From @cpansprout

stat and most filetest ops, like -r, leave errno alone when called with an unopened filehandle​:

$ ./perl -Ilib -le '$! = 7; print $!; stat foo; print $!'
Argument list too long
Argument list too long
$ ./perl -Ilib -le '$! = 7; print $!; -r foo; print $!'
Argument list too long
Argument list too long

But -T sets errno​:

$ ./perl -Ilib -le '$! = 7; print $!; -T foo; print $!'
Argument list too long
Bad file descriptor

What should be the correct behaviour?

close() sets errno​:

$ ./perl -Ilib -le '$! = 7; print $!; close foo; print $!'
Argument list too long
Bad file descriptor

Is it stat and -r that should change?

Currently, $! cannot be relied upon when a filetest op returns undef. And, apart from trapping the ‘unopened’ warning or fiddling with B.pm, there is no way to tell whether an IO thingy actually has an fp. So $! is useless.

Flags​:
  category=core
  severity=low

Site configuration information for perl 5.15.6​:

Configured by sprout at Sat Dec 31 10​:12​:16 PST 2011.

Summary of my perl5 (revision 5 version 15 subversion 6) configuration​:
  Local Commit​: b2635083831c8935c437465bbeb03aec8b599c01
  Ancestor​: 407287f
  Platform​:
  osname=darwin, osvers=10.5.0, archname=darwin-thread-multi-2level
  uname='darwin pint.local 10.5.0 darwin kernel version 10.5.0​: fri nov 5 23​:20​:39 pdt 2010; root​:xnu-1504.9.17~1release_i386 i386 '
  config_args='-de -Dusedevel -Duseithreads -DDEBUGGING -Dmad'
  hint=recommended, useposix=true, d_sigaction=define
  useithreads=define, usemultiplicity=define
  useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
  use64bitint=undef, use64bitall=undef, uselongdouble=undef
  usemymalloc=n, bincompat5005=undef
  Compiler​:
  cc='cc', ccflags ='-fno-common -DPERL_DARWIN -DDEBUGGING -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include',
  optimize='-O3 -g',
  cppflags='-fno-common -DPERL_DARWIN -DDEBUGGING -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include'
  ccversion='', gccversion='4.2.1 (Apple Inc. build 5664)', gccosandvers=''
  intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
  d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16
  ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8
  alignbytes=8, prototype=define
  Linker and Libraries​:
  ld='env MACOSX_DEPLOYMENT_TARGET=10.3 cc', ldflags =' -fstack-protector -L/usr/local/lib'
  libpth=/usr/local/lib /usr/lib
  libs=-ldbm -ldl -lm -lutil -lc
  perllibs=-ldl -lm -lutil -lc
  libc=, so=dylib, useshrplib=false, libperl=libperl.a
  gnulibc_version=''
  Dynamic Linking​:
  dlsrc=dl_dlopen.xs, dlext=bundle, d_dlsymun=undef, ccdlflags=' '
  cccdlflags=' ', lddlflags=' -bundle -undefined dynamic_lookup -L/usr/local/lib -fstack-protector'

Locally applied patches​:
 

@​INC for perl 5.15.6​:
  /usr/local/lib/perl5/site_perl/5.15.6/darwin-thread-multi-2level
  /usr/local/lib/perl5/site_perl/5.15.6
  /usr/local/lib/perl5/5.15.6/darwin-thread-multi-2level
  /usr/local/lib/perl5/5.15.6
  /usr/local/lib/perl5/site_perl
  .

Environment for perl 5.15.6​:
  DYLD_LIBRARY_PATH (unset)
  HOME=/Users/sprout
  LANG=en_US.UTF-8
  LANGUAGE (unset)
  LD_LIBRARY_PATH (unset)
  LOGDIR (unset)
  PATH=/usr/bin​:/bin​:/usr/sbin​:/sbin​:/usr/local/bin​:/usr/X11/bin​:/usr/local/bin
  PERL_BADLANG (unset)
  SHELL=/bin/bash

From zefram@fysh.org

Father Chrysostomos wrote​:

Is it stat and -r that should change?

Yes. It is clearly a bug for them to not set $! on error; the file
test operators are explicitly documented to do so. Fixed in commit
97c8f3e.

-zefram

The RT System itself - Status changed from 'new' to 'open'

@cpansprout - Status changed from 'open' to 'resolved'