.)

Is that expected?  What’s the meaning of empty entries in the load path?

Should ‘meta/uninstalled-env’ & co. clear $GUILE_LOAD_PATH?

Thanks,
Ludo’.

Re: Empty entries in $GUILE_LOAD_PATH

[Mark H Weaver]

ludo@gnu.org (Ludovic Courtès) writes:
> Try something like:
>
>   $ GUILE_LOAD_PATH=/foo/bar: make check
>
> … and see the LALR tests fail with:
>
>   ERROR: In procedure primitive-load-path: Unable to find file
> "home/ludo/src/guile/test-suite/lalr/common-test.scm" in load path
>
> (These tests use ‘load’.)
>
> Is that expected?  What’s the meaning of empty entries in the load path?

It seems to me that a valid load path should never contain empty
entries, because the empty string is not a valid path.

> Should ‘meta/uninstalled-env’ & co. clear $GUILE_LOAD_PATH?

I don't see why it should.

     Mark

Re: Empty entries in $GUILE_LOAD_PATH

[Ludovic Courtès]

Hi Mark,

Mark H Weaver <mhw@netris.org> skribis:

> ludo@gnu.org (Ludovic Courtès) writes:
>> Try something like:
>>
>>   $ GUILE_LOAD_PATH=/foo/bar: make check
>>
>> … and see the LALR tests fail with:
>>
>>   ERROR: In procedure primitive-load-path: Unable to find file
>> "home/ludo/src/guile/test-suite/lalr/common-test.scm" in load path
>>
>> (These tests use ‘load’.)
>>
>> Is that expected?  What’s the meaning of empty entries in the load path?
>
> It seems to me that a valid load path should never contain empty
> entries, because the empty string is not a valid path.

Apparently ‘search_path’ has always treated "" as the current directory:

  $ guile
  GNU Guile 2.0.5.132-ff4d3
  Copyright (C) 1995-2012 Free Software Foundation, Inc.

  Guile comes with ABSOLUTELY NO WARRANTY; for details type `,show w'.
  This program is free software, and you are welcome to redistribute it
  under certain conditions; type `,show c' for details.

  Enter `,help' for help.
  scheme@(guile-user)> (not (not (member "" %load-path)))
  $1 = #t
  scheme@(guile-user)> (chdir "/etc")
  scheme@(guile-user)> (search-path '("") "resolv.conf")
  $2 = "resolv.conf"

(Same with 1.8.)

So we probably can’t change that.

>> Should ‘meta/uninstalled-env’ & co. clear $GUILE_LOAD_PATH?
>
> I don't see why it should.

Actually the problem was:

  scheme@(guile-user)> (set! %load-path (cons "" %load-path))
  scheme@(guile-user)> (with-fluids ((%file-port-name-canonicalization 'relative))
                         (port-filename (open-input-file "/dev/null")))
  $1 = "dev/null"

I just fixed it.  Comments welcome!

Thanks,
Ludo’.

Re: Empty entries in $GUILE_LOAD_PATH

[Andy Wingo]

Heya,

On Tue 15 May 2012 00:30, Mark H Weaver <mhw@netris.org> writes:

> It seems to me that a valid load path should never contain empty
> entries, because the empty string is not a valid path.

Traditionally empty path components indicate the current directory,
AFAIK.  I think they're valid, and if we are not interpreting them that
way, that's probably a bug.  (Though, as you note, their existence is
itself probably a bug; perhaps we should emit a warning if one is
found...)

>> Should ‘meta/uninstalled-env’ & co. clear $GUILE_LOAD_PATH?
>
> I don't see why it should.

Me neither.

Andy
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