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What is new for perl v5.12.0

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NAME

perl5120delta - what is new for perl v5.12.0

DESCRIPTION

This document describes differences between the 5.10.0 release and the5.12.0 release.

Many of the bug fixes in 5.12.0 are already included in the 5.10.1maintenance release.

You can see the list of those changes in the 5.10.1 release notes(perl5101delta).

Core Enhancements

New package NAME VERSION syntax

This new syntax allows a module author to set the $VERSION of a namespacewhen the namespace is declared with 'package'. It eliminates the needfor our $VERSION = ... and similar constructs. E.g.

  1.   package Foo::Bar 1.23;
    2.  
  2.   # $Foo::Bar::VERSION == 1.23
    3.

There are several advantages to this:

  • $VERSION is parsed in exactly the same way as use NAME VERSION

  • $VERSION is set at compile time

  • $VERSION is a version object that provides proper overloading ofcomparison operators so comparing $VERSION to decimal (1.23) ordotted-decimal (v1.2.3) version numbers works correctly.

  • Eliminates $VERSION = ... and eval $VERSION clutter

  • As it requires VERSION to be a numeric literal or v-stringliteral, it can be statically parsed by toolchain moduleswithout eval the way MM->parse_version does for $VERSION = ...

It does not break old code with only package NAME, but code that usespackage NAME VERSION will need to be restricted to perl 5.12.0 or newerThis is analogous to the change to open from two-args to three-args.Users requiring the latest Perl will benefit, and perhaps after severalyears, it will become a standard practice.

However, package NAME VERSION requires a new, 'strict' versionnumber format. See Version number formats for details.

The ... operator

A new operator, ..., nicknamed the Yada Yada operator, has been added.It is intended to mark placeholder code that is not yet implemented.See Yada Yada Operator in perlop.

Implicit strictures

Using the use VERSION syntax with a version number greater or equalto 5.11.0 will lexically enable strictures just like use strictwould do (in addition to enabling features.) The following:

  1.  use 5.12.0;
    2.

means:

  1.  use strict;
    2.  
  2.  use feature ':5.12';
    3.

Unicode improvements

Perl 5.12 comes with Unicode 5.2, the latest version available tous at the time of release. This version of Unicode was released inOctober 2009. See http://www.unicode.org/versions/Unicode5.2.0 forfurther details about what's changed in this version of the standard.See perlunicode for instructions on installing and using other versionsof Unicode.

Additionally, Perl's developers have significantly improved Perl's Unicodeimplementation. For full details, see Unicode overhaul below.

Y2038 compliance

Perl's core time-related functions are now Y2038 compliant. (It may not mean much to you, but your kids will love it!)

qr overloading

It is now possible to overload the qr// operator, that is,conversion to regexp, like it was already possible to overloadconversion to boolean, string or number of objects. It is invoked whenan object appears on the right hand side of the =~ operator or whenit is interpolated into a regexp. See overload.

Pluggable keywords

Extension modules can now cleanly hook into the Perl parser to definenew kinds of keyword-headed expression and compound statement. Thesyntax following the keyword is defined entirely by the extension. Thisallow a completely non-Perl sublanguage to be parsed inline, with thecorrect ops cleanly generated.

See PL_keyword_plugin in perlapi for the mechanism. The Perl coresource distribution also includes a new moduleXS::APItest::KeywordRPN, which implements reverse Polish notationarithmetic via pluggable keywords. This module is mainly used for testpurposes, and is not normally installed, but also serves as an exampleof how to use the new mechanism.

Perl's developers consider this feature to be experimental. We may removeit or change it in a backwards-incompatible way in Perl 5.14.

APIs for more internals

The lowest layers of the lexer and parts of the pad system now have CAPIs available to XS extensions. These are necessary to support properuse of pluggable keywords, but have other uses too. The new APIs areexperimental, and only cover a small proportion of what would benecessary to take full advantage of the core's facilities in theseareas. It is intended that the Perl 5.13 development cycle will see theaddition of a full range of clean, supported interfaces.

Perl's developers consider this feature to be experimental. We may removeit or change it in a backwards-incompatible way in Perl 5.14.

Overridable function lookup

Where an extension module hooks the creation of rv2cv ops to modify thesubroutine lookup process, this now works correctly for barewordsubroutine calls. This means that prototypes on subroutines referencedthis way will be processed correctly. (Previously bareword subroutinenames were initially looked up, for parsing purposes, by an unhookablemechanism, so extensions could only properly influence subroutine namesthat appeared with an & sigil.)

A proper interface for pluggable Method Resolution Orders

As of Perl 5.12.0 there is a new interface for plugging and using methodresolution orders other than the default linear depth first search.The C3 method resolution order added in 5.10.0 has been re-implemented asa plugin, without changing its Perl-space interface. See perlmroapi formore information.

\N experimental regex escape

Perl now supports \N, a new regex escape which you can think of asthe inverse of \n. It will match any character that is not a newline,independently from the presence or absence of the single line matchmodifier /s. It is not usable within a character class. \N{3}means to match 3 non-newlines; \N{5,} means to match at least 5.\N{NAME} still means the character or sequence named NAME, butNAME no longer can be things like 3, or 5,.

This will break a custom charnames translator which allows numbers for character names, as \N{3} willnow mean to match 3 non-newline characters, and not the character whosename is 3. (No name defined by the Unicode standard is a number,so only custom translators might be affected.)

Perl's developers are somewhat concerned about possible user confusionwith the existing \N{...} construct which matches characters by theirUnicode name. Consequently, this feature is experimental. We may removeit or change it in a backwards-incompatible way in Perl 5.14.

DTrace support

Perl now has some support for DTrace. See "DTrace support" in INSTALL.

Support for configure_requires in CPAN module metadata

Both CPAN and CPANPLUS now support the configure_requireskeyword in the META.yml metadata file included in most recent CPANdistributions. This allows distribution authors to specify configurationprerequisites that must be installed before running Makefile.PLor Build.PL.

See the documentation for ExtUtils::MakeMaker or Module::Build formore on how to specify configure_requires when creating a distributionfor CPAN.

each, keys, values are now more flexible

The each, keys, values function can now operate on arrays.

when as a statement modifier

when is now allowed to be used as a statement modifier.

$, flexibility

The variable $, may now be tied.

// in when clauses

// now behaves like || in when clauses

Enabling warnings from your shell environment

You can now set -W from the PERL5OPT environment variable

delete local

delete local now allows you to locally delete a hash entry.

New support for Abstract namespace sockets

Abstract namespace sockets are Linux-specific socket type that live inAF_UNIX family, slightly abusing it to be able to use arbitrarycharacter arrays as addresses: They start with nul byte and are notterminated by nul byte, but with the length passed to the socket()system call.

32-bit limit on substr arguments removed

The 32-bit limit on substr arguments has now been removed. The fullrange of the system's signed and unsigned integers is now available forthe pos and len arguments.

Potentially Incompatible Changes

Deprecations warn by default

Over the years, Perl's developers have deprecated a number of languagefeatures for a variety of reasons. Perl now defaults to issuing awarning if a deprecated language feature is used. Many of the deprecationsPerl now warns you about have been deprecated for many years. You canfind a list of what was deprecated in a given release of Perl in theperl5xxdelta.pod file for that release.

To disable this feature in a given lexical scope, you should use nowarnings 'deprecated'; For information about which language featuresare deprecated and explanations of various deprecation warnings, pleasesee perldiag. See Deprecations below for the list of featuresand modules Perl's developers have deprecated as part of this release.

Version number formats

Acceptable version number formats have been formalized into "strict" and"lax" rules. package NAME VERSION takes a strict version number.UNIVERSAL::VERSION and the version object constructors take laxversion numbers. Providing an invalid version will result in a fatalerror. The version argument in use NAME VERSION is first parsed as anumeric literal or v-string and then passed to UNIVERSAL::VERSION(and must then pass the "lax" format test).

These formats are documented fully in the version module. To a firstapproximation, a "strict" version number is a positive decimal number(integer or decimal-fraction) without exponentiation or else adotted-decimal v-string with a leading 'v' character and at least threecomponents. A "lax" version number allows v-strings with fewer thanthree components or without a leading 'v'. Under "lax" rules, bothdecimal and dotted-decimal versions may have a trailing "alpha"component separated by an underscore character after a fractional ordotted-decimal component.

The version module adds version::is_strict and version::is_laxfunctions to check a scalar against these rules.

@INC reorganization

In @INC, ARCHLIB and PRIVLIB now occur after after the currentversion's site_perl and vendor_perl. Modules installed intosite_perl and vendor_perl will now be loaded in preference tothose installed in ARCHLIB and PRIVLIB.

REGEXPs are now first class

Internally, Perl now treats compiled regular expressions (such asthose created with qr//) as first class entities. Perl modules whichserialize, deserialize or otherwise have deep interaction with Perl'sinternal data structures need to be updated for this change. Mostaffected CPAN modules have already been updated as of this writing.

Switch statement changes

The given/when switch statement handles complex statements betterthan Perl 5.10.0 did (These enhancements are also available in5.10.1 and subsequent 5.10 releases.) There are two new cases wherewhen now interprets its argument as a boolean, instead of anexpression to be used in a smart match:

  • flip-flop operators

    The .. and ... flip-flop operators are now evaluated in booleancontext, following their usual semantics; see Range Operators in perlop.

    Note that, as in perl 5.10.0, when (1..10) will not work to testwhether a given value is an integer between 1 and 10; you should usewhen ([1..10]) instead (note the array reference).

    However, contrary to 5.10.0, evaluating the flip-flop operators inboolean context ensures it can now be useful in a when(), notablyfor implementing bistable conditions, like in:

    1.  when (/^=begin/ .. /^=end/) {
      2.  
    2.   # do something
      3.  
    3.  }
      4.
  • defined-or operator

    A compound expression involving the defined-or operator, as inwhen (expr1 // expr2), will be treated as boolean if the firstexpression is boolean. (This just extends the existing rule that appliesto the regular or operator, as in when (expr1 || expr2).)

Smart match changes

Since Perl 5.10.0, Perl's developers have made a number of changes tothe smart match operator. These, of course, also alter the behaviourof the switch statements where smart matching is implicitly used.These changes were also made for the 5.10.1 release, and will remain insubsequent 5.10 releases.

Changes to type-based dispatch

The smart match operator ~~ is no longer commutative. The behaviour ofa smart match now depends primarily on the type of its right handargument. Moreover, its semantics have been adjusted for greaterconsistency or usefulness in several cases. While the general backwardscompatibility is maintained, several changes must be noted:

  • Code references with an empty prototype are no longer treated specially.They are passed an argument like the other code references (even if theychoose to ignore it).

  • %hash ~~ sub {} and @array ~~ sub {} now test that the subroutinereturns a true value for each key of the hash (or element of thearray), instead of passing the whole hash or array as a reference tothe subroutine.

  • Due to the commutativity breakage, code references are no longertreated specially when appearing on the left of the ~~ operator,but like any vulgar scalar.

  • undef ~~ %hash is always false (since undef can't be a key in ahash). No implicit conversion to "" is done (as was the case in perl5.10.0).

  • $scalar ~~ @array now always distributes the smart match across theelements of the array. It's true if one element in @array verifies$scalar ~~ $element. This is a generalization of the old behaviourthat tested whether the array contained the scalar.

The full dispatch table for the smart match operator is given inSmart matching in detail in perlsyn.

Smart match and overloading

According to the rule of dispatch based on the rightmost argument type,when an object overloading ~~ appears on the right side of theoperator, the overload routine will always be called (with a 3rd argumentset to a true value, see overload.) However, when the object willappear on the left, the overload routine will be called only when therightmost argument is a simple scalar. This way, distributivity of smartmatch across arrays is not broken, as well as the other behaviours withcomplex types (coderefs, hashes, regexes). Thus, writers of overloadingroutines for smart match mostly need to worry only with comparingagainst a scalar, and possibly with stringification overloading; theother common cases will be automatically handled consistently.

~~ will now refuse to work on objects that do not overload it (in orderto avoid relying on the object's underlying structure). (However, if theobject overloads the stringification or the numification operators, andif overload fallback is active, it will be used instead, as usual.)

Other potentially incompatible changes

  • The definitions of a number of Unicode properties have changed to matchthose of the current Unicode standard. These are listed above underUnicode overhaul. This change may break code that expects the olddefinitions.

  • The boolkeys op has moved to the group of hash ops. This breaks binarycompatibility.

  • Filehandles are now always blessed into IO::File.

    The previous behaviour was to bless Filehandles into FileHandle(an empty proxy class) if it was loaded into memory and otherwiseto bless them into IO::Handle.

  • The semantics of use feature :5.10* have changed slightly.See Modules and Pragmata for more information.

  • Perl's developers now use git, rather than Perforce. This should bea purely internal change only relevant to people actively working onthe core. However, you may see minor difference in perl as a consequenceof the change. For example in some of details of the output of perl-V. See perlrepository for more information.

  • As part of the Test::Harness 2.x to 3.x upgrade, the experimentalTest::Harness::Straps module has been removed.See Modules and Pragmata for more details.

  • As part of the ExtUtils::MakeMaker upgrade, theExtUtils::MakeMaker::bytes and ExtUtils::MakeMaker::vmsish moduleshave been removed from this distribution.

  • Module::CoreList no longer contains the %:patchlevel hash.

  • length undef now returns undef.

  • Unsupported private C API functions are now declared "static" to preventleakage to Perl's public API.

  • To support the bootstrapping process, miniperl no longer builds withUTF-8 support in the regexp engine.

    This allows a build to complete with PERL_UNICODE set and a UTF-8 locale.Without this there's a bootstrapping problem, as miniperl can't loadthe UTF-8 components of the regexp engine, because they're not yet built.

  • miniperl's @INC is now restricted to just -I..., the split of$ENV{PERL5LIB}, and "."

  • A space or a newline is now required after a "#line XXX" directive.

  • Tied filehandles now have an additional method EOF which provides theEOF type.

  • To better match all other flow control statements, foreach may nolonger be used as an attribute.

  • Perl's command-line switch "-P", which was deprecated in version 5.10.0, hasnow been removed. The CPAN module Filter::cpp can be used as an alternative.

Deprecations

From time to time, Perl's developers find it necessary to deprecatefeatures or modules we've previously shipped as part of the coredistribution. We are well aware of the pain and frustration that abackwards-incompatible change to Perl can cause for developers buildingor maintaining software in Perl. You can be sure that when we deprecatea functionality or syntax, it isn't a choice we make lightly. Sometimes,we choose to deprecate functionality or syntax because it was found tobe poorly designed or implemented. Sometimes, this is because they'reholding back other features or causing performance problems. Sometimes,the reasons are more complex. Wherever possible, we try to keep deprecatedfunctionality available to developers in its previous form for at leastone major release. So long as a deprecated feature isn't activelydisrupting our ability to maintain and extend Perl, we'll try to leaveit in place as long as possible.

The following items are now deprecated:

  • suidperl

    suidperl is no longer part of Perl. It used to provide a mechanism toemulate setuid permission bits on systems that don't support it properly.

  • Use of := to mean an empty attribute list

    An accident of Perl's parser meant that these constructions were allequivalent:

    1.  my $pi := 4;
      2.  
    2.  my $pi : = 4;
      3.  
    3.  my $pi :  = 4;
      4.

    with the : being treated as the start of an attribute list, whichends before the =. As whitespace is not significant here, all areparsed as an empty attribute list, hence all the above are equivalentto, and better written as

    1.  my $pi = 4;
      2.

    because no attribute processing is done for an empty list.

    As is, this meant that := cannot be used as a new token, withoutsilently changing the meaning of existing code. Hence that particularform is now deprecated, and will become a syntax error. If it isabsolutely necessary to have empty attribute lists (for example,because of a code generator) then avoid the warning by adding a spacebefore the =.

  • UNIVERSAL->import()

    The method UNIVERSAL->import() is now deprecated. Attempting topass import arguments to a use UNIVERSAL statement will result in adeprecation warning.

  • Use of "goto" to jump into a construct

    Using goto to jump from an outer scope into an inner scope is nowdeprecated. This rare use case was causing problems in theimplementation of scopes.

  • Custom character names in \N{name} that don't look like names

    In \N{name}, name can be just about anything. The standardUnicode names have a very limited domain, but a custom name translatorcould create names that are, for example, made up entirely of punctuationsymbols. It is now deprecated to make names that don't begin with analphabetic character, and aren't alphanumeric or contain other thana very few other characters, namely spaces, dashes, parenthesesand colons. Because of the added meaning of \N (See \N experimental regex escape), names that look like curly brace -enclosedquantifiers won't work. For example, \N{3,4} now means to match 3 to4 non-newlines; before a custom name 3,4 could have been created.

  • Deprecated Modules

    The following modules will be removed from the core distribution in afuture release, and should be installed from CPAN instead. Distributionson CPAN which require these should add them to their prerequisites. Thecore versions of these modules warnings will issue a deprecation warning.

    If you ship a packaged version of Perl, either alone or as part of alarger system, then you should carefully consider the repercussions ofcore module deprecations. You may want to consider shipping your defaultbuild of Perl with packages for some or all deprecated modules whichinstall into vendor or site perl library directories. This willinhibit the deprecation warnings.

    Alternatively, you may want to consider patching lib/deprecate.pmto provide deprecation warnings specific to your packaging systemor distribution of Perl, consistent with how your packaging systemor distribution manages a staged transition from a release where theinstallation of a single package provides the given functionality, toa later release where the system administrator needs to know to installmultiple packages to get that same functionality.

    You can silence these deprecation warnings by installing the modulesin question from CPAN. To install the latest version of all of them,just install Task::Deprecations::5_12.

  • Assignment to $[
  • Use of the attribute :locked on subroutines
  • Use of "locked" with the attributes pragma
  • Use of "unique" with the attributes pragma
  • Perl_pmflag

    Perl_pmflag is no longer part of Perl's public API. Calling it nowgenerates a deprecation warning, and it will be removed in a futurerelease. Although listed as part of the API, it was never documented,and only ever used in toke.c, and prior to 5.10, regcomp.c. Incore, it has been replaced by a static function.

  • Numerous Perl 4-era libraries

    termcap.pl, tainted.pl, stat.pl, shellwords.pl, pwd.pl,open3.pl, open2.pl, newgetopt.pl, look.pl, find.pl,finddepth.pl, importenv.pl, hostname.pl, getopts.pl,getopt.pl, getcwd.pl, flush.pl, fastcwd.pl, exceptions.pl,ctime.pl, complete.pl, cacheout.pl, bigrat.pl, bigint.pl,bigfloat.pl, assert.pl, abbrev.pl, dotsh.pl, andtimelocal.pl are all now deprecated. Earlier, Perl's developersintended to remove these libraries from Perl's core for the 5.14.0 release.

    During final testing before the release of 5.12.0, several developersdiscovered current production code using these ancient libraries, someinside the Perl core itself. Accordingly, the pumpking granted thema stay of execution. They will begin to warn about their deprecationin the 5.14.0 release and will be removed in the 5.16.0 release.

Unicode overhaul

Perl's developers have made a concerted effort to update Perl to be insync with the latest Unicode standard. Changes for this include:

Perl can now handle every Unicode character property. New documentation,perluniprops, lists all available non-Unihan character properties. Bydefault, perl does not expose Unihan, deprecated or Unicode-internalproperties. See below for more details on these; there is also a sectionin the pod listing them, and explaining why they are not exposed.

Perl now fully supports the Unicode compound-style of using =and : in writing regular expressions: \p{property=value} and\p{property:value} (both of which mean the same thing).

Perl now fully supports the Unicode loose matching rules for text betweenthe braces in \p{...} constructs. In addition, Perl allows underscoresbetween digits of numbers.

Perl now accepts all the Unicode-defined synonyms for properties andproperty values.

qr/\X/, which matches a Unicode logical character, hasbeen expanded to work better with various Asian languages. Itnow is defined as an extended grapheme cluster. (Seehttp://www.unicode.org/reports/tr29/). Anything matched previouslyand that made sense will continue to be accepted. Additionally:

  • \X will not break apart a CR LF sequence.

  • \X will now match a sequence which includes the ZWJ and ZWNJcharacters.

  • \X will now always match at least one character, including an initialmark. Marks generally come after a base character, but it is possible inUnicode to have them in isolation, and \X will now handle that case,for example at the beginning of a line, or after a ZWSP. And this isthe part where \X doesn't match the things that it used to that don'tmake sense. Formerly, for example, you could have the nonsensical caseof an accented LF.

  • \X will now match a (Korean) Hangul syllable sequence, and the Thaiand Lao exception cases.

Otherwise, this change should be transparent for the non-affectedlanguages.

\p{...} matches using the Canonical_Combining_Class property werecompletely broken in previous releases of Perl. They should now workcorrectly.

Before Perl 5.12, the Unicode Decomposition_Type=Compat propertyand a Perl extension had the same name, which led to neither matchingall the correct values (with more than 100 mistakes in one, and severalthousand in the other). The Perl extension has now been renamed to beDecomposition_Type=Noncanonical (short: dt=noncanon). It has thesame meaning as was previously intended, namely the union of all thenon-canonical Decomposition types, with Unicode Compat being justone of those.

\p{Decomposition_Type=Canonical} now includes the Hangul syllables.

\p{Uppercase} and \p{Lowercase} now work as the Unicode standardsays they should. This means they each match a few more characters thanthey used to.

\p{Cntrl} now matches the same characters as \p{Control}. Thismeans it no longer will match Private Use (gc=co), Surrogates (gc=cs),nor Format (gc=cf) code points. The Format code points represent thebiggest possible problem. All but 36 of them are either officiallydeprecated or strongly discouraged from being used. Of those 36, likelythe most widely used are the soft hyphen (U+00AD), and BOM, ZWSP, ZWNJ,WJ, and similar characters, plus bidirectional controls.

\p{Alpha} now matches the same characters as \p{Alphabetic}. Before5.12, Perl's definition definition included a number of things that aren'treally alpha (all marks) while omitting many that were. The definitionsof \p{Alnum} and \p{Word} depend on Alpha's definition and havechanged accordingly.

\p{Word} no longer incorrectly matches non-word characters suchas fractions.

\p{Print} no longer matches the line control characters: Tab, LF,CR, FF, VT, and NEL. This brings it in line with standards and thedocumentation.

\p{XDigit} now matches the same characters as \p{Hex_Digit}. Thismeans that in addition to the characters it currently matches,[A-Fa-f0-9], it will also match the 22 fullwidth equivalents, forexample U+FF10: FULLWIDTH DIGIT ZERO.

The Numeric type property has been extended to include the Unihancharacters.

There is a new Perl extension, the 'Present_In', or simply 'In',property. This is an extension of the Unicode Age property, but\p{In=5.0} matches any code point whose usage has been determinedas of Unicode version 5.0. The \p{Age=5.0} only matches code pointsadded in precisely version 5.0.

A number of properties now have the correct values for unassignedcode points. The affected properties are Bidi_Class, East_Asian_Width,Joining_Type, Decomposition_Type, Hangul_Syllable_Type, Numeric_Type,and Line_Break.

The Default_Ignorable_Code_Point, ID_Continue, and ID_Start propertiesare now up to date with current Unicode definitions.

Earlier versions of Perl erroneously exposed certain properties thatare supposed to be Unicode internal-only. Use of these in regularexpressions will now generate, if enabled, a deprecation warning message.The properties are: Other_Alphabetic, Other_Default_Ignorable_Code_Point,Other_Grapheme_Extend, Other_ID_Continue, Other_ID_Start, Other_Lowercase,Other_Math, and Other_Uppercase.

It is now possible to change which Unicode properties Perl understandson a per-installation basis. As mentioned above, certain propertiesare turned off by default. These include all the Unihan properties(which should be accessible via the CPAN module Unicode::Unihan) and anydeprecated or Unicode internal-only property that Perl has never exposed.

The generated files in the lib/unicore/To directory are now moreclearly marked as being stable, directly usable by applications. New hashentries in them give the format of the normal entries, which allows foreasier machine parsing. Perl can generate files in this directory forany property, though most are suppressed. You can find instructionsfor changing which are written in perluniprops.

Modules and Pragmata

New Modules and Pragmata

  • autodie

    autodie is a new lexically-scoped alternative for the Fatal module.The bundled version is 2.06_01. Note that in this release, using a stringeval when autodie is in effect can cause the autodie behaviour to leakinto the surrounding scope. See BUGS in autodie for more details.

    Version 2.06_01 has been added to the Perl core.

  • Compress::Raw::Bzip2

    Version 2.024 has been added to the Perl core.

  • overloading

    overloading allows you to lexically disable or enable overloadingfor some or all operations.

    Version 0.001 has been added to the Perl core.

  • parent

    parent establishes an ISA relationship with base classes at compiletime. It provides the key feature of base without further unwantedbehaviors.

    Version 0.223 has been added to the Perl core.

  • Parse::CPAN::Meta

    Version 1.40 has been added to the Perl core.

  • VMS::DCLsym

    Version 1.03 has been added to the Perl core.

  • VMS::Stdio

    Version 2.4 has been added to the Perl core.

  • XS::APItest::KeywordRPN

    Version 0.003 has been added to the Perl core.

Updated Pragmata

  • base

    Upgraded from version 2.13 to 2.15.

  • bignum

    Upgraded from version 0.22 to 0.23.

  • charnames

    charnames now contains the Unicode NameAliases.txt database file.This has the effect of adding some extra \N character names thatformerly wouldn't have been recognised; for example, "\N{LATIN CAPITALLETTER GHA}".

    Upgraded from version 1.06 to 1.07.

  • constant

    Upgraded from version 1.13 to 1.20.

  • diagnostics

    diagnostics now supports %.0f formatting internally.

    diagnostics no longer suppresses Use of uninitialized value in range(or flip) warnings. [perl #71204]

    Upgraded from version 1.17 to 1.19.

  • feature

    In feature, the meaning of the :5.10 and :5.10.X featurebundles has changed slightly. The last component, if any (i.e. X) issimply ignored. This is predicated on the assumption that new featureswill not, in general, be added to maintenance releases. So :5.10and :5.10.X have identical effect. This is a change to the behaviourdocumented for 5.10.0.

    feature now includes the unicode_strings feature:

    1.  use feature "unicode_strings";
      2.

    This pragma turns on Unicode semantics for the case-changing operations(uc, lc, ucfirst, lcfirst) on strings that don't have theinternal UTF-8 flag set, but that contain single-byte characters between128 and 255.

    Upgraded from version 1.11 to 1.16.

  • less

    less now includes the stash_name method to allow subclasses ofless to pick where in %^H to store their stash.

    Upgraded from version 0.02 to 0.03.

  • lib

    Upgraded from version 0.5565 to 0.62.

  • mro

    mro is now implemented as an XS extension. The documented interface hasnot changed. Code relying on the implementation detail that some mro::methods happened to be available at all times gets to "keep both pieces".

    Upgraded from version 1.00 to 1.02.

  • overload

    overload now allow overloading of 'qr'.

    Upgraded from version 1.06 to 1.10.

  • threads

    Upgraded from version 1.67 to 1.75.

  • threads::shared

    Upgraded from version 1.14 to 1.32.

  • version

    version now has support for Version number formats as describedearlier in this document and in its own documentation.

    Upgraded from version 0.74 to 0.82.

  • warnings

    warnings has a new warnings::fatal_enabled() function. It alsoincludes a new illegalproto warning category. See also New or Changed Diagnostics for this change.

    Upgraded from version 1.06 to 1.09.

Updated Modules

  • Archive::Extract

    Upgraded from version 0.24 to 0.38.

  • Archive::Tar

    Upgraded from version 1.38 to 1.54.

  • Attribute::Handlers

    Upgraded from version 0.79 to 0.87.

  • AutoLoader

    Upgraded from version 5.63 to 5.70.

  • B::Concise

    Upgraded from version 0.74 to 0.78.

  • B::Debug

    Upgraded from version 1.05 to 1.12.

  • B::Deparse

    Upgraded from version 0.83 to 0.96.

  • B::Lint

    Upgraded from version 1.09 to 1.11_01.

  • CGI

    Upgraded from version 3.29 to 3.48.

  • Class::ISA

    Upgraded from version 0.33 to 0.36.

    NOTE: Class::ISA is deprecated and may be removed from a futureversion of Perl.

  • Compress::Raw::Zlib

    Upgraded from version 2.008 to 2.024.

  • CPAN

    Upgraded from version 1.9205 to 1.94_56.

  • CPANPLUS

    Upgraded from version 0.84 to 0.90.

  • CPANPLUS::Dist::Build

    Upgraded from version 0.06_02 to 0.46.

  • Data::Dumper

    Upgraded from version 2.121_14 to 2.125.

  • DB_File

    Upgraded from version 1.816_1 to 1.820.

  • Devel::PPPort

    Upgraded from version 3.13 to 3.19.

  • Digest

    Upgraded from version 1.15 to 1.16.

  • Digest::MD5

    Upgraded from version 2.36_01 to 2.39.

  • Digest::SHA

    Upgraded from version 5.45 to 5.47.

  • Encode

    Upgraded from version 2.23 to 2.39.

  • Exporter

    Upgraded from version 5.62 to 5.64_01.

  • ExtUtils::CBuilder

    Upgraded from version 0.21 to 0.27.

  • ExtUtils::Command

    Upgraded from version 1.13 to 1.16.

  • ExtUtils::Constant

    Upgraded from version 0.2 to 0.22.

  • ExtUtils::Install

    Upgraded from version 1.44 to 1.55.

  • ExtUtils::MakeMaker

    Upgraded from version 6.42 to 6.56.

  • ExtUtils::Manifest

    Upgraded from version 1.51_01 to 1.57.

  • ExtUtils::ParseXS

    Upgraded from version 2.18_02 to 2.21.

  • File::Fetch

    Upgraded from version 0.14 to 0.24.

  • File::Path

    Upgraded from version 2.04 to 2.08_01.

  • File::Temp

    Upgraded from version 0.18 to 0.22.

  • Filter::Simple

    Upgraded from version 0.82 to 0.84.

  • Filter::Util::Call

    Upgraded from version 1.07 to 1.08.

  • Getopt::Long

    Upgraded from version 2.37 to 2.38.

  • IO

    Upgraded from version 1.23_01 to 1.25_02.

  • IO::Zlib

    Upgraded from version 1.07 to 1.10.

  • IPC::Cmd

    Upgraded from version 0.40_1 to 0.54.

  • IPC::SysV

    Upgraded from version 1.05 to 2.01.

  • Locale::Maketext

    Upgraded from version 1.12 to 1.14.

  • Locale::Maketext::Simple

    Upgraded from version 0.18 to 0.21.

  • Log::Message

    Upgraded from version 0.01 to 0.02.

  • Log::Message::Simple

    Upgraded from version 0.04 to 0.06.

  • Math::BigInt

    Upgraded from version 1.88 to 1.89_01.

  • Math::BigInt::FastCalc

    Upgraded from version 0.16 to 0.19.

  • Math::BigRat

    Upgraded from version 0.21 to 0.24.

  • Math::Complex

    Upgraded from version 1.37 to 1.56.

  • Memoize

    Upgraded from version 1.01_02 to 1.01_03.

  • MIME::Base64

    Upgraded from version 3.07_01 to 3.08.

  • Module::Build

    Upgraded from version 0.2808_01 to 0.3603.

  • Module::CoreList

    Upgraded from version 2.12 to 2.29.

  • Module::Load

    Upgraded from version 0.12 to 0.16.

  • Module::Load::Conditional

    Upgraded from version 0.22 to 0.34.

  • Module::Loaded

    Upgraded from version 0.01 to 0.06.

  • Module::Pluggable

    Upgraded from version 3.6 to 3.9.

  • Net::Ping

    Upgraded from version 2.33 to 2.36.

  • NEXT

    Upgraded from version 0.60_01 to 0.64.

  • Object::Accessor

    Upgraded from version 0.32 to 0.36.

  • Package::Constants

    Upgraded from version 0.01 to 0.02.

  • PerlIO

    Upgraded from version 1.04 to 1.06.

  • Pod::Parser

    Upgraded from version 1.35 to 1.37.

  • Pod::Perldoc

    Upgraded from version 3.14_02 to 3.15_02.

  • Pod::Plainer

    Upgraded from version 0.01 to 1.02.

    NOTE: Pod::Plainer is deprecated and may be removed from a futureversion of Perl.

  • Pod::Simple

    Upgraded from version 3.05 to 3.13.

  • Safe

    Upgraded from version 2.12 to 2.22.

  • SelfLoader

    Upgraded from version 1.11 to 1.17.

  • Storable

    Upgraded from version 2.18 to 2.22.

  • Switch

    Upgraded from version 2.13 to 2.16.

    NOTE: Switch is deprecated and may be removed from a future versionof Perl.

  • Sys::Syslog

    Upgraded from version 0.22 to 0.27.

  • Term::ANSIColor

    Upgraded from version 1.12 to 2.02.

  • Term::UI

    Upgraded from version 0.18 to 0.20.

  • Test

    Upgraded from version 1.25 to 1.25_02.

  • Test::Harness

    Upgraded from version 2.64 to 3.17.

  • Test::Simple

    Upgraded from version 0.72 to 0.94.

  • Text::Balanced

    Upgraded from version 2.0.0 to 2.02.

  • Text::ParseWords

    Upgraded from version 3.26 to 3.27.

  • Text::Soundex

    Upgraded from version 3.03 to 3.03_01.

  • Thread::Queue

    Upgraded from version 2.00 to 2.11.

  • Thread::Semaphore

    Upgraded from version 2.01 to 2.09.

  • Tie::RefHash

    Upgraded from version 1.37 to 1.38.

  • Time::HiRes

    Upgraded from version 1.9711 to 1.9719.

  • Time::Local

    Upgraded from version 1.18 to 1.1901_01.

  • Time::Piece

    Upgraded from version 1.12 to 1.15.

  • Unicode::Collate

    Upgraded from version 0.52 to 0.52_01.

  • Unicode::Normalize

    Upgraded from version 1.02 to 1.03.

  • Win32

    Upgraded from version 0.34 to 0.39.

  • Win32API::File

    Upgraded from version 0.1001_01 to 0.1101.

  • XSLoader

    Upgraded from version 0.08 to 0.10.

Removed Modules and Pragmata

  • attrs

    Removed from the Perl core. Prior version was 1.02.

  • CPAN::API::HOWTO

    Removed from the Perl core. Prior version was 'undef'.

  • CPAN::DeferedCode

    Removed from the Perl core. Prior version was 5.50.

  • CPANPLUS::inc

    Removed from the Perl core. Prior version was 'undef'.

  • DCLsym

    Removed from the Perl core. Prior version was 1.03.

  • ExtUtils::MakeMaker::bytes

    Removed from the Perl core. Prior version was 6.42.

  • ExtUtils::MakeMaker::vmsish

    Removed from the Perl core. Prior version was 6.42.

  • Stdio

    Removed from the Perl core. Prior version was 2.3.

  • Test::Harness::Assert

    Removed from the Perl core. Prior version was 0.02.

  • Test::Harness::Iterator

    Removed from the Perl core. Prior version was 0.02.

  • Test::Harness::Point

    Removed from the Perl core. Prior version was 0.01.

  • Test::Harness::Results

    Removed from the Perl core. Prior version was 0.01.

  • Test::Harness::Straps

    Removed from the Perl core. Prior version was 0.26_01.

  • Test::Harness::Util

    Removed from the Perl core. Prior version was 0.01.

  • XSSymSet

    Removed from the Perl core. Prior version was 1.1.

Deprecated Modules and Pragmata

See Deprecated Modules above.

Documentation

New Documentation

  • perlhaiku contains instructions on how to build perl for the Haikuplatform.

  • perlmroapi describes the new interface for pluggable Method ResolutionOrders.

  • perlperf, by Richard Foley, provides an introduction to the use ofperformance and optimization techniques which can be used with particularreference to perl programs.

  • perlrepository describes how to access the perl source using the gitversion control system.

  • perlpolicy extends the "Social contract about contributed modules" intothe beginnings of a document on Perl porting policies.

Changes to Existing Documentation

  • The various large Changes* files (which listed every change madeto perl over the last 18 years) have been removed, and replaced by asmall file, also called Changes, which just explains how that sameinformation may be extracted from the git version control system.

  • Porting/patching.pod has been deleted, as it mainly describedinteracting with the old Perforce-based repository, which is now obsolete.Information still relevant has been moved to perlrepository.

  • The syntax unless (EXPR) BLOCK else BLOCK is now documented as valid,as is the syntax unless (EXPR) BLOCK elsif (EXPR) BLOCK ... elseBLOCK, although actually using the latter may not be the best idea forthe readability of your source code.

  • Documented -X overloading.

  • Documented that when() treats specially most of the filetest operators

  • Documented when as a syntax modifier.

  • Eliminated "Old Perl threads tutorial", which described 5005 threads.

    pod/perlthrtut.pod is the same material reworked for ithreads.

  • Correct previous documentation: v-strings are not deprecated

    With version objects, we need them to use MODULE VERSION syntax. Thispatch removes the deprecation notice.

  • Security contact information is now part of perlsec.

  • A significant fraction of the core documentation has been updated toclarify the behavior of Perl's Unicode handling.

    Much of the remaining core documentation has been reviewed and editedfor clarity, consistent use of language, and to fix the spelling of TomChristiansen's name.

  • The Pod specification (perlpodspec) has been updated to bring thespecification in line with modern usage already supported by most Podsystems. A parameter string may now follow the format name in a"begin/end" region. Links to URIs with a text description are nowallowed. The usage of L<"section"> has been marked asdeprecated.

  • if.pm has been documented in use as a means to getconditional loading of modules despite the implicit BEGIN block arounduse.

  • The documentation for $1 in perlvar.pod has been clarified.

  • \N{U+code point} is now documented.

Selected Performance Enhancements

  • A new internal cache means that isa() will often be faster.

  • The implementation of C3 Method Resolution Order has beenoptimised - linearisation for classes with single inheritance is 40%faster. Performance for multiple inheritance is unchanged.

  • Under use locale, the locale-relevant information is now cached onread-only values, such as the list returned by keys %hash. This makesoperations such as sort keys %hash in the scope of use localemuch faster.

  • Empty DESTROY methods are no longer called.

  • Perl_sv_utf8_upgrade() is now faster.

  • keys on empty hash is now faster.

  • if (%foo) has been optimized to be faster than if (keys %foo).

  • The string repetition operator ($str x $num) is now several timesfaster when $str has length one or $num is large.

  • Reversing an array to itself (as in @a = reverse @a) in void contextnow happens in-place and is several orders of magnitude faster thanit used to be. It will also preserve non-existent elements wheneverpossible, i.e. for non magical arrays or tied arrays with EXISTSand DELETE methods.

Installation and Configuration Improvements

  • perlapi, perlintern, perlmodlib and perltoc are now allgenerated at build time, rather than being shipped as part of the release.

  • If vendorlib and vendorarch are the same, then they are only addedto @INC once.

  • $Config{usedevel} and the C-level PERL_USE_DEVEL are now defined ifperl is built with -Dusedevel.

  • Configure will enable use of -fstack-protector, to provide protectionagainst stack-smashing attacks, if the compiler supports it.

  • Configure will now determine the correct prototypes for re-entrantfunctions and for gconvert if you are using a C++ compiler ratherthan a C compiler.

  • On Unix, if you build from a tree containing a git repository, theconfiguration process will note the commit hash you have checked out, fordisplay in the output of perl -v and perl -V. Unpushed local commitsare automatically added to the list of local patches displayed byperl -V.

  • Perl now supports SystemTap's dtrace compatibility layer and anissue with linking miniperl has been fixed in the process.

  • perldoc now uses less -R instead of less for improved behaviourin the face of groff's new usage of ANSI escape codes.

  • perl -V now reports use of the compile-time options USE_PERL_ATOF andUSE_ATTRIBUTES_FOR_PERLIO.

  • As part of the flattening of ext, all extensions on all platforms arebuilt by make_ext.pl. This replaces the Unix-specificext/util/make_ext, VMS-specific make_ext.com and Win32-specificwin32/buildext.pl.

Internal Changes

Each release of Perl sees numerous internal changes which shouldn'taffect day to day usage but may still be notable for developers workingwith Perl's source code.

  • The J.R.R. Tolkien quotes at the head of C source file have been checkedand proper citations added, thanks to a patch from Tom Christiansen.

  • The internal structure of the dual-life modules traditionally found inthe lib/ and ext/ directories in the perl source has changedsignificantly. Where possible, dual-lifed modules have been extractedfrom lib/ and ext/.

    Dual-lifed modules maintained by Perl's developers as part of the Perlcore now live in dist/. Dual-lifed modules maintained primarily onCPAN now live in cpan/. When reporting a bug in a module locatedunder cpan/, please send your bug report directly to the module'sbug tracker or author, rather than Perl's bug tracker.

  • \N{...} now compiles better, always forces UTF-8 internal representation

    Perl's developers have fixed several problems with the recognition of\N{...} constructs. As part of this, perl will store any scalaror regex containing \N{name} or \N{U+code point} in itsdefinition in UTF-8 format. (This was true previously for all occurrencesof \N{name} that did not use a custom translator, but now it'salways true.)

  • Perl_magic_setmglob now knows about globs, fixing RT #71254.

  • SVt_RV no longer exists. RVs are now stored in IVs.

  • Perl_vcroak() now accepts a null first argument. In addition, a fullaudit was made of the "not NULL" compiler annotations, and those forseveral other internal functions were corrected.

  • New macros dSAVEDERRNO, dSAVE_ERRNO, SAVE_ERRNO, RESTORE_ERRNOhave been added to formalise the temporary saving of the errnovariable.

  • The function Perl_sv_insert_flags has been added to augmentPerl_sv_insert.

  • The function Perl_newSV_type(type) has been added, equivalent toPerl_newSV() followed by Perl_sv_upgrade(type).

  • The function Perl_newSVpvn_flags() has been added, equivalent toPerl_newSVpvn() and then performing the action relevant to the flag.

    Two flag bits are currently supported.

    • SVf_UTF8 will call SvUTF8_on() for you. (Note that this doesnot convert an sequence of ISO 8859-1 characters to UTF-8). A wrapper,newSVpvn_utf8() is available for this.

    • SVs_TEMP now calls Perl_sv_2mortal() on the new SV.

    There is also a wrapper that takes constant strings, newSVpvs_flags().

  • The function Perl_croak_xs_usage has been added as a wrapper toPerl_croak.

  • Perl now exports the functions PerlIO_find_layer and PerlIO_list_alloc.

  • PL_na has been exterminated from the core code, replaced by localSTRLEN temporaries, or *_nolen() calls. Either approach is faster thanPL_na, which is a pointer dereference into the interpreter structureunder ithreads, and a global variable otherwise.

  • Perl_mg_free() used to leave freed memory accessible via SvMAGIC()on the scalar. It now updates the linked list to remove each piece ofmagic as it is freed.

  • Under ithreads, the regex in PL_reg_curpm is now referencecounted. This eliminates a lot of hackish workarounds to cope with itnot being reference counted.

  • Perl_mg_magical() would sometimes incorrectly turn on SvRMAGICAL().This has been fixed.

  • The public IV and NV flags are now not set if the string value hastrailing "garbage". This behaviour is consistent with not setting thepublic IV or NV flags if the value is out of range for the type.

  • Uses of Nullav, Nullcv, Nullhv, Nullop, Nullsv etc havebeen replaced by NULL in the core code, and non-dual-life modules,as NULL is clearer to those unfamiliar with the core code.

  • A macro MUTABLE_PTR(p) has been added, which on (non-pedantic) gcc willnot cast away const, returning a void *. Macros MUTABLE_SV(av),MUTABLE_SV(cv) etc build on this, casting to AV * etc withoutcasting away const. This allows proper compile-time auditing ofconst correctness in the core, and helped picked up some errors(now fixed).

  • Macros mPUSHs() and mXPUSHs() have been added, for pushing SVs on thestack and mortalizing them.

  • Use of the private structure mro_meta has changed slightly. Nothingoutside the core should be accessing this directly anyway.

  • A new tool, Porting/expand-macro.pl has been added, that allows youto view how a C preprocessor macro would be expanded when compiled.This is handy when trying to decode the macro hell that is the perlguts.

Testing

Testing improvements

  • Parallel tests

    The core distribution can now run its regression tests in parallel onUnix-like platforms. Instead of running make test, set TEST_JOBS inyour environment to the number of tests to run in parallel, and runmake test_harness. On a Bourne-like shell, this can be done as

    1.  TEST_JOBS=3 make test_harness  # Run 3 tests in parallel
      2.

    An environment variable is used, rather than parallel make itself, becauseTAP::Harness needs to be able to schedule individual non-conflicting testscripts itself, and there is no standard interface to make utilities tointeract with their job schedulers.

    Note that currently some test scripts may fail when run in parallel (mostnotably ext/IO/t/io_dir.t). If necessary run just the failing scriptsagain sequentially and see if the failures go away.

  • Test harness flexibility

    It's now possible to override PERL5OPT and friends in t/TEST

  • Test watchdog

    Several tests that have the potential to hang forever if they fail nowincorporate a "watchdog" functionality that will kill them after a timeout,which helps ensure that make test and make test_harness run tocompletion automatically.

New Tests

Perl's developers have added a number of new tests to the core.In addition to the items listed below, many modules updated from CPANincorporate new tests.

  • Significant cleanups to core tests to ensure that language andinterpreter features are not used before they're tested.

  • make test_porting now runs a number of important pre-commit checkswhich might be of use to anyone working on the Perl core.

  • t/porting/podcheck.t automatically checks the well-formedness ofPOD found in all .pl, .pm and .pod files in the MANIFEST, other than indual-lifed modules which are primarily maintained outside the Perl core.

  • t/porting/manifest.t now tests that all files listed in MANIFESTare present.

  • t/op/while_readdir.t tests that a bare readdir in while loop sets $_.

  • t/comp/retainedlines.t checks that the debugger can retain sourcelines from eval.

  • t/io/perlio_fail.t checks that bad layers fail.

  • t/io/perlio_leaks.t checks that PerlIO layers are not leaking.

  • t/io/perlio_open.t checks that certain special forms of open work.

  • t/io/perlio.t includes general PerlIO tests.

  • t/io/pvbm.t checks that there is no unexpected interaction betweenthe internal types PVBM and PVGV.

  • t/mro/package_aliases.t checks that mro works properly in the presenceof aliased packages.

  • t/op/dbm.t tests dbmopen and dbmclose.

  • t/op/index_thr.t tests the interaction of index and threads.

  • t/op/pat_thr.t tests the interaction of esoteric patterns and threads.

  • t/op/qr_gc.t tests that qr doesn't leak.

  • t/op/reg_email_thr.t tests the interaction of regex recursion and threads.

  • t/op/regexp_qr_embed_thr.t tests the interaction of patterns withembedded qr// and threads.

  • t/op/regexp_unicode_prop.t tests Unicode properties in regularexpressions.

  • t/op/regexp_unicode_prop_thr.t tests the interaction of Unicodeproperties and threads.

  • t/op/reg_nc_tie.t tests the tied methods of Tie::Hash::NamedCapture.

  • t/op/reg_posixcc.t checks that POSIX character classes behaveconsistently.

  • t/op/re.t checks that exportable re functions in universal.c work.

  • t/op/setpgrpstack.t checks that setpgrp works.

  • t/op/substr_thr.t tests the interaction of substr and threads.

  • t/op/upgrade.t checks that upgrading and assigning scalars works.

  • t/uni/lex_utf8.t checks that Unicode in the lexer works.

  • t/uni/tie.t checks that Unicode and tie work.

  • t/comp/final_line_num.t tests whether line numbers are correct at EOF

  • t/comp/form_scope.t tests format scoping.

  • t/comp/line_debug.t tests whether @{"_<$file"} works.

  • t/op/filetest_t.t tests if -t file test works.

  • t/op/qr.t tests qr.

  • t/op/utf8cache.t tests malfunctions of the utf8 cache.

  • t/re/uniprops.t test unicodes \p{} regex constructs.

  • t/op/filehandle.t tests some suitably portable filetest operatorsto check that they work as expected, particularly in the light of someinternal changes made in how filehandles are blessed.

  • t/op/time_loop.t tests that unix times greater than 2**63, whichcan now be handed to gmtime and localtime, do not cause an internaloverflow or an excessively long loop.

New or Changed Diagnostics

New Diagnostics

  • SV allocation tracing has been added to the diagnostics enabled by -Dm.The tracing can alternatively output via the PERL_MEM_LOG mechanism, ifthat was enabled when the perl binary was compiled.

  • Smartmatch resolution tracing has been added as a new diagnostic. Use-DM to enable it.

  • A new debugging flag -DB now dumps subroutine definitions, leaving-Dx for its original purpose of dumping syntax trees.

  • Perl 5.12 provides a number of new diagnostic messages to help you writebetter code. See perldiag for details of these new messages.

    • Bad plugin affecting keyword '%s'

    • gmtime(%.0f) too large

    • Lexing code attempted to stuff non-Latin-1 character into Latin-1 input

    • Lexing code internal error (%s)

    • localtime(%.0f) too large

    • Overloaded dereference did not return a reference

    • Overloaded qr did not return a REGEXP

    • Perl_pmflag() is deprecated, and will be removed from the XS API

    • lvalue attribute ignored after the subroutine has been defined

      This new warning is issued when one attempts to mark a subroutine aslvalue after it has been defined.

    • Perl now warns you if ++ or -- are unable to change the valuebecause it's beyond the limit of representation.

      This uses a new warnings category: "imprecision".

    • lc, uc, lcfirst, and ucfirst warn when passed undef.

    • Show constant in "Useless use of a constant in void context"

    • Prototype after '%s'

    • panic: sv_chop %s

      This new fatal error occurs when the C routine Perl_sv_chop() waspassed a position that is not within the scalar's string buffer. Thiscould be caused by buggy XS code, and at this point recovery is notpossible.

    • The fatal error Malformed UTF-8 returned by \N is now produced if thecharnames handler returns malformed UTF-8.

    • If an unresolved named character or sequence was encountered whencompiling a regex pattern then the fatal error \N{NAME} must be resolvedby the lexer is now produced. This can happen, for example, when using asingle-quotish context like $re = '\N{SPACE}'; /$re/;. See perldiagfor more examples of how the lexer can get bypassed.

    • Invalid hexadecimal number in \N{U+...} is a new fatal errortriggered when the character constant represented by ... is not avalid hexadecimal number.

    • The new meaning of \N as [^\n] is not valid in a bracketed characterclass, just like . in a character class loses its special meaning,and will cause the fatal error \N in a character class must be a namedcharacter: \N{...}.

    • The rules on what is legal for the ... in \N{...} have beentightened up so that unless the ... begins with an alphabeticcharacter and continues with a combination of alphanumerics, dashes,spaces, parentheses or colons then the warning Deprecated character(s)in \N{...} starting at '%s' is now issued.

    • The warning Using just the first characters returned by \N{} willbe issued if the charnames handler returns a sequence of characterswhich exceeds the limit of the number of characters that can be used. Themessage will indicate which characters were used and which were discarded.

Changed Diagnostics

A number of existing diagnostic messages have been improved or corrected:

  • A new warning category illegalproto allows finer-grained control ofwarnings around function prototypes.

    The two warnings:

    • Illegal character in prototype for %s : %s
    • Prototype after '%c' for %s : %s

    have been moved from the syntax top-level warnings category into a newfirst-level category, illegalproto. These two warnings are currentlythe only ones emitted during parsing of an invalid/illegal prototype,so one can now use

    1.   no warnings 'illegalproto';
      2.

    to suppress only those, but not other syntax-related warnings. Warningswhere prototypes are changed, ignored, or not met are still in theprototype category as before.

  • Deep recursion on subroutine "%s"

    It is now possible to change the depth threshold for this warning from thedefault of 100, by recompiling the perl binary, setting the Cpre-processor macro PERL_SUB_DEPTH_WARN to the desired value.

  • Illegal character in prototype warning is now more precisewhen reporting illegal characters after _

  • mro merging error messages are now very similar to those produced byAlgorithm::C3.

  • Amelioration of the error message "Unrecognized character %s in column %d"

    Changes the error message to "Unrecognized character %s; marked by <--HERE after %s<-- HERE near column %d". This should make it a littlesimpler to spot and correct the suspicious character.

  • Perl now explicitly points to $. when it causes an uninitializedwarning for ranges in scalar context.

  • split now warns when called in void context.

  • printf-style functions called with too few arguments will now issue thewarning "Missing argument in %s" [perl #71000]

  • Perl now properly returns a syntax error instead of segfaultingif each, keys, or values is used without an argument.

  • tell() now fails properly if called without an argument and when noprevious file was read.

    tell() now returns -1, and sets errno to EBADF, thus restoringthe 5.8.x behaviour.

  • overload no longer implicitly unsets fallback on repeated 'useoverload' lines.

  • POSIX::strftime() can now handle Unicode characters in the format string.

  • The syntax category was removed from 5 warnings that should only be indeprecated.

  • Three fatal pack/unpack error messages have been normalized topanic: %s

  • Unicode character is illegal has been rephrased to be more accurate

    It now reads Unicode non-character is illegal in interchange and theperldiag documentation has been expanded a bit.

  • Currently, all but the first of the several characters that thecharnames handler may return are discarded when used in a regularexpression pattern bracketed character class. If this happens then thewarning Using just the first character returned by \N{} in characterclass will be issued.

  • The warning Missing right brace on \N{} or unescaped left brace after\N. Assuming the latter will be issued if Perl encounters a \N{but doesn't find a matching }. In this case Perl doesn't know if itwas mistakenly omitted, or if "match non-newline" followed by "matcha {" was desired. It assumes the latter because that is actually avalid interpretation as written, unlike the other case. If you meantthe former, you need to add the matching right brace. If you did meanthe latter, you can silence this warning by writing instead \N\{.

  • gmtime and localtime called with numbers smaller than they canreliably handle will now issue the warnings gmtime(%.0f) too smalland localtime(%.0f) too small.

The following diagnostic messages have been removed:

  • Runaway format

  • Can't locate package %s for the parents of %s

    In general this warning it only got produced inconjunction with other warnings, and removing it allowed an ISA lookupoptimisation to be added.

  • v-string in use/require is non-portable

Utility Changes

  • h2ph now looks in include-fixed too, which is a recent additionto gcc's search path.

  • h2xs no longer incorrectly treats enum values like macros.It also now handles C++ style comments (//) properly in enums.

  • perl5db.pl now supports LVALUE subroutines. Additionally, thedebugger now correctly handles proxy constant subroutines, andsubroutine stubs.

  • perlbug now uses %Module::CoreList::bug_tracker to print outupstream bug tracker URLs. If a user identifies a particular moduleas the topic of their bug report and we're able to divine the URL forits upstream bug tracker, perlbug now provide a message to the userexplaining that the core copies the CPAN version directly, and providethe URL for reporting the bug directly to the upstream author.

    perlbug no longer reports "Message sent" when it hasn't actually sentthe message

  • perlthanks is a new utility for sending non-bug-reports to theauthors and maintainers of Perl. Getting nothing but bug reports canbecome a bit demoralising. If Perl 5.12 works well for you, please tryout perlthanks. It will make the developers smile.

  • Perl's developers have fixed bugs in a2p having to do with thematch() operator in list context. Additionally, a2p no longergenerates code that uses the $[ variable.

Selected Bug Fixes

  • U+0FFFF is now a legal character in regular expressions.

  • pp_qr now always returns a new regexp SV. Resolves RT #69852.

    Instead of returning a(nother) reference to the (pre-compiled) regexpin the optree, use reg_temp_copy() to create a copy of it, and return areference to that. This resolves issues about Regexp::DESTROY not beingcalled in a timely fashion (the original bug tracked by RT #69852), aswell as bugs related to blessing regexps, and of assigning to regexps,as described in correspondence added to the ticket.

    It transpires that we also need to undo the SvPVX() sharing when ithreadscloning a Regexp SV, because mother_re is set to NULL, instead of acloned copy of the mother_re. This change might fix bugs with regexpsand threads in certain other situations, but as yet neither tests norbug reports have indicated any problems, so it might not actually be anedge case that it's possible to reach.

  • Several compilation errors and segfaults when perl was built with -Dmadwere fixed.

  • Fixes for lexer API changes in 5.11.2 which broke NYTProf's savesrc option.

  • -t should only return TRUE for file handles connected to a TTY

    The Microsoft C version of isatty() returns TRUE for all character modedevices, including the /dev/null-style "nul" device and printers like"lpt1".

  • Fixed a regression caused by commit fafafbaf which caused a panic duringparameter passing [perl #70171]

  • On systems which in-place edits without backup files, -i'*' now works asthe documentation says it does [perl #70802]

  • Saving and restoring magic flags no longer loses readonly flag.

  • The malformed syntax grep EXPR LIST (note the missing comma) no longercauses abrupt and total failure.

  • Regular expressions compiled with qr{} literals properly set $' whenmatching again.

  • Using named subroutines with sort should no longer lead to bus errors[perl #71076]

  • Numerous bugfixes catch small issues caused by the recently-added Lexer API.

  • Smart match against @_ sometimes gave false negatives. [perl #71078]

  • $@ may now be assigned a read-only value (without error or bustingthe stack).

  • sort called recursively from within an active comparison subroutine nolonger causes a bus error if run multiple times. [perl #71076]

  • Tie::Hash::NamedCapture::* will not abort if passed bad input (RT #71828)

  • @_ and $_ no longer leak under threads (RT #34342 and #41138, also#70602, #70974)

  • -I on shebang line now adds directories in front of @INCas documented, and as does -I when specified on the command-line.

  • kill is now fatal when called on non-numeric process identifiers.Previously, an undef process identifier would be interpreted as arequest to kill process 0, which would terminate the current processgroup on POSIX systems. Since process identifiers are always integers,killing a non-numeric process is now fatal.

  • 5.10.0 inadvertently disabled an optimisation, which caused a measurableperformance drop in list assignment, such as is often used to assignfunction parameters from @_. The optimisation has been re-instated, andthe performance regression fixed. (This fix is also present in 5.10.1)

  • Fixed memory leak on while (1) { map 1, 1 } [RT #53038].

  • Some potential coredumps in PerlIO fixed [RT #57322,54828].

  • The debugger now works with lvalue subroutines.

  • The debugger's m command was broken on modules that defined constants[RT #61222].

  • crypt and string complement could return tainted values for untaintedarguments [RT #59998].

  • The -i.suffix command-line switch now recreates the file usingrestricted permissions, before changing its mode to match the originalfile. This eliminates a potential race condition [RT #60904].

  • On some Unix systems, the value in $? would not have the top bit set($? & 128) even if the child core dumped.

  • Under some circumstances, $^R could incorrectly become undefined[RT #57042].

  • In the XS API, various hash functions, when passed a pre-computed hash wherethe key is UTF-8, might result in an incorrect lookup.

  • XS code including XSUB.h before perl.h gave a compile-time error[RT #57176].

  • $object->isa('Foo') would report false if the package Foodidn't exist, even if the object's @ISA contained Foo.

  • Various bugs in the new-to 5.10.0 mro code, triggered by manipulating@ISA, have been found and fixed.

  • Bitwise operations on references could crash the interpreter, e.g.$x=\$y; $x |= "foo" [RT #54956].

  • Patterns including alternation might be sensitive to the internal UTF-8representation, e.g.

    1.  my $byte = chr(192);
      2.  
    2.  my $utf8 = chr(192); utf8::upgrade($utf8);
      3.  
    3.  $utf8 =~ /$byte|X}/i;# failed in 5.10.0
      4.

  • Within UTF8-encoded Perl source files (i.e. where use utf8 is ineffect), double-quoted literal strings could be corrupted where a \xNN,\0NNN or \N{} is followed by a literal character with ordinal valuegreater than 255 [RT #59908].

  • B::Deparse failed to correctly deparse various constructs:readpipe STRING [RT #62428], CORE::require(STRING) [RT #62488],sub foo(_) [RT #62484].

  • Using setpgrp with no arguments could corrupt the perl stack.

  • The block form of eval is now specifically trappable by Safe andops. Previously it was erroneously treated like string eval.

  • In 5.10.0, the two characters [~ were sometimes parsed as the smartmatch operator (~~) [RT #63854].

  • In 5.10.0, the * quantifier in patterns was sometimes treated as{0,32767} [RT #60034, #60464]. For example, this match would fail:

    1.  ("ab" x 32768) =~ /^(ab)*$/
      2.

  • shmget was limited to a 32 bit segment size on a 64 bit OS [RT #63924].

  • Using next or last to exit a given block no longer produces aspurious warning like the following:

    1.  Exiting given via last at foo.pl line 123
      2.

  • Assigning a format to a glob could corrupt the format; e.g.:

    1.  *bar=*foo{FORMAT}; # foo format now bad
      2.

  • Attempting to coerce a typeglob to a string or number could cause anassertion failure. The correct error message is now generated,Can't coerce GLOB to $type.

  • Under use filetest 'access', -x was using the wrong accessmode. This has been fixed [RT #49003].

  • length on a tied scalar that returned a Unicode value would not becorrect the first time. This has been fixed.

  • Using an array tie inside in array tie could SEGV. This has beenfixed. [RT #51636]

  • A race condition inside PerlIOStdio_close() has been identified andfixed. This used to cause various threading issues, including SEGVs.

  • In unpack, the use of () groups in scalar context was internallyplacing a list on the interpreter's stack, which manifested in variousways, including SEGVs. This is now fixed [RT #50256].

  • Magic was called twice in substr, \&$x, tie $x, $m and chop.These have all been fixed.

  • A 5.10.0 optimisation to clear the temporary stack within the implicitloop of s///ge has been reverted, as it turned out to be the cause ofobscure bugs in seemingly unrelated parts of the interpreter [commitef0d4e17921ee3de].

  • The line numbers for warnings inside elsif are now correct.

  • The .. operator now works correctly with ranges whose ends are at orclose to the values of the smallest and largest integers.

  • binmode STDIN, ':raw' could lead to segmentation faults on some platforms.This has been fixed [RT #54828].

  • An off-by-one error meant that index $str, ... was effectively beingexecuted as index "$str\0", .... This has been fixed [RT #53746].

  • Various leaks associated with named captures in regexes have been fixed[RT #57024].

  • A weak reference to a hash would leak. This was affecting DBI[RT #56908].

  • Using (?|) in a regex could cause a segfault [RT #59734].

  • Use of a UTF-8 tr// within a closure could cause a segfault [RT #61520].

  • Calling Perl_sv_chop() or otherwise upgrading an SV could result in anunaligned 64-bit access on the SPARC architecture [RT #60574].

  • In the 5.10.0 release, inc_version_list would incorrectly list5.10.* after 5.8.*; this affected the @INC search order[RT #67628].

  • In 5.10.0, pack "a*", $tainted_value returned a non-tainted value[RT #52552].

  • In 5.10.0, printf and sprintf could produce the fatal errorpanic: utf8_mg_pos_cache_update when printing UTF-8 strings[RT #62666].

  • In the 5.10.0 release, a dynamically created AUTOLOAD method might bemissed (method cache issue) [RT #60220,60232].

  • In the 5.10.0 release, a combination of use feature and //ee couldcause a memory leak [RT #63110].

  • -C on the shebang (#!) line is once more permitted if it is alsospecified on the command line. -C on the shebang line used to be asilent no-op if it was not also on the command line, so perl 5.10.0disallowed it, which broke some scripts. Now perl checks whether it isalso on the command line and only dies if it is not [RT #67880].

  • In 5.10.0, certain types of re-entrant regular expression could crash,or cause the following assertion failure [RT #60508]:

    1.  Assertion rx->sublen >= (s - rx->subbeg) + i failed
      2.

  • Perl now includes previously missing files from the Unicode CharacterDatabase.

  • Perl now honors TMPDIR when opening an anonymous temporary file.

Platform Specific Changes

Perl is incredibly portable. In general, if a platform has a C compiler,someone has ported Perl to it (or will soon). We're happy to announcethat Perl 5.12 includes support for several new platforms. At the sametime, it's time to bid farewell to some (very) old friends.

New Platforms

  • Haiku

    Perl's developers have merged patches from Haiku's maintainers. Perlshould now build on Haiku.

  • MirOS BSD

    Perl should now build on MirOS BSD.

Discontinued Platforms

  • Domain/OS
  • MiNT
  • Tenon MachTen

Updated Platforms

  • AIX

    • Removed libbsd for AIX 5L and 6.1. Only flock() was used fromlibbsd.

    • Removed libgdbm for AIX 5L and 6.1 if libgdbm < 1.8.3-5 isinstalled. The libgdbm is delivered as an optional package with theAIX Toolbox. Unfortunately the versions below 1.8.3-5 are broken.

    • Hints changes mean that AIX 4.2 should work again.

  • Cygwin

    • Perl now supports IPv6 on Cygwin 1.7 and newer.

    • On Cygwin we now strip the last number from the DLL. This has been thebehaviour in the cygwin.com build for years. The hints files have beenupdated.

  • Darwin (Mac OS X)

    • Skip testing the be_BY.CP1131 locale on Darwin 10 (Mac OS X 10.6),as it's still buggy.

    • Correct infelicities in the regexp used to identify buggy localeson Darwin 8 and 9 (Mac OS X 10.4 and 10.5, respectively).

  • DragonFly BSD

    • Fix thread library selection [perl #69686]

  • FreeBSD

    • The hints files now identify the correct threading libraries on FreeBSD 7and later.

  • Irix

    • We now work around a bizarre preprocessor bug in the Irix 6.5 compiler:cc -E - unfortunately goes into K&R mode, but cc -E file.c doesn't.

  • NetBSD

    • Hints now supports versions 5.*.

  • OpenVMS

    • -UDEBUGGING is now the default on VMS.

      Like it has been everywhere else for ages and ages. Also make command-lineselection of -UDEBUGGING and -DDEBUGGING work in configure.com; beforethe only way to turn it off was by saying no in answer to the interactivequestion.

    • The default pipe buffer size on VMS has been updated to 8192 on 64-bitsystems.

    • Reads from the in-memory temporary files of PerlIO::scalar used to failif $/ was set to a numeric reference (to indicate record-style reads).This is now fixed.

    • VMS now supports getgrgid.

    • Many improvements and cleanups have been made to the VMS file name handlingand conversion code.

    • Enabling the PERL_VMS_POSIX_EXIT logical name now encodes a POSIX exitstatus in a VMS condition value for better interaction with GNV's bashshell and other utilities that depend on POSIX exit values. See$? in perlvms for details.

    • File::Copy now detects Unix compatibility mode on VMS.

  • Stratus VOS

    • Various changes from Stratus have been merged in.

  • Symbian

    • There is now support for Symbian S60 3.2 SDK and S60 5.0 SDK.

  • Windows

    • Perl 5.12 supports Windows 2000 and later. The supporting code forlegacy versions of Windows is still included, but will be removedduring the next development cycle.

    • Initial support for building Perl with MinGW-w64 is now available.

    • perl.exe now includes a manifest resource to specify the trustInfosettings for Windows Vista and later. Without this setting Windowswould treat perl.exe as a legacy application and apply variousheuristics like redirecting access to protected file system areas(like the "Program Files" folder) to the users "VirtualStore"instead of generating a proper "permission denied" error.

      The manifest resource also requests the Microsoft Common-Controlsversion 6.0 (themed controls introduced in Windows XP). Check out theWin32::VisualStyles module on CPAN to switch back to old styleunthemed controls for legacy applications.

    • The -t filetest operator now only returns true if the filehandleis connected to a console window. In previous versions of Perl itwould return true for all character mode devices, including NULand LPT1.

    • The -p filetest operator now works correctly, and theFcntl::S_IFIFO constant is defined when Perl is compiled withMicrosoft Visual C. In previous Perl versions -p alwaysreturned a false value, and the Fcntl::S_IFIFO constantwas not defined.

      This bug is specific to Microsoft Visual C and never affectedPerl binaries built with MinGW.

    • The socket error codes are now more widely supported: The POSIXmodule will define the symbolic names, like POSIX::EWOULDBLOCK,and stringification of socket error codes in $! works as wellnow;

      1.   C:\>perl -MPOSIX -E "$!=POSIX::EWOULDBLOCK; say $!"
        2.  
      2.   A non-blocking socket operation could not be completed immediately.
        3.

    • flock() will now set sensible error codes in $!. Previous Perl versionscopied the value of $^E into $!, which caused much confusion.

    • select() now supports all empty fd_sets more correctly.

    • '.\foo' and '..\foo' were treated differently than'./foo' and '../foo' by do and require [RT #63492].

    • Improved message window handling means that alarm and kill messageswill no longer be dropped under race conditions.

    • Various bits of Perl's build infrastructure are no longer converted towin32 line endings at release time. If this hurts you, please report theproblem with the perlbug program included with perl.

Known Problems

This is a list of some significant unfixed bugs, which are regressionsfrom either 5.10.x or 5.8.x.

  • Some CPANPLUS tests may fail if there is a functioning file../../cpanp-run-perl outside your build directory. The failureshouldn't imply there's a problem with the actual functionalsoftware. The bug is already fixed in [RT #74188] and is scheduled forinclusion in perl-v5.12.1.

  • List::Util::first misbehaves in the presence of a lexical $_(typically introduced by my $_ or implicitly by given). The variablewhich gets set for each iteration is the package variable $_, not thelexical $_ [RT #67694].

    A similar issue may occur in other modules that provide functions whichtake a block as their first argument, like

    1.  foo { ... $_ ...} list
      2.

  • Some regexes may run much more slowly when run in a child thread comparedwith the thread the pattern was compiled into [RT #55600].

  • Things like "\N{LATIN SMALL LIGATURE FF}" =~ /\N{LATIN SMALL LETTER F}+/will appear to hang as they get into a very long running loop [RT #72998].

  • Several porters have reported mysterious crashes when Perl's entiretest suite is run after a build on certain Windows 2000 systems. Whenrun by hand, the individual tests reportedly work fine.

Errata

  • This one is actually a change introduced in 5.10.0, but it was missedfrom that release's perldelta, so it is mentioned here instead.

    A bugfix related to the handling of the /m modifier and qr resultedin a change of behaviour between 5.8.x and 5.10.0:

    1.  # matches in 5.8.x, doesn't match in 5.10.0
      2.  
    2.  $re = qr/^bar/; "foo\nbar" =~ /$re/m;
      3.

Acknowledgements

Perl 5.12.0 represents approximately two years of development sincePerl 5.10.0 and contains over 750,000 lines of changes across over3,000 files from over 200 authors and committers.

Perl continues to flourish into its third decade thanks to a vibrantcommunity of users and developers. The following people are known tohave contributed the improvements that became Perl 5.12.0:

Aaron Crane, Abe Timmerman, Abhijit Menon-Sen, Abigail, Adam Russell,Adriano Ferreira, Ævar Arnfjörð Bjarmason, Alan Grover, AlexandrCiornii, Alex Davies, Alex Vandiver, Andreas Koenig, Andrew Rodland,[email protected], Andy Armstrong, Andy Dougherty, Jose AUGUSTE-ETIENNE,Benjamin Smith, Ben Morrow, bharanee rathna, Bo Borgerson, Bo Lindbergh,Brad Gilbert, Bram, Brendan O'Dea, brian d foy, Charles Bailey,Chip Salzenberg, Chris 'BinGOs' Williams, Christoph Lamprecht, ChrisWilliams, chromatic, Claes Jakobsson, Craig A. Berry, Dan Dascalescu,Daniel Frederick Crisman, Daniel M. Quinlan, Dan Jacobson, Dan Kogai,Dave Mitchell, Dave Rolsky, David Cantrell, David Dick, David Golden,David Mitchell, David M. Syzdek, David Nicol, David Wheeler, DennisKaarsemaker, Dintelmann, Peter, Dominic Dunlop, Dr.Ruud, Duke Leto,Enrico Sorcinelli, Eric Brine, Father Chrysostomos, Florian Ragwitz,Frank Wiegand, Gabor Szabo, Gene Sullivan, Geoffrey T. Dairiki, GeorgeGreer, Gerard Goossen, Gisle Aas, Goro Fuji, Graham Barr, Green, Paul,Hans Dieter Pearcey, Harmen, H. Merijn Brand, Hugo van der Sanden,Ian Goodacre, Igor Sutton, Ingo Weinhold, James Bence, James Mastros,Jan Dubois, Jari Aalto, Jarkko Hietaniemi, Jay Hannah, Jerry Hedden,Jesse Vincent, Jim Cromie, Jody Belka, John E. Malmberg, John Malmberg,John Peacock, John Peacock via RT, John P. Linderman, John Wright,Josh ben Jore, Jos I. Boumans, Karl Williamson, Kenichi Ishigaki, KenWilliams, Kevin Brintnall, Kevin Ryde, Kurt Starsinic, Leon Brocard,Lubomir Rintel, Luke Ross, Marcel Grünauer, Marcus Holland-Moritz, MarkJason Dominus, Marko Asplund, Martin Hasch, Mashrab Kuvatov, Matt Kraai,Matt S Trout, Max Maischein, Michael Breen, Michael Cartmell, MichaelG Schwern, Michael Witten, Mike Giroux, Milosz Tanski, Moritz Lenz,Nicholas Clark, Nick Cleaton, Niko Tyni, Offer Kaye, Osvaldo Villalon,Paul Fenwick, Paul Gaborit, Paul Green, Paul Johnson, Paul Marquess,Philip Hazel, Philippe Bruhat, Rafael Garcia-Suarez, Rainer Tammer,Rajesh Mandalemula, Reini Urban, Renée Bäcker, Ricardo Signes,Ricardo SIGNES, Richard Foley, Rich Rauenzahn, Rick Delaney, RistoKankkunen, Robert May, Roberto C. Sanchez, Robin Barker, SADAHIROTomoyuki, Salvador Ortiz Garcia, Sam Vilain, Scott Lanning, SébastienAperghis-Tramoni, Sérgio Durigan Júnior, Shlomi Fish, Simon 'corecode'Schubert, Sisyphus, Slaven Rezic, Smylers, Steffen Müller, SteffenUllrich, Stepan Kasal, Steve Hay, Steven Schubiger, Steve Peters, Tels,The Doctor, Tim Bunce, Tim Jenness, Todd Rinaldo, Tom Christiansen,Tom Hukins, Tom Wyant, Tony Cook, Torsten Schoenfeld, Tye McQueen,Vadim Konovalov, Vincent Pit, Hio YAMASHINA, Yasuhiro Matsumoto,Yitzchak Scott-Thoennes, Yuval Kogman, Yves Orton, Zefram, Zsban Ambrus

This is woefully incomplete as it's automatically generated from versioncontrol history. In particular, it doesn't include the names of the(very much appreciated) contributors who reported issues in previousversions of Perl that helped make Perl 5.12.0 better. For a more completelist of all of Perl's historical contributors, please see the AUTHORSfile in the Perl 5.12.0 distribution.

Our "retired" pumpkings Nicholas Clark and Rafael Garcia-Suarezdeserve special thanks for their brilliant and substantive ongoingcontributions. Nicholas personally authored over 30% of the patchessince 5.10.0. Rafael comes in second in patch authorship with 11%,but is first by a long shot in committing patches authored by others,pushing 44% of the commits since 5.10.0 in this category, often afterproviding considerable coaching to the patch authors. These statisticsin no way comprise all of their contributions, but express in shorthandthat we couldn't have done it without them.

Many of the changes included in this version originated in the CPANmodules included in Perl's core. We're grateful to the entire CPANcommunity for helping Perl to flourish.

Reporting Bugs

If you find what you think is a bug, you might check the articlesrecently posted to the comp.lang.perl.misc newsgroup and the perlbug database at http://rt.perl.org/perlbug/. There may also beinformation at http://www.perl.org/, the Perl Home Page.

If you believe you have an unreported bug, please run the perlbugprogram included with your release. Be sure to trim your bug downto a tiny but sufficient test case. Your bug report, along with theoutput of perl -V, will be sent off to [email protected] to beanalyzed by the Perl porting team.

If the bug you are reporting has security implications, which make itinappropriate to send to a publicly archived mailing list, then please sendit to [email protected]. This points to a closed subscriptionunarchived mailing list, which includesall the core committers, who will be ableto help assess the impact of issues, figure out a resolution, and helpco-ordinate the release of patches to mitigate or fix the problem across allplatforms on which Perl is supported. Please only use this address forsecurity issues in the Perl core, not for modules independentlydistributed on CPAN.

SEE ALSO

The Changes file for an explanation of how to view exhaustive detailson what changed.

The INSTALL file for how to build Perl.

The README file for general stuff.

The Artistic and Copying files for copyright information.

http://dev.perl.org/perl5/errata.html for a list of issuesfound after this release, as well as a list of CPAN modules knownto be incompatible with this release.

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