do'.\dir\file' under -T on Windows

lamprecht has asked for the wisdom of the Perl Monks concerning the following question:

Hello Monks,

I'm seeing the following on WinXP running strawberry-perl:

C:\Dokumente und Einstellungen\perl\Desktop>md t

C:\Dokumente und Einstellungen\perl\Desktop>echo print "hi\n"; > t/t.p
+l

C:\Dokumente und Einstellungen\perl\Desktop>perl -e"do'.\t\t.pl'"
hi

C:\Dokumente und Einstellungen\perl\Desktop>perl -e"do'./t\t.pl'"
hi

C:\Dokumente und Einstellungen\perl\Desktop>perl -T -e"do'./t\t.pl'"
hi

C:\Dokumente und Einstellungen\perl\Desktop>perl -T -e"do'.\t\t.pl'"

C:\Dokumente und Einstellungen\perl\Desktop>perl -V
Summary of my perl5 (revision 5 version 8 subversion 8) configuration:
  Platform:
    osname=MSWin32, osvers=5.1, archname=MSWin32-x86-multi-thread
    uname=''
    config_args='undef'
    hint=recommended, useposix=true, d_sigaction=undef
    usethreads=define use5005threads=undef useithreads=define usemulti
+plicity=de
fine
    useperlio=define d_sfio=undef uselargefiles=define usesocks=undef
    use64bitint=undef use64bitall=undef uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='gcc', ccflags =' -s -O2 -DWIN32 -DHAVE_DES_FCRYPT  -DPERL_IMPL
+ICIT_CONTE
XT -DPERL_IMPLICIT_SYS -fno-strict-aliasing -DPERL_MSVCRT_READFIX',
    optimize='-s -O2',
    cppflags='-DWIN32'
    ccversion='', gccversion='3.4.5', gccosandvers=''
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
    d_longlong=undef, longlongsize=8, d_longdbl=define, longdblsize=12
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='long lo
+ng', lseek
size=8
    alignbytes=8, prototype=define
  Linker and Libraries:
    ld='g++', ldflags ='-s -L"c:\strawberry-perl\perl\lib\CORE" -L"c:\
+strawberry
-perl\mingw\lib"'
    libpth=c:\strawberry-perl\mingw\lib
    libs= -lmsvcrt -lmoldname -lkernel32 -luser32 -lgdi32 -lwinspool -
+lcomdlg32
-ladvapi32 -lshell32 -lole32 -loleaut32 -lnetapi32 -luuid -lws2_32 -lm
+pr -lwinmm
 -lversion -lodbc32 -lodbccp32
    perllibs= -lmsvcrt -lmoldname -lkernel32 -luser32 -lgdi32 -lwinspo
+ol -lcomdl
g32 -ladvapi32 -lshell32 -lole32 -loleaut32 -lnetapi32 -luuid -lws2_32
+ -lmpr -lw
inmm -lversion -lodbc32 -lodbccp32
    libc=-lmsvcrt, so=dll, useshrplib=yes, libperl=libperl58.a
    gnulibc_version=''
  Dynamic Linking:
    dlsrc=dl_win32.xs, dlext=dll, d_dlsymun=undef, ccdlflags=' '
    cccdlflags=' ', lddlflags='-mdll -s -L"c:\strawberry-perl\perl\lib
+\CORE" -L"
c:\strawberry-perl\mingw\lib"'


Characteristics of this binary (from libperl):
  Compile-time options: MULTIPLICITY PERL_IMPLICIT_CONTEXT
                        PERL_IMPLICIT_SYS PERL_MALLOC_WRAP
                        PL_OP_SLAB_ALLOC USE_ITHREADS USE_LARGE_FILES
                        USE_PERLIO
  Built under MSWin32
  Compiled at Aug 27 2006 17:17:50
  @INC:
    C:/strawberry-perl/perl/lib
    C:/strawberry-perl/perl/site/lib
    .
[download]

Is this behavior expected?

Shouldn't perl -T -e"do'./t\t.pl'" and perl -T -e"do'.\t\t.pl'" do the same thing (and print 'hi').

I came across this examining a false positive(failing) test in Scalar-List-Utils which uses an expression like above. http://rt.cpan.org/Public/Bug/Display.html?id=25430

Thank you for any insight.

Comment on do'.\dir\file' under -T on Windows Select or Download Code

Replies are listed 'Best First'.
Re: do'.\dir\file' under -T on Windows by ikegami (Patriarch) on Feb 25, 2009 at 15:06 UTC
Shouldn't `perl -T -e"do'./t\t.pl'"` and `perl -T -e"do'.\t\t.pl'"` do the same thing Yes. "/" and "\" are equivalent in Windows paths. I can replicate the problem with ActivePerl 5.6.0, 5.6.1, 5.8.0, 5.8.8, 5.10.0. Seems the logic for whether `@INC` should be used or not is broken. Under `-T`, `@INC` doesn't contain "`.`", and `do'.\t\t.pl'` is using `@INC` instead of the cd. (and print 'hi'). Seems so. 5.8.8 on linux: `$ perl -le'@INC=(); do "t/t.pl"' $ perl -le'@INC=(); do "./t/t.pl"' hi $ perl -T -le'@INC=(); do "t/t.pl"' $ perl -T -le'@INC=(); do "./t/t.pl"' hi` [download] Update: Added comparison to linux and explanation of problem.	[reply] [d/l] [select]
Re^2: do'.\dir\file' under -T on Windows by Bloodnok (Vicar) on Feb 25, 2009 at 16:19 UTC
Maybe perl is emulating one of the classic *NIX security fixes (removing the current working directory from the path) in `@INC` when run in taint checking mode... Just a thought ... A user level that continues to overstate my experience :-))	[reply] [d/l]
Re^3: do'.\dir\file' under -T on Windows by ikegami (Patriarch) on Feb 25, 2009 at 17:01 UTC
If a taint check for relative paths were to be added, it would throw an exception rather than setting `$!` to file not found. Note that this taint check would be a departure from the current model which allows the current directory to be used. `$ cat script.pl #!/usr/bin/perl print "unsafe?\n"; $ perl -T -e'$ENV{PATH}=""; system "script.pl";' unsafe?` [download] `$ cat Mod.pm print "unsafe?\n"; 1; $ perl -T -e'@INC = "."; require Mod;' unsafe?` [download] Sounds like a pretty good idea to me, though. It would break stuff, but nothing that can't be fixed.	[reply] [d/l] [select]
Re^4: do'.\dir\file' under -T on Windows by Anonymous Monk on Feb 26, 2009 at 07:58 UTC
Re^5: do'.\dir\file' under -T on Windows by lamprecht (Friar) on Feb 26, 2009 at 08:03 UTC
Re^3: do'.\dir\file' under -T on Windows by ikegami (Patriarch) on Feb 25, 2009 at 16:30 UTC
That's fine. The problem isn't that "`.`" isn't present in `@INC`, it's that `@INC` is used at all. The documented behaviour is to use `@INC`, but that's clearly not what other systems do when the path can't be a module path, or even on Windows when "`/`" is used as the separator. I'm not sure how "looks like a module path" is defined, but it's obviously buggy.	[reply] [d/l] [select]
Re: do'.\dir\file' under -T on Windows by Anonymous Monk on Feb 25, 2009 at 15:23 UTC
No, its not expected, but some insight `C:\>perl -T -e"do'.\t\t.pl' or die sprintf '(%d)(%s)(%d)(%s)($@)(%s)', +int($!),$!,int($^E),$^E,$@" (2)(No such file or directory)(3)(The system cannot find the path spec +ified)($@)() at -e line 1.` [download] `D:\>perl -Te" require 'New.pm'" Can't locate New.pm in @INC (@INC contains:... D:\>perl -Te" require 'New.pl'" Can't locate New.pl in @INC (@INC contains:... D:\>perl -Te" require './New.pm'" hi D:\>perl -Te" require './New.pl'" hi D:\>perl -Te" require '.\New.pl'" Can't locate .\New.pl in @INC (@INC contains:... D:\>perl -Te" require '.\New.pm'" Can't locate .\New.pm in @INC (@INC contains:...` [download]	[reply] [d/l] [select]