From mboxrd@z Thu Jan  1 00:00:00 1970
From: =?utf-8?Q?Ludovic_Court=C3=A8s?= <ludo@gnu.org>
Subject: Re: bootstrapping SED-4.5, circular dependency?
Date: Sun, 09 Dec 2018 14:42:07 +0100
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In-Reply-To: <87o99vmjuf.fsf@gnu.org> (Jan Nieuwenhuizen's message of "Sun, 09
	Dec 2018 04:59:04 +0100")
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To: Jan Nieuwenhuizen <janneke@gnu.org>
Cc: guix-devel@gnu.org, Assaf Gordon <assafgordon@gmail.com>, sed-devel@gnu.org

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Hi!

Jan Nieuwenhuizen <janneke@gnu.org> skribis:

> Ludovic Court=C3=A8s writes:
>
> Hello,
>
>> Jan, could it be that the =E2=80=98basename=E2=80=99 and =E2=80=98dirnam=
e=E2=80=99 implementations in
>> Gash fail this test?  It might be that sed is not needed if you get
>> these right.
>
> Ah, yes!  I have added some test to Gash and this
>
>     basename -- /
>
> failed, producing the empty string, where coreutils' basename returns
> `/'.
>
> Gash "simply" (there is som if'ing involved) calls Guile's basename,
> which disagrees here and returns "" for "/".
>
> I'm assuming that this is expected behaviour for Guile?... so I
> special-cased this for Gash' basename.

Looking at
<http://pubs.opengroup.org/onlinepubs/9699919799/functions/basename.html>,
I think it=E2=80=99s a bug of Guile=E2=80=99s =E2=80=98basename=E2=80=99 (w=
hich is not implemented in
terms of libc=E2=80=99s =E2=80=98basename=E2=80=99.)

The fix might be as simple as the patch below, WDYT?

In the meantime Gash should work around the bug.

Thanks,
Ludo=E2=80=99.


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diff --git a/libguile/filesys.c b/libguile/filesys.c
index e1aeeed1b..c1cd50e21 100644
--- a/libguile/filesys.c
+++ b/libguile/filesys.c
@@ -1602,11 +1602,20 @@ SCM_DEFINE (scm_basename, "basename", 1, 1, 0,
   c_filename = scm_to_utf8_string (filename);
   scm_dynwind_free (c_filename);
 
+  if (strcmp (c_filename, "/") == 0
+      || strcmp (c_filename, "//") == 0)
+    /* As per
+       <http://pubs.opengroup.org/onlinepubs/9699919799/functions/basename.html>,
+       "/" and "//" are treated specially.  */
+    res = scm_from_utf8_string ("/");
+  else
+    {
       c_last_component = last_component (c_filename);
       if (!c_last_component)
         res = filename;
       else
         res = scm_from_utf8_string (c_last_component);
+    }
   scm_dynwind_end ();
 
   if (!SCM_UNBNDP (suffix) &&

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