PERL51310DELTA(1) Perl Programmers Reference Guide PERL51310DELTA(1)NAMEperl51310delta - what is new for perl v5.13.10
DESCRIPTION
This document describes differences between the 5.13.9 release and the
5.13.10 release.
If you are upgrading from an earlier release such as 5.13.8, first read
perl5139delta, which describes differences between 5.13.8 and 5.13.9.
Core Enhancements
The new regular expression modifiers available in suffix form
Various releases of the 5.13.x series have added new regular expression
modifiers, "/a", "/d", "/l", and "/u". They were only available in
infix form (e.g., "(?a:...)") until this release; now they are usable
in suffix form. This change was made too late to change all the
affected documentation, so there are a number of places that
erroneously say these must be used in infix form.
However, there is an ambiguity with the construct, "s/foo/bar/le...".
Due to backward compatibility constraints, in Perl 5.14 only, it will
be resolved as "s/foo/bar/ le...", that is, as meaning to take the
result of the substitution, and see if it is stringwise less-than-or-
equal-to what follows. In Perl 5.16 and later, it will instead be
resolved as meaning to do the pattern match using the rules of the
current locale, and evaluate the rhs as an expression when doing the
substitution. In 5.14, if you want the latter interpretation, you can
write "el" instead.
Add "\p{Titlecase}" as a synonym for "\p{Title}"
This synonym is added for symmetry with the Unicode property names
"\p{Uppercase}" and "\p{Lowercase}".
New regular expression modifier option "/aa"
Doubling the "/a" regular expression modifier increases its effect, so
that in case-insensitive matching, no ASCII character will match a non-
ASCII character. For example, normally,
'k' =~ /\N{KELVIN SIGN}/i
will match; it won't under "/aa".
New warnings categories for problematic (non-)Unicode code points.
Three new warnings subcategories of <utf8> have been added. These
allow you to turn off warnings for their covered events, while allowing
the other UTF-8 warnings to remain on. The three categories are:
"surrogate" when UTF-16 surrogates are encountered; "nonchar" when
Unicode non-character code points are encountered; and "non_unicode"
when code points that are above the legal Unicode maximum of 0x10FFFF
are encountered.
Incompatible Changes
Most "\p{}" properties are now immune from case-insensitive matching
For most Unicode properties, it doesn't make sense to have them match
differently under "/i" case-insensitive matching than not. And doing
so leads to unexpected results and potential security holes. For
example
m/\p{ASCII_Hex_Digit}+/i
could previously match non-ASCII characters because of the Unicode
matching rules. There were a number of bugs in this feature until an
earlier release in the 5.13 series. Now this release reverts, and
removes the feature completely except for the few properties where
people have come to expect it, namely the ones where casing is an
integral part of their functionality, such as "m/\p{Uppercase}/i" and
"m/\p{Lowercase}/i", both of which match the exact same code points,
namely those matched by "m/\p{Cased}/i". Details are in "Unicode
Properties" in perlrecharclass.
User-defined property handlers that need to match differently under
"/i" must change to read the new boolean parameter passed it which is
non-zero if case-insensitive matching is in effect; 0 if not. See
"User-Defined Character Properties" in perluniprops.
regex: \p{} in pattern implies Unicode semantics
Now, a Unicode property match specified in the pattern will indicate
that the pattern is meant for matching according to Unicode rules
(e40e74f)
add GvCV_set() and GvGP_set() macros and change GvGP()
This allows a future commit to eliminate some backref magic between GV
and CVs, which will require complete control over assignment to the
gp_cv slot.
If you've been using GvGP() in lvalue context this change will break
your code, you should use GvGP_set() instead. (c43ae56)
_swash_inversion_hash is no longer exported as part of the API
This function shouldn't be called from XS code. (4c2e113)
Unreferenced objects in global destruction
The fix for [perl #36347], which made sure that destructors were called
on unreferenced objects, broke the tests for three CPAN modules, which
apparently rely on the bug.
To provide more time for fixing them (as this is such a minor bug), we
have reverted the fix until after perl 5.14.0.
This resolves [perl #82542] and other related tickets.
"close" on shared pipes
The "close" function no longer waits for the child process to exit if
the underlying file descriptor is still in use by another thread, to
avoid deadlocks. It returns true in such cases.
Deprecations
Deprecated Modules
The following modules will be removed from the core distribution in
a future release, and should be installed from CPAN instead.
Distributions on CPAN which require these should add them to their
prerequisites. The core versions of these modules warnings will
issue a deprecation warning.
If you ship a packaged version of Perl, either alone or as part of
a larger system, then you should carefully consider the
repercussions of core module deprecations. You may want to consider
shipping your default build of Perl with packages for some or all
deprecated modules which install into "vendor" or "site" perl
library directories. This will inhibit the deprecation warnings.
Alternatively, you may want to consider patching lib/deprecate.pm
to provide deprecation warnings specific to your packaging system
or distribution of Perl, consistent with how your packaging system
or distribution manages a staged transition from a release where
the installation of a single package provides the given
functionality, to a later release where the system administrator
needs to know to install multiple packages to get that same
functionality.
You can silence these deprecation warnings by installing the
modules in question from CPAN. To install the latest version of
all of them, just install "Task::Deprecations::5_14".
Devel::DProf
We strongly recommend that you install and used Devel::NYTProf
in preference, as it offers significantly improved profiling
and reporting.
User-defined case-mapping
This feature is being deprecated due to its many issues, as documented
in "User-Defined Case Mappings (for serious hackers only)" in
perlunicode. It is planned to remove this feature in Perl 5.16. A
CPAN module providing improved functionality is being prepared for
release by the time 5.14 is.
Modules and Pragmata
New Modules and Pragmata
· "CPAN::Meta" version 2.110440 has been added as a dual-life module.
It provides a standard library to read, interpret and write CPAN
distribution metadata files (e.g. META.json and META.yml) which
describes a distribution, its contents, and the requirements for
building it and installing it. The latest CPAN distribution
metadata specification is included as "CPAN::Meta::Spec" and notes
on changes in the specification over time are given in
"CPAN::Meta::History".
· "Version::Requirements" version 0.101020 has been added as a dual-
life module. It provides a standard library to model and
manipulates module prerequisites and version constraints as defined
in the CPAN::Meta::Spec.
Updated Modules and Pragmata
· "B" has been upgraded from version 1.27 to 1.28.
· "Carp" has been upgraded from version 1.19 to 1.20.
[perl #82854] It now avoids using regular expressions that cause
perl to load its Unicode tables, in order to avoid the 'BEGIN not
safe after errors' error that will ensue if there has been a syntax
error.
· "CGI" has been upgraded from version 3.51 to 3.52
· "CPAN" has been upgraded from version 1.94_64 to 1.94_65
Includes support for META.json and MYMETA.json.
· "CPANPLUS" has been upgraded from version 0.9011 to 0.9101
Includes support for META.json and MYMETA.json and a change to
using Digest::SHA for CPAN checksums.
· "deprecate" has been upgraded from version 0.01 to 0.02.
· "diagnostics" has been upgraded from version 1.21 to 1.22.
It now renders pod links slightly better, and has been taught to
find descriptions for messages that share their descriptions with
other messages.
· "Devel::DProf" has been upgraded from version 20080331.00 to
20110217.00.
Merely loading "Devel::DProf" now no longer triggers profiling to
start. "use Devel::DProf" and "perl -d:DProf ..." still behave as
before and start the profiler.
NOTE: "Devel::DProf" is deprecated and will be removed from a
future version of Perl. We strongly recommend that you install and
use Devel::NYTProf instead, as it offers significantly improved
profiling and reporting.
· "DynaLoader" has been upgraded from version 1.12 to 1.13.
[perl #84358] It no longer inherits from AutoLoader; hence it no
longer produces weird error messages for unsuccessful method calls
on classes that inherit from DynaLoader.
· "IO::Select" has been upgraded from version 1.17 to 1.18.
It now allows IO::Handle objects (and objects in derived classes)
to be removed from an IO::Select set even if the underlying file
descriptor is closed or invalid.
· "IPC::Cmd" has been upgraded from version 0.68 to 0.70
· "HTTP::Tiny" has been upgraded from version 0.009 to 0.010
· "Math::BigInt" has been upgraded from version 1.99_04 to 1.992.
· "Module::Build" has been upgraded from version 0.3607 to 0.37_05.
A notable change is the deprecation of several modules.
Module::Build::Version has been deprecated and Module::Build now
relies directly upon version. Module::Build::ModuleInfo has been
deprecated in favor of a standalone copy of it called
Module::Metadata. Module::Build::YAML has been deprecated in favor
of CPAN::Meta::YAML.
Module::Build now also generates META.json and MYMETA.json files in
accordance with version 2 of the CPAN distribution metadata
specification, CPAN::Meta::Spec. The older format META.yml and
MYMETA.yml files are still generated, as well.
· "Module::Load::Conditional" has been upgraded from version 0.40 to
0.44
· "Module::Metadata" has been upgraded from version 1.000003 to
1.000004.
· "overload" has been upgraded from version 1.12 to 1.13.
The documentation has greatly improved. See "Documentation" below.
· "Parse::CPAN::Meta" has been upgraded from version 1.40 to 1.4401.
The latest Parse::CPAN::Meta can now read YAML or JSON files using
CPAN::Meta::YAML and JSON::PP, which are now part of the Perl core.
· "re" has been upgraded from version 0.16 to 0.17.
It now supports the double-a flag: "use re '/aa';"
The "regmust" function used to crash when called on a regular
expression belonging to a pluggable engine. Now it has been
disabled for those.
"regmust" no longer leaks memory.
· "Term::UI" has been upgraded from version 0.24 to 0.26
· "Unicode::Collate" has been upgraded from version 0.68 to 0.72
This also sees the switch from using the pure-perl version of this
module to the XS version.`
· "VMS::DCLsym" has been upgraded from version 1.04 to 1.05.
Two bugs have been fixed [perl #84086]:
The symbol table name was lost when tying a hash, due to a thinko
in "TIEHASH". The result was that all tied hashes interacted with
the local symbol table.
Unless a symbol table name had been explicitly specified in the
call to the constructor, querying the special key ':LOCAL' failed
to identify objects connected to the local symbol table.
· Added new function "Unicode::UCD::num()". This function will
return the numeric value of the string passed it; "undef" if the
string in its entirety has no safe numeric value.
To be safe, a string must be a single character which has a numeric
value, or consist entirely of characters that match \d, coming from
the same Unicode block of digits. Thus, a mix of Bengali and
Western digits would be considered unsafe, as well as a mix of
half- and full-width digits, but strings consisting entirely of
Devanagari digits or of "Mathematical Bold" digits would would be
safe.
· "CPAN" has been upgraded from version 1.94_63 to 1.94_64.
Documentation
Changes to Existing Documentation
overload
· overload's documentation has practically undergone a rewrite. It is
now much more straightforward and clear.
perlhack and perlrepository
· The perlhack and perlrepository documents have been heavily edited
and split up into several new documents.
The perlhack document is now much shorter, and focuses on the Perl
5 development process and submitting patches to Perl. The technical
content has been moved to several new documents, perlsource,
perlinterp, perlhacktut, and perlhacktips. This technical content
has only been lightly edited.
The perlrepository document has been renamed to perlgit. This new
document is just a how-to on using git with the Perl source code.
Any other content that used to be in perlrepository has been moved
to perlhack.
perlfunc
· The documentation for the "map" function now contains more
examples, see perldoc -f map (f947627)
perlfaq4
· Examples in perlfaq4 have been updated to show the use of
Time::Piece. (9243591)
Miscellaneous
· Many POD related RT bugs and other issues which are too numerous to
enumerate have been solved by Michael Stevens.
Diagnostics
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.
New Diagnostics
"\b{" is deprecated; use "\b\{" instead
"\B{" is deprecated; use "\B\{" instead
Use of an unescaped "{" immediately following a "\b" or "\B" is now
deprecated so as to reserve its use for Perl itself in a future
release.
regcomp: Add warning if \p is used under locale. (fb2e24c)
"\p" implies Unicode matching rules, which are likely going to be
different than the locale's.
panic: gp_free failed to free glob pointer - something is repeatedly
re-creating entries
This new error is triggered if a destructor called on an object in
a typeglob that is being freed creates a new typeglob entry
containing an object with a destructor that creates a new entry
containing an object....
refcnt: fd %d%s
This new error only occurs if a internal consistency check fails
when a pipe is about to be closed.
Changes to Existing Diagnostics
· The warning message about regex unrecognized escapes passed through
is changed to include any literal '{' following the 2-char escape.
e.g., "\q{" will include the { in the message as part of the escape
(216bfc0).
· "binmode $fh, ':scalar'" no longer warns (8250589)
Perl will now no longer produce this warning:
$ perl -we 'open my $f, ">", \my $x; binmode $f, "scalar"'
Use of uninitialized value in binmode at -e line 1.
Utility Changes
perlbug
· [perl #82996] Use the user's from address as return-path in perlbug
Many systems these days don't have a valid Internet domain name and
perlbug@perl.org does not accept email with a return-path that does
not resolve. Therefore pass the user's address to sendmail so it's
less likely to get stuck in a mail queue somewhere. (019cfd2)
Configuration and Compilation
· make reg_eval_scope.t TODOs consistently fail (daaf7ac)
Some of the TODO tests in reg_eval_scope.t spuriously passed under
non-threaded builds. Make the tests harder so they always fail.
Since one of the key bugs in (?{..}) is the trashing of the parent
pad, add some extra lexical vars to the parent scope and check
they're still there at the end.
· Stop EU::CBuilder's tests from failing in parallel (cbf59d5)
It used to use the same paths for temporary files in all tests.
This blew up randomly when the tests were run in parallel.
Testing
· porting/FindExt.t now skips all tests on a static (-Uusedl) build
of perl.
· porting/FindExt.t now passes on non-Win32 platforms when some
extensions are built statically.
Platform Support
Platform-Specific Notes
Windows
· The "test-prep" build target now depends on pod/perltoc.pod to
allow the t/porting/buildtoc.t test to run successfully.
MirBSD
· [perl #82988] Skip hanging taint.t test on MirBSD 10 (1fb83d0)
Skip a hanging test under MirBSD that was already being skipped
under OpenBSD.
· Previously if you build perl with a shared libperl.so on MirBSD
(the default config), it will work up to the installation;
however, once installed, it will be unable to find libperl.
Treat path handling like in the other BSD dialects.
Internal Changes
· Fix harmless invalid read in Perl_re_compile() (f6d9469)
[perl #2460] described a case where electric fence reported an
invalid read. This could be reproduced under valgrind with blead
and -e'/x/', but only on a non-debugging build.
This was because it was checking for certain pairs of nodes (e.g.
BOL + END) and wasn't allowing for EXACT nodes, which have the
string at the next node position when using a naive
NEXTOPER(first). In the non-debugging build, the nodes aren't
initialised to zero, and a 1-char EXACT node isn't long enough to
spill into the type field of the "next node".
Fix this by only using NEXTOPER(first) when we know the first node
is kosher.
· Break out the generated function Perl_keywords() into keywords.c, a
new file. (26ea9e1)
As it and Perl_yylex() both need FEATURE_IS_ENABLED,
feature_is_enabled() is no longer static, and the two macro
definitions move from toke.c to perl.h
Previously, one had to cut and paste the output of perl_keywords.pl
into the middle of toke.c, and it was not clear that it was
generated code.
· A lot of tests have been ported from Test to Test::More, e.g. in
3842ad6.
· Increase default PerlIO buffer size. (b83080d)
The previous default size of a PerlIO buffer (4096 bytes) has been
increased to the larger of 8192 bytes and your local BUFSIZ.
Benchmarks show that doubling this decade-old default increases
read and write performance in the neighborhood of 25% to 50% when
using the default layers of perlio on top of unix. To choose a
non-default size, such as to get back the old value or to obtain
and even larger value, configure with:
./Configure -Accflags=-DPERLIOBUF_DEFAULT_BUFSIZ=N
where N is the desired size in bytes; it should probably be a
multiple of your page size.
Selected Bug Fixes
· A Unicode "\p{}" property match in a regular expression pattern
will now force Unicode rules for the rest of the regular expression
· [perl #38456] binmode FH, ":crlf" only modifies top crlf layer
(7826b36)
When pushed on top of the stack, crlf will no longer enable crlf
layers lower in the stack. This will prevent unexpected results.
· Fix 'raw' layer for RT #80764 (ecfd064)
Made a ':raw' open do what it advertises to do (first open the
file, then binmode it), instead of leaving off the top layer.
· Use PerlIOBase_open for pop, utf8 and bytes layers (c0888ac)
Three of Perl's builtin PerlIO layers (":pop", ":utf8" and
":bytes") didn't allow stacking when opening a file. For example
this:
open FH, '>:pop:perlio', 'some.file' or die $!;
Would throw an error: "Invalid argument". This has been fixed in
this release.
· An issue present since 5.13.1, where s/A/B/ with A utf8 and B
non-utf8, could cause corruption or segfaults has been fixed.
(c95ca9b)
· String evals will no longer fail after 2 billion scopes have been
compiled (d1bfb64, 2df5bdd, 0d311cd and 6012dc8)
· [perl #81750] When strict 'refs' mode is off, "%{...}" in rvalue
context returns "undef" if its argument is undefined. An
optimisation introduced in perl 5.12.0 to make "keys %{...}" faster
when used as a boolean did not take this into account, causing
"keys %{+undef}" (and "keys %$foo" when $foo is undefined) to be an
error, which it should only be in strict mode.
· [perl #83194] Combining the vector (%v) flag and dynamic precision
would cause sprintf to confuse the order of its arguments, making
it treat the string as the precision and vice versa.
· [perl #77692] Sometimes the UTF8 length cache would not be reset on
a value returned by substr, causing
"length(substr($uni_string,...))" to give wrong answers. With
"${^UTF8CACHE}" set to -1, it would produce a 'panic' error
message, too.
· During the restoration of a localised typeglob on scope exit, any
destructors called as a result would be able to see the typeglob in
an inconsistent state, containing freed entries, which could result
in a crash. This would affect code like this:
local *@;
eval { die bless [] }; # puts an object in $@
sub DESTROY {
local $@; # boom
}
Now the glob entries are cleared before any destructors are called.
This also means that destructors can vivify entries in the glob. So
perl tries again and, if the entries are re-created too many times,
dies with a 'panic: gp_free...' error message.
· [perl #78494] When pipes are shared between threads, the "close"
function (and any implicit close, such as on thread exit) no longer
blocks.
· Several contexts no longer allow a Unicode character to begin a
word that should never begin words, for an example an accent that
must follow another character previously could precede all other
characters.
· Case insensitive matching in regular expressions compiled under
"use locale" now works much more sanely when the pattern and/or
target string are encoded in UTF-8. Previously, under these
conditions the localeness was completely lost. Now, code points
above 255 are treated as Unicode, but code points between 0 and 255
are treated using the current locale rules, regardless of whether
the pattern or string are encoded in UTF-8. The few case
insensitive matches that cross the 255/256 boundary are not
allowed. For example, 0xFF does not caselessly match the character
at 0x178, LATIN CAPITAL LETTER Y WITH DIAERESIS, because 0xFF may
not be LATIN SMALL LETTER Y in the current locale, and Perl has no
way of knowing if that character even exists in the locale, much
less what code point it is.
Acknowledgements
Perl 5.13.10 represents approximately one month of development since
Perl 5.13.9 and contains approximately 63000 lines of changes across
609 files from 38 authors and committers:
Abigail, Alexander Hartmaier, brian d foy, Charles Bailey, Chip
Salzenberg, Chris 'BinGOs' Williams, Craig A. Berry, Curtis Jewell,
Dave Rolsky, David Golden, David Leadbeater, David Mitchell, David
Wheeler, Father Chrysostomos, Florian Ragwitz, Franz Fasching, George
Greer, H.Merijn Brand, Hongwen Qiu, Hugo van der Sanden, Jay Hannah,
Jesse Vincent, Karl Williamson, Larwan Berke, Leon Timmermans, Michael
Breen, Michael Stevens, Nicholas Clark, Noirin Shirley, Paul Evans,
Peter John Acklam, Ricardo Signes, Robin Barker, Steven Schubiger, Tom
Christiansen, Tony Cook, Zsban Ambrus and var Arnfjoer` Bjarmason
Reporting Bugs
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 http://rt.perl.org/perlbug/ . 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 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.
SEE ALSO
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.
perl v5.14.2 2011-09-26 PERL51310DELTA(1)
