perl5280delta - what is new for perl v5.28.0
This document describes differences between the 5.26.0 release and
the 5.28.0 release.
If you are upgrading from an earlier release such as 5.24.0, first
read perl5260delta, which describes differences between 5.24.0 and
5.26.0.
A list of changes is at
<http://www.unicode.org/versions/Unicode10.0.0>.
"delete" can now be used on
key/value hash slices, returning the keys along with the deleted values. [GH
#15982] <https://github.com/Perl/perl5/issues/15982>
If you find it difficult to remember how to write certain of the
pattern assertions, there are now alphabetic synonyms.
CURRENT NEW SYNONYMS
------ ------------
(?=...) (*pla:...) or (*positive_lookahead:...)
(?!...) (*nla:...) or (*negative_lookahead:...)
(?<=...) (*plb:...) or (*positive_lookbehind:...)
(?<!...) (*nlb:...) or (*negative_lookbehind:...)
(?>...) (*atomic:...)
These are considered experimental, so using any of these will
raise (unless turned off) a warning in the
"experimental::alpha_assertions"
category.
A mixture of scripts, such as Cyrillic and Latin, in a string is
often the sign of a spoofing attack. A new regular expression construct now
allows for easy detection of these. For example, you can say
qr/(*script_run: \d+ \b )/x
And the digits matched will all be from the same set of 10. You
won't get a look-alike digit from a different script that has a different
value than what it appears to be.
Or:
qr/(*sr: \b \w+ \b )/x
makes sure that all the characters come from the same script.
You can also combine script runs with
"(?>...)" (or
"*atomic:...)").
Instead of writing:
(*sr:(?<...))
you can now run:
(*asr:...)
# or
(*atomic_script_run:...)
This is considered experimental, so using it will raise (unless
turned off) a warning in the
"experimental::script_run" category.
See "Script Runs" in perlre.
Previously in-place editing ("perl
-i") would delete or rename the input file as soon as you
started working on a new file.
Without backups this would result in loss of data if there was an
error, such as a full disk, when writing to the output file.
This has changed so that the input file isn't replaced until the
output file has been completely written and successfully closed.
This works by creating a work file in the same directory, which is
renamed over the input file once the output file is complete.
Incompatibilities:
- Since this renaming needs to only happen once, if you create a thread or
child process, that renaming will only happen in the original thread or
process.
- If you change directories while processing a file, and your operating
system doesn't provide the "unlinkat()",
"renameat()" and
"fchmodat()" functions, the final rename
step may fail.
[GH #15216] <https://github.com/Perl/perl5/issues/15216>
A persistent lexical array or hash variable can now be
initialized, by an expression such as "state @a = qw(x
y z)". Initialization of a list of persistent lexical variables
is still not possible.
On platforms where inode numbers are of a type larger than perl's
native integer numerical types, stat will preserve the full content of large
inode numbers by returning them in the form of strings of decimal digits.
Exact comparison of inode numbers can thus be achieved by comparing with
"eq" rather than
"==". Comparison with
"==", and other numerical operations
(which are usually meaningless on inode numbers), work as well as they did
before, which is to say they fall back to floating point, and ultimately
operate on a fairly useless rounded inode number if the real inode number is
too big for the floating point format.
The actual size used depends on the platform, so remains
unportable.
When opening a file descriptor, perl now generally opens it with
its close-on-exec flag already set, on platforms that support doing so. This
improves thread safety, because it means that an
"exec" initiated by one thread can no
longer cause a file descriptor in the process of being opened by another
thread to be accidentally passed to the executed program.
Additionally, perl now sets the close-on-exec flag more reliably,
whether it does so atomically or not. Most file descriptors were getting the
flag set, but some were being missed.
The new string-specific ("&. |. ^.
~.") and number-specific ("& | ^
~") bitwise operators introduced in Perl 5.22 that are available
within the scope of "use feature
'bitwise'" are no longer experimental. Because the
number-specific ops are spelled the same way as the existing operators that
choose their behaviour based on their operands, these operators must still
be enabled via the "bitwise" feature, in either of these two
ways:
use feature "bitwise";
use v5.28; # "bitwise" now included
They are also now enabled by the -E command-line
switch.
The "bitwise" feature no longer emits a warning.
Existing code that disables the "experimental::bitwise" warning
category that the feature previously used will continue to work.
One caveat that module authors ought to be aware of is that the
numeric operators now pass a fifth TRUE argument to overload methods. Any
methods that check the number of operands may croak if they do not expect so
many. XS authors in particular should be aware that this:
SV *
bitop_handler (lobj, robj, swap)
may need to be changed to this:
SV *
bitop_handler (lobj, robj, swap, ...)
These systems include Windows starting with Visual Studio 2005,
and in POSIX 2008 systems.
The implication is that you are now free to use locales and change
them in a threaded environment. Your changes affect only your thread. See
"Multi-threaded operation" in perllocale
This variable is 1 if the Perl interpreter is operating in an
environment where it is safe to use and change locales (see perllocale.)
This variable is true when the perl is unthreaded, or compiled in a platform
that supports thread-safe locale operation (see previous item).
[CVE-2017-12837] Heap buffer overflow in regular expression
compiler
Compiling certain regular expression patterns with the
case-insensitive modifier could cause a heap buffer overflow and crash perl.
This has now been fixed. [GH #16021]
<https://github.com/Perl/perl5/issues/16021>
[CVE-2017-12883] Buffer over-read in regular expression
parser
For certain types of syntax error in a regular expression pattern,
the error message could either contain the contents of a random, possibly
large, chunk of memory, or could crash perl. This has now been fixed. [GH
#16025] <https://github.com/Perl/perl5/issues/16025>
[CVE-2017-12814] $ENV{$key} stack buffer overflow on Windows
A possible stack buffer overflow in the
%ENV code on Windows has been fixed by removing the
buffer completely since it was superfluous anyway. [GH #16051]
<https://github.com/Perl/perl5/issues/16051>
Perl 5.28.0 retires various older hash functions which are not
viewed as sufficiently secure for use in Perl. We now support four general
purpose hash functions, Siphash (2-4 and 1-3 variants), and Zaphod32, and
StadtX hash. In addition we support SBOX32 (a form of tabular hashing) for
hashing short strings, in conjunction with any of the other hash functions
provided.
By default Perl is configured to support SBOX hashing of strings
up to 24 characters, in conjunction with StadtX hashing on 64 bit builds,
and Zaphod32 hashing for 32 bit builds.
You may control these settings with the following options to
Configure:
-DPERL_HASH_FUNC_SIPHASH
-DPERL_HASH_FUNC_SIPHASH13
-DPERL_HASH_FUNC_STADTX
-DPERL_HASH_FUNC_ZAPHOD32
To disable SBOX hashing you can use
-DPERL_HASH_USE_SBOX32_ALSO=0
And to set the maximum length to use SBOX32 hashing on with:
-DSBOX32_MAX_LEN=16
The maximum length allowed is 256. There probably isn't much point
in setting it higher than the default.
The experimental subroutine signatures feature has been changed so
that subroutine attributes must now come before the signature rather than
after. This is because attributes like
":lvalue" can affect the compilation of
code within the signature, for example:
sub f :lvalue ($a = do { $x = "abc"; return substr($x,0,1)}) { ...}
Note that this the second time they have been flipped:
sub f :lvalue ($a, $b) { ... }; # 5.20; 5.28 onwards
sub f ($a, $b) :lvalue { ... }; # 5.22 - 5.26
Omitting the commas between variables passed to formats is no
longer allowed. This has been deprecated since Perl 5.000.
These have been no-ops and deprecated since Perl 5.12 and 5.10,
respectively.
This has been deprecated since Perl 5.24.
Using "open()" and
"opendir()" to associate both a filehandle
and a dirhandle to the same symbol (glob or scalar) has been deprecated
since Perl 5.10.
Use of a bare terminator has been deprecated since Perl 5.000.
This used to work like setting it to
"undef", but has been deprecated since
Perl 5.20.
This was deprecated since Perl 5.24.
Use "B::Concise::b_terse"
instead.
This was deprecated in Perl 5.004.
Code points over 0xFF do not make sense
for bitwise operators and such an operation will now croak, except for a few
remaining cases. See perldeprecation.
This was deprecated in Perl 5.24.
This has been deprecated since Perl 5.22 and a no-op since Perl
5.26.
Previously the "-S" switch
incorrectly treated backslash ("\") as an escape for colon when
traversing the "PATH" environment
variable. [GH #15584] <https://github.com/Perl/perl5/issues/15584>
On a perl built with debugging support, the
"H" flag to the
"-D" debugging option has been removed.
This was supposed to dump hash values, but has been broken for many
years.
By the time of its initial stable release in Perl 5.12, the
"..." (yada-yada) operator was explicitly
intended to serve as a statement, not an expression. However, the original
implementation was confused on this point, leading to inconsistent parsing.
The operator was accidentally accepted in a few situations where it did not
serve as a complete statement, such as
... . "foo";
... if $a < $b;
The parsing has now been made consistent, permitting yada-yada
only as a statement. Affected code can use
"do{...}" to put a yada-yada into an
arbitrary expression context.
Since Perl 5.8, the sort pragma has had subpragmata
"_mergesort",
"_quicksort", and
"_qsort" that can be used to specify which
algorithm perl should use to implement the sort builtin. This was always
considered a dubious feature that might not last, hence the underscore
spellings, and they were documented as not being portable beyond Perl 5.8.
These subpragmata have now been deleted, and any attempt to use them is an
error. The sort pragma otherwise remains, and the algorithm-neutral
"stable" subpragma can be used to control
sorting behaviour. [GH #13234]
<https://github.com/Perl/perl5/issues/13234>
Octal and binary floating point literals used to permit any
hexadecimal digit to appear after the radix point. The digits are now
restricted to those appropriate for the radix, as digits before the radix
point always were.
The return types of the C API functions
"unpackstring()" and
"unpack_str()" have changed from
"I32" to
"SSize_t", in order to accommodate
datasets of more than two billion items.
Such strings are represented internally in UTF-8, and
"vec" is a bit-oriented operation that
will likely give unexpected results on those strings.
Perl 5.26.0 fatalized some uses of an unescaped left brace, but an
exception was made at the last minute, specifically crafted to be a minimal
change to allow GNU Autoconf to work. That tool is heavily depended upon,
and continues to use the deprecated usage. Its use of an unescaped left
brace is one where we have no intention of repurposing
"{" to be something other than itself.
That exception is now generalized to include various other such
cases where the "{" will not be
repurposed.
Note that these uses continue to raise a deprecation message.
Using unescaped left braces is officially deprecated everywhere,
but it is not enforced in contexts where their use does not interfere with
expected extensions to the language. A deprecation is added in this release
when the brace appears immediately after an opening parenthesis. Before
this, even if the brace was part of a legal quantifier, it was not
interpreted as such, but as the literal characters, unlike other quantifiers
that follow a "(" which are considered
errors. Now, their use will raise a deprecation message, unless turned
off.
Assigning a non-zero value to $[ has been
deprecated since Perl 5.12, but was never given a deadline for removal. This
has now been scheduled for Perl 5.30.
hostname() won't accept arguments in Perl 5.32
Passing arguments to
"Sys::Hostname::hostname()" was already
deprecated, but didn't have a removal date. This has now been scheduled for
Perl 5.32. [GH #14662]
<https://github.com/Perl/perl5/issues/14662>
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 these are (with rare exceptions) fine modules that you
are encouraged to continue to use. Their disinclusion from core primarily
hinges on their necessity to bootstrapping a fully functional, CPAN-capable
Perl installation, not usually on concerns over their design.
- B::Debug
- Locale::Codes
and its associated Country, Currency and Language modules
- The start up overhead for creating regular expression patterns with
Unicode properties ("\p{...}") has been
greatly reduced in most cases.
- Many string concatenation expressions are now considerably faster, due to
the introduction internally of a
"multiconcat" opcode which combines
multiple concatenations, and optionally a
"=" or
".=", into a single action. For example,
apart from retrieving $s,
$a and $b, this whole
expression is now handled as a single op:
$s .= "a=$a b=$b\n"
As a special case, if the LHS of an assignment is a lexical
variable or "my $s", the op itself
handles retrieving the lexical variable, which is faster.
In general, the more the expression includes a mix of constant
strings and variable expressions, the longer the expression, and the
more it mixes together non-utf8 and utf8 strings, the more marked the
performance improvement. For example on a
"x86_64" system, this code has been
benchmarked running four times faster:
my $s;
my $a = "ab\x{100}cde";
my $b = "fghij";
my $c = "\x{101}klmn";
for my $i (1..10_000_000) {
$s = "\x{100}wxyz";
$s .= "foo=$a bar=$b baz=$c";
}
In addition, "sprintf"
expressions which have a constant format containing only
%s and "%%"
format elements, and which have a fixed number of arguments, are now
also optimised into a "multiconcat"
op.
- The "ref()" builtin is now much faster
in boolean context, since it no longer bothers to construct a temporary
string like "Foo=ARRAY(0x134af48)".
- "keys()" in void and scalar contexts is
now more efficient.
- The common idiom of comparing the result of index() with -1 is now
specifically optimised, e.g.
if (index(...) != -1) { ... }
- "for()" loops and similar constructs are
now more efficient in most cases.
- File::Glob has been modified to remove unnecessary backtracking and
recursion, thanks to Russ Cox. See <https://research.swtch.com/glob>
for more details.
- The XS-level "SvTRUE()" API function is
now more efficient.
- Various integer-returning ops are now more efficient in scalar/boolean
context.
- Slightly improved performance when parsing stash names. [GH #15689]
<https://github.com/Perl/perl5/issues/15689>
- Calls to "require" for an already loaded
module are now slightly faster. [GH #16175]
<https://github.com/Perl/perl5/issues/16175>
- The performance of pattern matching
"[[:ascii:]]" and
"[[:^ascii:]]" has been improved
significantly except on EBCDIC platforms.
- Various optimizations have been applied to matching regular expression
patterns, so under the right circumstances, significant performance gains
may be noticed. But in an application with many varied patterns, little
overall improvement likely will be seen.
- Other optimizations have been applied to UTF-8 handling, but these are not
typically a major factor in most applications.
Key highlights in this release across several modules:
The usage of "use vars" has been
discouraged since the introduction of
"our" in Perl 5.6.0. Where possible the
usage of this pragma has now been removed from the Perl source code.
This had a slight effect (for the better) on the output of
WARNING_BITS in B::Deparse.
XSLoader is more modern, and most modules already require perl 5.6
or greater, so no functionality is lost by switching. In some cases, we have
also made changes to the local implementation that may not be reflected in
the version on CPAN due to a desire to maintain more backwards
compatibility.
- Archive::Tar has been upgraded from version 2.24 to 2.30.
This update also handled CVE-2018-12015: directory traversal
vulnerability. [cpan #125523]
<https://rt.cpan.org/Ticket/Display.html?id=125523>
- arybase has been upgraded from version 0.12 to 0.15.
- Attribute::Handlers has been upgraded from version 0.99 to 1.01.
- attributes has been upgraded from version 0.29 to 0.33.
- B has been upgraded from version 1.68 to 1.74.
- B::Concise has been upgraded from version 0.999 to 1.003.
- B::Debug has been upgraded from version 1.24 to 1.26.
NOTE: B::Debug is deprecated and may be removed from a future
version of Perl.
- B::Deparse has been upgraded from version 1.40 to 1.48.
It includes many bug fixes, and in particular, it now deparses
variable attributes correctly:
my $x :foo; # used to deparse as
# 'attributes'->import('main', \$x, 'foo'), my $x;
- base has been upgraded from version 2.25 to 2.27.
- bignum has been upgraded from version 0.47 to 0.49.
- blib has been upgraded from version 1.06 to 1.07.
- bytes has been upgraded from version 1.05 to 1.06.
- Carp has been upgraded from version 1.42 to 1.50.
If a package on the call stack contains a constant named
"ISA", Carp no longer throws a
"Not a GLOB reference" error.
Carp, when generating stack traces, now attempts to work
around longstanding bugs resulting from Perl's non-reference-counted
stack. [GH #9282] <https://github.com/Perl/perl5/issues/9282>
Carp has been modified to avoid assuming that objects cannot
be overloaded without the overload module loaded (this can happen with
objects created by XS modules). Previously, infinite recursion would
result if an XS-defined overload method itself called Carp. [GH #16407]
<https://github.com/Perl/perl5/issues/16407>
Carp now avoids using
"overload::StrVal", partly because
older versions of overload (included with perl 5.14 and earlier) load
Scalar::Util at run time, which will fail if Carp has been invoked after
a syntax error.
- charnames has been upgraded from version 1.44 to 1.45.
- Compress::Raw::Zlib has been upgraded from version 2.074 to 2.076.
This addresses a security vulnerability in older versions of
the 'zlib' library (which is bundled with Compress-Raw-Zlib).
- Config::Extensions has been upgraded from version 0.01 to 0.02.
- Config::Perl::V has been upgraded from version 0.28 to 0.29.
- CPAN has been upgraded from version 2.18 to 2.20.
- Data::Dumper has been upgraded from version 2.167 to 2.170.
Quoting of glob names now obeys the Useqq option [GH #13274]
<https://github.com/Perl/perl5/issues/13274>.
Attempts to set an option to
"undef" through a combined
getter/setter method are no longer mistaken for getter calls [GH #12135]
<https://github.com/Perl/perl5/issues/12135>.
- Devel::Peek has been upgraded from version 1.26 to 1.27.
- Devel::PPPort has been upgraded from version 3.35 to 3.40.
Devel::PPPort has moved from cpan-first to perl-first
maintenance
Primary responsibility for the code in Devel::PPPort has moved
into core perl. In a practical sense there should be no change except
that hopefully it will stay more up to date with changes made to symbols
in perl, rather than needing to be updated after the fact.
- Digest::SHA has been upgraded from version 5.96 to 6.01.
- DirHandle has been upgraded from version 1.04 to 1.05.
- DynaLoader has been upgraded from version 1.42 to 1.45.
Its documentation now shows the use of
"__PACKAGE__" and direct object syntax
[GH #16190] <https://github.com/Perl/perl5/issues/16190>.
- Encode has been upgraded from version 2.88 to 2.97.
- encoding has been upgraded from version 2.19 to 2.22.
- Errno has been upgraded from version 1.28 to 1.29.
- experimental has been upgraded from version 0.016 to 0.019.
- Exporter has been upgraded from version 5.72 to 5.73.
- ExtUtils::CBuilder has been upgraded from version 0.280225 to
0.280230.
- ExtUtils::Constant has been upgraded from version 0.23 to 0.25.
- ExtUtils::Embed has been upgraded from version 1.34 to 1.35.
- ExtUtils::Install has been upgraded from version 2.04 to 2.14.
- ExtUtils::MakeMaker has been upgraded from version 7.24 to 7.34.
- ExtUtils::Miniperl has been upgraded from version 1.06 to 1.08.
- ExtUtils::ParseXS has been upgraded from version 3.34 to 3.39.
- ExtUtils::Typemaps has been upgraded from version 3.34 to 3.38.
- ExtUtils::XSSymSet has been upgraded from version 1.3 to 1.4.
- feature has been upgraded from version 1.47 to 1.52.
- fields has been upgraded from version 2.23 to 2.24.
- File::Copy has been upgraded from version 2.32 to 2.33.
It will now use the sub-second precision variant of
utime() supplied by Time::HiRes where available. [GH #16225]
<https://github.com/Perl/perl5/issues/16225>.
- File::Fetch has been upgraded from version 0.52 to 0.56.
- File::Glob has been upgraded from version 1.28 to 1.31.
- File::Path has been upgraded from version 2.12_01 to 2.15.
- File::Spec and Cwd have been upgraded from version 3.67 to 3.74.
- File::stat has been upgraded from version 1.07 to 1.08.
- FileCache has been upgraded from version 1.09 to 1.10.
- Filter::Simple has been upgraded from version 0.93 to 0.95.
- Filter::Util::Call has been upgraded from version 1.55 to 1.58.
- GDBM_File has been upgraded from version 1.15 to 1.17.
Its documentation now explains that
"each" and
"delete" don't mix in hashes tied to
this module [GH #12894]
<https://github.com/Perl/perl5/issues/12894>.
It will now retry opening with an acceptable block size if
asking gdbm to default the block size failed [GH #13232]
<https://github.com/Perl/perl5/issues/13232>.
- Getopt::Long has been upgraded from version 2.49 to 2.5.
- Hash::Util::FieldHash has been upgraded from version 1.19 to 1.20.
- I18N::Langinfo has been upgraded from version 0.13 to 0.17.
This module is now available on all platforms, emulating the
system nl_langinfo(3) on systems that lack it. Some caveats
apply, as detailed in its documentation, the most severe being that,
except for MS Windows, the "CODESET"
item is not implemented on those systems, always returning
"".
It now sets the UTF-8 flag in its returned scalar if the
string contains legal non-ASCII UTF-8, and the locale is UTF-8 [GH
#15131] <https://github.com/Perl/perl5/issues/15131>.
This update also fixes a bug in which the underlying locale
was ignored for the "RADIXCHAR"
(always was returned as a dot) and the
"THOUSEP" (always empty). Now the
locale-appropriate values are returned.
- I18N::LangTags has been upgraded from version 0.42 to 0.43.
- if has been upgraded from version 0.0606 to 0.0608.
- IO has been upgraded from version 1.38 to 1.39.
- IO::Socket::IP has been upgraded from version 0.38 to 0.39.
- IPC::Cmd has been upgraded from version 0.96 to 1.00.
- JSON::PP has been upgraded from version 2.27400_02 to 2.97001.
- The "libnet" distribution has been
upgraded from version 3.10 to 3.11.
- List::Util has been upgraded from version 1.46_02 to 1.49.
- Locale::Codes has been upgraded from version 3.42 to 3.56.
NOTE: Locale::Codes scheduled to be removed from core
in Perl 5.30.
- Locale::Maketext has been upgraded from version 1.28 to 1.29.
- Math::BigInt has been upgraded from version 1.999806 to 1.999811.
- Math::BigInt::FastCalc has been upgraded from version 0.5005 to
0.5006.
- Math::BigRat has been upgraded from version 0.2611 to 0.2613.
- Module::CoreList has been upgraded from version 5.20170530 to
5.20180622.
- mro has been upgraded from version 1.20 to 1.22.
- Net::Ping has been upgraded from version 2.55 to 2.62.
- NEXT has been upgraded from version 0.67 to 0.67_01.
- ODBM_File has been upgraded from version 1.14 to 1.15.
- Opcode has been upgraded from version 1.39 to 1.43.
- overload has been upgraded from version 1.28 to 1.30.
- PerlIO::encoding has been upgraded from version 0.25 to 0.26.
- PerlIO::scalar has been upgraded from version 0.26 to 0.29.
- PerlIO::via has been upgraded from version 0.16 to 0.17.
- Pod::Functions has been upgraded from version 1.11 to 1.13.
- Pod::Html has been upgraded from version 1.2202 to 1.24.
A title for the HTML document will now be automatically
generated by default from a "NAME" section in the POD
document, as it used to be before the module was rewritten to use
Pod::Simple::XHTML to do the core of its job [GH #11954]
<https://github.com/Perl/perl5/issues/11954>.
- Pod::Perldoc has been upgraded from version 3.28 to 3.2801.
- The "podlators" distribution has been
upgraded from version 4.09 to 4.10.
Man page references and function names now follow the Linux
man page formatting standards, instead of the Solaris standard.
- POSIX has been upgraded from version 1.76 to 1.84.
Some more cautions were added about using locale-specific
functions in threaded applications.
- re has been upgraded from version 0.34 to 0.36.
- Scalar::Util has been upgraded from version 1.46_02 to 1.50.
- SelfLoader has been upgraded from version 1.23 to 1.25.
- Socket has been upgraded from version 2.020_03 to 2.027.
- sort has been upgraded from version 2.02 to 2.04.
- Storable has been upgraded from version 2.62 to 3.08.
- Sub::Util has been upgraded from version 1.48 to 1.49.
- subs has been upgraded from version 1.02 to 1.03.
- Sys::Hostname has been upgraded from version 1.20 to 1.22.
- Term::ReadLine has been upgraded from version 1.16 to 1.17.
- Test has been upgraded from version 1.30 to 1.31.
- Test::Harness has been upgraded from version 3.38 to 3.42.
- Test::Simple has been upgraded from version 1.302073 to 1.302133.
- threads has been upgraded from version 2.15 to 2.22.
The documentation now better describes the problems that arise
when returning values from threads, and no longer warns about creating
threads in "BEGIN" blocks. [GH #11563]
<https://github.com/Perl/perl5/issues/11563>
- threads::shared has been upgraded from version 1.56 to 1.58.
- Tie::Array has been upgraded from version 1.06 to 1.07.
- Tie::StdHandle has been upgraded from version 4.4 to 4.5.
- Time::gmtime has been upgraded from version 1.03 to 1.04.
- Time::HiRes has been upgraded from version 1.9741 to 1.9759.
- Time::localtime has been upgraded from version 1.02 to 1.03.
- Time::Piece has been upgraded from version 1.31 to 1.3204.
- Unicode::Collate has been upgraded from version 1.19 to 1.25.
- Unicode::Normalize has been upgraded from version 1.25 to 1.26.
- Unicode::UCD has been upgraded from version 0.68 to 0.70.
The function "num" now
accepts an optional parameter to help in diagnosing error returns.
- User::grent has been upgraded from version 1.01 to 1.02.
- User::pwent has been upgraded from version 1.00 to 1.01.
- utf8 has been upgraded from version 1.19 to 1.21.
- vars has been upgraded from version 1.03 to 1.04.
- version has been upgraded from version 0.9917 to 0.9923.
- VMS::DCLsym has been upgraded from version 1.08 to 1.09.
- VMS::Stdio has been upgraded from version 2.41 to 2.44.
- warnings has been upgraded from version 1.37 to 1.42.
It now includes new functions with names ending in
"_at_level", allowing callers to
specify the exact call frame. [GH #16257]
<https://github.com/Perl/perl5/issues/16257>
- XS::Typemap has been upgraded from version 0.15 to 0.16.
- XSLoader has been upgraded from version 0.27 to 0.30.
Its documentation now shows the use of
"__PACKAGE__", and direct object
syntax for example "DynaLoader" usage
[GH #16190] <https://github.com/Perl/perl5/issues/16190>.
Platforms that use
"mod2fname" to edit the names of
loadable libraries now look for bootstrap (.bs) files under the correct,
non-edited name.
- •
- The "VMS::stdio" compatibility shim has
been removed.
We have attempted to update the documentation to reflect the
changes listed in this document. If you find any we have missed, send email
to perlbug@perl.org <mailto:perlbug@perl.org>.
Additionally, the following selected changes have been made:
perlapi
- The API functions "perl_parse()",
"perl_run()", and
"perl_destruct()" are now documented
comprehensively, where previously the only documentation was a reference
to the perlembed tutorial.
- The documentation of "newGIVENOP()" has
been belatedly updated to account for the removal of lexical
$_.
- The API functions "newCONSTSUB()" and
"newCONSTSUB_flags()" are documented
much more comprehensively than before.
perldata
- •
- The section "Truth and Falsehood" in perlsyn has been moved into
perldata.
perldebguts
- •
- The description of the conditions under which
"DB::sub()" will be called has been
clarified. [GH #16055]
<https://github.com/Perl/perl5/issues/16055>
perldiag
- "Variable length lookbehind not implemented in regex m/%s/" in
perldiag
This now gives more ideas as to workarounds to the issue that
was introduced in Perl 5.18 (but not documented explicitly in its
perldelta) for the fact that some Unicode
"/i" rules cause a few sequences such
as
(?<!st)
to be considered variable length, and hence disallowed.
- "Use of state $_ is experimental" in
perldiag
This entry has been removed, as the experimental support of
this construct was removed in perl 5.24.0.
- The diagnostic "Initialization of state variables in
list context currently forbidden" has
changed to "Initialization of state variables
in list currently forbidden", because
list-context initialization of single aggregate state variables is now
permitted.
perlembed
- The examples in perlembed have been made more portable in the way they
exit, and the example that gets an exit code from the embedded Perl
interpreter now gets it from the right place. The examples that pass a
constructed argv to Perl now show the mandatory null
"argv[argc]".
- An example in perlembed used the string value of
"ERRSV" as a format string when calling
croak(). If that string contains format codes such as
%s this could crash the program.
This has been changed to a call to croak_sv().
An alternative could have been to supply a trivial format
string:
croak("%s", SvPV_nolen(ERRSV));
or as a special case for
"ERRSV" simply:
croak(NULL);
perlfunc
perlgit
- •
- The precise rules for identifying
"smoke-me" branches are now stated.
perlguts
- The section on reference counting in perlguts has been heavily revised, to
describe references in the way a programmer needs to think about them
rather than in terms of the physical data structures.
- Improve documentation related to UTF-8 multibytes.
perlintern
- •
- The internal functions
"newXS_len_flags()" and
"newATTRSUB_x()" are now
documented.
perlobj
- •
- The documentation about "DESTROY"
methods has been corrected, updated, and revised, especially in regard to
how they interact with exceptions. [GH #14083]
<https://github.com/Perl/perl5/issues/14083>
perlop
- The description of the "x" operator in
perlop has been clarified. [GH #16253]
<https://github.com/Perl/perl5/issues/16253>
- perlop has been updated to note that
"qw"'s whitespace rules differ from that
of "split"'s in that only ASCII
whitespace is used.
- The general explanation of operator precedence and associativity has been
corrected and clarified. [GH #15153]
<https://github.com/Perl/perl5/issues/15153>
- The documentation for the "\"
referencing operator now explains the unusual context that it supplies to
its operand. [GH #15932]
<https://github.com/Perl/perl5/issues/15932>
perlrequick
- •
- Clarifications on metacharacters and character classes
perlretut
- •
- Clarify metacharacters.
perlrun
- •
- Clarify the differences between -M and -m. [GH #15998]
<https://github.com/Perl/perl5/issues/15998>
perlsec
- The documentation about set-id scripts has been updated and revised. [GH
#10289] <https://github.com/Perl/perl5/issues/10289>
- A section about using "sudo" to run Perl
scripts has been added.
perlsyn
- The section "Truth and Falsehood" in perlsyn has been removed
from that document, where it didn't belong, and merged into the existing
paragraph on the same topic in perldata.
- The means to disambiguate between code blocks and hash constructors,
already documented in perlref, are now documented in perlsyn too. [GH
#15918] <https://github.com/Perl/perl5/issues/15918>
perluniprops
- perluniprops has been updated to note that
"\p{Word}" now includes code points
matching the "\p{Join_Control}"
property. The change to the property was made in Perl 5.18, but not
documented until now. There are currently only two code points that match
this property U+200C (ZERO WIDTH NON-JOINER) and U+200D (ZERO WIDTH
JOINER).
- For each binary table or property, the documentation now includes which
characters in the range "\x00-\xFF" it
matches, as well as a list of the first few ranges of code points matched
above that.
perlvar
- •
- The entry for $+ in perlvar has been expanded upon
to describe handling of multiply-named capturing groups.
perlfunc, perlop, perlsyn
- •
- In various places, improve the documentation of the special cases in the
condition expression of a while loop, such as implicit
"defined" and assignment to
$_. [GH #16334]
<https://github.com/Perl/perl5/issues/16334>
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 Errors
- Can't "goto" into a "given" block
(F) A "goto" statement was executed to jump into the
middle of a "given" block. You can't
get there from here. See "goto" in perlfunc.
- Can't "goto" into a binary or list expression
Use of "goto" to jump into
the parameter of a binary or list operator has been prohibited, to
prevent crashes and stack corruption. [GH #15914]
<https://github.com/Perl/perl5/issues/15914>
You may only enter the first argument of an operator
that takes a fixed number of arguments, since this is a case that will
not cause stack corruption. [GH #16415]
<https://github.com/Perl/perl5/issues/16415>
New Warnings
- Old package separator used in string
(W syntax) You used the old package separator, "'",
in a variable named inside a double-quoted string; e.g.,
"In $name's house". This is equivalent
to "In $name::s house". If you meant
the former, put a backslash before the apostrophe
("In $name\'s house").
- "Locale '%s' contains (at least) the following characters which have
unexpected meanings: %s The Perl program will use
the expected meanings" in perldiag
- A false-positive warning that was issued when using a
numerically-quantified sub-pattern in a recursive regex has been silenced.
[GH #16106] <https://github.com/Perl/perl5/issues/16106>
- The warning about useless use of a concatenation operator in void context
is now generated for expressions with multiple concatenations, such as
"$a.$b.$c", which used to mistakenly not
warn. [GH #3990] <https://github.com/Perl/perl5/issues/3990>
- Warnings that a variable or subroutine "masks earlier declaration in
same ...", or that an "our"
variable has been redeclared, have been moved to a new warnings category
"shadow". Previously they were in category
"misc".
- The deprecation warning from
"Sys::Hostname::hostname()" saying that
it doesn't accept arguments now states the Perl version in which the
warning will be upgraded to an error. [GH #14662]
<https://github.com/Perl/perl5/issues/14662>
- The perldiag entry for the error regarding a set-id script has been
expanded to make clear that the error is reporting a specific security
vulnerability, and to advise how to fix it.
- The "Unable to flush stdout" error
message was missing a trailing newline. [debian #875361]
- •
- "--help" and
"--version" options have been
added.
- C89 requirement
Perl has been documented as requiring a C89 compiler to build
since October 1998. A variety of simplifications have now been made to
Perl's internals to rely on the features specified by the C89 standard.
We believe that this internal change hasn't altered the set of platforms
that Perl builds on, but please report a bug if Perl now has new
problems building on your platform.
- On GCC, "-Werror=pointer-arith" is now
enabled by default, disallowing arithmetic on void and function
pointers.
- Where an HTML version of the documentation is installed, the HTML
documents now use relative links to refer to each other. Links from the
index page of perlipc to the individual section documents are now correct.
[GH #11941] <https://github.com/Perl/perl5/issues/11941>
- lib/unicore/mktables now correctly canonicalizes the names of the
dependencies stored in the files it generates.
regen/mk_invlists.pl, unlike the other
regen/*.pl scripts, used $0 to name
itself in the dependencies stored in the files it generates. It now uses
a literal so that the path stored in the generated files doesn't depend
on how regen/mk_invlists.pl is invoked.
This lack of canonical names could cause test failures in
t/porting/regen.t. [GH #16446]
<https://github.com/Perl/perl5/issues/16446>
- New probes
- Testing of the XS-APItest directory is now done in parallel, where
applicable.
- Perl now includes a default .travis.yml file for Travis CI testing
on github mirrors. [GH #14558]
<https://github.com/Perl/perl5/issues/14558>
- The watchdog timer count in re/pat_psycho.t can now be overridden.
This test can take a long time to run, so there is a timer to
keep this in check (currently, 5 minutes). This commit adds checking the
environment variable
"PERL_TEST_TIME_OUT_FACTOR"; if set,
the time out setting is multiplied by its value.
- harness no longer waits for 30 seconds when running
t/io/openpid.t. [GH #13535]
<https://github.com/Perl/perl5/issues/13535> [GH #16420]
<https://github.com/Perl/perl5/issues/16420>
For the past few years we have released perl using three different
archive formats: bzip (".bz2"), LZMA2
(".xz") and gzip
(".gz"). Since xz compresses better and
decompresses faster, and gzip is more compatible and uses less memory, we
have dropped the ".bz2" archive format
with this release. (If this poses a problem, do let us know; see
"Reporting Bugs", below.)
- PowerUX / Power MAX
OS
- Compiler hints and other support for these apparently long-defunct
platforms has been removed.
- CentOS
- Compilation on CentOS 5 is now fixed.
- Cygwin
- A build with the quadmath library can now be done on Cygwin.
- Darwin
- Perl now correctly uses reentrant functions, like
"asctime_r", on versions of Darwin that
have support for them.
- FreeBSD
- FreeBSD's /usr/share/mk/sys.mk specifies
"-O2" for architectures other than ARM
and MIPS. By default, perl is now compiled with the same optimization
levels.
- VMS
- Several fix-ups for configure.com, marking function VMS has (or
doesn't have).
CRTL features can now be set by embedders before invoking Perl
by using the "decc$feature_set" and
"decc$feature_set_value" functions.
Previously any attempt to set features after image initialization were
ignored.
- Windows
- Support for compiling perl on Windows using Microsoft Visual Studio 2017
(containing Visual C++ 14.1) has been added.
- Visual C++ compiler version detection has been improved to work on
non-English language systems.
- We now set $Config{libpth} correctly for 64-bit
builds using Visual C++ versions earlier than 14.1.
- A new optimisation phase has been added to the compiler,
"optimize_optree()", which does a
top-down scan of a complete optree just before the peephole optimiser is
run. This phase is not currently hookable.
- An "OP_MULTICONCAT" op has been added.
At "optimize_optree()" time, a chain of
"OP_CONCAT" and
"OP_CONST" ops, together optionally with
an "OP_STRINGIFY" and/or
"OP_SASSIGN", are combined into a single
"OP_MULTICONCAT" op. The op is of type
"UNOP_AUX", and the aux array contains
the argument count, plus a pointer to a constant string and a set of
segment lengths. For example with
my $x = "foo=$foo, bar=$bar\n";
the constant string would be "foo=,
bar=\n" and the segment lengths would be (4,6,1). If the
string contains characters such as
"\x80", whose representation changes
under utf8, two sets of strings plus lengths are precomputed and
stored.
- Direct access to "PL_keyword_plugin" is
not safe in the presence of multithreading. A new
"wrap_keyword_plugin" function has been
added to allow XS modules to safely define custom keywords even when
loaded from a thread, analogous to
"PL_check" /
"wrap_op_checker".
- The "PL_statbuf" interpreter variable
has been removed.
- The deprecated function
"to_utf8_case()", accessible from XS
code, has been removed.
- A new function
"is_utf8_invariant_string_loc()" has
been added that is like
"is_utf8_invariant_string()" but takes
an extra pointer parameter into which is stored the location of the first
variant character, if any are found.
- A new function, "Perl_langinfo()" has
been added. It is an (almost) drop-in replacement for the system
nl_langinfo(3), but works on platforms that lack
that; as well as being more thread-safe, and hiding some gotchas with
locale handling from the caller. Code that uses this, needn't use
localeconv(3) (and be affected by the gotchas) to
find the decimal point, thousands separator, or currency symbol. See
"Perl_langinfo" in perlapi.
- A new API function "sv_rvunweaken()" has
been added to complement
"sv_rvweaken()". The implementation was
taken from "unweaken" in Scalar::Util.
- A new flag, "SORTf_UNSTABLE", has been
added. This will allow a future commit to make mergesort unstable when the
user specifies Xno sort stableX, since it has been decided that mergesort
should remain stable by default.
- XS modules can now automatically get reentrant versions of system
functions on threaded perls.
By adding
#define PERL_REENTRANT
near the beginning of an
"XS" file, it will be compiled so that
whatever reentrant functions perl knows about on that system will
automatically and invisibly be used instead of the plain, non-reentrant
versions. For example, if you write
"getpwnam()" in your code, on a system
that has "getpwnam_r()" all calls to
the former will be translated invisibly into the latter. This does not
happen except on threaded perls, as they aren't needed otherwise. Be
aware that which functions have reentrant versions varies from system to
system.
- The "PERL_NO_OP_PARENT" build define is
no longer supported, which means that perl is now always built with
"PERL_OP_PARENT" enabled.
- The format and content of the non-utf8 transliteration table attached to
the "op_pv" field of
"OP_TRANS"/"OP_TRANSR"
ops has changed. It's now a "struct
OPtrans_map".
- A new compiler "#define",
"dTHX_DEBUGGING". has been added. This
is useful for XS or C code that only need the thread context because their
debugging statements that get compiled only under
"-DDEBUGGING" need one.
- A new API function "Perl_setlocale" in perlapi has been
added.
- "sync_locale" in perlapi has been revised to return a boolean as
to whether the system was using the global locale or not.
- A new kind of magic scalar, called a "nonelem" scalar, has been
introduced. It is stored in an array to denote a non-existent element,
whenever such an element is accessed in a potential lvalue context. It
replaces the existing "defelem" (deferred element) magic
wherever this is possible, being significantly more efficient. This means
that "some_sub($sparse_array[$nonelem])"
no longer has to create a new magic defelem scalar each time, as long as
the element is within the array.
It partially fixes the rare bug of deferred elements getting
out of synch with their arrays when the array is shifted or unshifted.
[GH #16364] <https://github.com/Perl/perl5/issues/16364>
- List assignment ("aassign") could in
some rare cases allocate an entry on the mortals stack and leave the entry
uninitialized, leading to possible crashes. [GH #16017]
<https://github.com/Perl/perl5/issues/16017>
- Attempting to apply an attribute to an
"our" variable where a function of that
name already exists could result in a NULL pointer being supplied where an
SV was expected, crashing perl. [perl #131597]
<https://rt.perl.org/Ticket/Display.html?id=131597>
- "split ' '" now correctly handles the
argument being split when in the scope of the
"unicode_strings" feature. Previously,
when a string using the single-byte internal representation contained
characters that are whitespace by Unicode rules but not by ASCII rules, it
treated those characters as part of fields rather than as field
separators. [GH #15904]
<https://github.com/Perl/perl5/issues/15904>
- Several built-in functions previously had bugs that could cause them to
write to the internal stack without allocating room for the item being
written. In rare situations, this could have led to a crash. These bugs
have now been fixed, and if any similar bugs are introduced in future,
they will be detected automatically in debugging builds.
These internal stack usage checks introduced are also done by
the "entersub" operator when calling
XSUBs. This means we can report which XSUB failed to allocate enough
stack space. [GH #16126]
<https://github.com/Perl/perl5/issues/16126>
- Using a symbolic ref with postderef syntax as the key in a hash lookup was
yielding an assertion failure on debugging builds. [GH #16029]
<https://github.com/Perl/perl5/issues/16029>
- Array and hash variables whose names begin with a caret now admit indexing
inside their curlies when interpolated into strings, as in
"${^CAPTURE[0]}" to index
"@{^CAPTURE}". [GH #16050]
<https://github.com/Perl/perl5/issues/16050>
- Fetching the name of a glob that was previously UTF-8 but wasn't any
longer would return that name flagged as UTF-8. [GH #15971]
<https://github.com/Perl/perl5/issues/15971>
- The perl "sprintf()" function (via the
underlying C function
"Perl_sv_vcatpvfn_flags()") has been
heavily reworked to fix many minor bugs, including the integer wrapping of
large width and precision specifiers and potential buffer overruns. It has
also been made faster in many cases.
- Exiting from an "eval", whether normally
or via an exception, now always frees temporary values (possibly calling
destructors) before setting $@. For
example:
sub DESTROY { eval { die "died in DESTROY"; } }
eval { bless []; };
# $@ used to be equal to "died in DESTROY" here; it's now "".
- Fixed a duplicate symbol failure with "-flto
-mieee-fp" builds. pp.c defined
"_LIB_VERSION" which
"-lieee" already defines. [GH #16086]
<https://github.com/Perl/perl5/issues/16086>
- The tokenizer no longer consumes the exponent part of a floating point
number if it's incomplete. [GH #16073]
<https://github.com/Perl/perl5/issues/16073>
- On non-threaded builds, for "m/$null/"
where $null is an empty string is no longer
treated as if the "/o" flag was present
when the previous matching match operator included the
"/o" flag. The rewriting used to
implement this behavior could confuse the interpreter. This matches the
behaviour of threaded builds. [GH #14668]
<https://github.com/Perl/perl5/issues/14668>
- Parsing a "sub" definition could cause a
use after free if the "sub" keyword was
followed by whitespace including newlines (and comments.) [GH #16097]
<https://github.com/Perl/perl5/issues/16097>
- The tokenizer now correctly adjusts a parse pointer when skipping
whitespace in a "${identifier}"
construct. [perl #131949]
<https://rt.perl.org/Public/Bug/Display.html?id=131949>
- Accesses to "${^LAST_FH}" no longer
assert after using any of a variety of I/O operations on a non-glob. [GH
#15372] <https://github.com/Perl/perl5/issues/15372>
- The XS-level "Copy()",
"Move()",
"Zero()" macros and their variants now
assert if the pointers supplied are
"NULL". ISO C considers supplying NULL
pointers to the functions these macros are built upon as undefined
behaviour even when their count parameters are zero. Based on these
assertions and the original bug report three macro calls were made
conditional. [GH #16079]
<https://github.com/Perl/perl5/issues/16079> [GH #16112]
<https://github.com/Perl/perl5/issues/16112>
- Only the "=" operator is permitted for
defining defaults for parameters in subroutine signatures. Previously
other assignment operators, e.g. "+=",
were also accidentally permitted. [GH #16084]
<https://github.com/Perl/perl5/issues/16084>
- Package names are now always included in
":prototype" warnings [perl #131833]
<https://rt.perl.org/Public/Bug/Display.html?id=131833>
- The "je_old_stack_hwm" field, previously
only found in the "jmpenv" structure on
debugging builds, has been added to non-debug builds as well. This fixes
an issue with some CPAN modules caused by the size of this structure
varying between debugging and non-debugging builds. [GH #16122]
<https://github.com/Perl/perl5/issues/16122>
- The arguments to the "ninstr()" macro
are now correctly parenthesized.
- A NULL pointer dereference in the
"S_regmatch()" function has been fixed.
[perl #132017]
<https://rt.perl.org/Public/Bug/Display.html?id=132017>
- Calling exec PROGRAM LIST with an empty
"LIST" has been fixed. This should call
"execvp()" with an empty
"argv" array (containing only the
terminating "NULL" pointer), but was
instead just returning false (and not setting $!).
[GH #16075] <https://github.com/Perl/perl5/issues/16075>
- The "gv_fetchmeth_sv" C function stopped
working properly in Perl 5.22 when fetching a constant with a UTF-8 name
if that constant subroutine was stored in the stash as a simple scalar
reference, rather than a full typeglob. This has been corrected.
- Single-letter debugger commands followed by an argument which starts with
punctuation (e.g. "p$^V" and
"x@ARGV") now work again. They had been
wrongly requiring a space between the command and the argument. [GH
#13342] <https://github.com/Perl/perl5/issues/13342>
- splice now throws an exception ("Modification of a read-only value
attempted") when modifying a read-only array. Until now it had been
silently modifying the array. The new behaviour is consistent with the
behaviour of push and unshift. [GH #15923]
<https://github.com/Perl/perl5/issues/15923>
- "stat()",
"lstat()", and file test operators now
fail if given a filename containing a nul character, in the same way that
"open()" already fails.
- "stat()",
"lstat()", and file test operators now
reliably set $! when failing due to being applied
to a closed or otherwise invalid file handle.
- File test operators for Unix permission bits that don't exist on a
particular platform, such as "-k"
(sticky bit) on Windows, now check that the file being tested exists
before returning the blanket false result, and yield the appropriate
errors if the argument doesn't refer to a file.
- Fixed a 'read before buffer' overrun when parsing a range starting with
"\N{}" at the beginning of the character
set for the transliteration operator. [GH #16189]
<https://github.com/Perl/perl5/issues/16189>
- Fixed a leaked scalar when parsing an empty
"\N{}" at compile-time. [GH #16189]
<https://github.com/Perl/perl5/issues/16189>
- Calling "do $path" on a directory or
block device now yields a meaningful error code in
$!. [GH #14841]
<https://github.com/Perl/perl5/issues/14841>
- Regexp substitution using an overloaded replacement value that provides a
tainted stringification now correctly taints the resulting string. [GH
#12495] <https://github.com/Perl/perl5/issues/12495>
- Lexical sub declarations in "do" blocks
such as "do { my sub lex; 123 }" could
corrupt the stack, erasing items already on the stack in the enclosing
statement. This has been fixed. [GH #16243]
<https://github.com/Perl/perl5/issues/16243>
- "pack" and
"unpack" can now handle repeat counts
and lengths that exceed two billion. [GH #13179]
<https://github.com/Perl/perl5/issues/13179>
- Digits past the radix point in octal and binary floating point literals
now have the correct weight on platforms where a floating point
significand doesn't fit into an integer type.
- The canonical truth value no longer has a spurious special meaning as a
callable subroutine. It used to be a magic placeholder for a missing
"import" or
"unimport" method, but is now treated
like any other string 1. [GH #14902]
<https://github.com/Perl/perl5/issues/14902>
- "system" now reduces its arguments to
strings in the parent process, so any effects of stringifying them (such
as overload methods being called or warnings being emitted) are visible in
the way the program expects. [GH #13561]
<https://github.com/Perl/perl5/issues/13561>
- The "readpipe()" built-in function now
checks at compile time that it has only one parameter expression, and puts
it in scalar context, thus ensuring that it doesn't corrupt the stack at
runtime. [GH #2793] <https://github.com/Perl/perl5/issues/2793>
- "sort" now performs correct reference
counting when aliasing $a and
$b, thus avoiding premature destruction and
leakage of scalars if they are re-aliased during execution of the sort
comparator. [GH #11422]
<https://github.com/Perl/perl5/issues/11422>
- "reverse" with no operand, reversing
$_ by default, is no longer in danger of
corrupting the stack. [GH #16291]
<https://github.com/Perl/perl5/issues/16291>
- "exec",
"system", et al are no longer liable to
have their argument lists corrupted by reentrant calls and by magic such
as tied scalars. [GH #15660]
<https://github.com/Perl/perl5/issues/15660>
- Perl's own "malloc" no longer gets
confused by attempts to allocate more than a gigabyte on a 64-bit
platform. [GH #13273]
<https://github.com/Perl/perl5/issues/13273>
- Stacked file test operators in a sort comparator expression no longer
cause a crash. [GH #15626]
<https://github.com/Perl/perl5/issues/15626>
- An identity "tr///" transformation on a
reference is no longer mistaken for that reference for the purposes of
deciding whether it can be assigned to. [GH #15812]
<https://github.com/Perl/perl5/issues/15812>
- Lengthy hexadecimal, octal, or binary floating point literals no longer
cause undefined behaviour when parsing digits that are of such low
significance that they can't affect the floating point value. [GH #16114]
<https://github.com/Perl/perl5/issues/16114>
- "open $$scalarref..." and similar
invocations no longer leak the file handle. [GH #12593]
<https://github.com/Perl/perl5/issues/12593>
- Some convoluted kinds of regexp no longer cause an arithmetic overflow
when compiled. [GH #16113]
<https://github.com/Perl/perl5/issues/16113>
- The default typemap, by avoiding
"newGVgen", now no longer leaks when
XSUBs return file handles ("PerlIO *" or
"FILE *"). [GH #12593]
<https://github.com/Perl/perl5/issues/12593>
- Creating a "BEGIN" block as an XS
subroutine with a prototype no longer crashes because of the early freeing
of the subroutine.
- The "printf" format specifier
"%.0f" no longer rounds incorrectly [GH
#9125] <https://github.com/Perl/perl5/issues/9125>, and now shows
the correct sign for a negative zero.
- Fixed an issue where the error "Scalar value
@arrayname[0] better written as
$arrayname" would give an error "Cannot
printf Inf with 'c'" when arrayname starts with
"Inf". [GH #16335]
<https://github.com/Perl/perl5/issues/16335>
- The Perl implementation of "getcwd()" in
"Cwd" in the PathTools distribution now
behaves the same as XS implementation on errors: it returns an error, and
sets $!. [GH #16338]
<https://github.com/Perl/perl5/issues/16338>
- Vivify array elements when putting them on the stack. Fixes [GH #5310]
<https://github.com/Perl/perl5/issues/5310> (reported in April
2002).
- Fixed parsing of braced subscript after parens. Fixes [GH #4688]
<https://github.com/Perl/perl5/issues/4688> (reported in December
2001).
- "tr/non_utf8/long_non_utf8/c" could give
the wrong results when the length of the replacement character list was
greater than 0x7fff.
- "tr/non_utf8/non_utf8/cd" failed to add
the implied "\x{100}-\x{7fffffff}" to
the search character list.
- Compilation failures within "perl-within-perl" constructs, such
as with string interpolation and the right part of
"s///e", now cause compilation to abort
earlier.
Previously compilation could continue in order to report other
errors, but the failed sub-parse could leave partly parsed constructs on
the parser shift-reduce stack, confusing the parser, leading to perl
crashes. [GH #14739]
<https://github.com/Perl/perl5/issues/14739>
- On threaded perls where the decimal point (radix) character is not a dot,
it has been possible for a race to occur between threads when one needs to
use the real radix character (such as with
"sprintf"). This has now been fixed by
use of a mutex on systems without thread-safe locales, and the problem
just doesn't come up on those with thread-safe locales.
- Errors while compiling a regex character class could sometime trigger an
assertion failure. [GH #16172]
<https://github.com/Perl/perl5/issues/16172>
Perl 5.28.0 represents approximately 13 months of development
since Perl 5.26.0 and contains approximately 730,000 lines of changes across
2,200 files from 77 authors.
Excluding auto-generated files, documentation and release tools,
there were approximately 580,000 lines of changes to 1,300 .pm, .t, .c and
.h files.
Perl continues to flourish into its fourth decade thanks to a
vibrant community of users and developers. The following people are known to
have contributed the improvements that became Perl 5.28.0:
Aaron Crane, Abigail, AEvar Arnfjoerd` Bjarmason, Alberto Simo~es,
Alexandr Savca, Andrew Fresh, Andy Dougherty, Andy Lester, Aristotle
Pagaltzis, Ask Bjorn Hansen, Chris 'BinGOs' Williams, Craig A. Berry,
Dagfinn Ilmari Mannsaaker, Dan Collins, Daniel Dragan, David Cantrell, David
Mitchell, Dmitry Ulanov, Dominic Hargreaves, E. Choroba, Eric Herman, Eugen
Konkov, Father Chrysostomos, Gene Sullivan, George Hartzell, Graham Knop,
Harald Joerg, H.Merijn Brand, Hugo van der Sanden, Jacques Germishuys, James
E Keenan, Jarkko Hietaniemi, Jerry D. Hedden, J. Nick Koston, John Lightsey,
John Peacock, John P. Linderman, John SJ Anderson, Karen Etheridge, Karl
Williamson, Ken Brown, Ken Cotterill, Leon Timmermans, Lukas Mai, Marco
Fontani, Marc-Philip Werner, Matthew Horsfall, Neil Bowers, Nicholas Clark,
Nicolas R., Niko Tyni, Pali, Paul Marquess, Peter John Acklam, Reini Urban,
Renee Baecker, Ricardo Signes, Robin Barker, Sawyer X, Scott Lanning, Sergey
Aleynikov, Shirakata Kentaro, Shoichi Kaji, Slaven Rezic, Smylers, Steffen
Mueller, Steve Hay, Sullivan Beck, Thomas Sibley, Todd Rinaldo, Tomasz
Konojacki, Tom Hukins, Tom Wyant, Tony Cook, Vitali Peil, Yves Orton,
Zefram.
The list above is almost certainly incomplete as it is
automatically generated from version control history. In particular, it does
not include the names of the (very much appreciated) contributors who
reported issues to the Perl bug tracker.
Many of the changes included in this version originated in the
CPAN modules included in Perl's core. We're grateful to the entire CPAN
community for helping Perl to flourish.
For a more complete list of all of Perl's historical contributors,
please see the AUTHORS file in the Perl source distribution.
If you find what you think is a bug, you might check the perl bug
database at <https://rt.perl.org/> . There may also be information at
<http://www.perl.org/> , the Perl Home Page.
If you believe you have an unreported bug, please run the perlbug
program included with your release. Be sure to trim your bug down to a tiny
but sufficient test case. Your bug report, along with the output of
"perl -V", will be sent off to
perlbug@perl.org to be analysed by the Perl porting team.
If the bug you are reporting has security implications which make
it inappropriate to send to a publicly archived mailing list, then see
"SECURITY VULNERABILITY CONTACT INFORMATION" in perlsec for
details of how to report the issue.
If you wish to thank the Perl 5 Porters for the work we had done
in Perl 5, you can do so by running the
"perlthanks" program:
perlthanks
This will send an email to the Perl 5 Porters list with your show
of thanks.
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.