Provided by: perl-doc_5.38.2-3.2build2_all 
NAME
perl5380delta - what is new for perl v5.38.0
DESCRIPTION
This document describes differences between the 5.36.0 release and the 5.38.0 release.
Core Enhancements
New "class" Feature
A new experimental syntax is now available for defining object classes, where per-instance
data is stored in "field" variables that behave like lexicals.
use feature 'class';
class Point
{
field $x;
field $y;
method zero { $x = $y = 0; }
}
This is described in more detail in perlclass. Notes on the internals of its
implementation and other related details can be found in perlclassguts.
This remains a new and experimental feature, and is very much still under development. It
will be the subject of much further addition, refinement and alteration in future
releases. As it is experimental, it yields warnings in the "experimental::class"
category. These can be silenced by a "no warnings" statement.
use feature 'class';
no warnings 'experimental::class';
Unicode 15.0 is supported
See <https://www.unicode.org/versions/Unicode15.0.0/> for details.
Deprecation warnings now have specific subcategories
All deprecation warnings now have their own specific deprecation category which can be
disabled individually. You can see a list of all deprecated features in perldeprecation,
and in warnings. The following list is from warnings:
+- deprecated ----+
| |
| +- deprecated::apostrophe_as_package_separator
| |
| +- deprecated::delimiter_will_be_paired
| |
| +- deprecated::dot_in_inc
| |
| +- deprecated::goto_construct
| |
| +- deprecated::smartmatch
| |
| +- deprecated::unicode_property_name
| |
| +- deprecated::version_downgrade
It is still possible to disable all deprecation warnings in a single statement with
no warnings 'deprecated';
but now is possible to have a finer grained control. As has historically been the case
these warnings are automatically enabled with
use warnings;
%{^HOOK} API introduced
For various reasons it can be difficult to create subroutine wrappers for some of perls
keywords. Any keyword which has an undefined prototype simply cannot be wrapped with a
subroutine, and some keywords which perl permits to be wrapped are in practice very tricky
to wrap. For example "require" is tricky to wrap, it is possible but doing so changes the
stack depth, and the standard methods of exporting assume that they will be exporting to a
package at certain stack depth up the stack, and the wrapper will thus change where
functions are exported to unless implemented with a great deal of care. This can be very
awkward to deal with.
Accordingly we have introduced a new hash called "%{^HOOK}" which is intended to
facilitate such cases. When a keyword supports any kind of special hook then the hook will
live in this new hash. Hooks in this hash will be named after the function they are called
by, followed by two underbars and then the phase they are executed in, currently either
before or after the keyword is executed.
In this initial release we support two hooks "require__before" and "require__after". These
are provided to make it easier to perform tasks before and after a require statement.
See perlvar for more details.
PERL_RAND_SEED
Added a new environment variable "PERL_RAND_SEED" which can be used to cause a perl
program which uses "rand" without using srand() explicitly or which uses srand() with no
arguments to be repeatable. See perlrun. This feature can be disabled at compile time by
passing
-Accflags=-DNO_PERL_RAND_SEED
to Configure during the build process.
Defined-or and logical-or assignment default expressions in signatures
The default expression for a subroutine signature parameter can now be assigned using the
"//=" or "||=" operators, to apply the defaults whenever the caller provided an undefined
or false value (respectively), rather than simply when the parameter is missing entirely.
For more detail see the documentation in perlsub.
@INC Hook Enhancements and $INC and INCDIR
The internals for @INC hooks have been hardened to handle various edge cases and should no
longer segfault or throw assert failures when hooks modify @INC during a require
operation. As part of this we now ensure that any given hook is executed at most once
during a require call, and that any duplicate directories do not trigger additional
directory probes.
To provide developers more control over dynamic module lookup, a new hook method "INCDIR"
is now supported. An object supporting this method may be injected into the @INC array,
and when it is encountered in the module search process it will be executed, just like how
INC hooks are executed, and its return value used as a list of directories to search for
the module. Returning an empty list acts as a no-op. Note that since any references
returned by this hook will be stringified and used as strings, you may not return a hook
to be executed later via this API.
When an @INC hook (either "INC" or "INCDIR") is called during require, the $INC variable
will be localized to be the value of the index of @INC that the hook came from. If the
hook wishes to override what the "next" index in @INC should be it may update $INC to be
one less than the desired index ("undef" is equivalent to -1). This allows an @INC hook to
completely rewrite the @INC array and have perl restart its directory probes from the
beginning of @INC.
Blessed CODE references in @INC that do not support the "INC" or "INCDIR" methods will no
longer trigger an exception, and instead will be treated the same as unblessed coderefs
are, and executed as though they were an "INC" hook.
Forbidden control flow out of "defer" or "finally" now detected at compile-time
It is forbidden to attempt to leave a "defer" or "finally" block by means of control flow
such as "return" or "goto". Previous versions of perl could only detect this when actually
attempted at runtime.
This version of perl adds compile-time detection for many cases that can be statically
determined. This may mean that code which compiled successfully on a previous version of
perl is now reported as a compile-time error with this one. This only happens in cases
where it would have been an error to actually execute the code anyway; the error simply
happens at an earlier time.
Optimistic Eval in Patterns
The use of "(?{ ... })" and "(??{ ... })" in a pattern disables various optimisations
globally in that pattern. This may or may not be desired by the programmer. This release
adds the "(*{ ... })" equivalent. The only difference is that it does not and will never
disable any optimisations in the regex engine. This may make it more unstable in the sense
that it may be called more or less times in the future, however the number of times it
executes will truly match how the regex engine functions. For example, certain types of
optimisation are disabled when "(?{ ... })" is included in a pattern, so that patterns
which are O(N) in normal use become O(N*N) with a "(?{ ... })" pattern in them. Switching
to "(*{ ... })" means the pattern will stay O(N).
REG_INF has been raised from 65,536 to 2,147,483,647
Many regex quantifiers used to be limited to "U16_MAX" in the past, but are now limited to
"I32_MAX", thus it is now possible to write "/(?:word){1000000}/" for example. Note that
doing so may cause the regex engine to run longer and use more memory.
New API functions optimize_optree and finalize_optree
There are two new API functions for operating on optree fragments, ensuring you can invoke
the required parts of the optree-generation process that might otherwise not get invoked
(e.g. when creating a custom LOGOP). To get access to these functions, you first need to
set a "#define" to opt-in to using these functions.
#define PERL_USE_VOLATILE_API
These functions are closely tied to the internals of how the interpreter works, and could
be altered or removed at any time if other internal changes make that necessary.
Some "goto"s are now permitted in "defer" and "finally" blocks
Perl version 5.36.0 added "defer" blocks and permitted the "finally" keyword to also add
similar behaviour to "try"/"catch" syntax. These did not permit any "goto" expression
within the body, as it could have caused control flow to jump out of the block. Now, some
"goto" expressions are allowed, if they have a constant target label, and that label is
found within the block.
use feature 'defer';
defer {
goto LABEL;
print "This does not execute\n";
LABEL: print "This does\n";
}
New regexp variable ${^LAST_SUCCESSFUL_PATTERN}
This allows access to the last succesful pattern that matched in the current scope. Many
aspects of the regex engine refer to the "last successful pattern". The empty pattern
reuses it, and all of the magic regex vars relate to it. This allows access to its
pattern. The following code
if (m/foo/ || m/bar/) {
s//PQR/;
}
can be rewritten as follows
if (m/foo/ || m/bar/) {
s/${^LAST_SUCCESSFUL_PATTERN}/PQR/;
}
and it will do the exactly same thing.
Locale category LC_NAME now supported on participating platforms
On platforms that have the GNU extension "LC_NAME" category, you may now use it as the
category parameter to "setlocale" in POSIX to set and query its locale.
Incompatible Changes
readline() no longer clears the stream error and eof flags
readline(), also spelled "<>", would clear the handle's error and eof flags after an error
occurred on the stream.
In nearly all cases this clear is no longer done, so the error and eof flags now properly
reflect the status of the stream after readline().
Since the error flag is no longer cleared calling close() on the stream may fail and if
the stream was not explicitly closed, the implicit close of the stream may produce a
warning.
This has resulted in two main types of problems in downstream CPAN modules, and these may
also occur in your code:
• If your code reads to end of file, and then rebinds the handle to a new file
descriptor, previously since the eof flag wasn't set you could continue to read from
the stream. You now need to clear the eof flag yourself with "$handle->clearerr()" to
continue reading.
• If your code encounters an error on the stream while reading with readline() you will
need to call "$handle->clearerr" to continue reading. The one case this occurred the
underlying file descriptor was marked non-blocking, so the read() system call was
failing with "EAGAIN", which resulted in the error flag being set on the stream.
The only case where error and eof flags continue to cleared on error is when reading from
the child process for glob() in miniperl. This allows it to correctly report errors from
the child process on close(). This is unlikely to be an issue during normal perl
development.
[GH #20060 <https://github.com/Perl/perl5/issues/20060>]
"INIT" blocks no longer run after an exit() in "BEGIN"
"INIT" blocks will no longer run after an exit() performed inside of a "BEGIN". This means
that the combination of the "-v" option and the "-c" option no longer executes a compile
check as well as showing the perl version. The "-v" option executes an exit(0) after
printing the version information inside of a "BEGIN" block, and the "-c" check is
implemented by using "INIT" hooks, resulting in the "-v" option taking precedence.
[GH #1537 <https://github.com/Perl/perl5/issues/1537>] [GH #20181
<https://github.com/Perl/perl5/issues/20181>]
Syntax errors no longer produce "phantom error messages"
Generally perl will continue parsing the source code even after encountering a compile
error. In many cases this is helpful, for instance with misspelled variable names it is
helpful to show as many examples of the error as possible. But in the case of syntax
errors continuing often produces bizarre error messages and may even cause segmentation
faults during the compile process. In this release the compiler will halt at the first
syntax error encountered. This means that any code expecting to see the specific error
messages we used to produce will be broken. The error that is emitted will be one of the
diagnostics that used to be produced, but in some cases some messages that used to be
produced will no longer be displayed.
See "Changes to Existing Diagnostics" for more details.
utf8::upgrade()
Starting in this release, if the input string is "undef", it remains "undef". Previously
it would be changed into a defined, zero-length string.
Changes to "thread-safe" locales
Perl 5.28 introduced "thread-safe" locales on systems that supported them, namely modern
Windows, and systems supporting POSIX 2008 locale operations. These systems accomplish
this by having per-thread locales, while continuing to support the older global locale
operations for code that doesn't take the steps necessary to use the newer per-thread
ones.
It turns out that some POSIX 2008 platforms have or have had buggy implementations, which
forced perl to not use them. The "${^SAFE_LOCALES}" scalar variable contains 0 or 1 to
indicate whether or not the current platform is considered by perl to have a working
thread-safe implementation. Some implementations have been fixed already, but FreeBSD and
Cygwin have been newly discovered to be sufficiently buggy that the thread-safe operations
are no longer used by perl, starting in this release. Hence, "${^SAFE_LOCALES}" is now 0
for them. Older versions of perl can be configured to avoid these buggy implementations
by adding the Configure option "-DNO_POSIX_2008_LOCALE".
And v5.38 fixes a bug in all previous perls that led to locales not being fully thread-
safe. The first thread that finishes caused the main thread (named "thread0") to revert
to the global locale in effect at startup, discarding whatever the thread's locale had
been previously set to. If any other thread had switched to the global locale by calling
switch_to_global_locale() in XS code, those threads would all share the global locale, and
"thread0" would not be thread-safe.
Deprecations
Use of "'" as a package name separator is deprecated
Using "'" as package separator in a variable named in a double-quoted string has warned
since 5.28. It is now deprecated in both string interpolation and non-interpolated
contexts, and will be removed in Perl 5.42.
Switch and Smart Match operator
The "switch" feature and the smartmatch operator, "~~", were introduced in v5.10. Their
behavior was significantly changed in v5.10.1. When the "experiment" system was added in
v5.18.0, switch and smartmatch were retroactively declared experimental. Over the years,
proposals to fix or supplement the features have come and gone.
In v5.38.0, we are declaring the experiment a failure. Some future system may take the
conceptual place of smartmatch, but it has not yet been designed or built.
These features will be entirely removed from perl in v5.42.0.
Performance Enhancements
• Additional optree optimizations for common OP patterns. For example, multiple simple
OPs replaced by a single streamlined OP, so as to be more efficient at runtime. [GH
#19943 <https://github.com/Perl/perl5/pull/19943>], [GH #20063
<https://github.com/Perl/perl5/pull/20063>], [GH #20077
<https://github.com/Perl/perl5/pull/20077>].
• Creating an anonymous sub no longer generates an "srefgen" op, the reference
generation is now done in the "anoncode" or "anonconst" op, saving runtime. [GH #20290
<https://github.com/Perl/perl5/pull/20290>]
Modules and Pragmata
Updated Modules and Pragmata
• Added the is_tainted() builtin function. [GH #19854
<https://github.com/Perl/perl5/issues/19854>]
• Added the export_lexically() builtin function as per PPC 0020
<https://github.com/Perl/PPCs/blob/main/ppcs/ppc0020-lexical-export.md>. [GH #19895
<https://github.com/Perl/perl5/issues/19895>]
• Support for PPC 0018 <https://github.com/Perl/PPCs/blob/main/ppcs/ppc0018-module-
true.md>, "use feature "module_true";" has been added to the default feature bundle
for v5.38 and later. It may also be used explicitly. When enabled inside of a module
the module does not need to return true explicitly, and in fact the return will be
forced to a simple true value regardless of what it originally was.
• Attribute::Handlers has been upgraded from version 1.02 to 1.03.
• attributes has been upgraded from version 0.34 to 0.35.
• autodie has been upgraded from version 2.34 to 2.36.
• B has been upgraded from version 1.83 to 1.88.
• B::Concise has been upgraded from version 1.006 to 1.007.
• B::Deparse has been upgraded from version 1.64 to 1.74.
• Benchmark has been upgraded from version 1.23 to 1.24.
• bignum has been upgraded from version 0.65 to 0.66.
• Carp has been upgraded from version 1.52 to 1.54.
• Class::Struct has been upgraded from version 0.66 to 0.68.
• Compress::Raw::Bzip2 has been upgraded from version 2.103 to 2.204_001.
• Compress::Raw::Zlib has been upgraded from version 2.105 to 2.204_001.
• Config::Perl::V has been upgraded from version 0.33 to 0.36.
• CPAN has been upgraded from version 2.33 to 2.36.
• Data::Dumper has been upgraded from version 2.184 to 2.188.
• DB_File has been upgraded from version 1.857 to 1.858.
• Devel::Peek has been upgraded from version 1.32 to 1.33.
• Devel::PPPort has been upgraded from version 3.68 to 3.71.
• Digest::MD5 has been upgraded from version 2.58 to 2.58_01.
• Digest::SHA has been upgraded from version 6.02 to 6.04.
• DynaLoader has been upgraded from version 1.52 to 1.54.
• Encode has been upgraded from version 3.17 to 3.19.
• encoding::warnings has been upgraded from version 0.13 to 0.14.
• Env has been upgraded from version 1.05 to 1.06.
• Errno has been upgraded from version 1.36 to 1.37.
• experimental has been upgraded from version 0.028 to 0.031.
• ExtUtils::CBuilder has been upgraded from version 0.280236 to 0.280238.
• ExtUtils::Install has been upgraded from version 2.20 to 2.22.
• ExtUtils::MakeMaker has been upgraded from version 7.64 to 7.70.
• ExtUtils::Miniperl has been upgraded from version 1.11 to 1.13.
• ExtUtils::ParseXS has been upgraded from version 3.45 to 3.51.
• ExtUtils::PL2Bat has been upgraded from version 0.004 to 0.005.
• ExtUtils::Typemaps has been upgraded from version 3.45 to 3.51.
• feature has been upgraded from version 1.72 to 1.82.
• File::Basename has been upgraded from version 2.85 to 2.86.
• File::Copy has been upgraded from version 2.39 to 2.41.
• File::Find has been upgraded from version 1.40 to 1.43.
• File::Glob has been upgraded from version 1.37 to 1.40.
• File::Spec has been upgraded from version 3.84 to 3.89.
• File::stat has been upgraded from version 1.12 to 1.13.
• FileHandle has been upgraded from version 2.03 to 2.05.
• Filter::Util::Call has been upgraded from version 1.60 to 1.64.
• GDBM_File has been upgraded from version 1.23 to 1.24.
• Getopt::Long has been upgraded from version 2.52 to 2.54.
• Hash::Util has been upgraded from version 0.28 to 0.30.
• HTTP::Tiny has been upgraded from version 0.080 to 0.083.
• I18N::Langinfo has been upgraded from version 0.21 to 0.22.
• IO has been upgraded from version 1.50 to 1.52.
• IO-Compress has been upgraded from version 2.106 to 2.204.
• IO::Socket::IP has been upgraded from version 0.41 to 0.41_01.
On DragonflyBSD, detect setsockopt() not actually clearing "IPV6_V6ONLY" even when
setsockopt() returns success. [cpan #148293
<https://rt.cpan.org/Ticket/Display.html?id=148293>]
• IO::Zlib has been upgraded from version 1.11 to 1.14.
• JSON::PP has been upgraded from version 4.07 to 4.16.
• libnet has been upgraded from version 3.14 to 3.15.
• Locale::Maketext has been upgraded from version 1.31 to 1.33.
• Math::BigInt has been upgraded from version 1.999830 to 1.999837.
• Math::BigInt::FastCalc has been upgraded from version 0.5012 to 0.5013.
• Math::BigRat has been upgraded from version 0.2621 to 0.2624.
• Math::Complex has been upgraded from version 1.5902 to 1.62.
• Memoize has been upgraded from version 1.03_01 to 1.16.
• MIME::Base64 has been upgraded from version 3.16 to 3.16_01.
• Module::CoreList has been upgraded from version 5.20220520 to 5.20230520.
• mro has been upgraded from version 1.26 to 1.28.
• NDBM_File has been upgraded from version 1.15 to 1.16.
• Net::Ping has been upgraded from version 2.74 to 2.76.
• ODBM_File has been upgraded from version 1.17 to 1.18.
• Opcode has been upgraded from version 1.57 to 1.64.
• overload has been upgraded from version 1.35 to 1.37.
• parent has been upgraded from version 0.238 to 0.241.
• PerlIO::via::QuotedPrint has been upgraded from version 0.09 to 0.10.
• Pod::Checker has been upgraded from version 1.74 to 1.75.
• Pod::Html has been upgraded from version 1.33 to 1.34.
• Pod::Usage has been upgraded from version 2.01 to 2.03.
• podlators has been upgraded from version 4.14 to 5.01.
• POSIX has been upgraded from version 2.03 to 2.13.
• re has been upgraded from version 0.43 to 0.44.
• Safe has been upgraded from version 2.43 to 2.44.
• Scalar::Util has been upgraded from version 1.62 to 1.63.
• SDBM_File has been upgraded from version 1.15 to 1.17.
• Socket has been upgraded from version 2.033 to 2.036.
• Storable has been upgraded from version 3.26 to 3.32.
• Sys::Hostname has been upgraded from version 1.24 to 1.25.
• Term::Cap has been upgraded from version 1.17 to 1.18.
• Test::Simple has been upgraded from version 1.302190 to 1.302194.
• Text::Balanced has been upgraded from version 2.04 to 2.06.
• threads has been upgraded from version 2.27 to 2.36.
• threads::shared has been upgraded from version 1.64 to 1.68.
• Tie::File has been upgraded from version 1.06 to 1.07.
• Time::HiRes has been upgraded from version 1.9770 to 1.9775.
• Time::Piece has been upgraded from version 1.3401 to 1.3401_01.
• Unicode::Normalize has been upgraded from version 1.31 to 1.32.
• UNIVERSAL has been upgraded from version 1.14 to 1.15.
• User::grent has been upgraded from version 1.03 to 1.04.
• User::pwent has been upgraded from version 1.01 to 1.02.
• utf8 has been upgraded from version 1.24 to 1.25.
• warnings has been upgraded from version 1.58 to 1.65.
• XS::APItest has been upgraded from version 1.22 to 1.32.
• XSLoader has been upgraded from version 0.31 to 0.32.
Documentation
New Documentation
perlclass
Describes the new "class" feature.
perlclassguts
Describes the internals of the new "class" feature.
Changes to Existing Documentation
We have attempted to update the documentation to reflect the changes listed in this
document. If you find any we have missed, open an issue at
<https://github.com/Perl/perl5/issues>.
Additionally, the following selected changes have been made:
perlapi
• Documented "hv_ksplit"
• Documented "hv_name_set"
• "hv_store" and "hv_stores" documentation have been greatly improved.
• Documented "gv_autoload_pv"
• Documented "gv_autoload_pvn"
• Documented "gv_autoload_sv"
• Documented "gv_name_set"
• Documented "start_subparse"
• Documented "SV_CHECK_THINKFIRST_COW_DROP"
• Documented "SV_CHECK_THINKFIRST"
• Documented "SvPV_shrink_to_cur"
• Documented "save_aelem"
• Documented "save_aelem_flags"
• Documented "save_helem"
• Documented "save_helem_flags"
perldeprecation
• Added information about unscheduled deprecations and their categories.
• Added category information for existing scheduled deprecations.
• Added smartmatch and apostrophe as a package separator deprecation data.
perlintern
• Documented "save_pushptr"
• Documented "save_scalar_at"
• Entries have been added to perlguts for the new "newAV_alloc_x", "newAV_alloc_xz" and
*_simple functions.
• References to the now-defunct PrePAN service have been removed from perlcommunity and
perlmodstyle.
• A section on symbol naming has been added to perlhacktips.
• perlexperiment has been edited to properly reference the warning categories for the
defer block modifier and extra paired delimiters for quote-like operators.
perlexperiment
• Smartmatch has been moved from experimental status to deprecated status.
Unfortunately the experiment did not work out.
perlfunc
• Some wording improvements have been made for the "ucfirst", "push", "unshift" and
"bless" functions, as well as additional examples added.
perlhacktips
• A new section, "Writing safer macros" in perlhacktips has been added to discuss
pitfalls and solutions to using C macros in C and XS code.
• A new section, "Choosing good symbol names" in perlhacktips, has been added to discuss
unexpected gotchas with names.
perlop
• Document the behavior of matching the empty pattern better and specify its
relationship to the new "${^LAST_SUCCESSFUL_PATTERN}" properly.
perlvar
• Added a section on "Scoping Rules of Regex Variables", and other wording improvements
made throughout.
• Added information on the new "%{^HOOK}" interface, and the new "require__before" and
"require__after" hooks which it exposes.
• Correct information on the regex variables "${^PREMATCH}", "${^MATCH}" and
"${^POSTMATCH}", all of which were incorrectly documented due to an oversight.
Specifically they only work properly after a regex operation that used the /p modifier
to enable them.
• Added information on the new regex variable "${^LAST_SUCCESSFUL_PATTERN}", which
represents the pattern of the last successful regex match in scope.
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
• A new syntax error has been added for the error that a "catch" block does not have its
required variable declaration. See catch block requires a (VAR)
• Too many nested BEGIN blocks, maximum of %d allowed
• Execution of %s aborted due to compilation errors.
• Can't locate object method "INC", nor "INCDIR" nor string overload via package "%s" %s
in @INC
• Attempt to bless into a class
(F) You are attempting to call "bless" with a package name that is a new-style
"class". This is not necessary, as instances created by the constructor are already
in the correct class. Instances cannot be created by other means, such as "bless".
• Cannot assign :param(%s) to field %s because that name is already in use
(F) An attempt was made to apply a parameter name to a field, when the name is already
being used by another field in the same class, or one of its parent classes. This
would cause a name clash so is not allowed.
• Cannot create class %s as it already has a non-empty @ISA
(F) An attempt was made to create a class out of a package that already has an @ISA
array, and the array is not empty. This is not permitted, as it would lead to a class
with inconsistent inheritance.
• Cannot invoke a method of "%s" on an instance of "%s"
(F) You tried to directly call a "method" subroutine of one class by passing in a
value that is an instance of a different class. This is not permitted, as the method
would not have access to the correct instance fields.
• Cannot invoke method on a non-instance
(F) You tried to directly call a "method" subroutine of a class by passing in a value
that is not an instance of that class. This is not permitted, as the method would not
then have access to its instance fields.
• Cannot '%s' outside of a 'class'
(F) You attempted to use one of the keywords that only makes sense inside a "class"
definition, at a location that is not inside such a class.
• Cannot reopen existing class "%s"
(F) You tried to begin a "class" definition for a class that already exists. A class
may only have one definition block.
• Can't bless an object reference
(F) You attempted to call "bless" on a value that already refers to a real object
instance.
• can't convert empty path
(F) On Cygwin, you called a path conversion function with an empty path. Only non-
empty paths are legal.
• Class already has a superclass, cannot add another
(F) You attempted to specify a second superclass for a "class" by using the ":isa"
attribute, when one is already specified. Unlike classes whose instances are created
with "bless", classes created via the "class" keyword cannot have more than one
superclass.
• Class attribute %s requires a value
(F) You specified an attribute for a class that would require a value to be passed in
parentheses, but did not provide one. Remember that whitespace is not permitted
between the attribute name and its value; you must write this as
class Example::Class :attr(VALUE) ...
• Class :isa attribute requires a class but "%s" is not one
(F) When creating a subclass using the "class" ":isa" attribute, the named superclass
must also be a real class created using the "class" keyword.
• Field already has a parameter name, cannot add another
(F) A field may have at most one application of the ":param" attribute to assign a
parameter name to it; once applied a second one is not allowed.
• Field attribute %s requires a value
(F) You specified an attribute for a field that would require a value to be passed in
parentheses, but did not provide one. Remember that whitespace is not permitted
between the attribute name and its value; you must write this as
field $var :attr(VALUE) ...
• Field %s is not accessible outside a method
(F) An attempt was made to access a field variable of a class from code that does not
appear inside the body of a "method" subroutine. This is not permitted, as only
methods will have access to the fields of an instance.
• Field %s of "%s" is not accessible in a method of "%s"
(F) An attempt was made to access a field variable of a class, from a method of
another class nested inside the one that actually defined it. This is not permitted,
as only methods defined by a given class are permitted to access fields of that class.
• Only scalar fields can take a :param attribute
(F) You tried to apply the ":param" attribute to an array or hash field. Currently
this is not permitted.
• Required parameter '%s' is missing for %s constructor
(F) You called the constructor for a class that has a required named parameter, but
did not pass that parameter at all.
• Unexpected characters while parsing class :isa attribute: %s
(F) You tried to specify something other than a single class name with an optional
trailing version number as the value for a "class" ":isa" attribute. This confused
the parser.
• Unrecognized class attribute %s
(F) You attempted to add a named attribute to a "class" definition, but perl does not
recognise the name of the requested attribute.
• Unrecognized field attribute %s
(F) You attempted to add a named attribute to a "field" definition, but perl does not
recognise the name of the requested attribute.
• ${^HOOK}{%s} may only be a CODE reference or undef
• Attempt to set unknown hook '%s' in %{^HOOK}
• Missing or undefined argument to %s via %{^HOOK}{require__before}
• Too many capture groups (limit is %d) in regex m/%s/
New Warnings
• Unknown locale category %d
This is a shortened form of an already existing diagnostic, for use when there is no
new locale being switched to. The previous diagnostic was misleading in such
circumstances.
• Locale '%s' is unsupported, and may crash the interpreter.
• Treating %s::INIT block as BEGIN block as workaround
• Filehandle STD%s reopened as %s only for input
• %s on BEGIN block ignored
• ADJUST is experimental
(S experimental::class) This warning is emitted if you use the "ADJUST" keyword of
"use feature 'class'". This keyword is currently experimental and its behaviour may
change in future releases of Perl.
• class is experimental
(S experimental::class) This warning is emitted if you use the "class" keyword of "use
feature 'class'". This keyword is currently experimental and its behaviour may change
in future releases of Perl.
• Method %s redefined
(W redefine) You redefined a method. To suppress this warning, say
{
no warnings 'redefine';
*name = method { ... };
}
• Odd number of elements in hash field initialization
(W misc) You specified an odd number of elements to initialise a hash field of an
object. Hashes are initialised from a list of key/value pairs so there must be a
corresponding value to every key. The final missing value will be filled in with
undef instead.
• Old package separator "'" deprecated
(W deprecated, syntax) You used the old package separator "'" in a variable,
subroutine or package name. Support for the old package separator will be removed in
Perl 5.40.
• field is experimental
(S experimental::class) This warning is emitted if you use the "field" keyword of "use
feature 'class'". This keyword is currently experimental and its behaviour may change
in future releases of Perl.
• method is experimental
(S experimental::class) This warning is emitted if you use the "method" keyword of
"use feature 'class'". This keyword is currently experimental and its behaviour may
change in future releases of Perl.
• Can't call destructor for 0x%p in global destruction
Changes to Existing Diagnostics
• The compiler will now stop parsing on the first syntax error it encounters.
Historically the compiler would attempt to "skip past" the error and continue parsing
so that it could list multiple errors. For things like undeclared variables under
strict this makes sense. For syntax errors however it has been found that continuing
tends to result in a storm of unrelated or bizarre errors that mostly just obscure the
true error. In extreme cases it can even lead to segfaults and other incorrect
behavior.
Therefore we have reformed the continuation logic so that the parse will stop after
the first seen syntax error. Semantic errors like undeclared variables will not stop
the parse, so you may still see multiple errors when compiling code. However if there
is a syntax error it will be the last error message reported by perl and all of the
errors that you see will be something that actually needs to be fixed.
• Error messages that output class or package names have been modified to output double
quoted strings with various characters escaped so as to make the exact value clear to
a reader. The exact rules on which characters are escaped may change over time but
currently are that printable ASCII codepoints, with the exception of """ and "\", and
unicode word characters whose codepoint is over 255 are output raw, and any other
symbols are escaped much as Data::Dumper might escape them, using "\n" for newline and
"\"" for double quotes, etc. Codepoints in the range 128-255 are always escaped as
they can cause trouble on unicode terminals when output raw.
In older versions of perl the one liner
$ perl -le'"thing\n"->foo()'
would output the following error message exactly as shown here, with text spread over
multiple lines because the "\n" would be emitted as a raw newline character:
Can't locate object method "foo" via package "thing
" (perhaps you forgot to load "thing
"?) at -e line 1.
As of this release we would output this instead (as one line):
Can't locate object method "foo" via package "thing\n"
(perhaps you forgot to load "thing\n"?) at -e line 1.
Notice the newline in the package name has been quoted and escaped, and thus the error
message is a single line. The text is shown here wrapped to two lines only for
readability.
• When package or class names in errors are very large the middle excess portion will be
elided from the message. As of this release error messages will show only up to the
first 128 characters and the last 128 characters in a package or class name in error
messages. For example
$ perl -le'("Foo" x 1000)->new()'
will output the following as one line:
Can't locate object method "new" via package "FooFooFooFooFooFooFoo
FooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFoo
FooFooFooFooFooFooFooFooFooFooFooFooFooFo"..."oFooFooFooFooFooFooFoo
FooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFoo
FooFooFooFooFooFooFooFooFooFooFooFooFoo" (perhaps you forgot to load
"FooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFoo
FooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFo"...
"oFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFoo
FooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFooFoo"?)
at -e line 1.
Notice the "prefix"..."suffix" form of the package name in this case. In previous
versions of perl the complete string would have been shown making the error message
over 6k long and there was no upper limit on the length of the error message at all.
If you accidentally used a 1MB string as a class name then the error message would be
over 2MB long. In this perl the upper limit should be around 2k when eliding and
escaping are taken into account.
• Removed "Complex regular subexpression recursion limit (%d) exceeded"
The regular expresion engine has not used recursion in some time. This warning no
longer makes sense.
See [GH #19636 <https://github.com/Perl/perl5/pull/19636>].
• Various warnings that used to produce parenthesized hints underneath the main warning
message and after its "location data" were chanaged to put the hint inline with the
main message. For instance:
Bareword found where operator expected at -e line 1, near "foo bar"
(Do you need to predeclare foo?)
will now look like this but as one line:
Bareword found where operator expected (Do you need to predeclare
foo?) at -e line 1, near "foo bar"
as a result such warnings will no longer trigger $SIG{__WARN__} twice, and the hint
will be visible when fatal warnings is in effect.
• The error message that is produced when a "require" or "use" statement fails has been
changed. It used to contain the words "@INC contains:", and it used to show the state
of @INC *after* the require had completed and failed. The error message has been
changed to say "@INC entries checked:" and to reflect the actual directories or hooks
that were executed during the require statement. For example:
perl -e'push @INC, sub {@INC=()}; eval "require Frobnitz"
or die $@'
Can't locate Frobnitz.pm in @INC (you may need to install the
Frobnitz module) (@INC contains:) at (eval 1) line 1.
Will change to (with some output elided for clarity):
perl -e'push @INC, sub {@INC=()}; eval "require Frobnitz"
or die $@'
Can't locate Frobnitz.pm in @INC (you may need to install the
Frobnitz module) (@INC entries checked:
.../site_perl/5.38.0/x86_64-linux .../site_perl/5.38.0
.../5.38.0/x86_64-linux .../5.38.0 CODE(0x562745e684b8))
at (eval 1) line 1.
thus showing the actual directories checked. Code that checks for "@INC contains:" in
error messages should be hardened against any future wording changes between the @INC
and ":", for instance use "qr/\@INC[ \w]+:/" instead of using "qr/\@INC contains:/" or
"qr/\@INC entries checked:/" in tests as this will ensure both forward and backward
compatibility.
• Old package separator used in string
This diagnostic is now also part of the "deprecated" category.
• given is deprecated replaces "given is experimental".
• when is deprecated replaces "when is experimental".
• Smartmatch is deprecated replaces "Smartmatch is experimental".
Configuration and Compilation
• "make -j6 minitest" could fail due to a build conflict in building "$(MINIPERL_EXE)"
between the main make process and a child process. [GH #19829
<https://github.com/Perl/perl5/issues/19829>]
• Properly populate osvers on Dragonfly BSD when the hostname isn't set.
• Fix typos for C99 macro name "PRIX64".
• Remove ancient and broken GCC for VMS support
• Remove vestigial reference to "/VAXC" qualifier
• Remove sharedperl option on VMS
• VMS now has mkostemp
• "Configure" now properly handles quoted elements outputted by gcc. [GH #20606
<https://github.com/Perl/perl5/issues/20606>]
• "Configure" probed for the return type of malloc() and free() by testing whether
declarations for those functions produced a function type mismatch with the
implementation. On Solaris, with a C++ compiler, this check always failed, since
Solaris instead imports malloc() and free() from "std::" with "using" for C++ builds.
Since the return types of malloc() and free() are well defined by the C standard, skip
probing for them. "Configure" command-line arguments and hints can still override
these type in the unlikely case that is needed. [GH #20806
<https://github.com/Perl/perl5/issues/20806>]
Testing
Tests were added and changed to reflect the other additions and changes in this release.
Furthermore, these significant changes were made:
• Unicode normalization tests have been added.
• t/test.pl: Add ability to cancel an watchdog timer
Platform Support
Discontinued Platforms
Ultrix
Support code for DEC Ultrix has been removed. Ultrix was the native Unix-like
operating system for various Digital Equipment Corporation machines. Its final
release was in 1995.
Platform-Specific Notes
DragonflyBSD
Skip tests to workaround an apparent bug in setproctitle(). [GH #19894
<https://github.com/Perl/perl5/issues/19894>]
FreeBSD
FreeBSD no longer uses thread-safe locale operations, to avoid a bug in FreeBSD
<https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=265950>
Replace the first part of archname with "uname -p" [GH #19791
<https://github.com/Perl/perl5/issues/19791>]
Solaris
Avoid some compiler and compilation issues on NetBSD/Solaris from regexec.c and
regcomp.c.
Synology
Update Synology Readme for DSM 7.
Windows
Fix win32 memory alignment needed for gcc-12 from vmem.h.
utimes() on Win32 would print a message to stderr if it failed to convert a supplied
"time_t" to to a "FILETIME". [GH #19668 <https://github.com/Perl/perl5/issues/19668>]
In some cases, timestamps returned by stat() and lstat() failed to take daylight
saving time into account. [GH #20018 <https://github.com/Perl/perl5/issues/20018>]
[GH #20061 <https://github.com/Perl/perl5/issues/20061>]
stat() now works on "AF_UNIX" socket files. [GH #20204
<https://github.com/Perl/perl5/issues/20204>]
readlink() now returns the "PrintName" from a symbolic link reparse point instead of
the "SubstituteName", which should make it better match the name the link was created
with. [GH #20271 <https://github.com/Perl/perl5/pull/20271>]
lstat() on Windows now returns the length of the link target as the size of the file,
as it does on POSIX systems. [GH #20476 <https://github.com/Perl/perl5/issues/20476>]
symlink() on Windows now replaces any "/" in the target with "\", since Windows does
not recognise "/" in symbolic links. The reverse translation is not done by
readlink(). [GH #20506 <https://github.com/Perl/perl5/issues/20506>]
symlink() where the target was an absolute path to a directory was incorrectly created
as a file symbolic link. [GH #20533 <https://github.com/Perl/perl5/issues/20533>]
"POSIX::dup2" no longer creates broken sockets. [GH #20920
<https://github.com/Perl/perl5/issues/20920>]
Closing a busy pipe could cause Perl to hang. [GH #19963
<https://github.com/Perl/perl5/issues/19963>]
Internal Changes
• Removed many deprecated C functions.
These have been deprecated for a long time. See
<https://github.com/perl/perl5/commit/7008caa915ad99e650acf2aea40612b5e48b7ba2> for a
full list.
• "get_op_descs", "get_op_names", "get_opargs", "get_no_modify" and "get_ppaddr" have
been marked deprecated.
• "hv_free_ent" has been marked as internal API.
• "save_pushptr", "save_pushptrptr", and "save_pushi32ptr" have been marked as internal
API.
• New bool related functions and macros have been added to complement the new bool type
introduced in 5.36:
The functions are:
"newSVbool(const bool bool_val)"
newSV_true()
newSV_false()
"sv_set_true(SV *sv)"
"sv_set_false(SV *sv)"
"sv_set_bool(SV *sv, const bool bool_val)"
The macros are:
SvIandPOK(sv)
SvIandPOK_off(sv)
"SvIandPOK_on"
• Perl is no longer manipulating the "environ" array directly. The variable
"PL_use_safe_putenv" has been removed and "PERL_USE_SAFE_PUTENV" is always defined.
This means XS modules can now call "setenv" and "putenv" without causing segfaults.
[perl #19399 <https://github.com/Perl/perl5/issues/19399>]
• Internal C API functions are now hidden with "__attribute__((hidden))" on the
platforms that support it. This means they are no longer callable from XS modules on
those platforms.
It should be noted that those functions have always been hidden on Windows. This
change merely brings that to the other platforms. [perl #19655
<https://github.com/Perl/perl5/pull/19655>]
• New formatting symbols were added for printing values declared as "U32" or "I32":
I32df -- Like %d
U32of -- Like %o
U32uf -- Like %u
U32xf -- Like %x
U32Xf -- Like %X
These are used in the same way already existing similar symbols, such as "IVdf", are
used. See "I/O Formats" in perlapi.
• new 'HvHasAUX' macro
• regexec.c: Add some branch predictions reorder conds
• locale: Change macro name to be C conformant
• Rename the "PADNAMEt_*" constants to "PADNAMEf_*"
• Changes all the API macros that retrieve a PV into a call to an inline function so as
to evaluate the parameter just once.
• regexec.c: multiple code refactor to make the code more readable
• perl.h: Change macro name to be C conformant (remove leading _ from NOT_IN_NUMERIC
macros)
• regcomp.h: add new "BITMAP_BIT" macro in addition to the existing "BITMAP_BYTE" and
"BITMAP_TEST" ones.
• Create new regnode type ANYOFH. populate_ANYOF_from_invlist was renamed to
populate_bitmap_from_invlist
• regex: Refactor bitmap vs non-bitmap of qr/[]/
• regcomp.c: add new functions to convert from an inversion list to a bitmap (and vice
versa) "populate_bitmap_from_invlist" and "populate_invlist_from_bitmap".
• Add newAVav() to create an AV from an existing AV. Add newAVhv() to create an AV
using keys and values from an existing HV.
• Fix definition of "Perl_atof".
• Fix undefined behavior with overflow related "OPTIMIZE_INFTY" and delta in regcomp.c.
• Fix regnode pointer alignment issue in regcomp.h.
• The "CVf_METHOD" CV flag and associated "CvMETHOD" macro has been renamed to
"CVf_NOWARN_AMBIGUOUS" and "CvNOWARN_AMBIGUOUS". This closer reflects its actual
behaviour (it suppresses a warning that would otherwise be generated about ambiguous
names), in order to be less confusing with "CvIsMETHOD", which indicates that a CV is
a "method" subroutine relating to the "class" feature.
• The "OPf_SPECIAL" flag is no longer set on the "OP_ENTERSUB" op constructed to call
the "VERSION", "import" and "unimport" methods as part of a "use" statement and
attribute application, nor when assigning to an ":lvalue" subroutine.
• A new CV flag "CVf_REFCOUNTED_ANYSV" has been added, which indicates that the CV is an
XSUB and stores an SV pointer in the "CvXSUBANY.any_sv" union field. Perl core
operations such as cloning or destroying the CV will maintain the reference count of
the pointed-to SV, destroying it when required.
• A new API function ""Perl_localeconv"" in perlapi is added. This is the same as
"POSIX::localeconv" (returning a hash of the localeconv() fields), but directly
callable from XS code.
• A new API function, ""Perl_langinfo8"" in perlapi is added. This is the same as plain
""Perl_langinfo"" in perlapi, but with an extra parameter that allows the caller to
simply and reliably know if the returned string is UTF-8.
• We have introduced a limit on the number of nested "eval EXPR"/"BEGIN" blocks and
"require"/"BEGIN" (and thus "use" statements as well) to prevent C stack overflows.
This variable can also be used to forbid "BEGIN" blocks from executing during "eval
EXPR" compilation. The limit defaults to 1000 but can be overridden by setting the
"${^MAX_NESTED_EVAL_BEGIN_BLOCKS}" variable. The default itself can be changed at
compile time with
-Accflags='-DPERL_MAX_NESTED_EVAL_BEGIN_BLOCKS_DEFAULT=12345'
Note that this value relates to the size of your C stack and if you choose an
inappropriately large value Perl may segfault, be conservative about what you choose.
• A new magic type "PERL_MAGIC_extvalue" has been added. This is available for use like
"PERL_MAGIC_ext", but is a value magic: upon localization the new value will not be
magical.
• The SSNEW(), SSNEWt(), SSNEWa() and SSNEWat() APIs now return a "SSize_t" value. The
SSPTR() and SSPTRt() macros now expect a "SSize_t" parameter, and enforce that on
debugging builds. [GH #20411 <https://github.com/Perl/perl5/issues/20411>]
• Filenames in cops are now refcounted under threads. Under threads we were copying the
filenames into each opcode. This is because in theory opcodes created in one thread
can be destroyed in another. The change adds a new struct/type "RCPV", which is a
refcounted string using shared memory. This is implemented in such a way that code
that previously used a char * can continue to do so, as the refcounting data is
located a specific offset before the char * pointer itself.
• Added "HvNAMEf" and "HvNAMEf_QUOTEDPREFIX" special formats. They take an "HV *" as an
argument and use HvNAME() and related macros to determine the string, its length, and
whether it is utf8.
• The underlying "Perl_dowantarray" function implementing the long-deprecated "GIMME"
macro has been marked as deprecated, so that use of the macro emits a compile-time
warning. "GIMME" has been documented as deprecated in favour of "GIMME_V" since Perl
v5.6.0, but had not previously issued a warning.
• The API function "utf8_length" in perlapi is now more efficient.
• Added SAVERCPV() and SAVEFREERCPV() for better support for working with "RCPV"
(reference counted string/pointer value) structures which currently are used in
opcodes to share filename and warning bit data in a memory efficient manner.
• Added MORTALSVFUNC_SV() and MORTALDESTRUCTOR_SV() macros, which make it possible to
create a destructor which is fired at the end of the current statement. This uses the
"PERL_MAGIC_destruct" magic to use "free" magic to trigger an action when a variable
is freed. The action can be specified as a C function or as a Perl code reference.
• Added the "%{^HOOK}" api and related "PERL_MAGIC_hook" and "PERL_MAGIC_hookelem" for
providing ways to hook selected perl functions which for one reason or another are
problematic to wrap with a customized subroutine.
• Added support for "${^HOOK}{require__before}" which can be used to rewrite the
filename that "require" will try to load, and also to block "require" from loading a
specific module, even via fully qualified filename. The hook can also be used to
perform "pre-require" and "post-require" actions.
• Added support for "${^HOOK}{require__after}" which can be used to track what modules
have been required after the fact.
• Regular expression opcodes (regops) now use a standardized structure layout that uses
unions to expose data in different format. This means it should be much easier to
extend or modify regops to use more memory. This has been used to make a number of
regops track how many parens they contain.
Selected Bug Fixes
• Avoid recursion and stack overflow parsing 'pack' template
[GH #16319 <https://github.com/Perl/perl5/issues/16319>]
• An eval() as the last statement in a regex code block could trigger an interpreter
panic; e.g.
/(?{ ...; eval {....}; })/
[GH #19680 <https://github.com/Perl/perl5/issues/19680>]
• Disabling the "bareword_filehandles" feature no longer treats "print Class->method" as
an error. [GH #19704 <https://github.com/Perl/perl5/issues/19704>]
• When a Perl subroutine tail-calls an XS subroutine using "goto &xs_sub", the XS
subroutine can now correctly determine its calling context. Previously it was always
reported as scalar.
In addition, where the Perl subroutine is freed at the same time:
sub foo { *foo = sub {}; goto &xs_sub }
this formerly could lead to crashes if the XS subroutine tried to use the value of
"PL_op", since this was being set to NULL. This is now fixed.
[GH #19936 <https://github.com/Perl/perl5/issues/19936>]
• setsockopt() now uses the mechanism added in 5.36 to better distinguish between
numeric and string values supplied as the "OPTVAL" parameter. [GH #18761
<https://github.com/Perl/perl5/issues/18761>]
• 4-argument select() now rejects strings with code points above 255. Additionally, for
code points 128-255, this operator will now always give the corresponding octet to the
OS, regardless of how Perl stores such code points in memory. (Previously Perl leaked
its internal string storage to the OS.) [GH #19882
<https://github.com/Perl/perl5/issues/19882>]
• Fix panic issue from "val {} inside /(?{...})/" [GH #19390
<https://github.com/Perl/perl5/issues/19390>]
• Fix multiple compiler warnings from regexp.c, locale.c [GH #19915
<https://github.com/Perl/perl5/issues/19915>]
• Fix a bug with querying locales on platforms that don't have "LC_NUMERIC" [GH #19890
<https://github.com/Perl/perl5/issues/19890>]
• Prevent undefined behaviour in S_maybe_multideref().
• Avoid signed integer overflow in "use integer" ops.
• Avoid adding an offset to a NULL pointer in "hv_delete_common".
• PerlIO::get_layers will now accept IO references too
Previously it would only take glob references or names of globs. Now it will also
accept IO references.
• Fixes to memory handling for "PL_splitstr":
• If a thread was created the allocated string would be freed twice.
• If two "-F" switches were supplied the memory allocated for the first switch
wouldn't be freed.
• Correctly handle "OP_ANONCODE" ops generated by CPAN modules that don't include the
OPf_REF flag when propagating lvalue context. [GH #20532
<https://github.com/Perl/perl5/pull/20532>]
• POSIX::strxfrm now uses the "LC_CTYPE" locale category to specify its collation,
ignoring any differing "LC_COLLATE". It doesn't make sense for a string to be encoded
in one locale (say, ISO-8859-6, Arabic) and to collate it based on another (like
ISO-8859-7, Greek). Perl assumes that the current "LC_CTYPE" locale correctly
represents the encoding, and collates accordingly.
Also, embedded "NUL" characters are now allowed in the input.
If locale collation is not enabled on the platform ("LC_COLLATE"), the input is
returned unchanged.
• Double FETCH during stringification of tied scalars returning an overloaded object
have been fixed. The FETCH method should only be called once, but prior to this
release was actually called twice. [GH #20574
<https://github.com/Perl/perl5/pull/20574>]
• Writing to a magic variables associated with the selected output handle, $^, $~, $=,
"$-" and $%, no longer crashes perl if the IO object has been cleared from the
selected output handle. [GH #20733 <https://github.com/Perl/perl5/issues/20733>]
• Redefining a "use constant" list constant with "use constant" now properly warns.
This changes the behaviour of "use constant" but is a core change, not a change to
constant.pm. [GH #20742 <https://github.com/Perl/perl5/issues/20742>]
• Redefining a "use constant" list constant with an empty prototype constant sub would
result in an assertion failure. [GH #20742
<https://github.com/Perl/perl5/issues/20742>]
• Fixed a regression where the "INC" method for objects in @INC would not be resolved by
"AUTOLOAD", while it was in 5.36. The "INCDIR" method for objects in @INC cannot be
resolved by "AUTOLOAD" as "INC" would have been resolved first. [GH #20665
<https://github.com/Perl/perl5/issues/20665>]
• $SIG{__DIE__} will now be called from eval when the code dies during compilation
regardless of how it dies. This means that code expecting to be able to upgrade $@
into an object will be called consistently. In earlier versions of perl $SIG{__DIE__}
would not be called for certain compilation errors, for instance undeclared variables.
For other errors it might be called if there were more than a certain number of
errors, but not if there were less. Now you can expect that it will be called in every
case.
• Compilation of code with errors used to inconsistently stop depending on the count and
type of errors encountered. The intent was that after 10 errors compilation would
halt, but bugs in this logic meant that certain types of error would be counted, but
would not trigger the threshold check to stop compilation. Other errors would. With
this release after at most 10 errors compilation will terminate, regardless of what
type of error they were.
Note that you can change the maximum count by defining
"PERL_STOP_PARSING_AFTER_N_ERRORS" to be something else during the configuration
process. For instance
./Configure ... -Accflags='-DPERL_STOP_PARSING_AFTER_N_ERRORS=100'
would allow up to 100 errors.
• The API function "my_snprintf" in perlapi now prints a non-dot decimal point if the
perl code it ultimately is called from is in the scope of "use locale" and the locale
in effect calls for that.
• A number of bugs related to capture groups in quantified groups in regular expression
have been fixed, especially in alternations. For example in a pattern like:
"foobazfoobar" =~ /((foo)baz|foo(bar))+/
the regex variable $2 will not be "foo" as it once was, it will be undef.
• Bugs with regex backreference operators that are inside of a capture group have been
fixed. For instance:
"xa=xaaa" =~ /^(xa|=?\1a){2}\z/
will now correctly not match. [GH #10073 <https://github.com/Perl/perl5/issues/10073>]
• SSGROW() and SSCHECK() have been reworked to ensure that the requested space is
actually allocated. SSCHECK() is now an alias for SSGROW().
Acknowledgements
Perl 5.38.0 represents approximately 12 months of development since Perl 5.36.0 and
contains approximately 290,000 lines of changes across 1,500 files from 100 authors.
Excluding auto-generated files, documentation and release tools, there were approximately
190,000 lines of changes to 970 .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 5.38.0:
Alex, Alexander Nikolov, Alex Davies, Andreas König, Andrew Fresh, Andrew Ruthven, Andy
Lester, Aristotle Pagaltzis, Arne Johannessen, A. Sinan Unur, Bartosz Jarzyna, Bart Van
Assche, Benjamin Smith, Bram, Branislav Zahradník, Brian Greenfield, Bruce Gray, Chad
Granum, Chris 'BinGOs' Williams, chromatic, Clemens Wasser, Craig A. Berry, Dagfinn Ilmari
Mannsåker, Dan Book, danielnachun, Dan Jacobson, Dan Kogai, David Cantrell, David Golden,
David Mitchell, E. Choroba, Ed J, Ed Sabol, Elvin Aslanov, Eric Herman, Felipe Gasper,
Ferenc Erki, Firas Khalil Khana, Florian Weimer, Graham Knop, Håkon Hægland, Harald Jörg,
H.Merijn Brand, Hugo van der Sanden, James E Keenan, James Raspass, jkahrman, Joe McMahon,
Johan Vromans, Jonathan Stowe, Jon Gentle, Karen Etheridge, Karl Williamson, Kenichi
Ishigaki, Kenneth Ölwing, Kurt Fitzner, Leon Timmermans, Li Linjie, Loren Merritt, Lukas
Mai, Marcel Telka, Mark Jason Dominus, Mark Shelor, Matthew Horsfall, Matthew O. Persico,
Mattia Barbon, Max Maischein, Mohammad S Anwar, Nathan Mills, Neil Bowers, Nicholas Clark,
Nicolas Mendoza, Nicolas R, Paul Evans, Paul Marquess, Peter John Acklam, Peter Levine,
Philippe Bruhat (BooK), Reini Urban, Renee Baecker, Ricardo Signes, Richard Leach, Russ
Allbery, Scott Baker, Sevan Janiyan, Sidney Markowitz, Sisyphus, Steve Hay, TAKAI Kousuke,
Todd Rinaldo, Tomasz Konojacki, Tom Stellard, Tony Cook, Tsuyoshi Watanabe, Unicode
Consortium, vsfos, Yves Orton, Zakariyya Mughal, Zefram, 小鸡.
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 perl bug database at
<https://github.com/Perl/perl5/issues>. There may also be information at
<http://www.perl.org/>, the Perl Home Page.
If you believe you have an unreported bug, please open an issue at
<https://github.com/Perl/perl5/issues>. Be sure to trim your bug down to a tiny but
sufficient test case.
If the bug you are reporting has security implications which make it inappropriate to send
to a public issue tracker, then see "SECURITY VULNERABILITY CONTACT INFORMATION" in
perlsec for details of how to report the issue.
Give Thanks
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.
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.