perl5215delta - what is new for perl v5.21.5
This document describes differences between the 5.21.4 release and the 5.21.5 release.
If you are upgrading from an earlier release such as 5.21.3, first read perl5214delta, which describes differences between 5.21.3 and 5.21.4.
<<>>
is like <>
but uses three-argument open to open
each file in @ARGV. So each element of @ARGV is an actual file name, and
"|foo" won't be treated as a pipe open.
Variables and subroutines can now be aliased by assigning to a reference:
- \$c = \$d;
- \&x = \&y;
Or by using a backslash before a foreach
iterator variable, which is
perhaps the most useful idiom this feature provides:
- foreach \%hash (@array_of_hash_refs) { ... }
This feature is experimental and must be enabled via use feature
'refaliasing'
. It will warn unless the experimental::refaliasing
warnings category is disabled.
See Assigning to References in perlref
On platforms that are able to handle POSIX.1-2008, the
hash returned by
POSIX::localeconv()
includes the international currency fields added by that version of the
POSIX standard. These are
int_n_cs_precedes
,
int_n_sep_by_space
,
int_n_sign_posn
,
int_p_cs_precedes
,
int_p_sep_by_space
,
and
int_p_sign_posn
.
Before, when trying to pack infinity or not-a-number into a
(signed) character, Perl would warn, and assumed you tried to
pack 0xFF
; if you gave it as an argument to chr,
U+FFFD
was returned.
But now, all such actions (pack, chr, and print '%c'
)
result in a fatal error.
Many small improvements, bug fixes and added test cases for dealing with math related to infinity and not-a-number.
Perl has been compiled with the anti-stack-smashing option
-fstack-protector
since 5.10.1. Now Perl uses the newer variant
called -fstack-protector-strong
, if available. (This was added
already in 5.21.4.)
It is now deprecated to say something like any of the following:
- qr/foo/xx;
- /(?xax:foo)/;
- use re qw(/amxx);
That is, now x
should only occur once in any string of contiguous
regular expression pattern modifiers. We do not believe there are any
occurrences of this in all of CPAN. This is in preparation for a future
Perl release having /xx
mean to allow white-space for readability in
bracketed character classes (those enclosed in square brackets:
[...]
).
length is up to 20% faster for non-magical/non-tied scalars containing a
string if it is a non-utf8 string or if use bytes;
is in scope.
Non-magical/non-tied scalars that contain only a floating point value and are on most Perl builds with 64 bit integers now use 8-32 less bytes of memory depending on OS.
In @array = split
, the assignment can be optimized away with split
writing directly to the array. This optimisation was happening only for
package arrays other than @_ and only
sometimes. Now this optimisation happens
almost all the time.
join is now subject to constant folding. Moreover, join with a
scalar or constant for the separator and a single-item list to join is
simplified to a stringification. The separator doesn't even get evaluated.
qq(@array) is implemented using two ops: a stringify op and a join op.
If the qq contains nothing but a single array, the stringification is
optimized away.
our $var
and our($s,@a,%h) in void context are no longer evaluated at
run time. Even a whole sequence of our $foo;
statements will simply be
skipped over. The same applies to state variables.
attributes has been upgraded from version 0.23 to 0.24.
Avoid reading beyond the end of a buffer. [perl #122629]
B has been upgraded from version 1.51 to 1.52.
B::Concise has been upgraded from version 0.993 to 0.994.
Null ops that are part of the execution chain are now given sequence numbers.
Private flags for nulled ops are now dumped with mnemonics as they would be for the non-nulled counterparts.
B::Deparse has been upgraded from version 1.28 to 1.29.
Parenthesised arrays in lists passed to \
are now correctly deparsed
with parentheses (e.g., \(@a, (@b), @c)
now retains the parentheses
around @b), this preserving the flattening behaviour of referenced
parenthesised arrays. Formerly, it only worked for one array: \(@a)
.
local our
is now deparsed correctly, with the our included.
for($foo; !$bar; $baz) {...}
was deparsed without the !
(or not
).
This has been fixed.
Core keywords that conflict with lexical subroutines are now deparsed with
the CORE::
prefix.
foreach state $x (...) {...}
now deparses correctly with state and
not my.
our @array = split(...)
now deparses correctly with our in those
cases where the assignment is optimized away.
B::Debug has been upgraded from version 1.21 to 1.22.
B::Deparse has been upgraded from version 1.28 to 1.29.
Compress::Raw::Bzip2 has been upgraded from version 2.064 to 2.066.
Compress::Raw::Zlib has been upgraded from version 2.065 to 2.066.
CPAN::Meta has been upgraded from version 2.142060 to 2.142690.
DynaLoader has been upgraded from version 1.26 to 1.27.
Remove dl_nonlazy global if unused in Dynaloader. [perl #122926]
Errno has been upgraded from version 1.20_04 to 1.21.
experimental has been upgraded from version 0.010 to 0.012.
ExtUtils::CBuilder has been upgraded from version 0.280219 to 0.280220.
ExtUtils::Miniperl has been upgraded from version 1.02 to 1.03.
Fcntl has been upgraded from version 1.11 to 1.13.
Add support for the Linux pipe buffer size fcntl() commands.
feature has been upgraded from version 1.37 to 1.38.
File::Find has been upgraded from version 1.28 to 1.29.
Slightly faster module loading time.
File::Spec has been upgraded from version 3.50 to 3.51.
HTTP::Tiny has been upgraded from version 0.049 to 0.050.
The IO-Compress set of modules has been upgraded from version 2.064 to 2.066.
JSON::PP has been upgraded from version 2.27203 to 2.27300.
The libnet collection of modules has been upgraded from version 1.27 to 3.02.
Support for IPv6 and SSL to Net::FTP, Net::NNTP, Net::POP3 and Net::SMTP.
Improvements in Net::SMTP authentication.
Module::CoreList has been upgraded from version 5.20140920 to 5.20141020.
Updated to cover the latest releases of Perl.
Opcode has been upgraded from version 1.28 to 1.29.
The PathTools module collection has been upgraded from version 3.50 to 3.51.
Slightly faster module loading time.
perlfaq has been upgraded from version 5.0150045 to version 5.0150046. [perl #123008]
POSIX has been upgraded from version 1.43 to 1.45.
POSIX::tmpnam() now produces a deprecation warning. [perl #122005]
re has been upgraded from version 0.26 to 0.27.
Socket has been upgraded from version 2.015 to 2.016.
Test::Simple has been upgraded from version 1.001006 to 1.001008.
threads::shared has been upgraded from version 1.46 to 1.47.
warnings has been upgraded from version 1.26 to 1.28.
XSLoader has been upgraded from version 0.17 to 0.18.
Allow XSLoader to load modules from a different namespace. [perl #122455]
Clarifications have been added to Character Ranges in perlrecharclass
to the effect that Perl guarantees that [A-Z]
, [a-z]
, [0-9]
and
any subranges thereof in regular expression bracketed character classes
are guaranteed to match exactly what a naive English speaker would
expect them to match, even on platforms (such as EBCDIC) where special
handling is required to accomplish this.
The following additions or changes have been made to diagnostic output, including warnings and fatal error messages. For the complete list of diagnostic messages, see perldiag.
'"my" variable &foo::bar can't be in a package' has been reworded to say 'subroutine' instead of 'variable'.
Some regular expression tests are written in such a way that they will
run very slowly if certain optimizations break. These tests have been
moved into new files, t/re/speed.t and t/re/speed_thr.t,
and are run with a watchdog()
.
IRIX and Tru64 platforms are working again.
(Some make test
failures remain.)
Special handling is required on EBCDIC platforms to get qr/[i-j]/ to
match only "i"
and "j"
, since there are 7 characters between the
code points for "i"
and "j"
. This special handling had only been
invoked when both ends of the range are literals. Now it is also
invoked if any of the \N{...}
forms for specifying a character by
name or Unicode code point is used instead of a literal. See
Character Ranges in perlrecharclass.
SVs of type SVt_NV are now bodyless when a build configure and platform allow
it, specifically sizeof(NV) <= sizeof(IV)
. The bodyless trick is the same one
as for IVs since 5.9.2, but for NVs, unlike IVs, is not guaranteed on all
platforms and build configurations.
The $DB::single
, $DB::signal
and $DB::trace
now have set and
get magic that stores their values as IVs and those IVs are used when
testing their values in pp_dbstate
. This prevents perl from
recursing infinity if an overloaded object is assigned to any of those
variables. [perl #122445]
Perl_tmps_grow
which is marked as public API but undocumented has been
removed from public API. If you use EXTEND_MORTAL
macro in your XS code to
preextend the mortal stack, you are unaffected by this change.
cv_name
, which was introduced in 5.21.4, has been changed incompatibly.
It now has a flags field that allows the caller to specify whether the name
should be fully qualified. See cv_name in perlapi.
Internally Perl no longer uses the SVs_PADMY
flag. SvPADMY()
now
returns a true value for anything not marked PADTMP. SVs_PADMY
is now
defined as 0.
The macros SETsv and SETsvUN have been removed. They were no longer used in the core since commit 6f1401dc2a, and have not been found present on CPAN.
The SvFAKE
bit (unused on HVs) got informally reserved by
David Mitchell for future work on vtables.
The sv_catpvn_flags
function accepts SV_CATBYTES
and SV_CATUTF8
flags, which specify whether the appended string is bytes or utf8,
respectively.
A new opcode class, METHOP
has been introduced, which holds
class/method related info needed at runtime to improve performance
of class/object method calls.
OP_METHOD
and OP_METHOD_NAMED
are moved from being
UNOP/SVOP
to being METHOP
.
Locking and unlocking values via Hash::Util or Internals::SvREADONLY
no longer has any effect on values that are read-only to begin.
Previously, unlocking such values could result in crashes, hangs or
other erratic behaviour.
The internal looks_like_number
function (which Scalar::Util provides
access to) began erroneously to return true for "-e1" in 5.21.4, affecting
also -'-e1'
. This has been fixed.
The flip-flop operator (..
in scalar context) would return the same
scalar each time, unless the containing subroutine was called recursively.
Now it always returns a new scalar. [perl #122829]
Some unterminated (?(...)...)
constructs in regular expressions would
either crash or give erroneous error messages. /(?(1)/
is one such
example.
pack "w", $tied
no longer calls FETCH twice.
List assignments like ($x, $z) = (1, $y)
now work correctly if $x and $y
have been aliased by foreach
.
Some patterns including code blocks with syntax errors, such as
/ (?{(^{})/
, would hang or fail assertions on debugging builds. Now
they produce errors.
An assertion failure when parsing sort with debugging enabled has been
fixed. [perl #122771]
*a = *b; @a = split //, $b[1]
could do a bad read and produce junk
results.
In () = @array = split
, the () =
at the beginning no longer confuses
the optimizer, making it assume a limit of 1.
Fatal warnings no longer prevent the output of syntax errors. [perl #122966]
Fixed a NaN double to long double conversion error on VMS. For quiet NaNs (and only on Itanium, not Alpha) negative infinity instead of NaN was produced.
Fixed the issue that caused make distclean
to leave files behind
that shouldn't. [perl #122820]
AIX now sets the length in getsockopt correctly. [perl #120835],
[rt #91183], [rt #85570].
During the pattern optimization phase, we no longer recurse into GOSUB/GOSTART when not SCF_DO_SUBSTR. This prevents the optimizer to run "forever" and exhaust all memory. [perl #122283]
t/op/crypt.t now performs SHA-256 algorithm if the default one is disabled. [perl #121591]
Fixed an off-by-one error when setting the size of shared array. [perl #122950]
Fixed a bug that could cause perl to execute an infinite loop during compilation. [perl #122995]
Perl 5.21.5 represents approximately 4 weeks of development since Perl 5.21.4 and contains approximately 40,000 lines of changes across 530 files from 33 authors.
Excluding auto-generated files, documentation and release tools, there were approximately 29,000 lines of changes to 390 .pm, .t, .c and .h files.
Perl continues to flourish into its third decade thanks to a vibrant community of users and developers. The following people are known to have contributed the improvements that became Perl 5.21.5:
Aaron Crane, Abigail, Alberto Simões, Andrew Fresh, Chris 'BinGOs' Williams, Craig A. Berry, Dagfinn Ilmari Mannsåker, Daniel Dragan, David Mitchell, Doug Bell, Ed J, Father Chrysostomos, George Greer, Graham Knop, James E Keenan, Jarkko Hietaniemi, Karen Etheridge, Karl Williamson, Leon Timmermans, Lukas Mai, Niko Tyni, Peter Martini, Petr Písař, Rafael Garcia-Suarez, Reini Urban, Ricardo Signes, Shlomi Fish, Steve Hay, syber, Tony Cook, Vincent Pit, Yves Orton, Ævar Arnfjörð Bjarmason.
The list above is almost certainly incomplete as it is automatically generated from version control history. In particular, it does not include the names of the (very much appreciated) contributors who reported issues to the Perl bug tracker.
Many of the changes included in this version originated in the CPAN modules included in Perl's core. We're grateful to the entire CPAN community for helping Perl to flourish.
For a more complete list of all of Perl's historical contributors, please see the AUTHORS file in the Perl source distribution.
If you find what you think is a bug, you might check the articles recently posted to the comp.lang.perl.misc newsgroup and the perl bug database at https://rt.perl.org/ . There may also be information at http://www.perl.org/ , the Perl Home Page.
If you believe you have an unreported bug, please run the perlbug program
included with your release. Be sure to trim your bug down to a tiny but
sufficient test case. Your bug report, along with the output of perl -V
,
will be sent off to perlbug@perl.org to be analysed by the Perl porting team.
If the bug you are reporting has security implications, which make it inappropriate to send to a publicly archived mailing list, then please send it to perl5-security-report@perl.org. This points to a closed subscription unarchived mailing list, which includes all the core committers, who will be able to help assess the impact of issues, figure out a resolution, and help co-ordinate the release of patches to mitigate or fix the problem across all platforms on which Perl is supported. Please only use this address for security issues in the Perl core, not for modules independently distributed on CPAN.
The Changes file for an explanation of how to view exhaustive details on what changed.
The INSTALL file for how to build Perl.
The README file for general stuff.
The Artistic and Copying files for copyright information.