From @andk

git bisect

commit 5608dcc
Author​: Father Chrysostomos <sprout@​cpan.org>
Date​: Sat Jun 22 18​:46​:00 2013 -0700

  [perl #3105] Make 1..3 modification safe

diagnostics

http​://www.cpantesters.org/cpan/report/7a2bb4ea-f66c-11e2-a9e3-d7e6f1ff63fb

rt.cpan ticket

https://rt.cpan.org/Ticket/Display.html?id=95174

perl -V

Summary of my perl5 (revision 5 version 19 subversion 3) configuration​:
  Commit id​: 9e4ab80
  Platform​:
  osname=linux, osvers=3.9-1-amd64, archname=x86_64-linux-thread-multi-ld
  uname='linux k83 3.9-1-amd64 #1 smp debian 3.9.8-1 x86_64 gnulinux '
  config_args='-Dprefix=/home/sand/src/perl/repoperls/installed-perls/perl/v5.19.2-149-g9e4ab80/a2da -Dmyhostname=k83 -Dinstallusrbinperl=n -Uversiononly -Dusedevel -des -Ui_db -Duseithreads -Duselongdouble -DDEBUGGING=-g'
  hint=recommended, useposix=true, d_sigaction=define
  useithreads=define, usemultiplicity=define
  useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
  use64bitint=define, use64bitall=define, uselongdouble=define
  usemymalloc=n, bincompat5005=undef
  Compiler​:
  cc='cc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
  optimize='-O2 -g',
  cppflags='-D_REENTRANT -D_GNU_SOURCE -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include'
  ccversion='', gccversion='4.8.1', 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='long double', nvsize=16, Off_t='off_t', lseeksize=8
  alignbytes=16, prototype=define
  Linker and Libraries​:
  ld='cc', ldflags =' -fstack-protector -L/usr/local/lib'
  libpth=/usr/local/lib /lib/x86_64-linux-gnu /lib/../lib /usr/lib/x86_64-linux-gnu /usr/lib/../lib /lib /usr/lib
  libs=-lnsl -lgdbm -ldb -ldl -lm -lcrypt -lutil -lpthread -lc -lgdbm_compat
  perllibs=-lnsl -ldl -lm -lcrypt -lutil -lpthread -lc
  libc=, so=so, useshrplib=false, libperl=libperl.a
  gnulibc_version='2.17'
  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​: HAS_TIMES MULTIPLICITY PERLIO_LAYERS
  PERL_DONT_CREATE_GVSV
  PERL_HASH_FUNC_ONE_AT_A_TIME_HARD
  PERL_IMPLICIT_CONTEXT PERL_MALLOC_WRAP
  PERL_NEW_COPY_ON_WRITE PERL_PRESERVE_IVUV
  PERL_USE_DEVEL USE_64_BIT_ALL USE_64_BIT_INT
  USE_ITHREADS USE_LARGE_FILES USE_LOCALE
  USE_LOCALE_COLLATE USE_LOCALE_CTYPE
  USE_LOCALE_NUMERIC USE_LONG_DOUBLE USE_PERLIO
  USE_PERL_ATOF USE_REENTRANT_API
  Built under linux
  Compiled at Jul 26 2013 09​:28​:56
  %ENV​:
  PERL5LIB=""
  PERL5OPT=""
  PERL5_CPANPLUS_IS_RUNNING="12638"
  PERL5_CPAN_IS_RUNNING="12638"
  PERL_MM_USE_DEFAULT="1"
  @​INC​:
  /home/sand/src/perl/repoperls/installed-perls/perl/v5.19.2-149-g9e4ab80/a2da/lib/site_perl/5.19.3/x86_64-linux-thread-multi-ld
  /home/sand/src/perl/repoperls/installed-perls/perl/v5.19.2-149-g9e4ab80/a2da/lib/site_perl/5.19.3
  /home/sand/src/perl/repoperls/installed-perls/perl/v5.19.2-149-g9e4ab80/a2da/lib/5.19.3/x86_64-linux-thread-multi-ld
  /home/sand/src/perl/repoperls/installed-perls/perl/v5.19.2-149-g9e4ab80/a2da/lib/5.19.3
  .
--
andreas

From @tonycoz

On Fri May 02 00​:09​:57 2014, andreas.koenig.7os6VVqR@​franz.ak.mind.de wrote​:

git bisect
----------
commit 5608dcc
Author​: Father Chrysostomos <sprout@​cpan.org>
Date​: Sat Jun 22 18​:46​:00 2013 -0700

[perl #3105] Make 1..3 modification safe

If I understand what is going on here, the above patch fixes this bug​:

5.14​:

perl -le 'sub foo { sub { \@​_ }->(1..3) } foo()->[1] = 4; print @​{foo()}'
143

blead​:

perl -le 'sub foo { sub { \@​_ }->(1..3) } foo()->[1] = 4; print @​{foo()}'
123

ie. previously we allowed the caller to modify the result of a constant folded range operator.

Note the test immediately following does exactly the same thing, except it uses non-constants for the list, but expects a different result.

Here's the tests​:

{
  my ($x, $y) = map & \(1 .. 3), 1 .. 2;
  $_ += 10 for @​$x;
  t 'map & \(1 .. 3), 1 .. 2',
  is => "@​$x : @​$y", '11 12 13 : 11 12 13';
}
{
  my ($low, $high) = (1, 3);
  my ($x, $y) = map &\($low .. $high), 1 .. 2;
  $_ += 10 for @​$x;
  t 'map &\($low .. $high), 1 .. 2',
  is => "@​$x : @​$y", '11 12 13 : 1 2 3';
}

sub & is an alias for sub cap, implemented as​:

  sub cap {\@​_}

I don't think this is a bug in perl, but fix in perl, which broke a test that expected the strange result we produced previously.

Tony

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

From @rjbs

Closed as "not a bug in perl." The CPAN ticket is https://rt.cpan.org/Ticket/Display.html?id=95174

--
rjbs

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