On 07/12/2012 07:06 PM, Eric Blake wrote:
> On 07/12/2012 10:23 AM, Stefano Lattarini wrote:
> 
>>> Other than that, the only supported method in existing POSIX for
>>> checking for equal files is by parsing 'ls -i' output; but I don't know
>>> if 'ls -i' is portable to ancient hosts.
>>>
>> I was fearing this would have got quickly complex and messy ...
>>
>> So I think I'll stick to my dumber and safer "test -f /bin/RMDIR" as a
>> way to detect case-insensible filesystems.
> 
> Assuming it was intentional, I like your re-wording of
> "case-insensible", as an apt description of the pain case-insensitive
> systems cause on portability :)
>
Sorry, no deliberate pun, just a lexical error.  But I can keep it if
you like it :-)

> That said, /bin/RMDIR is probably not completely portable, but seems
> like it would be reliable in practice.
>
That is my impression.  And anyway, there aren't too many people running
the Automake testsuite on Mac OS X or Cygwin, so if the patch manages to
fix Peter's and Max's issue, it is good enough for me (at least until
somebody else reports a similar issue).  Finally, consider that the
result of a botch-up of this new configure check would simple be one or
two spurious testsuite failures -- so just a small annoyance, nothing to
really worry about.

> POSIX doesn't reqiure /bin/rmdir to
> exist (about the only files that you can guarantee with POSIX are /tmp,
> /dev/null, /dev/tty, and /dev/console).  Since /dev/ generally doesn't
> exist on mingw, that almost limits you to just testing if /tmp and /TMP
> are the same directory to detect a case-insensitive system.  But I don't
> know of any systems that lack /bin/rmdir on a default installation, nor
> do I suspect many users intentionally create /bin/RMDIR (or even better,
> /bIn/rMdIr),
>
Good idea for an improved test; I've implemented it in my patch.

> so using it as a hueristic seems okay for a first cut at
> the problem at hand.  Or, maybe you should just create a file in /tmp
> under one spelling and check existence of the file by another spelling.
> 

In the light of our discussion, attached is the patch I'd finally like
to push.  WDYT?

Thanks,
  Stefano