[perl #4514] two bugs: substitution on a list

On Fri Jun 10 00:01:29 2011, chorny wrote:
> Same result on perl 5.14.0.
> 
> http://rt.perl.org/rt3/Ticket/Display.html?id=4514
> 
> On Wed Oct 25 08:41:02 2000, hv@crypt.compulink.co.uk wrote:
> > (After a report in clp.moderated from Peter Scott <peter@psdt.com>.)
> > 
> > perl -Dr -we '(($y) = "x") =~ s/a/b/'
> > 
> > shows that a) perl is trying to perform the substitution on the string
> > '1' which is not what the caller intended, and b) '1' is not marked
> > readonly in this context, so no error is reported. I think both of
> > these are bugs: I think the former should be fixed by giving an error
> > if the LHS of a binding operator is supplied as a list, and that the
> > latter should be fixed (if still relevant) by marking the count of
> > list elements as readonly.
> 
> 

This is what I got after doing a debugging build on blead:

#####
./perl -Dr -we '(($y) = "x") =~ s/a/b/'
#####
Compiling REx "a"
rarest char a at 0
Final program:
   1: EXACT <a> (3)
   3: END (0)
anchored "a" at 0 (checking anchored isall) minlen 1 
Name "main::y" used only once: possible typo at -e line 1.
Enabling $` $& $' support (0x7).

EXECUTING...

Matching REx "a" against "1"
Did not find anchored substr "a"...
Match rejected by optimizer
Freeing REx: "a"
#####

$ ./perl -Ilib -V
Summary of my perl5 (revision 5 version 19 subversion 4) configuration:
  Commit id: 3a76eb2801fceebb5a48fa4f8884157132cee30e
  Platform:
    osname=linux, osvers=2.6.32-358.el6.x86_64, archname=x86_64-linux
    uname='linux dromedary-001.ams6.corp.booking.com
2.6.32-358.el6.x86_64 #1 smp fri feb 22 00:31:26 utc 2013 x86_64 x86_64
x86_64 gnulinux '
    config_args='-des -Dusedevel -DDEBUGGING'
    hint=recommended, useposix=true, d_sigaction=define
    useithreads=undef, usemultiplicity=undef
    useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
    use64bitint=define, use64bitall=define, uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='cc', ccflags ='-DDEBUGGING -fno-strict-aliasing -pipe
-fstack-protector -I/usr/local/include -D_LARGEFILE_SOURCE
-D_FILE_OFFSET_BITS=64',
    optimize='-O2 -g',
    cppflags='-DDEBUGGING -fno-strict-aliasing -pipe -fstack-protector
-I/usr/local/include'
    ccversion='', gccversion='4.4.7 20120313 (Red Hat 4.4.7-3)',
gccosandvers=''
    intsize=4, longsize=8, ptrsize=8, doublesize=8, byteorder=12345678
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16
    ivtype='long', ivsize=8, nvtype='double', nvsize=8, Off_t='off_t',
lseeksize=8
    alignbytes=8, prototype=define
  Linker and Libraries:
    ld='cc', ldflags =' -fstack-protector -L/usr/local/lib'
    libpth=/usr/local/lib /lib/../lib64 /usr/lib/../lib64 /lib /usr/lib
/lib64 /usr/lib64 /usr/local/lib64
    libs=-lnsl -ldl -lm -lcrypt -lutil -lc
    perllibs=-lnsl -ldl -lm -lcrypt -lutil -lc
    libc=/lib/libc-2.12.so, so=so, useshrplib=false, libperl=libperl.a
    gnulibc_version='2.12'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E'
    cccdlflags='-fPIC', lddlflags='-shared -O2 -g -L/usr/local/lib
-fstack-protector'


Characteristics of this binary (from libperl): 
  Compile-time options: DEBUGGING HAS_TIMES PERLIO_LAYERS
                        PERL_DONT_CREATE_GVSV
                        PERL_HASH_FUNC_ONE_AT_A_TIME_HARD PERL_MALLOC_WRAP
                        PERL_NEW_COPY_ON_WRITE PERL_PRESERVE_IVUV
                        PERL_USE_DEVEL USE_64_BIT_ALL USE_64_BIT_INT
                        USE_LARGE_FILES USE_LOCALE USE_LOCALE_COLLATE
                        USE_LOCALE_CTYPE USE_LOCALE_NUMERIC USE_PERLIO
                        USE_PERL_ATOF
  Built under linux
  Compiled at Sep  7 2013 04:19:53
  %ENV:
    PERLBREW_BASHRC_VERSION="0.63"
    PERLBREW_HOME="/home/jkeenan/.perlbrew"
    PERLBREW_ROOT="/home/jkeenan/perl5/perlbrew"
  @INC:
    lib
    /usr/local/lib/perl5/site_perl/5.19.4/x86_64-linux
    /usr/local/lib/perl5/site_perl/5.19.4
    /usr/local/lib/perl5/5.19.4/x86_64-linux
    /usr/local/lib/perl5/5.19.4
    /usr/local/lib/perl5/site_perl
    .


---
via perlbug:  queue: perl5 status: open
https://rt.perl.org:443/rt3/Ticket/Display.html?id=4514

• [perl #4514] two bugs: substitution on a list by James E Keenan via RT
• Re: [perl #4514] two bugs: substitution on a list by Dave Mitchell
• [perl #4514] two bugs: substitution on a list by Father Chrysostomos via RT
• Re: [perl #4514] two bugs: substitution on a list by Dave Mitchell
• [perl #4514] two bugs: substitution on a list by James E Keenan via RT
• [perl #4514] two bugs: substitution on a list by Sawyer X via RT
• [perl #4514] two bugs: substitution on a list by Father Chrysostomos via RT