Re: [FYI] {master} refactor: use modern semantics of 'open'

[Eric Blake]

On 04/24/2012 04:50 PM, Russ Allbery wrote:
> Eric Blake <address@hidden> writes:
> 
>> Help!  I can't release autoconf 2.69 until I figure out how to work
>> around this patch.  After updating to the latest shared files, as well
>> as applying this patch, I'm now stuck with output going to a literal
>> file named '-' instead of going to stdout.  I suspect that the
>> conversion to the 2-arg form is mishandling our idiom of '-' as standard
>> in/out.
> 
> If you call open with three arguments, "-" has no special meaning and
> refers to a file named "-" (since the whole point of three-argument open
> is to remove all magic interpretations of the filename string).  The
> easiest way to work around this is probably to change the Automake helper
> functions that sit between the code and the Perl open command and have
> them switch to calling open with two arguments if the file name is "-".

Indeed, this hack gets me further, but still not complete success:

diff --git i/lib/Autom4te/XFile.pm w/lib/Autom4te/XFile.pm
index 19b73aa..95a452b 100644
--- i/lib/Autom4te/XFile.pm
+++ w/lib/Autom4te/XFile.pm
@@ -138,7 +138,14 @@ sub open
   # comment in IO::Handle.
   ${*$fh}{'autom4te_xfile_file'} = "$file";

-  if (!$fh->SUPER::open (@_))
+  if (defined $mode && "$file" eq '-')
+    {
+      if (!$fh->SUPER::open ("$mode$file"))
+       {
+         fatal "cannot open $file: $!";
+       }
+    }
+  elsif (!$fh->SUPER::open (@_))
     {
       fatal "cannot open $file: $!";
     }

-- 
Eric Blake   address@hidden    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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