NAME¶
perl5200delta - what is new for perl v5.20.0
DESCRIPTION¶
This document describes differences between the 5.18.0 release and the 5.20.0
release.
If you are upgrading from an earlier release such as 5.16.0, first read
perl5180delta, which describes differences between 5.16.0 and 5.18.0.
Core Enhancements¶
Experimental Subroutine signatures¶
Declarative syntax to unwrap argument list into lexical variables. "sub foo
($a,$b) {...}" checks the number of arguments and puts the arguments into
lexical variables. Signatures are not equivalent to the existing idiom of
"sub foo { my($a,$b) = @_; ... }". Signatures are only available by
enabling a non-default feature, and generate warnings about being
experimental. The syntactic clash with prototypes is managed by disabling the
short prototype syntax when signatures are enabled.
See "Signatures" in perlsub for details.
"sub"s now take a "prototype" attribute¶
When declaring or defining a "sub", the prototype can now be specified
inside of a "prototype" attribute instead of in parens following the
name.
For example, "sub foo($$){}" could be rewritten as "sub foo :
prototype($$){}".
More consistent prototype parsing¶
Multiple semicolons in subroutine prototypes have long been tolerated and
treated as a single semicolon. There was one case where this did not happen. A
subroutine whose prototype begins with "*" or ";*" can
affect whether a bareword is considered a method name or sub call. This now
applies also to ";;;*".
Whitespace has long been allowed inside subroutine prototypes, so "sub( $ $
)" is equivalent to "sub($$)", but until now it was stripped
when the subroutine was parsed. Hence, whitespace was
not allowed in
prototypes set by "Scalar::Util::set_prototype". Now it is
permitted, and the parser no longer strips whitespace. This means
"prototype &mysub" returns the original prototype, whitespace
and all.
"rand" now uses a consistent random number generator¶
Previously perl would use a platform specific random number generator, varying
between the libc
rand(),
random() or
drand48().
This meant that the quality of perl's random numbers would vary from platform to
platform, from the 15 bits of
rand() on Windows to 48-bits on POSIX
platforms such as Linux with
drand48().
Perl now uses its own internal
drand48() implementation on all platforms.
This does not make perl's "rand" cryptographically secure. [perl
#115928]
New slice syntax¶
The new %hash{...} and %array[...] syntax returns a list of key/value (or
index/value) pairs. See "Key/Value Hash Slices" in perldata.
Experimental Postfix Dereferencing¶
When the "postderef" feature is in effect, the following syntactical
equivalencies are set up:
$sref->$*; # same as ${ $sref } # interpolates
$aref->@*; # same as @{ $aref } # interpolates
$href->%*; # same as %{ $href }
$cref->&*; # same as &{ $cref }
$gref->**; # same as *{ $gref }
$aref->$#*; # same as $#{ $aref }
$gref->*{ $slot }; # same as *{ $gref }{ $slot }
$aref->@[ ... ]; # same as @$aref[ ... ] # interpolates
$href->@{ ... }; # same as @$href{ ... } # interpolates
$aref->%[ ... ]; # same as %$aref[ ... ]
$href->%{ ... }; # same as %$href{ ... }
Those marked as interpolating only interpolate if the associated
"postderef_qq" feature is also enabled. This feature is
experimental and will trigger
"experimental::postderef"-category warnings when used, unless they
are suppressed.
For more information, consult the Postfix Dereference Syntax section of perlref.
Unicode 6.3 now supported¶
Perl now supports and is shipped with Unicode 6.3 (though Perl may be recompiled
with any previous Unicode release as well). A detailed list of Unicode 6.3
changes is at <
http://www.unicode.org/versions/Unicode6.3.0/>.
New "\p{Unicode}" regular expression pattern property¶
This is a synonym for "\p{Any}" and matches the set of Unicode-defined
code points 0 - 0x10FFFF.
Better 64-bit support¶
On 64-bit platforms, the internal array functions now use 64-bit offsets,
allowing Perl arrays to hold more than 2**31 elements, if you have the memory
available.
The regular expression engine now supports strings longer than 2**31 characters.
[perl #112790, #116907]
The functions PerlIO_get_bufsiz, PerlIO_get_cnt, PerlIO_set_cnt and
PerlIO_set_ptrcnt now have SSize_t, rather than int, return values and
parameters.
"use locale" now works on UTF-8 locales¶
Until this release, only single-byte locales, such as the ISO 8859 series were
supported. Now, the increasingly common multi-byte UTF-8 locales are also
supported. A UTF-8 locale is one in which the character set is Unicode and the
encoding is UTF-8. The POSIX "LC_CTYPE" category operations (case
changing (like "lc()", "\U"), and character classification
("\w", "\D", "qr/[[:punct:]]/")) under such a
locale work just as if not under locale, but instead as if under
"use feature 'unicode_strings'", except taint rules
are followed. Sorting remains by code point order in this release. [perl
#56820].
"use locale" now compiles on systems without locale ability¶
Previously doing this caused the program to not compile. Within its scope the
program behaves as if in the "C" locale. Thus programs written for
platforms that support locales can run on locale-less platforms without
change. Attempts to change the locale away from the "C" locale will,
of course, fail.
More locale initialization fallback options¶
If there was an error with locales during Perl start-up, it immediately gave up
and tried to use the "C" locale. Now it first tries using other
locales given by the environment variables, as detailed in
"ENVIRONMENT" in perllocale. For example, if "LC_ALL" and
"LANG" are both set, and using the "LC_ALL" locale fails,
Perl will now try the "LANG" locale, and only if that fails, will it
fall back to "C". On Windows machines, Perl will try, ahead of using
"C", the system default locale if all the locales given by
environment variables fail.
"-DL" runtime option now added for tracing locale setting¶
This is designed for Perl core developers to aid in field debugging bugs
regarding locales.
-F now implies -a and -a implies -n¶
Previously
-F without
-a was a no-op, and
-a without
-n or
-p was a no-op, with this change, if you supply
-F
then both
-a and
-n are implied and if you supply
-a then
-n is implied.
You can still use
-p for its extra behaviour. [perl #116190]
$a and $b warnings exemption¶
The special variables $a and $b, used in "sort", are now exempt from
"used once" warnings, even where "sort" is not used. This
makes it easier for CPAN modules to provide functions using $a and $b for
similar purposes. [perl #120462]
Security¶
Avoid possible read of free()d memory during parsing¶
It was possible that
free()d memory could be read during parsing in the
unusual circumstance of the Perl program ending with a heredoc and the last
line of the file on disk having no terminating newline character. This has now
been fixed.
Incompatible Changes¶
"do" can no longer be used to call subroutines¶
The "do SUBROUTINE(LIST)" form has resulted in a deprecation warning
since Perl v5.0.0, and is now a syntax error.
Quote-like escape changes¶
The character after "\c" in a double-quoted string ("..." or
qq(...)) or regular expression must now be a printable character and may not
be "{".
A literal "{" after "\B" or "\b" is now fatal.
These were deprecated in perl v5.14.0.
This affects regular expression matching and changing the case of a string
("lc", "\U",
etc.) within the scope of "use
locale". The result is now tainted based on the operation, no matter what
the contents of the string were, as the documentation (perlsec,
"SECURITY" in perllocale) indicates it should. Previously, for the
case change operation, if the string contained no characters whose case change
could be affected by the locale, the result would not be tainted. For example,
the result of "uc()" on an empty string or one containing only
above-Latin1 code points is now tainted, and wasn't before. This leads to more
consistent tainting results. Regular expression patterns taint their
non-binary results (like $&, $2) if and only if the pattern contains
elements whose matching depends on the current (potentially tainted) locale.
Like the case changing functions, the actual contents of the string being
matched now do not matter, whereas formerly it did. For example, if the
pattern contains a "\w", the results will be tainted even if the
match did not have to use that portion of the pattern to succeed or fail,
because what a "\w" matches depends on locale. However, for example,
a "." in a pattern will not enable tainting, because the dot matches
any single character, and what the current locale is doesn't change in any way
what matches and what doesn't.
"\p{}", "\P{}" matching has changed for non-Unicode code points.¶
"\p{}" and "\P{}" are defined by Unicode only on
Unicode-defined code points ("U+0000" through "U+10FFFF").
Their behavior on matching these legal Unicode code points is unchanged, but
there are changes for code points 0x110000 and above. Previously, Perl treated
the result of matching "\p{}" and "\P{}" against these as
"undef", which translates into "false". For
"\P{}", this was then complemented into "true". A warning
was supposed to be raised when this happened. However, various optimizations
could prevent the warning, and the results were often counter-intuitive, with
both a match and its seeming complement being false. Now all non-Unicode code
points are treated as typical unassigned Unicode code points. This generally
is more Do-What-I-Mean. A warning is raised only if the results are arguably
different from a strict Unicode approach, and from what Perl used to do. Code
that needs to be strictly Unicode compliant can make this warning fatal, and
then Perl always raises the warning.
Details are in "Beyond Unicode code points" in perlunicode.
"\p{All}" has been expanded to match all possible code points¶
The Perl-defined regular expression pattern element "\p{All}", unused
on CPAN, used to match just the Unicode code points; now it matches all
possible code points; that is, it is equivalent to "qr/./s". Thus
"\p{All}" is no longer synonymous with "\p{Any}", which
continues to match just the Unicode code points, as Unicode says it should.
Data::Dumper's output may change¶
Depending on the data structures dumped and the settings set for Data::Dumper,
the dumped output may have changed from previous versions.
If you have tests that depend on the exact output of Data::Dumper, they may
fail.
To avoid this problem in your code, test against the data structure from
evaluating the dumped structure, instead of the dump itself.
Locale decimal point character no longer leaks outside of "use locale" scope¶
This is actually a bug fix, but some code has come to rely on the bug being
present, so this change is listed here. The current locale that the program is
running under is not supposed to be visible to Perl code except within the
scope of a "use locale". However, until now under certain
circumstances, the character used for a decimal point (often a comma) leaked
outside the scope. If your code is affected by this change, simply add a
"use locale".
Assignments of Windows sockets error codes to $! now prefer errno.h values over WSAGetLastError() values¶
In previous versions of Perl, Windows sockets error codes as returned by
WSAGetLastError() were assigned to $!, and some constants such as
ECONNABORTED, not in
errno.h in VC++ (or the various Windows ports of
gcc) were defined to corresponding WSAE* values to allow $! to be tested
against the E* constants exported by Errno and POSIX.
This worked well until VC++ 2010 and later, which introduced new E* constants
with values > 100 into
errno.h, including some being (re)defined by
perl to WSAE* values. That caused problems when linking XS code against other
libraries which used the original definitions of
errno.h constants.
To avoid this incompatibility, perl now maps WSAE* error codes to E* values
where possible, and assigns those values to $!. The E* constants exported by
Errno and POSIX are updated to match so that testing $! against them, wherever
previously possible, will continue to work as expected, and all E* constants
found in
errno.h are now exported from those modules with their
original
errno.h values.
In order to avoid breakage in existing Perl code which assigns WSAE* values to
$!, perl now intercepts the assignment and performs the same mapping to E*
values as it uses internally when assigning to $! itself.
However, one backwards-incompatibility remains: existing Perl code which
compares $! against the numeric values of the WSAE* error codes that were
previously assigned to $! will now be broken in those cases where a
corresponding E* value has been assigned instead. This is only an issue for
those E* values < 100, which were always exported from Errno and POSIX with
their original
errno.h values, and therefore could not be used for
WSAE* error code tests (e.g. WSAEINVAL is 10022, but the corresponding EINVAL
is 22). (E* values > 100, if present, were redefined to WSAE* values
anyway, so compatibility can be achieved by using the E* constants, which will
work both before and after this change, albeit using different numeric values
under the hood.)
Functions "PerlIO_vsprintf" and "PerlIO_sprintf" have been removed¶
These two functions, undocumented, unused in CPAN, and problematic, have been
removed.
Deprecations¶
The "/\C/" character class¶
The "/\C/" regular expression character class is deprecated. From perl
5.22 onwards it will generate a warning, and from perl 5.24 onwards it will be
a regular expression compiler error. If you need to examine the individual
bytes that make up a UTF8-encoded character, then use
"utf8::encode()" on the string (or a copy) first.
Literal control characters in variable names¶
This deprecation affects things like $\cT, where \cT is a literal control (such
as a "NAK" or "NEGATIVE ACKNOWLEDGE" character) in the
source code. Surprisingly, it appears that originally this was intended as the
canonical way of accessing variables like $^T, with the caret form only being
added as an alternative.
The literal control form is being deprecated for two main reasons. It has what
are likely unfixable bugs, such as $\cI not working as an alias for $^I, and
their usage not being portable to non-ASCII platforms: While $^T will work
everywhere, \cT is whitespace in EBCDIC. [perl #119123]
References to non-integers and non-positive integers in $/¶
Setting $/ to a reference to zero or a reference to a negative integer is now
deprecated, and will behave
exactly as though it was set to
"undef". If you want slurp behavior set $/ to "undef"
explicitly.
Setting $/ to a reference to a non integer is now forbidden and will throw an
error. Perl has never documented what would happen in this context and while
it used to behave the same as setting $/ to the address of the references in
future it may behave differently, so we have forbidden this usage.
Character matching routines in POSIX¶
Use of any of these functions in the "POSIX" module is now deprecated:
"isalnum", "isalpha", "iscntrl",
"isdigit", "isgraph", "islower",
"isprint", "ispunct", "isspace",
"isupper", and "isxdigit". The functions are buggy and
don't work on UTF-8 encoded strings. See their entries in POSIX for more
information.
A warning is raised on the first call to any of them from each place in the code
that they are called. (Hence a repeated statement in a loop will raise just
the one warning.)
Interpreter-based threads are now discouraged¶
The "interpreter-based threads" provided by Perl are not the fast,
lightweight system for multitasking that one might expect or hope for. Threads
are implemented in a way that make them easy to misuse. Few people know how to
use them correctly or will be able to provide help.
The use of interpreter-based threads in perl is officially discouraged.
Module removals¶
The following modules will be removed from the core distribution in a future
release, and will at that time need to be installed from CPAN. Distributions
on CPAN which require these modules will need to list them as prerequisites.
The core versions of these modules will now issue
"deprecated"-category warnings to alert you to this fact. To silence
these deprecation warnings, install the modules in question from CPAN.
Note that the planned removal of these modules from core does not reflect a
judgement about the quality of the code and should not be taken as a
suggestion that their use be halted. Their disinclusion from core primarily
hinges on their necessity to bootstrapping a fully functional, CPAN-capable
Perl installation, not on concerns over their design.
- CGI and its associated CGI:: packages
- inc::latest
- Package::Constants
- Module::Build and its associated Module::Build:: packages
Utility removals¶
The following utilities will be removed from the core distribution in a future
release, and will at that time need to be installed from CPAN.
- find2perl
- s2p
- a2p
- •
- Perl has a new copy-on-write mechanism that avoids the need to copy the
internal string buffer when assigning from one scalar to another. This
makes copying large strings appear much faster. Modifying one of the two
(or more) strings after an assignment will force a copy internally. This
makes it unnecessary to pass strings by reference for efficiency.
This feature was already available in 5.18.0, but wasn't enabled by default.
It is the default now, and so you no longer need build perl with the
Configure argument:
-Accflags=-DPERL_NEW_COPY_ON_WRITE
It can be disabled (for now) in a perl build with:
-Accflags=-DPERL_NO_COW
On some operating systems Perl can be compiled in such a way that any
attempt to modify string buffers shared by multiple SVs will crash. This
way XS authors can test that their modules handle copy-on-write scalars
correctly. See "Copy on Write" in perlguts for detail.
- •
- Perl has an optimizer for regular expression patterns. It analyzes the
pattern to find things such as the minimum length a string has to be to
match, etc. It now better handles code points that are above the Latin1
range.
- •
- Executing a regex that contains the "^" anchor (or its variant
under the "/m" flag) has been made much faster in several
situations.
- •
- Precomputed hash values are now used in more places during method
lookup.
- •
- Constant hash key lookups ($hash{key} as opposed to $hash{$key}) have long
had the internal hash value computed at compile time, to speed up lookup.
This optimisation has only now been applied to hash slices as well.
- •
- Combined "and" and "or" operators in void context,
like those generated for "unless ($a && $b)" and
"if ($a || b)" now short circuit directly to the end of the
statement. [perl #120128]
- •
- In certain situations, when "return" is the last statement in a
subroutine's main scope, it will be optimized out. This means code like:
sub baz { return $cat; }
will now behave like:
sub baz { $cat; }
which is notably faster.
[perl #120765]
- •
- Code like:
my $x; # or @x, %x
my $y;
is now optimized to:
my ($x, $y);
In combination with the padrange optimization introduced in v5.18.0, this
means longer uninitialized my variable statements are also optimized, so:
my $x; my @y; my %z;
becomes:
my ($x, @y, %z);
[perl #121077]
- •
- The creation of certain sorts of lists, including array and hash slices,
is now faster.
- •
- The optimisation for arrays indexed with a small constant integer is now
applied for integers in the range -128..127, rather than 0..255. This
should speed up Perl code using expressions like $x[-1], at the expense of
(presumably much rarer) code using expressions like $x[200].
- •
- The first iteration over a large hash (using "keys" or
"each") is now faster. This is achieved by preallocating the
hash's internal iterator state, rather than lazily creating it when the
hash is first iterated. (For small hashes, the iterator is still created
only when first needed. The assumption is that small hashes are more
likely to be used as objects, and therefore never allocated. For large
hashes, that's less likely to be true, and the cost of allocating the
iterator is swamped by the cost of allocating space for the hash
itself.)
- •
- When doing a global regex match on a string that came from the
"readline" or "<>" operator, the data is no
longer copied unnecessarily. [perl #121259]
- •
- Dereferencing (as in "$obj->[0]" or "$obj->{k}")
is now faster when $obj is an instance of a class that has overloaded
methods, but doesn't overload any of the dereferencing methods
"@{}", "%{}", and so on.
- •
- Perl's optimiser no longer skips optimising code that follows certain
"eval {}" expressions (including those with an apparent infinite
loop).
- •
- The implementation now does a better job of avoiding meaningless work at
runtime. Internal effect-free "null" operations (created as a
side-effect of parsing Perl programs) are normally deleted during
compilation. That deletion is now applied in some situations that weren't
previously handled.
- •
- Perl now does less disk I/O when dealing with Unicode properties that
cover up to three ranges of consecutive code points.
Modules and Pragmata¶
New Modules and Pragmata¶
- •
- experimental 0.007 has been added to the Perl core.
- •
- IO::Socket::IP 0.29 has been added to the Perl core.
Updated Modules and Pragmata¶
- •
- Archive::Tar has been upgraded from version 1.90 to 1.96.
- •
- arybase has been upgraded from version 0.06 to 0.07.
- •
- Attribute::Handlers has been upgraded from version 0.94 to 0.96.
- •
- attributes has been upgraded from version 0.21 to 0.22.
- •
- autodie has been upgraded from version 2.13 to 2.23.
- •
- AutoLoader has been upgraded from version 5.73 to 5.74.
- •
- autouse has been upgraded from version 1.07 to 1.08.
- •
- B has been upgraded from version 1.42 to 1.48.
- •
- B::Concise has been upgraded from version 0.95 to 0.992.
- •
- B::Debug has been upgraded from version 1.18 to 1.19.
- •
- B::Deparse has been upgraded from version 1.20 to 1.26.
- •
- base has been upgraded from version 2.18 to 2.22.
- •
- Benchmark has been upgraded from version 1.15 to 1.18.
- •
- bignum has been upgraded from version 0.33 to 0.37.
- •
- Carp has been upgraded from version 1.29 to 1.3301.
- •
- CGI has been upgraded from version 3.63 to 3.65. NOTE: CGI is deprecated
and may be removed from a future version of Perl.
- •
- charnames has been upgraded from version 1.36 to 1.40.
- •
- Class::Struct has been upgraded from version 0.64 to 0.65.
- •
- Compress::Raw::Bzip2 has been upgraded from version 2.060 to 2.064.
- •
- Compress::Raw::Zlib has been upgraded from version 2.060 to 2.065.
- •
- Config::Perl::V has been upgraded from version 0.17 to 0.20.
- •
- constant has been upgraded from version 1.27 to 1.31.
- •
- CPAN has been upgraded from version 2.00 to 2.05.
- •
- CPAN::Meta has been upgraded from version 2.120921 to 2.140640.
- •
- CPAN::Meta::Requirements has been upgraded from version 2.122 to
2.125.
- •
- CPAN::Meta::YAML has been upgraded from version 0.008 to 0.012.
- •
- Data::Dumper has been upgraded from version 2.145 to 2.151.
- •
- DB has been upgraded from version 1.04 to 1.07.
- •
- DB_File has been upgraded from version 1.827 to 1.831.
- •
- DBM_Filter has been upgraded from version 0.05 to 0.06.
- •
- deprecate has been upgraded from version 0.02 to 0.03.
- •
- Devel::Peek has been upgraded from version 1.11 to 1.16.
- •
- Devel::PPPort has been upgraded from version 3.20 to 3.21.
- •
- diagnostics has been upgraded from version 1.31 to 1.34.
- •
- Digest::MD5 has been upgraded from version 2.52 to 2.53.
- •
- Digest::SHA has been upgraded from version 5.84 to 5.88.
- •
- DynaLoader has been upgraded from version 1.18 to 1.25.
- •
- Encode has been upgraded from version 2.49 to 2.60.
- •
- encoding has been upgraded from version 2.6_01 to 2.12.
- •
- English has been upgraded from version 1.06 to 1.09.
- •
- Errno has been upgraded from version 1.18 to 1.20_03.
- •
- Exporter has been upgraded from version 5.68 to 5.70.
- •
- ExtUtils::CBuilder has been upgraded from version 0.280210 to
0.280216.
- •
- ExtUtils::Command has been upgraded from version 1.17 to 1.18.
- •
- ExtUtils::Embed has been upgraded from version 1.30 to 1.32.
- •
- ExtUtils::Install has been upgraded from version 1.59 to 1.67.
- •
- ExtUtils::MakeMaker has been upgraded from version 6.66 to 6.98.
- •
- ExtUtils::Miniperl has been upgraded from version to 1.01.
- •
- ExtUtils::ParseXS has been upgraded from version 3.18 to 3.24.
- •
- ExtUtils::Typemaps has been upgraded from version 3.19 to 3.24.
- •
- ExtUtils::XSSymSet has been upgraded from version 1.2 to 1.3.
- •
- feature has been upgraded from version 1.32 to 1.36.
- •
- fields has been upgraded from version 2.16 to 2.17.
- •
- File::Basename has been upgraded from version 2.84 to 2.85.
- •
- File::Copy has been upgraded from version 2.26 to 2.29.
- •
- File::DosGlob has been upgraded from version 1.10 to 1.12.
- •
- File::Fetch has been upgraded from version 0.38 to 0.48.
- •
- File::Find has been upgraded from version 1.23 to 1.27.
- •
- File::Glob has been upgraded from version 1.20 to 1.23.
- •
- File::Spec has been upgraded from version 3.40 to 3.47.
- •
- File::Temp has been upgraded from version 0.23 to 0.2304.
- •
- FileCache has been upgraded from version 1.08 to 1.09.
- •
- Filter::Simple has been upgraded from version 0.89 to 0.91.
- •
- Filter::Util::Call has been upgraded from version 1.45 to 1.49.
- •
- Getopt::Long has been upgraded from version 2.39 to 2.42.
- •
- Getopt::Std has been upgraded from version 1.07 to 1.10.
- •
- Hash::Util::FieldHash has been upgraded from version 1.10 to 1.15.
- •
- HTTP::Tiny has been upgraded from version 0.025 to 0.043.
- •
- I18N::Langinfo has been upgraded from version 0.10 to 0.11.
- •
- I18N::LangTags has been upgraded from version 0.39 to 0.40.
- •
- if has been upgraded from version 0.0602 to 0.0603.
- •
- inc::latest has been upgraded from version 0.4003 to 0.4205. NOTE:
inc::latest is deprecated and may be removed from a future version of
Perl.
- •
- integer has been upgraded from version 1.00 to 1.01.
- •
- IO has been upgraded from version 1.28 to 1.31.
- •
- IO::Compress::Gzip and friends have been upgraded from version 2.060 to
2.064.
- •
- IPC::Cmd has been upgraded from version 0.80 to 0.92.
- •
- IPC::Open3 has been upgraded from version 1.13 to 1.16.
- •
- IPC::SysV has been upgraded from version 2.03 to 2.04.
- •
- JSON::PP has been upgraded from version 2.27202 to 2.27203.
- •
- List::Util has been upgraded from version 1.27 to 1.38.
- •
- locale has been upgraded from version 1.02 to 1.03.
- •
- Locale::Codes has been upgraded from version 3.25 to 3.30.
- •
- Locale::Maketext has been upgraded from version 1.23 to 1.25.
- •
- Math::BigInt has been upgraded from version 1.9991 to 1.9993.
- •
- Math::BigInt::FastCalc has been upgraded from version 0.30 to 0.31.
- •
- Math::BigRat has been upgraded from version 0.2604 to 0.2606.
- •
- MIME::Base64 has been upgraded from version 3.13 to 3.14.
- •
- Module::Build has been upgraded from version 0.4003 to 0.4205. NOTE:
Module::Build is deprecated and may be removed from a future version of
Perl.
- •
- Module::CoreList has been upgraded from version 2.89 to 3.10.
- •
- Module::Load has been upgraded from version 0.24 to 0.32.
- •
- Module::Load::Conditional has been upgraded from version 0.54 to
0.62.
- •
- Module::Metadata has been upgraded from version 1.000011 to 1.000019.
- •
- mro has been upgraded from version 1.11 to 1.16.
- •
- Net::Ping has been upgraded from version 2.41 to 2.43.
- •
- Opcode has been upgraded from version 1.25 to 1.27.
- •
- Package::Constants has been upgraded from version 0.02 to 0.04. NOTE:
Package::Constants is deprecated and may be removed from a future version
of Perl.
- •
- Params::Check has been upgraded from version 0.36 to 0.38.
- •
- parent has been upgraded from version 0.225 to 0.228.
- •
- Parse::CPAN::Meta has been upgraded from version 1.4404 to 1.4414.
- •
- Perl::OSType has been upgraded from version 1.003 to 1.007.
- •
- perlfaq has been upgraded from version 5.0150042 to 5.0150044.
- •
- PerlIO has been upgraded from version 1.07 to 1.09.
- •
- PerlIO::encoding has been upgraded from version 0.16 to 0.18.
- •
- PerlIO::scalar has been upgraded from version 0.16 to 0.18.
- •
- PerlIO::via has been upgraded from version 0.12 to 0.14.
- •
- Pod::Escapes has been upgraded from version 1.04 to 1.06.
- •
- Pod::Functions has been upgraded from version 1.06 to 1.08.
- •
- Pod::Html has been upgraded from version 1.18 to 1.21.
- •
- Pod::Parser has been upgraded from version 1.60 to 1.62.
- •
- Pod::Perldoc has been upgraded from version 3.19 to 3.23.
- •
- Pod::Usage has been upgraded from version 1.61 to 1.63.
- •
- POSIX has been upgraded from version 1.32 to 1.38_03.
- •
- re has been upgraded from version 0.23 to 0.26.
- •
- Safe has been upgraded from version 2.35 to 2.37.
- •
- Scalar::Util has been upgraded from version 1.27 to 1.38.
- •
- SDBM_File has been upgraded from version 1.09 to 1.11.
- •
- Socket has been upgraded from version 2.009 to 2.013.
- •
- Storable has been upgraded from version 2.41 to 2.49.
- •
- strict has been upgraded from version 1.07 to 1.08.
- •
- subs has been upgraded from version 1.01 to 1.02.
- •
- Sys::Hostname has been upgraded from version 1.17 to 1.18.
- •
- Sys::Syslog has been upgraded from version 0.32 to 0.33.
- •
- Term::Cap has been upgraded from version 1.13 to 1.15.
- •
- Term::ReadLine has been upgraded from version 1.12 to 1.14.
- •
- Test::Harness has been upgraded from version 3.26 to 3.30.
- •
- Test::Simple has been upgraded from version 0.98 to 1.001002.
- •
- Text::ParseWords has been upgraded from version 3.28 to 3.29.
- •
- Text::Tabs has been upgraded from version 2012.0818 to 2013.0523.
- •
- Text::Wrap has been upgraded from version 2012.0818 to 2013.0523.
- •
- Thread has been upgraded from version 3.02 to 3.04.
- •
- Thread::Queue has been upgraded from version 3.02 to 3.05.
- •
- threads has been upgraded from version 1.86 to 1.93.
- •
- threads::shared has been upgraded from version 1.43 to 1.46.
- •
- Tie::Array has been upgraded from version 1.05 to 1.06.
- •
- Tie::File has been upgraded from version 0.99 to 1.00.
- •
- Tie::Hash has been upgraded from version 1.04 to 1.05.
- •
- Tie::Scalar has been upgraded from version 1.02 to 1.03.
- •
- Tie::StdHandle has been upgraded from version 4.3 to 4.4.
- •
- Time::HiRes has been upgraded from version 1.9725 to 1.9726.
- •
- Time::Piece has been upgraded from version 1.20_01 to 1.27.
- •
- Unicode::Collate has been upgraded from version 0.97 to 1.04.
- •
- Unicode::Normalize has been upgraded from version 1.16 to 1.17.
- •
- Unicode::UCD has been upgraded from version 0.51 to 0.57.
- •
- utf8 has been upgraded from version 1.10 to 1.13.
- •
- version has been upgraded from version 0.9902 to 0.9908.
- •
- vmsish has been upgraded from version 1.03 to 1.04.
- •
- warnings has been upgraded from version 1.18 to 1.23.
- •
- Win32 has been upgraded from version 0.47 to 0.49.
- •
- XS::Typemap has been upgraded from version 0.10 to 0.13.
- •
- XSLoader has been upgraded from version 0.16 to 0.17.
Documentation¶
New Documentation¶
perlrepository
This document was removed (actually, renamed perlgit and given a major overhaul)
in Perl v5.14, causing Perl documentation websites to show the now out of date
version in Perl v5.12 as the latest version. It has now been restored in stub
form, directing readers to current information.
Changes to Existing Documentation¶
perldata
- •
- New sections have been added to document the new index/value array slice
and key/value hash slice syntax.
perldebguts
- •
- The "DB::goto" and "DB::lsub" debugger subroutines are
now documented. [perl #77680]
perlexperiment
- •
- "\s" matching "\cK" is marked experimental.
- •
- ithreads were accepted in v5.8.0 (but are discouraged as of v5.20.0).
- •
- Long doubles are not considered experimental.
- •
- Code in regular expressions, regular expression backtracking verbs, and
lvalue subroutines are no longer listed as experimental. (This also
affects perlre and perlsub.)
perlfunc
- •
- "chop" and "chomp" now note that they can reset the
hash iterator.
- •
- "exec"'s handling of arguments is now more clearly
documented.
- •
- "eval EXPR" now has caveats about expanding floating point
numbers in some locales.
- •
- "goto EXPR" is now documented to handle an expression that
evalutes to a code reference as if it was "goto &$coderef".
This behavior is at least ten years old.
- •
- Since Perl v5.10, it has been possible for subroutines in @INC to return a
reference to a scalar holding initial source code to prepend to the file.
This is now documented.
- •
- The documentation of "ref" has been updated to recommend the use
of "blessed", "isa" and "reftype" when
dealing with references to blessed objects.
perlguts
- •
- Numerous minor changes have been made to reflect changes made to the perl
internals in this release.
- •
- New sections on Read-Only Values and Copy on Write have been added.
perlhack
- •
- The Super Quick Patch Guide section has been updated.
perlhacktips
- •
- The documentation has been updated to include some more examples of
"gdb" usage.
perllexwarn
- •
- The perllexwarn documentation used to describe the hierarchy of warning
categories understood by the warnings pragma. That description has now
been moved to the warnings documentation itself, leaving perllexwarn as a
stub that points to it. This change consolidates all documentation for
lexical warnings in a single place.
perllocale
- •
- The documentation now mentions fc() and
"\F", and includes many clarifications and corrections in
general.
perlop
- •
- The language design of Perl has always called for monomorphic operators.
This is now mentioned explicitly.
perlopentut
- •
- The "open" tutorial has been completely rewritten by Tom
Christiansen, and now focuses on covering only the basics, rather than
providing a comprehensive reference to all things openable. This rewrite
came as the result of a vigorous discussion on perl5-porters kicked off by
a set of improvements written by Alexander Hartmaier to the existing
perlopentut. A "more than you ever wanted to know about
"open"" document may follow in subsequent versions of
perl.
perlre
- •
- The fact that the regexp engine makes no effort to call (?{}) and (??{})
constructs any specified number of times (although it will basically DWIM
in case of a successful match) has been documented.
- •
- The "/r" modifier (for non-destructive substitution) is now
documented. [perl #119151]
- •
- The documentation for "/x" and "(?# comment)" has been
expanded and clarified.
perlreguts
- •
- The documentation has been updated in the light of recent changes to
regcomp.c.
perlsub
- •
- The need to predeclare recursive functions with prototypes in order for
the prototype to be honoured in the recursive call is now documented.
[perl #2726]
- •
- A list of subroutine names used by the perl implementation is now
included. [perl #77680]
perltrap
- •
- There is now a JavaScript section.
perlunicode
- •
- The documentation has been updated to reflect "Bidi_Class"
changes in Unicode 6.3.
perlvar
- •
- A new section explaining the performance issues of $`, $& and $',
including workarounds and changes in different versions of Perl, has been
added.
- •
- Three English variable names which have long been documented but do not
actually exist have been removed from the documentation. These were
$OLD_PERL_VERSION, $OFMT, and $ARRAY_BASE.
perlxs
- •
- Several problems in the "MY_CXT" example have been fixed.
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¶
New Errors
- •
- delete argument is index/value array slice, use array slice
(F) You used index/value array slice syntax (%array[...]) as the argument to
"delete". You probably meant @array[...] with an @ symbol
instead.
- •
- delete argument is key/value hash slice, use hash slice
(F) You used key/value hash slice syntax (%hash{...}) as the argument to
"delete". You probably meant @hash{...} with an @ symbol
instead.
- •
- Magical list constants are not supported
(F) You assigned a magical array to a stash element, and then tried to use
the subroutine from the same slot. You are asking Perl to do something it
cannot do, details subject to change between Perl versions.
- •
- Added Setting $/ to a %s reference is forbidden
New Warnings
- •
- %s on reference is experimental:
The "auto-deref" feature is experimental.
Starting in v5.14.0, it was possible to use push, pop, keys, and other
built-in functions not only on aggregate types, but on references to them.
The feature was not deployed to its original intended specification, and
now may become redundant to postfix dereferencing. It has always been
categorized as an experimental feature, and in v5.20.0 is carries a
warning as such.
Warnings will now be issued at compile time when these operations are
detected.
no if $] >= 5.01908, warnings => "experimental::autoderef";
Consider, though, replacing the use of these features, as they may change
behavior again before becoming stable.
- •
- A sequence of multiple spaces in a charnames alias definition is
deprecated
Trailing white-space in a charnames alias definition is deprecated
These two deprecation warnings involving "\N{...}" were
incorrectly implemented. They did not warn by default (now they do) and
could not be made fatal via "use warnings FATAL =>
'deprecated'" (now they can).
- •
- Attribute prototype(%s) discards earlier prototype attribute in same sub
(W misc) A sub was declared as "sub foo : prototype(A) : prototype(B)
{}", for example. Since each sub can only have one prototype, the
earlier declaration(s) are discarded while the last one is applied.
- •
- Invalid \0 character in %s for %s: %s\0%s
(W syscalls) Embedded \0 characters in pathnames or other system call
arguments produce a warning as of 5.20. The parts after the \0 were
formerly ignored by system calls.
- •
- Matched non-Unicode code point 0x%X against Unicode property; may not be
portable.
This replaces the message "Code point 0x%X is not Unicode, all \p{}
matches fail; all \P{} matches succeed".
- •
- Missing ']' in prototype for %s : %s
(W illegalproto) A grouping was started with "[" but never closed
with "]".
- •
- Possible precedence issue with control flow operator
(W syntax) There is a possible problem with the mixing of a control flow
operator (e.g. "return") and a low-precedence operator like
"or". Consider:
sub { return $a or $b; }
This is parsed as:
sub { (return $a) or $b; }
Which is effectively just:
sub { return $a; }
Either use parentheses or the high-precedence variant of the operator.
Note this may be also triggered for constructs like:
sub { 1 if die; }
- •
- Postfix dereference is experimental
(S experimental::postderef) This warning is emitted if you use the
experimental postfix dereference syntax. Simply suppress the warning if
you want to use the feature, but know that in doing so you are taking the
risk of using an experimental feature which may change or be removed in a
future Perl version:
no warnings "experimental::postderef";
use feature "postderef", "postderef_qq";
$ref->$*;
$aref->@*;
$aref->@[@indices];
... etc ...
- •
- Prototype '%s' overridden by attribute 'prototype(%s)' in %s
(W prototype) A prototype was declared in both the parentheses after the sub
name and via the prototype attribute. The prototype in parentheses is
useless, since it will be replaced by the prototype from the attribute
before it's ever used.
- •
- Scalar value @%s[%s] better written as $%s[%s]
(W syntax) In scalar context, you've used an array index/value slice
(indicated by %) to select a single element of an array. Generally it's
better to ask for a scalar value (indicated by $). The difference is that
$foo[&bar] always behaves like a scalar, both in the value it returns
and when evaluating its argument, while %foo[&bar] provides a list
context to its subscript, which can do weird things if you're expecting
only one subscript. When called in list context, it also returns the index
(what &bar returns) in addition to the value.
- •
- Scalar value @%s{%s} better written as $%s{%s}
(W syntax) In scalar context, you've used a hash key/value slice (indicated
by %) to select a single element of a hash. Generally it's better to ask
for a scalar value (indicated by $). The difference is that $foo{&bar}
always behaves like a scalar, both in the value it returns and when
evaluating its argument, while @foo{&bar} and provides a list context
to its subscript, which can do weird things if you're expecting only one
subscript. When called in list context, it also returns the key in
addition to the value.
- •
- Setting $/ to a reference to %s as a form of slurp is deprecated, treating
as undef
- •
- Unexpected exit %u
(S) exit() was called or the script otherwise finished gracefully
when "PERL_EXIT_WARN" was set in "PL_exit_flags".
- •
- Unexpected exit failure %d
(S) An uncaught die() was called when "PERL_EXIT_WARN" was
set in "PL_exit_flags".
- •
- Use of literal control characters in variable names is deprecated
(D deprecated) Using literal control characters in the source to refer to
the ^FOO variables, like $^X and ${^GLOBAL_PHASE} is now deprecated. This
only affects code like $\cT, where \cT is a control (like a
"SOH") in the source code: ${"\cT"} and $^T remain
valid.
- •
- Useless use of greediness modifier
This fixes [Perl #42957].
Changes to Existing Diagnostics¶
- •
- Warnings and errors from the regexp engine are now UTF-8 clean.
- •
- The "Unknown switch condition" error message has some slight
changes. This error triggers when there is an unknown condition in a
"(?(foo))" conditional. The error message used to read:
Unknown switch condition (?(%s in regex;
But what %s could be was mostly up to luck. For "(?(foobar))", you
might have seen "fo" or "f". For Unicode characters,
you would generally get a corrupted string. The message has been changed
to read:
Unknown switch condition (?(...)) in regex;
Additionally, the '<-- HERE' marker in the error will now point to the
correct spot in the regex.
- •
- The "%s "\x%X" does not map to Unicode" warning is now
correctly listed as a severe warning rather than as a fatal error.
- •
- Under rare circumstances, one could get a "Can't coerce readonly REF
to string" instead of the customary "Modification of a read-only
value". This alternate error message has been removed.
- •
- "Ambiguous use of * resolved as operator *": This and similar
warnings about "%" and "&" used to occur in some
circumstances where there was no operator of the type cited, so the
warning was completely wrong. This has been fixed [perl #117535,
#76910].
- •
- Warnings about malformed subroutine prototypes are now more consistent in
how the prototypes are rendered. Some of these warnings would truncate
prototypes containing nulls. In other cases one warning would suppress
another. The warning about illegal characters in prototypes no longer says
"after '_'" if the bad character came before the
underscore.
- •
- Perl folding rules are not up-to-date for 0x%X; please use the perlbug
utility to report; in regex; marked by <-- HERE in m/%s/
This message is now only in the regexp category, and not in the deprecated
category. It is still a default (i.e., severe) warning [perl #89648].
- •
- %%s[%s] in scalar context better written as $%s[%s]
This warning now occurs for any %array[$index] or %hash{key} known to be in
scalar context at compile time. Previously it was worded "Scalar
value %%s[%s] better written as $%s[%s]".
- •
- Switch condition not recognized in regex; marked by <-- HERE in m/%s/:
The description for this diagnostic has been extended to cover all cases
where the warning may occur. Issues with the positioning of the arrow
indicator have also been resolved.
- •
- The error messages for "my($a?$b$c)" and "my(do{})"
now mention "conditional expression" and "do block",
respectively, instead of reading 'Can't declare null operation in
"my"'.
- •
- When "use re "debug"" executes a regex containing a
backreference, the debugging output now shows what string is being
matched.
- •
- The now fatal error message "Character following "\c" must
be ASCII" has been reworded as "Character following
"\c" must be printable ASCII" to emphasize that in "\c
X", X must be a printable (non-control) ASCII
character.
Utility Changes¶
a2p
- •
- A possible crash from an off-by-one error when trying to access before the
beginning of a buffer has been fixed. [perl #120244]
bisect.pl
The git bisection tool
Porting/bisect.pl has had many enhancements.
It is provided as part of the source distribution but not installed because it
is not self-contained as it relies on being run from within a git checkout.
Note also that it makes no attempt to fix tests, correct runtime bugs or make
something useful to install - its purpose is to make minimal changes to get
any historical revision of interest to build and run as close as possible to
"as-was", and thereby make "git bisect" easy to use.
- •
- Can optionally run the test case with a timeout.
- •
- Can now run in-place in a clean git checkout.
- •
- Can run the test case under "valgrind".
- •
- Can apply user supplied patches and fixes to the source checkout before
building.
- •
- Now has fixups to enable building several more historical ranges of
bleadperl, which can be useful for pinpointing the origins of bugs or
behaviour changes.
find2perl
- •
- find2perl now handles "?" wildcards correctly. [perl
#113054]
perlbug
- •
- perlbug now has a "-p" option for attaching patches with
a bug report.
- •
- perlbug has been modified to supply the report template with CRLF line
endings on Windows. [perl #121277
<https://rt.perl.org/Public/Bug/Display.html?id=121277>]
- •
- perlbug now makes as few assumptions as possible about the encoding of the
report. This will likely change in the future to assume UTF-8 by default
but allow a user override.
Configuration and Compilation¶
- •
- The Makefile.PL for SDBM_File now generates a better
Makefile, which avoids a race condition during parallel makes,
which could cause the build to fail. This is the last known parallel make
problem (on *nix platforms), and therefore we believe that a parallel make
should now always be error free.
- •
- installperl and installman's option handling has been
refactored to use Getopt::Long. Both are used by the Makefile
"install" targets, and are not installed, so these changes are
only likely to affect custom installation scripts.
- •
- Single letter options now also have long names.
- •
- Invalid options are now rejected.
- •
- Command line arguments that are not options are now rejected.
- •
- Each now has a "--help" option to display the usage
message.
The behaviour for all valid documented invocations is unchanged.
- •
- Where possible, the build now avoids recursive invocations of make
when building pure-Perl extensions, without removing any parallelism from
the build. Currently around 80 extensions can be processed directly by the
make_ext.pl tool, meaning that 80 invocations of make and
160 invocations of miniperl are no longer made.
- •
- The build system now works correctly when compiling under GCC or Clang
with link-time optimization enabled (the "-flto" option). [perl
#113022]
- •
- Distinct library basenames with "d_libname_unique".
When compiling perl with this option, the library files for XS modules are
named something "unique" -- for example, Hash/Util/Util.so
becomes Hash/Util/PL_Hash__Util.so. This behavior is similar to what
currently happens on VMS, and serves as groundwork for the Android
port.
- •
- "sysroot" option to indicate the logical root directory under
gcc and clang.
When building with this option set, both Configure and the compilers search
for all headers and libraries under this new sysroot, instead of /.
This is a huge time saver if cross-compiling, but can also help on native
builds if your toolchain's files have non-standard locations.
- •
- The cross-compilation model has been renovated. There's several new
options, and some backwards-incompatible changes:
We now build binaries for miniperl and generate_uudmap to be used on the
host, rather than running every miniperl call on the target; this means
that, short of 'make test', we no longer need access to the target system
once Configure is done. You can provide already-built binaries through the
"hostperl" and "hostgenerate" options to Configure.
Additionally, if targeting an EBCDIC platform from an ASCII host, or
viceversa, you'll need to run Configure with "-Uhostgenerate",
to indicate that generate_uudmap should be run on the target.
Finally, there's also a way of having Configure end early, right after
building the host binaries, by cross-compiling without specifying a
"targethost".
The incompatible changes include no longer using xconfig.h, xlib, or
Cross.pm, so canned config files and Makefiles will have to be
updated.
- •
- Related to the above, there is now a way of specifying the location of sh
(or equivalent) on the target system: "targetsh".
For example, Android has its sh in /system/bin/sh, so if cross-compiling
from a more normal Unixy system with sh in /bin/sh, "targetsh"
would end up as /system/bin/sh, and "sh" as /bin/sh.
- •
- By default, gcc 4.9 does some optimizations that break perl. The
-fwrapv option disables those optimizations (and probably others),
so for gcc 4.3 and later (since the there might be similar problems
lurking on older versions too, but -fwrapv was broken before 4.3,
and the optimizations probably won't go away), Configure now adds
-fwrapv unless the user requests -fno-wrapv, which disables
-fwrapv, or -fsanitize=undefined, which turns the overflows
-fwrapv ignores into runtime errors. [perl #121505
<https://rt.perl.org/Public/Bug/Display.html?id=121505>]
Testing¶
- •
- The "test.valgrind" make target now allows tests to be run in
parallel. This target allows Perl's test suite to be run under Valgrind,
which detects certain sorts of C programming errors, though at significant
cost in running time. On suitable hardware, allowing parallel execution
claws back a lot of that additional cost. [perl #121431]
- •
- Various tests in t/porting/ are no longer skipped when the perl
.git directory is outside the perl tree and pointed to by $GIT_DIR.
[perl #120505]
- •
- The test suite no longer fails when the user's interactive shell maintains
a $PWD environment variable, but the /bin/sh used for running tests
doesn't.
- Android
- Perl can now be built for Android, either natively or through
cross-compilation, for all three currently available architectures (ARM,
MIPS, and x86), on a wide range of versions.
- Bitrig
- Compile support has been added for Bitrig, a fork of OpenBSD.
- FreeMiNT
- Support has been added for FreeMiNT, a free open-source OS for the Atari
ST system and its successors, based on the original MiNT that was
officially adopted by Atari.
- Synology
- Synology ships its NAS boxes with a lean Linux distribution (DSM) on
relative cheap CPU's (like the Marvell Kirkwood mv6282 - ARMv5tel or
Freescale QorIQ P1022 ppc - e500v2) not meant for workstations or
development. These boxes should build now. The basic problems are the
non-standard location for tools.
- "sfio"
- Code related to supporting the "sfio" I/O system has been
removed.
Perl 5.004 added support to use the native API of "sfio",
AT&T's Safe/Fast I/O library. This code still built with v5.8.0,
albeit with many regression tests failing, but was inadvertently broken
before the v5.8.1 release, meaning that it has not worked on any version
of Perl released since then. In over a decade we have received no bug
reports about this, hence it is clear that no-one is using this
functionality on any version of Perl that is still supported to any
degree.
- AT&T 3b1
- Configure support for the 3b1, also known as the AT&T Unix PC (and the
similar AT&T 7300), has been removed.
- DG/UX
- DG/UX was a Unix sold by Data General. The last release was in April 2001.
It only runs on Data General's own hardware.
- EBCDIC
- In the absence of a regular source of smoke reports, code intended to
support native EBCDIC platforms will be removed from perl before
5.22.0.
- Cygwin
- •
- recv() on a connected handle would populate the returned sender
address with whatever happened to be in the working buffer. recv()
now uses a workaround similar to the Win32 recv() wrapper and
returns an empty string when recvfrom(2) doesn't modify the
supplied address length. [perl #118843]
- •
- Fixed a build error in cygwin.c on Cygwin 1.7.28.
Tests now handle the errors that occur when "cygserver" isn't
running.
- GNU/Hurd
- The BSD compatibility library "libbsd" is no longer required for
builds.
- Linux
- The hints file now looks for "libgdbm_compat" only if
"libgdbm" itself is also wanted. The former is never useful
without the latter, and in some circumstances, including it could actually
prevent building.
- Mac OS
- The build system now honors an "ld" setting supplied by the user
running Configure.
- MidnightBSD
- "objformat" was removed from version 0.4-RELEASE of MidnightBSD
and had been deprecated on earlier versions. This caused the build
environment to be erroneously configured for "a.out" rather than
"elf". This has been now been corrected.
- Mixed-endian platforms
- The code supporting "pack" and "unpack" operations on
mixed endian platforms has been removed. We believe that Perl has long
been unable to build on mixed endian architectures (such as PDP-11s), so
we don't think that this change will affect any platforms which were able
to build v5.18.0.
- VMS
- •
- The "PERL_ENV_TABLES" feature to control the population of %ENV
at perl start-up was broken in Perl 5.16.0 but has now been fixed.
- •
- Skip access checks on remotes in opendir(). [perl #121002]
- •
- A check for glob metacharacters in a path returned by the
"glob()" operator has been replaced with a check for VMS
wildcard characters. This saves a significant number of unnecessary
"lstat()" calls such that some simple glob operations become
60-80% faster.
- Win32
- •
- "rename" and "link" on Win32 now set $! to ENOSPC and
EDQUOT when appropriate. [perl #119857]
- •
- The BUILD_STATIC and ALL_STATIC makefile options for linking some or
(nearly) all extensions statically (into perl520.dll, and into a separate
perl-static.exe too) were broken for MinGW builds. This has now been
fixed.
The ALL_STATIC option has also been improved to include the Encode and Win32
extensions (for both VC++ and MinGW builds).
- •
- Support for building with Visual C++ 2013 has been added. There are
currently two possible test failures (see "Testing Perl on
Windows" in perlwin32) which will hopefully be resolved soon.
- •
- Experimental support for building with Intel C++ Compiler has been added.
The nmake makefile (win32/Makefile) and the dmake makefile
(win32/makefile.mk) can be used. A "nmake test" will not pass at
this time due to cpan/CGI/t/url.t.
- •
- Killing a process tree with "kill" in perlfunc and a negative
signal, was broken starting in 5.18.0. In this bug, "kill"
always returned 0 for a negative signal even for valid PIDs, and no
processes were terminated. This has been fixed [perl #121230].
- •
- The time taken to build perl on Windows has been reduced quite
significantly (time savings in the region of 30-40% are typically seen) by
reducing the number of, usually failing, I/O calls for each
"require()" (for miniperl.exe only). [perl #121119
<https://rt.perl.org/Public/Bug/Display.html?id=121119>]
- •
- About 15 minutes of idle sleeping was removed from running "make
test" due to a bug in which the timeout monitor used for tests could
not be cancelled once the test completes, and the full timeout period
elapsed before running the next test file. [perl #121395
<https://rt.perl.org/Public/Bug/Display.html?id=121395>]
- •
- On a perl built without pseudo-fork (pseudo-fork builds were not affected
by this bug), killing a process tree with "kill()" and a
negative signal resulted in "kill()" inverting the returned
value. For example, if "kill()" killed 1 process tree PID then
it returned 0 instead of 1, and if "kill()" was passed 2 invalid
PIDs then it returned 2 instead of 0. This has probably been the case
since the process tree kill feature was implemented on Win32. It has now
been corrected to follow the documented behaviour. [perl #121230
<https://rt.perl.org/Public/Bug/Display.html?id=121230>]
- •
- When building a 64-bit perl, an uninitialized memory read in
miniperl.exe, used during the build process, could lead to a 4GB
wperl.exe being created. This has now been fixed. (Note that
perl.exe itself was unaffected, but obviously wperl.exe
would have been completely broken.) [perl #121471
<https://rt.perl.org/Public/Bug/Display.html?id=121471>]
- •
- Perl can now be built with gcc version 4.8.1 from
<http://www.mingw.org>. This was previously broken due to an
incorrect definition of DllMain() in one of perl's source files.
Earlier gcc versions were also affected when using version 4 of the
w32api package. Versions of gcc available from
<http://mingw-w64.sourceforge.net/> were not affected. [perl #121643
<https://rt.perl.org/Public/Bug/Display.html?id=121643>]
- •
- The test harness now has no failures when perl is built on a FAT drive
with the Windows OS on an NTFS drive. [perl #21442
<https://rt.perl.org/Public/Bug/Display.html?id=21442>]
- •
- When cloning the context stack in fork() emulation,
Perl_cx_dup() would crash accessing parameter information for
context stack entries that included no parameters, as with
"&foo;". [perl #121721
<https://rt.perl.org/Public/Bug/Display.html?id=121721>]
- •
- Introduced by perl #113536
<https://rt.perl.org/Public/Bug/Display.html?id=113536>, a memory
leak on every call to "system" and backticks (" `` "),
on most Win32 Perls starting from 5.18.0 has been fixed. The memory leak
only occurred if you enabled psuedo-fork in your build of Win32 Perl, and
were running that build on Server 2003 R2 or newer OS. The leak does not
appear on WinXP SP3. [perl #121676
<https://rt.perl.org/Public/Bug/Display.html?id=121676>]
- WinCE
- •
- The building of XS modules has largely been restored. Several still cannot
(yet) be built but it is now possible to build Perl on WinCE with only a
couple of further patches (to Socket and ExtUtils::MakeMaker), hopefully
to be incorporated soon.
- •
- Perl can now be built in one shot with no user intervention on WinCE by
running "nmake -f Makefile.ce all".
Support for building with EVC (Embedded Visual C++) 4 has been restored.
Perl can also be built using Smart Devices for Visual C++ 2005 or
2008.
Internal Changes¶
- •
- The internal representation has changed for the match variables $1, $2
etc., $`, $&, $', ${^PREMATCH}, ${^MATCH} and ${^POSTMATCH}. It uses
slightly less memory, avoids string comparisons and numeric conversions
during lookup, and uses 23 fewer lines of C. This change should not affect
any external code.
- •
- Arrays now use NULL internally to represent unused slots, instead of
&PL_sv_undef. &PL_sv_undef is no longer treated as a special
value, so av_store(av, 0, &PL_sv_undef) will cause element 0 of that
array to hold a read-only undefined scalar. "$array[0] =
anything" will croak and "\$array[0]" will compare equal to
"\undef".
- •
- The SV returned by HeSVKEY_force() now correctly reflects the
UTF8ness of the underlying hash key when that key is not stored as a SV.
[perl #79074]
- •
- Certain rarely used functions and macros available to XS code are now
deprecated. These are: "utf8_to_uvuni_buf" (use
"utf8_to_uvchr_buf" instead), "valid_utf8_to_uvuni"
(use "utf8_to_uvchr_buf" instead), "NATIVE_TO_NEED"
(this did not work properly anyway), and "ASCII_TO_NEED" (this
did not work properly anyway).
Starting in this release, almost never does application code need to
distinguish between the platform's character set and Latin1, on which the
lowest 256 characters of Unicode are based. New code should not use
"utf8n_to_uvuni" (use "utf8_to_uvchr_buf" instead),
nor "uvuni_to_utf8" (use "uvchr_to_utf8"
instead),
- •
- The Makefile shortcut targets for many rarely (or never) used testing and
profiling targets have been removed, or merged into the only other
Makefile target that uses them. Specifically, these targets are gone,
along with documentation that referenced them or explained how to use
them:
check.third check.utf16 check.utf8 coretest minitest.prep
minitest.utf16 perl.config.dashg perl.config.dashpg
perl.config.gcov perl.gcov perl.gprof perl.gprof.config
perl.pixie perl.pixie.atom perl.pixie.config perl.pixie.irix
perl.third perl.third.config perl.valgrind.config purecovperl
pureperl quantperl test.deparse test.taintwarn test.third
test.torture test.utf16 test.utf8 test_notty.deparse
test_notty.third test_notty.valgrind test_prep.third
test_prep.valgrind torturetest ucheck ucheck.third ucheck.utf16
ucheck.valgrind utest utest.third utest.utf16 utest.valgrind
It's still possible to run the relevant commands by "hand" - no
underlying functionality has been removed.
- •
- It is now possible to keep Perl from initializing locale handling. For the
most part, Perl doesn't pay attention to locale. (See perllocale.)
Nonetheless, until now, on startup, it has always initialized locale
handling to the system default, just in case the program being executed
ends up using locales. (This is one of the first things a locale-aware
program should do, long before Perl knows if it will actually be needed or
not.) This works well except when Perl is embedded in another application
which wants a locale that isn't the system default. Now, if the
environment variable "PERL_SKIP_LOCALE_INIT" is set at the time
Perl is started, this initialization step is skipped. Prior to this, on
Windows platforms, the only workaround for this deficiency was to use a
hacked-up copy of internal Perl code. Applications that need to use older
Perls can discover if the embedded Perl they are using needs the
workaround by testing that the C preprocessor symbol
"HAS_SKIP_LOCALE_INIT" is not defined. [RT #38193]
- •
- "BmRARE" and "BmPREVIOUS" have been removed. They were
not used anywhere and are not part of the API. For XS modules, they are
now #defined as 0.
- •
- "sv_force_normal", which usually croaks on read-only values,
used to allow read-only values to be modified at compile time. This has
been changed to croak on read-only values regardless. This change
uncovered several core bugs.
- •
- Perl's new copy-on-write mechanism (which is now enabled by default),
allows any "SvPOK" scalar to be automatically upgraded to a
copy-on-write scalar when copied. A reference count on the string buffer
is stored in the string buffer itself.
For example:
$ perl -MDevel::Peek -e'$a="abc"; $b = $a; Dump $a; Dump $b'
SV = PV(0x260cd80) at 0x2620ad8
REFCNT = 1
FLAGS = (POK,IsCOW,pPOK)
PV = 0x2619bc0 "abc"\0
CUR = 3
LEN = 16
COW_REFCNT = 1
SV = PV(0x260ce30) at 0x2620b20
REFCNT = 1
FLAGS = (POK,IsCOW,pPOK)
PV = 0x2619bc0 "abc"\0
CUR = 3
LEN = 16
COW_REFCNT = 1
Note that both scalars share the same PV buffer and have a COW_REFCNT
greater than zero.
This means that XS code which wishes to modify the "SvPVX()"
buffer of an SV should call "SvPV_force()" or similar first, to
ensure a valid (and unshared) buffer, and to call "SvSETMAGIC()"
afterwards. This in fact has always been the case (for example hash keys
were already copy-on-write); this change just spreads the COW behaviour to
a wider variety of SVs.
One important difference is that before 5.18.0, shared hash-key scalars used
to have the "SvREADONLY" flag set; this is no longer the case.
This new behaviour can still be disabled by running Configure with
-Accflags=-DPERL_NO_COW. This option will probably be removed in
Perl 5.22.
- •
- "PL_sawampersand" is now a constant. The switch this variable
provided (to enable/disable the pre-match copy depending on whether $&
had been seen) has been removed and replaced with copy-on-write,
eliminating a few bugs.
The previous behaviour can still be enabled by running Configure with
-Accflags=-DPERL_SAWAMPERSAND.
- •
- The functions "my_swap", "my_htonl" and
"my_ntohl" have been removed. It is unclear why these functions
were ever marked as A, part of the API. XS code can't call them
directly, as it can't rely on them being compiled. Unsurprisingly, no code
on CPAN references them.
- •
- The signature of the "Perl_re_intuit_start()" regex function has
changed; the function pointer "intuit" in the regex engine
plugin structure has also changed accordingly. A new parameter,
"strbeg" has been added; this has the same meaning as the
same-named parameter in "Perl_regexec_flags". Previously intuit
would try to guess the start of the string from the passed SV (if any),
and would sometimes get it wrong (e.g. with an overloaded SV).
- •
- The signature of the "Perl_regexec_flags()" regex function has
changed; the function pointer "exec" in the regex engine plugin
structure has also changed to match. The "minend" parameter now
has type "SSize_t" to better support 64-bit systems.
- •
- XS code may use various macros to change the case of a character or code
point (for example "toLOWER_utf8()"). Only a couple of these
were documented until now; and now they should be used in preference to
calling the underlying functions. See "Character case changing"
in perlapi.
- •
- The code dealt rather inconsistently with uids and gids. Some places
assumed that they could be safely stored in UVs, others in IVs, others in
ints. Four new macros are introduced: SvUID(), sv_setuid(),
SvGID(), and sv_setgid()
- •
- "sv_pos_b2u_flags" has been added to the API. It is similar to
"sv_pos_b2u", but supports long strings on 64-bit
platforms.
- •
- "PL_exit_flags" can now be used by perl embedders or other XS
code to have perl "warn" or "abort" on an attempted
exit. [perl #52000]
- •
- Compiling with "-Accflags=-PERL_BOOL_AS_CHAR" now allows C99 and
C++ compilers to emulate the aliasing of "bool" to
"char" that perl does for C89 compilers. [perl #120314]
- •
- The "sv" argument in "sv_2pv_flags" in perlapi,
"sv_2iv_flags" in perlapi, "sv_2uv_flags" in perlapi,
and "sv_2nv_flags" in perlapi and their older wrappers sv_2pv,
sv_2iv, sv_2uv, sv_2nv, is now non-NULL. Passing NULL now will crash. When
the non-NULL marker was introduced en masse in 5.9.3 the functions were
marked non-NULL, but since the creation of the SV API in 5.0 alpha 2, if
NULL was passed, the functions returned 0 or false-type values. The code
that supports "sv" argument being non-NULL dates to 5.0 alpha 2
directly, and indirectly to Perl 1.0 (pre 5.0 api). The lack of
documentation that the functions accepted a NULL "sv" was
corrected in 5.11.0 and between 5.11.0 and 5.19.5 the functions were
marked NULLOK. As an optimization the NULLOK code has now been removed,
and the functions became non-NULL marked again, because core getter-type
macros never pass NULL to these functions and would crash before ever
passing NULL.
The only way a NULL "sv" can be passed to sv_2*v* functions is if
XS code directly calls sv_2*v*. This is unlikely as XS code uses Sv*V*
macros to get the underlying value out of the SV. One possible situation
which leads to a NULL "sv" being passed to sv_2*v* functions, is
if XS code defines its own getter type Sv*V* macros, which check for NULL
before dereferencing and checking the SV's flags through public API
Sv*OK* macros or directly using private API "SvFLAGS", and if
"sv" is NULL, then calling the sv_2*v functions with a NULL
litteral or passing the "sv" containing a NULL value.
- •
- newATTRSUB is now a macro
The public API newATTRSUB was previously a macro to the private function
Perl_newATTRSUB. Function Perl_newATTRSUB has been removed. newATTRSUB is
now macro to a different internal function.
- •
- Changes in warnings raised by "utf8n_to_uvchr()"
This bottom level function decodes the first character of a UTF-8 string
into a code point. It is accessible to "XS" level code, but it's
discouraged from using it directly. There are higher level functions that
call this that should be used instead, such as
"utf8_to_uvchr_buf" in perlapi. For completeness though, this
documents some changes to it. Now, tests for malformations are done before
any tests for other potential issues. One of those issues involves code
points so large that they have never appeared in any official standard
(the current standard has scaled back the highest acceptable code point
from earlier versions). It is possible (though not done in CPAN) to warn
and/or forbid these code points, while accepting smaller code points that
are still above the legal Unicode maximum. The warning message for this
now includes the code point if representable on the machine. Previously it
always displayed raw bytes, which is what it still does for
non-representable code points.
- •
- Regexp engine changes that affect the pluggable regex engine interface
Many flags that used to be exposed via regexp.h and used to populate the
extflags member of struct regexp have been removed. These fields were
technically private to Perl's own regexp engine and should not have been
exposed there in the first place.
The affected flags are:
RXf_NOSCAN
RXf_CANY_SEEN
RXf_GPOS_SEEN
RXf_GPOS_FLOAT
RXf_ANCH_BOL
RXf_ANCH_MBOL
RXf_ANCH_SBOL
RXf_ANCH_GPOS
As well as the follow flag masks:
RXf_ANCH_SINGLE
RXf_ANCH
All have been renamed to PREGf_ equivalents and moved to regcomp.h.
The behavior previously achieved by setting one or more of the RXf_ANCH_
flags (via the RXf_ANCH mask) have now been replaced by a *single* flag
bit in extflags:
RXf_IS_ANCHORED
pluggable regex engines which previously used to set these flags should now
set this flag ALONE.
- •
- The Perl core now consistently uses "av_tindex()" ("the top
index of an array") as a more clearly-named synonym for
"av_len()".
- •
- The obscure interpreter variable "PL_timesbuf" is expected to be
removed early in the 5.21.x development series, so that Perl 5.22.0 will
not provide it to XS authors. While the variable still exists in 5.20.0,
we hope that this advance warning of the deprecation will help anyone who
is using that variable.
Selected Bug Fixes¶
Regular Expressions¶
- •
- Fixed a small number of regexp constructions that could either fail to
match or crash perl when the string being matched against was allocated
above the 2GB line on 32-bit systems. [RT #118175]
- •
- Various memory leaks involving the parsing of the "(?[...])"
regular expression construct have been fixed.
- •
- "(?[...])" now allows interpolation of precompiled patterns
consisting of "(?[...])" with bracketed character classes inside
("$pat = qr/(?[ [a] ])/;
/(?[ $pat ])/"). Formerly, the brackets would confuse
the regular expression parser.
- •
- The "Quantifier unexpected on zero-length expression" warning
message could appear twice starting in Perl v5.10 for a regular expression
also containing alternations (e.g., "a|b") triggering the trie
optimisation.
- •
- Perl v5.18 inadvertently introduced a bug whereby interpolating mixed up-
and down-graded UTF-8 strings in a regex could result in malformed UTF-8
in the pattern: specifically if a downgraded character in the range
"\x80..\xff" followed a UTF-8 string, e.g.
utf8::upgrade( my $u = "\x{e5}");
utf8::downgrade(my $d = "\x{e5}");
/$u$d/
[RT #118297]
- •
- In regular expressions containing multiple code blocks, the values of $1,
$2, etc., set by nested regular expression calls would leak from one block
to the next. Now these variables always refer to the outer regular
expression at the start of an embedded block [perl #117917].
- •
- "/$qr/p" was broken in Perl 5.18.0; the "/p" flag was
ignored. This has been fixed. [perl #118213]
- •
- Starting in Perl 5.18.0, a construct like "/[#](?{})/x" would
have its "#" incorrectly interpreted as a comment. The code
block would be skipped, unparsed. This has been corrected.
- •
- Starting in Perl 5.001, a regular expression like "/[#$a]/x" or
"/[#]$a/x" would have its "#" incorrectly interpreted
as a comment, so the variable would not interpolate. This has been
corrected. [perl #45667]
- •
- Perl 5.18.0 inadvertently made dereferenced regular expressions
("${ qr// }") false as booleans. This has been
fixed.
- •
- The use of "\G" in regular expressions, where it's not at the
start of the pattern, is now slightly less buggy (although it is still
somewhat problematic).
- •
- Where a regular expression included code blocks ("/(?{...})/"),
and where the use of constant overloading triggered a re-compilation of
the code block, the second compilation didn't see its outer lexical scope.
This was a regression in Perl 5.18.0.
- •
- The string position set by "pos" could shift if the string
changed representation internally to or from utf8. This could happen,
e.g., with references to objects with string overloading.
- •
- Taking references to the return values of two "pos" calls with
the same argument, and then assigning a reference to one and
"undef" to the other, could result in assertion failures or
memory leaks.
- •
- Elements of @- and @+ now update correctly when they refer to non-existent
captures. Previously, a referenced element ("$ref = \$-[1]")
could refer to the wrong match after subsequent matches.
- •
- The code that parses regex backrefs (or ambiguous backref/octals) such as
\123 did a simple atoi(), which could wrap round to negative values
on long digit strings and cause segmentation faults. This has now been
fixed. [perl #119505]
- •
- Assigning another typeglob to "*^R" no longer makes the regular
expression engine crash.
- •
- The "\N" regular expression escape, when used without the curly
braces (to mean "[^\n]"), was ignoring a following "*"
if followed by whitespace under /x. It had been this way since
"\N" to mean "[^\n]" was introduced in 5.12.0.
- •
- "s///", "tr///" and "y///" now work when a
wide character is used as the delimiter. [perl #120463]
- •
- Some cases of unterminated (?...) sequences in regular expressions (e.g.,
"/(?</") have been fixed to produce the proper error message
instead of "panic: memory wrap". Other cases (e.g.,
"/(?(/") have yet to be fixed.
- •
- When a reference to a reference to an overloaded object was returned from
a regular expression "(??{...})" code block, an incorrect
implicit dereference could take place if the inner reference had been
returned by a code block previously.
- •
- A tied variable returned from "(??{...})" sees the inner values
of match variables (i.e., the $1 etc. from any matches inside the block)
in its FETCH method. This was not the case if a reference to an overloaded
object was the last thing assigned to the tied variable. Instead, the
match variables referred to the outer pattern during the FETCH call.
- •
- Fix unexpected tainting via regexp using locale. Previously, under certain
conditions, the use of character classes could cause tainting when it
shouldn't. Some character classes are locale-dependent, but before this
patch, sometimes tainting was happening even for character classes that
don't depend on the locale. [perl #120675]
- •
- Under certain conditions, Perl would throw an error if in an lookbehind
assertion in a regexp, the assertion referred to a named subpattern,
complaining the lookbehind was variable when it wasn't. This has been
fixed. [perl #120600], [perl #120618]. The current fix may be improved on
in the future.
- •
- $^R wasn't available outside of the regular expression that initialized
it. [perl #121070]
- •
- A large set of fixes and refactoring for re_intuit_start() was
merged, the highlights are:
- •
- Fixed a panic when compiling the regular expression
"/\x{100}[xy]\x{100}{2}/".
- •
- Fixed a performance regression when performing a global pattern match
against a UTF-8 string. [perl #120692]
- •
- Fixed another performance issue where matching a regular expression like
"/ab.{1,2}x/" against a long UTF-8 string would unnecessarily
calculate byte offsets for a large portion of the string. [perl
#120692]
- •
- Fixed an alignment error when compiling regular expressions when built
with GCC on HP-UX 64-bit.
- •
- On 64-bit platforms "pos" can now be set to a value higher than
2**31-1. [perl #72766]
Perl 5 Debugger and -d¶
- •
- The debugger's "man" command been fixed. It was broken in the
v5.18.0 release. The "man" command is aliased to the names
"doc" and "perldoc" - all now work again.
- •
- @_ is now correctly visible in the debugger, fixing a regression
introduced in v5.18.0's debugger. [RT #118169]
- •
- Under copy-on-write builds (the default as of 5.20.0)
"${'_<-e'}[0]" no longer gets mangled. This is the first line
of input saved for the debugger's use for one-liners [perl #118627].
- •
- On non-threaded builds, setting "${"_<filename"}"
to a reference or typeglob no longer causes "__FILE__" and some
error messages to produce a corrupt string, and no longer prevents
"#line" directives in string evals from providing the source
lines to the debugger. Threaded builds were unaffected.
- •
- Starting with Perl 5.12, line numbers were off by one if the -d
switch was used on the #! line. Now they are correct.
- •
- "*DB::DB = sub {} if 0" no longer stops Perl's debugging mode
from finding "DB::DB" subs declared thereafter.
- •
- "%{'_<...'}" hashes now set breakpoints on the corresponding
"@{'_<...'}" rather than whichever array @DB::dbline is
aliased to. [perl #119799]
- •
- Call set-magic when setting $DB::sub. [perl #121255]
- •
- The debugger's "n" command now respects lvalue subroutines and
steps over them [perl #118839].
Lexical Subroutines¶
- •
- Lexical constants ("my sub a() { 42 }") no longer crash when
inlined.
- •
- Parameter prototypes attached to lexical subroutines are now respected
when compiling sub calls without parentheses. Previously, the prototypes
were honoured only for calls with parentheses. [RT #116735]
- •
- Syntax errors in lexical subroutines in combination with calls to the same
subroutines no longer cause crashes at compile time.
- •
- Deep recursion warnings no longer crash lexical subroutines. [RT
#118521]
- •
- The dtrace sub-entry probe now works with lexical subs, instead of
crashing [perl #118305].
- •
- Undefining an inlinable lexical subroutine ("my sub foo() { 42 }
undef &foo") would result in a crash if warnings were turned
on.
- •
- An undefined lexical sub used as an inherited method no longer
crashes.
- •
- The presence of a lexical sub named "CORE" no longer stops the
CORE:: prefix from working.
Everything Else¶
- •
- The OP allocation code now returns correctly aligned memory in all cases
for "struct pmop". Previously it could return memory only
aligned to a 4-byte boundary, which is not correct for an ithreads build
with 64 bit IVs on some 32 bit platforms. Notably, this caused the build
to fail completely on sparc GNU/Linux. [RT #118055]
- •
- Evaluating large hashes in scalar context is now much faster, as the
number of used chains in the hash is now cached for larger hashes. Smaller
hashes continue not to store it and calculate it when needed, as this
saves one IV. That would be 1 IV overhead for every object built from a
hash. [RT #114576]
- •
- Perl v5.16 inadvertently introduced a bug whereby calls to XSUBs that were
not visible at compile time were treated as lvalues and could be assigned
to, even when the subroutine was not an lvalue sub. This has been fixed.
[RT #117947]
- •
- In Perl v5.18.0 dualvars that had an empty string for the string part but
a non-zero number for the number part starting being treated as true. In
previous versions they were treated as false, the string representation
taking precedeence. The old behaviour has been restored. [RT #118159]
- •
- Since Perl v5.12, inlining of constants that override built-in keywords of
the same name had countermanded "use subs", causing subsequent
mentions of the constant to use the built-in keyword instead. This has
been fixed.
- •
- The warning produced by "-l $handle" now applies to IO refs and
globs, not just to glob refs. That warning is also now UTF8-clean. [RT
#117595]
- •
- "delete local $ENV{nonexistent_env_var}" no longer leaks
memory.
- •
- "sort" and "require" followed by a keyword prefixed
with "CORE::" now treat it as a keyword, and not as a subroutine
or module name. [RT #24482]
- •
- Through certain conundrums, it is possible to cause the current package to
be freed. Certain operators ("bless", "reset",
"open", "eval") could not cope and would crash. They
have been made more resilient. [RT #117941]
- •
- Aliasing filehandles through glob-to-glob assignment would not update
internal method caches properly if a package of the same name as the
filehandle existed, resulting in filehandle method calls going to the
package instead. This has been fixed.
- •
- "./Configure -de -Dusevendorprefix" didn't default. [RT
#64126]
- •
- The "Statement unlikely to be reached" warning was listed in
perldiag as an "exec"-category warning, but was enabled and
disabled by the "syntax" category. On the other hand, the
"exec" category controlled its fatal-ness. It is now entirely
handled by the "exec" category.
- •
- The "Replacement list is longer that search list" warning for
"tr///" and "y///" no longer occurs in the presence of
the "/c" flag. [RT #118047]
- •
- Stringification of NVs are not cached so that the lexical locale controls
stringification of the decimal point. [perl #108378] [perl #115800]
- •
- There have been several fixes related to Perl's handling of locales. perl
#38193 was described above in "Internal Changes". Also fixed is
#118197, where the radix (decimal point) character had to be an ASCII
character (which doesn't work for some non-Western languages); and
#115808, in which "POSIX::setlocale()" on failure returned an
"undef" which didn't warn about not being defined even if those
warnings were enabled.
- •
- Compiling a "split" operator whose third argument is a named
constant evaulating to 0 no longer causes the constant's value to
change.
- •
- A named constant used as the second argument to "index" no
longer gets coerced to a string if it is a reference, regular expression,
dualvar, etc.
- •
- A named constant evaluating to the undefined value used as the second
argument to "index" no longer produces "uninitialized"
warnings at compile time. It will still produce them at run time.
- •
- When a scalar was returned from a subroutine in @INC, the referenced
scalar was magically converted into an IO thingy, possibly resulting in
"Bizarre copy" errors if that scalar continued to be used
elsewhere. Now Perl uses an internal copy of the scalar instead.
- •
- Certain uses of the "sort" operator are optimised to modify an
array in place, such as "@a = sort @a". During the sorting, the
array is made read-only. If a sort block should happen to die, then the
array remained read-only even outside the "sort". This has been
fixed.
- •
- $a and $b inside a sort block are aliased to the actual arguments to
"sort", so they can be modified through those two variables.
This did not always work, e.g., for lvalue subs and $#ary, and probably
many other operators. It works now.
- •
- The arguments to "sort" are now all in list context. If the
"sort" itself were called in void or scalar context, then
some, but not all, of the arguments used to be in void or scalar
context.
- •
- Subroutine prototypes with Unicode characters above U+00FF were getting
mangled during closure cloning. This would happen with subroutines closing
over lexical variables declared outside, and with lexical subs.
- •
- "UNIVERSAL::can" now treats its first argument the same way that
method calls do: Typeglobs and glob references with non-empty IO slots are
treated as handles, and strings are treated as filehandles, rather than
packages, if a handle with that name exists [perl #113932].
- •
- Method calls on typeglobs (e.g., "*ARGV->getline") used to
stringify the typeglob and then look it up again. Combined with changes in
Perl 5.18.0, this allowed "*foo->bar" to call methods on the
"foo" package (like "foo->bar"). In some cases it
could cause the method to be called on the wrong handle. Now a typeglob
argument is treated as a handle (just like "(\*foo)->bar"),
or, if its IO slot is empty, an error is raised.
- •
- Assigning a vstring to a tied variable or to a subroutine argument aliased
to a nonexistent hash or array element now works, without flattening the
vstring into a regular string.
- •
- "pos", "tie", "tied" and "untie"
did not work properly on subroutine arguments aliased to nonexistent hash
and array elements [perl #77814, #27010].
- •
- The "=>" fat arrow operator can now quote built-in keywords
even if it occurs on the next line, making it consistent with how it
treats other barewords.
- •
- Autovivifying a subroutine stub via "\&$glob" started
causing crashes in Perl 5.18.0 if the $glob was merely a copy of a real
glob, i.e., a scalar that had had a glob assigned to it. This has been
fixed. [perl #119051]
- •
- Perl used to leak an implementation detail when it came to referencing the
return values of certain operators. "for ($a+$b) { warn \$_; warn \$_
}" used to display two different memory addresses, because the
"\" operator was copying the variable. Under threaded builds, it
would also happen for constants ("for(1) { ... }"). This has
been fixed. [perl #21979, #78194, #89188, #109746, #114838, #115388]
- •
- The range operator ".." was returning the same modifiable
scalars with each call, unless it was the only thing in a
"foreach" loop header. This meant that changes to values within
the list returned would be visible the next time the operator was
executed. [perl #3105]
- •
- Constant folding and subroutine inlining no longer cause operations that
would normally return new modifiable scalars to return read-only values
instead.
- •
- Closures of the form "sub () { $some_variable }" are no longer
inlined, causing changes to the variable to be ignored by callers of the
subroutine. [perl #79908]
- •
- Return values of certain operators such as "ref" would sometimes
be shared between recursive calls to the same subroutine, causing the
inner call to modify the value returned by "ref" in the outer
call. This has been fixed.
- •
- "__PACKAGE__" and constants returning a package name or hash key
are now consistently read-only. In various previous Perl releases, they
have become mutable under certain circumstances.
- •
- Enabling "used once" warnings no longer causes crashes on stash
circularities created at compile time ("*Foo::Bar::Foo:: =
*Foo::").
- •
- Undef constants used in hash keys ("use constant u => undef;
$h{+u}") no longer produce "uninitialized" warnings at
compile time.
- •
- Modifying a substitution target inside the substitution replacement no
longer causes crashes.
- •
- The first statement inside a string eval used to use the wrong pragma
setting sometimes during constant folding. "eval 'uc chr 0xe0'"
would randomly choose between Unicode, byte, and locale semantics. This
has been fixed.
- •
- The handling of return values of @INC filters (subroutines returned by
subroutines in @INC) has been fixed in various ways. Previously tied
variables were mishandled, and setting $_ to a reference or typeglob could
result in crashes.
- •
- The "SvPVbyte" XS function has been fixed to work with tied
scalars returning something other than a string. It used to return utf8 in
those cases where "SvPV" would.
- •
- Perl 5.18.0 inadvertently made "--" and "++" crash on
dereferenced regular expressions, and stopped "++" from
flattening vstrings.
- •
- "bless" no longer dies with "Can't bless non-reference
value" if its first argument is a tied reference.
- •
- "reset" with an argument no longer skips copy-on-write scalars,
regular expressions, typeglob copies, and vstrings. Also, when
encountering those or read-only values, it no longer skips any array or
hash with the same name.
- •
- "reset" with an argument now skips scalars aliased to typeglobs
("for $z (*foo) { reset "z" }"). Previously it would
corrupt memory or crash.
- •
- "ucfirst" and "lcfirst" were not respecting the bytes
pragma. This was a regression from Perl 5.12. [perl #117355]
- •
- Changes to "UNIVERSAL::DESTROY" now update DESTROY caches in all
classes, instead of causing classes that have already had objects
destroyed to continue using the old sub. This was a regression in Perl
5.18. [perl #114864]
- •
- All known false-positive occurrences of the deprecation warning
"Useless use of '\'; doesn't escape metacharacter '%c'", added
in Perl 5.18.0, have been removed. [perl #119101]
- •
- The value of $^E is now saved across signal handlers on Windows. [perl
#85104]
- •
- A lexical filehandle (as in "open my $fh...") is usually given a
name based on the current package and the name of the variable, e.g.
"main::$fh". Under recursion, the filehandle was losing the
"$fh" part of the name. This has been fixed.
- •
- Uninitialized values returned by XSUBs are no longer exempt from
uninitialized warnings. [perl #118693]
- •
- "elsif ("")" no longer erroneously produces a warning
about void context. [perl #118753]
- •
- Passing "undef" to a subroutine now causes @_ to contain the
same read-only undefined scalar that "undef" returns.
Furthermore, "exists $_[0]" will now return true if
"undef" was the first argument. [perl #7508, #109726]
- •
- Passing a non-existent array element to a subroutine does not usually
autovivify it unless the subroutine modifies its argument. This did not
work correctly with negative indices and with non-existent elements within
the array. The element would be vivified immediately. The delayed
vivification has been extended to work with those. [perl #118691]
- •
- Assigning references or globs to the scalar returned by $#foo after the
@foo array has been freed no longer causes assertion failures on debugging
builds and memory leaks on regular builds.
- •
- On 64-bit platforms, large ranges like 1..1000000000000 no longer crash,
but eat up all your memory instead. [perl #119161]
- •
- "__DATA__" now puts the "DATA" handle in the right
package, even if the current package has been renamed through glob
assignment.
- •
- When "die", "last", "next",
"redo", "goto" and "exit" unwind the scope,
it is possible for "DESTROY" recursively to call a subroutine or
format that is currently being exited. It that case, sometimes the lexical
variables inside the sub would start out having values from the outer
call, instead of being undefined as they should. This has been fixed.
[perl #119311]
- •
- ${^MPEN} is no longer treated as a synonym for ${^MATCH}.
- •
- Perl now tries a little harder to return the correct line number in
"(caller)[2]". [perl #115768]
- •
- Line numbers inside multiline quote-like operators are now reported
correctly. [perl #3643]
- •
- "#line" directives inside code embedded in quote-like operators
are now respected.
- •
- Line numbers are now correct inside the second here-doc when two here-doc
markers occur on the same line.
- •
- An optimization in Perl 5.18 made incorrect assumptions causing a bad
interaction with the Devel::CallParser CPAN module. If the module was
loaded then lexical variables declared in separate statements following a
"my(...)" list might fail to be cleared on scope exit.
- •
- &xsub and "goto &xsub" calls now allow the called
subroutine to autovivify elements of @_.
- •
- &xsub and "goto &xsub" no longer crash if *_ has been
undefined and has no ARRAY entry (i.e. @_ does not exist).
- •
- &xsub and "goto &xsub" now work with tied @_.
- •
- Overlong identifiers no longer cause a buffer overflow (and a crash). They
started doing so in Perl 5.18.
- •
- The warning "Scalar value @hash{foo} better written as
$hash{foo}" now produces far fewer false positives. In particular,
@hash{+function_returning_a_list} and @hash{ qw "foo bar baz" }
no longer warn. The same applies to array slices. [perl #28380,
#114024]
- •
- "$! = EINVAL; waitpid(0, WNOHANG);" no longer goes into an
internal infinite loop. [perl #85228]
- •
- A possible segmentation fault in filehandle duplication has been
fixed.
- •
- A subroutine in @INC can return a reference to a scalar containing the
initial contents of the file. However, that scalar was freed prematurely
if not referenced elsewhere, giving random results.
- •
- "last" no longer returns values that the same statement has
accumulated so far, fixing amongst other things the long-standing bug that
"push @a, last" would try to return the @a, copying it like a
scalar in the process and resulting in the error, "Bizarre copy of
ARRAY in last." [perl #3112]
- •
- In some cases, closing file handles opened to pipe to or from a process,
which had been duplicated into a standard handle, would call perl's
internal waitpid wrapper with a pid of zero. With the fix for [perl
#85228] this zero pid was passed to "waitpid", possibly blocking
the process. This wait for process zero no longer occurs. [perl
#119893]
- •
- "select" used to ignore magic on the fourth (timeout) argument,
leading to effects such as "select" blocking indefinitely rather
than the expected sleep time. This has now been fixed. [perl #120102]
- •
- The class name in "for my class $foo" is now parsed correctly.
In the case of the second character of the class name being followed by a
digit (e.g. 'a1b') this used to give the error "Missing $ on loop
variable". [perl #120112]
- •
- Perl 5.18.0 accidentally disallowed "-bareword" under "use
strict" and "use integer". This has been fixed. [perl
#120288]
- •
- "-a" at the start of a line (or a hyphen with any single letter
that is not a filetest operator) no longer produces an erroneous 'Use of
"-a" without parentheses is ambiguous' warning. [perl
#120288]
- •
- Lvalue context is now properly propagated into bare blocks and
"if" and "else" blocks in lvalue subroutines.
Previously, arrays and hashes would sometimes incorrectly be flattened
when returned in lvalue list context, or "Bizarre copy" errors
could occur. [perl #119797]
- •
- Lvalue context is now propagated to the branches of "||" and
"&&" (and their alphabetic equivalents, "or"
and "and"). This means "foreach (pos $x || pos $y)
{...}" now allows "pos" to be modified through $_.
- •
- "stat" and "readline" remember the last handle used;
the former for the special "_" filehandle, the latter for
"${^LAST_FH}". "eval "*foo if 0"" where *foo
was the last handle passed to "stat" or "readline"
could cause that handle to be forgotten if the handle were not opened yet.
This has been fixed.
- •
- Various cases of "delete $::{a}", "delete $::{ENV}"
etc. causing a crash have been fixed. [perl #54044]
- •
- Setting $! to EACCESS before calling "require" could affect
"require"'s behaviour. This has been fixed.
- •
- The "Can't use \1 to mean $1 in expression" warning message now
only occurs on the right-hand (replacement) part of a substitution.
Formerly it could happen in code embedded in the left-hand side, or in any
other quote-like operator.
- •
- Blessing into a reference ("bless $thisref, $thatref") has long
been disallowed, but magical scalars for the second like $/ and those tied
were exempt. They no longer are. [perl #119809]
- •
- Blessing into a reference was accidentally allowed in 5.18 if the class
argument were a blessed reference with stale method caches (i.e., whose
class had had subs defined since the last method call). They are
disallowed once more, as in 5.16.
- •
- "$x->{key}" where $x was declared as "my Class $x"
no longer crashes if a Class::FIELDS subroutine stub has been
declared.
- •
- @$obj{'key'} and "${$obj}{key}" used to be exempt from
compile-time field checking ("No such class field"; see fields)
but no longer are.
- •
- A nonexistent array element with a large index passed to a subroutine that
ties the array and then tries to access the element no longer results in a
crash.
- •
- Declaring a subroutine stub named NEGATIVE_INDICES no longer makes
negative array indices crash when the current package is a tied array
class.
- •
- Declaring a "require", "glob", or "do"
subroutine stub in the CORE::GLOBAL:: package no longer makes compilation
of calls to the corresponding functions crash.
- •
- Aliasing CORE::GLOBAL:: functions to constants stopped working in Perl
5.10 but has now been fixed.
- •
- When "`...`" or "qx/.../" calls a "readpipe"
override, double-quotish interpolation now happens, as is the case when
there is no override. Previously, the presence of an override would make
these quote-like operators act like "q{}", suppressing
interpolation. [perl #115330]
- •
- "<<<`...`" here-docs (with backticks as the delimiters)
now call "readpipe" overrides. [perl #119827]
- •
- "&CORE::exit()" and "&CORE::die()" now respect
vmsish hints.
- •
- Undefining a glob that triggers a DESTROY method that undefines the same
glob is now safe. It used to produce "Attempt to free unreferenced
glob pointer" warnings and leak memory.
- •
- If subroutine redefinition ("eval 'sub foo{}'" or
"newXS" for XS code) triggers a DESTROY method on the sub that
is being redefined, and that method assigns a subroutine to the same slot
("*foo = sub {}"), $_[0] is no longer left pointing to a freed
scalar. Now DESTROY is delayed until the new subroutine has been
installed.
- •
- On Windows, perl no longer calls CloseHandle() on a socket handle.
This makes debugging easier on Windows by removing certain irrelevant bad
handle exceptions. It also fixes a race condition that made socket
functions randomly fail in a Perl process with multiple OS threads, and
possible test failures in dist/IO/t/cachepropagate-tcp.t. [perl
#120091/118059]
- •
- Formats involving UTF-8 encoded strings, or strange vars like ties,
overloads, or stringified refs (and in recent perls, pure NOK vars) would
generally do the wrong thing in formats when the var is treated as a
string and repeatedly chopped, as in "^<<<~~" and
similar. This has now been resolved. [perl
#33832/45325/113868/119847/119849/119851]
- •
- "semctl(..., SETVAL, ...)" would set the semaphore to the top
32-bits of the supplied integer instead of the bottom 32-bits on 64-bit
big-endian systems. [perl #120635]
- •
- "readdir()" now only sets $! on error. $! is no longer set to
"EBADF" when then terminating "undef" is read from the
directory unless the system call sets $!. [perl #118651]
- •
- &CORE::glob no longer causes an intermittent crash due to perl's stack
getting corrupted. [perl #119993]
- •
- "open" with layers that load modules (e.g.,
"<:encoding(utf8)") no longer runs the risk of crashing due
to stack corruption.
- •
- Perl 5.18 broke autoloading via "->SUPER::foo" method calls
by looking up AUTOLOAD from the current package rather than the current
package's superclass. This has been fixed. [perl #120694]
- •
- A longstanding bug causing "do {} until CONSTANT", where the
constant holds a true value, to read unallocated memory has been resolved.
This would usually happen after a syntax error. In past versions of Perl
it has crashed intermittently. [perl #72406]
- •
- Fix HP-UX $! failure. HP-UX strerror() returns an empty string for
an unknown error code. This caused an assertion to fail under DEBUGGING
builds. Now instead, the returned string for "$!" contains text
indicating the code is for an unknown error.
- •
- Individually-tied elements of @INC (as in "tie $INC[0]...") are
now handled correctly. Formerly, whether a sub returned by such a tied
element would be treated as a sub depended on whether a FETCH had occurred
previously.
- •
- "getc" on a byte-sized handle after the same "getc"
operator had been used on a utf8 handle used to treat the bytes as utf8,
resulting in erratic behavior (e.g., malformed UTF-8 warnings).
- •
- An initial "{" at the beginning of a format argument line was
always interpreted as the beginning of a block prior to v5.18. In Perl
v5.18, it started being treated as an ambiguous token. The parser would
guess whether it was supposed to be an anonymous hash constructor or a
block based on the contents. Now the previous behavious has been restored.
[perl #119973]
- •
- In Perl v5.18 "undef *_; goto &sub" and "local *_; goto
&sub" started crashing. This has been fixed. [perl #119949]
- •
- Backticks (" `` " or " qx// ") combined with multiple
threads on Win32 could result in output sent to stdout on one thread being
captured by backticks of an external command in another thread.
This could occur for pseudo-forked processes too, as Win32's pseudo-fork is
implemented in terms of threads. [perl #77672]
- •
- "open $fh, ">+", undef" no longer leaks memory when
TMPDIR is set but points to a directory a temporary file cannot be created
in. [perl #120951]
- •
- " for ( $h{k} || '' ) " no longer auto-vivifies $h{k}. [perl
#120374]
- •
- On Windows machines, Perl now emulates the POSIX use of the environment
for locale initialization. Previously, the environment was ignored. See
"ENVIRONMENT" in perllocale.
- •
- Fixed a crash when destroying a self-referencing GLOB. [perl #121242]
Known Problems¶
- •
- IO::Socket is known to fail tests on AIX 5.3. There is a patch
<https://rt.perl.org/Ticket/Display.html?id=120835> in the request
tracker, #120835, which may be applied to future releases.
- •
- The following modules are known to have test failures with this version of
Perl. Patches have been submitted, so there will hopefully be new releases
soon:
- •
- Data::Structure::Util version 0.15
- •
- HTML::StripScripts version 1.05
- •
- List::Gather version 0.08.
Obituary¶
Diana Rosa, 27, of Rio de Janeiro, went to her long rest on May 10, 2014, along
with the plush camel she kept hanging on her computer screen all the time. She
was a passionate Perl hacker who loved the language and its community, and who
never missed a Rio.pm event. She was a true artist, an enthusiast about
writing code, singing arias and graffiting walls. We'll never forget you.
Greg McCarroll died on August 28, 2013.
Greg was well known for many good reasons. He was one of the organisers of the
first YAPC::Europe, which concluded with an unscheduled auction where he
frantically tried to raise extra money to avoid the conference making a loss.
It was Greg who mistakenly arrived for a london.pm meeting a week late; some
years later he was the one who sold the choice of official meeting date at a
YAPC::Europe auction, and eventually as glorious leader of london.pm he got to
inherit the irreverent confusion that he had created.
Always helpful, friendly and cheerfully optimistic, you will be missed, but
never forgotten.
Acknowledgements¶
Perl 5.20.0 represents approximately 12 months of development since Perl 5.18.0
and contains approximately 470,000 lines of changes across 2,900 files from
124 authors.
Excluding auto-generated files, documentation and release tools, there were
approximately 280,000 lines of changes to 1,800 .pm, .t, .c and .h files.
Perl continues to flourish into its third decade thanks to a vibrant community
of users and developers. The following people are known to have contributed
the improvements that became Perl 5.20.0:
Aaron Crane, Abhijit Menon-Sen, Abigail, Abir Viqar, Alan Haggai Alavi, Alan
Hourihane, Alexander Voronov, Alexandr Ciornii, Andy Dougherty, Anno Siegel,
Aristotle Pagaltzis, Arthur Axel 'fREW' Schmidt, Brad Gilbert, Brendan Byrd,
Brian Childs, Brian Fraser, Brian Gottreu, Chris 'BinGOs' Williams, Christian
Millour, Colin Kuskie, Craig A. Berry, Dabrien 'Dabe' Murphy, Dagfinn Ilmari
Mannsaaker, Daniel Dragan, Darin McBride, David Golden, David Leadbeater,
David Mitchell, David Nicol, David Steinbrunner, Dennis Kaarsemaker, Dominic
Hargreaves, Ed Avis, Eric Brine, Evan Zacks, Father Chrysostomos, Florian
Ragwitz, Francois Perrad, Gavin Shelley, Gideon Israel Dsouza, Gisle Aas,
Graham Knop, H.Merijn Brand, Hauke D, Heiko Eissfeldt, Hiroo Hayashi, Hojung
Youn, James E Keenan, Jarkko Hietaniemi, Jerry D. Hedden, Jess Robinson, Jesse
Luehrs, Johan Vromans, John Gardiner Myers, John Goodyear, John P. Linderman,
John Peacock, kafka, Kang-min Liu, Karen Etheridge, Karl Williamson, Keedi
Kim, Kent Fredric, kevin dawson, Kevin Falcone, Kevin Ryde, Leon Timmermans,
Lukas Mai, Marc Simpson, Marcel Gruenauer, Marco Peereboom, Marcus
Holland-Moritz, Mark Jason Dominus, Martin McGrath, Matthew Horsfall, Max
Maischein, Mike Doherty, Moritz Lenz, Nathan Glenn, Nathan Trapuzzano, Neil
Bowers, Neil Williams, Nicholas Clark, Niels Thykier, Niko Tyni, Olivier
Mengue, Owain G. Ainsworth, Paul Green, Paul Johnson, Peter John Acklam, Peter
Martini, Peter Rabbitson, Petr PisaX, Philip Boulain, Philip Guenther, Piotr
Roszatycki, Rafael Garcia-Suarez, Reini Urban, Reuben Thomas, Ricardo Signes,
Ruslan Zakirov, Sergey Alekseev, Shirakata Kentaro, Shlomi Fish, Slaven Rezic,
Smylers, Steffen Mueller, Steve Hay, Sullivan Beck, Thomas Sibley, Tobias
Leich, Toby Inkster, Tokuhiro Matsuno, Tom Christiansen, Tom Hukins, Tony
Cook, Victor Efimov, Viktor Turskyi, Vladimir Timofeev, YAMASHINA Hio, Yves
Orton, Zefram, Zsban Ambrus, AEvar Arnfjoerd` Bjarmason.
The list above is almost certainly incomplete as it is automatically generated
from version control history. In particular, it does not include the names of
the (very much appreciated) contributors who reported issues to the Perl bug
tracker.
Many of the changes included in this version originated in the CPAN modules
included in Perl's core. We're grateful to the entire CPAN community for
helping Perl to flourish.
For a more complete list of all of Perl's historical contributors, please see
the
AUTHORS file in the Perl source distribution.
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 will be
able to help assess the impact of issues, figure out a resolution, and help
co-ordinate the release of patches to mitigate or fix the problem across all
platforms on which Perl is supported. Please only use this address for
security issues in the Perl core, not for modules independently distributed on
CPAN.
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.