[ this is a template for a new perldelta file. Any text flagged as XXX needs to be processed before release. ]
perldelta - what is new for perl v5.21.1
This document describes differences between the 5.21.0 release and the 5.21.1 release.
If you are upgrading from an earlier release such as 5.20.0, first read perl5210delta, which describes differences between 5.20.0 and 5.21.0.
XXX Any important notices here
XXX New core language features go here. Summarize user-visible core language enhancements. Particularly prominent performance optimisations could go here, but most should go in the "Performance Enhancements" section.
[ List each enhancement as a =head2 entry ]
Starting from Perl 5.21.1, on some platforms Perl supports retrieving the C level backtrace (similar to what symbolic debuggers like gdb do).
The backtrace returns the stack trace of the C call frames, with the symbol names (function names), the object names (like "perl"), and if it can, also the source code locations (file:line).
The supported platforms are Linux and OS X (some *BSD might work at least partly, but they have not yet been tested).
The feature needs to be enabled with Configure -Dusecbacktrace.
Also included is a C API to retrieve backtraces.
See "C backtrace" in perlhacktips for more information.
The /x regular expression modifier allows the pattern to contain white space and comments, both of which are ignored, for improved readability. Until now, not all the white space characters that Unicode designates for this purpose were handled. The additional ones now recognized are U+0085 NEXT LINE, U+200E LEFT-TO-RIGHT MARK, U+200F RIGHT-TO-LEFT MARK, U+2028 LINE SEPARATOR, and U+2029 PARAGRAPH SEPARATOR.
It is now possible to pass a parameter to use locale to specify a subset of locale categories to be locale-aware, with the remaining ones unaffected. See "The "use locale" pragma" in perllocale for details.
XXX Any security-related notices go here. In particular, any security vulnerabilities closed should be noted here rather than in the "Selected Bug Fixes" section.
[ List each security issue as a =head2 entry ]
XXX For a release on a stable branch, this section aspires to be:
There are no changes intentionally incompatible with 5.XXX.XXX
If any exist, they are bugs, and we request that you submit a
report. See L</Reporting Bugs> below.This has been deprecated since v5.18.
In prior releases, failure to do this raised a deprecation warning.
These had been deprecated since v5.18.
The use of these characters with /x outside bracketed character classes and when not preceeded by a backslash has raised a deprecation warning since v5.18. Now they will be ignored. See "qr/foo/x" for the list of the five characters.
(?[ ]) is an experimental feature, introduced in v5.18. It operates as if /x is always enabled. But there was a difference, comment lines (following a # character) were terminated by anything matching \R which includes all vertical whitespace, such as form feeds. For consistency, this is now changed to match what terminates comment lines outside (?[ ]), namely a \n (even if escaped), which is the same as what terminates a heredoc string and formats.
Really old Perl let you omit the @ on array names and the % on hash names in some spots. This has issued a deprecation warning since Perl 5.0, and is no longer permitted.
Previously, the text, unlike almost everything else, always came out based on the current underlying locale of the program. (Also affected on some systems is "$^E".) For programs that are unprepared to handle locale, this can cause garbage text to be displayed. It's better to display text that is translatable via some tool than garbage text which is much harder to figure out.
The stringification of $! and $^E will have the UTF-8 flag set when the text is actually non-ASCII UTF-8. This will enable programs that are set up to be locale-aware to properly output messages in the user's native language. Code that needs to continue the 5.20 and earlier behavior can do the stringification within the scopes of both 'use bytes' and 'use locale ":messages". No other Perl operations will be affected by locale; only $! and $^E stringification. The 'bytes' pragma causes the UTF-8 flag to not be set, just as in previous Perl releases. This resolves [perl #112208].
XXX Any deprecated features, syntax, modules etc. should be listed here.
This non-graphic character is essentially indistinguishable from a regular space, and so should not be allowed. See "CUSTOM ALIASES" in charnames.
XXX Remove this section if inapplicable.
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.
- XXX
-
XXX Note that deprecated modules should be listed here even if they are listed as an updated module in the "Modules and Pragmata" section.
[ List each other deprecation as a =head2 entry ]
XXX Changes which enhance performance without changing behaviour go here. There may well be none in a stable release.
[ List each enhancement as a =item entry ]
Many internal functions have been refactored to improve performance and reduce their memory footprints.
-Tand-Bfiletests will return sooner when an empty file is detected.
XXX All changes to installed files in cpan/, dist/, ext/ and lib/ go here. If Module::CoreList is updated, generate an initial draft of the following sections using Porting/corelist-perldelta.pl. A paragraph summary for important changes should then be added by hand. In an ideal world, dual-life modules would have a Changes file that could be cribbed.
[ Within each section, list entries as a =item entry ]
XXX
Carp has been upgraded from version 1.3301 to 1.34.
Carp::Heavy now ignores version mismatches with Carp if Carp is newer than 1.12, since Carp::Heavy's guts were merged into Carp at that point. [perl #121574]
Data::Dumper has been upgraded from version 2.151 to 2.152.
Changes to resolve Coverity issues.
XS dumps incorrectly stored the name of code references stored in a GLOB. [perl #122070]
Encode has been upgraded from version 2.60_01 to 2.62.
piconv now has better error handling when the encoding name is nonexistent, and a build breakage when upgrading Encode in perl-5.8.2 and earlier has been fixed.
Hash::Util has been upgraded from version 0.16 to 0.17.
Minor bug fixes and documentation fixes to Hash::Util::hash_stats()
The libnet collection of modules has been upgraded from version 1.25 to 1.27.
There are only whitespace changes to the installed files.
The Locale-Codes collection of modules has been upgraded from vesion 3.30 to 3.31.
Fixed a bug in the scripts used to extract data from spreadsheets that prevented the SHP currency code from being found. [cpan #94229]
Math::BigInt has been upgraded from version 1.9993 to 1.9994.
Synchronize POD changes from the CPAN release.
Math::BigFloat->blog(x)would sometimes return blog(2*x) when the accuracy was greater than 70 digits.The result of
Math::BigFloat->bdiv()in list context now satisfiesx = quotient * divisor + remainder.Math::BigRat has been upgraded from version 0.2606 to 0.2607.
Synchronize POD changes from the CPAN release.
Module::Metadata has been upgraded from version 1.000022 to 1.000024.
Support installations on older perls with an ExtUtils::MakeMaker earlier than 6.63_03
OS2::Process has been upgraded from version 1.09 to 1.10.
perl5db.pl has been upgraded from version 1.44 to 1.45.
fork() in the debugger under
tmuxwill now create a new window for the forked process. [perl #121333]The debugger now saves the current working directory on startup and restores it when you restart your program with
Ror <rerun>. [perl #121509]PerlIO::encoding has been upgraded from version 0.18 to 0.19.
No changes in behaviour.
PerlIO::mmap has been upgraded from version 0.012 to 0.013.
No changes in behaviour.
PerlIO::scalar has been upgraded from version 0.18 to 0.19.
No changes in behaviour.
Unicode::Collate has been upgraded from version 1.04 to 1.07.
Version 0.67's improved discontiguous contractions is invalidated by default and is supported as a parameter 'long_contraction'.
Unicode::Normalize has been upgraded from version 1.17 to 1.18.
The XSUB implementation has been removed in favour of pure Perl.
A mismatch between the documentation and the code in utf8::downgrade() was fixed in favour of the documentation. The optional second argument is now correctly treated as a perl boolean (true/false semantics) and not as an integer.
XXX
XXX Changes to files in pod/ go here. Consider grouping entries by file and be sure to link to the appropriate page, e.g. perlfunc.
XXX Changes which create new files in pod/ go here.
XXX Description of the purpose of the new file here
XXX Changes which significantly change existing files in pod/ go here. However, any changes to pod/perldiag.pod should go in the "Diagnostics" section.
-lnow notes that it will return false if symlinks aren't supported by the file system.Note that
exec LISTandsystem LISTmay fall back to the shell on Win32. Onlyexec PROGRAM LISTandsystem PROGRAM LISTindirect object syntax will reliably avoid using the shell.This has also been noted in perlport.
sv_usepvn_flags- Fix documentation to mention the use ofNewXinstead ofmalloc.Clarify where
NULmay be embedded or is required to terminate a string.Previously missing documentation due to formatting errors are now included.
Entries are now organized into groups rather than by file where they are found.
Alphabetical sorting of entries is now handled by the POD generator to make entries easier to find when scanning.
Updated documentation for the
test.valgrindmaketarget.
The
/xmodifier has been clarified to note that comments cannot be continued onto the next line by escaping them.
The documentation includes many clarifications and fixes.
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.
XXX New or changed warnings emitted by the core's C code go here. Also include any changes in perldiag that reconcile it to the C code.
XXX Newly added diagnostic messages go under here, separated into New Errors and New Warnings
XXX message
PerlIO layer ':win32' is experimental:
(S experimental::win32_perlio) The
:win32PerlIO layer is experimental. If you want to take the risk of using this layer, simply disable this warning:no warnings "experimental::win32_perlio";
XXX Changes (i.e. rewording) of diagnostic messages go here
<> should be quotes
This warning has been changed to <> at require-statement should be quotes to make the issue more identifiable.
Unsuccessful %s on filename containing newline
This warning is now only produced when the newline is at the end of the filename.
XXX Changes to installed programs such as perlbug and xsubpp go here. Most of these are built within the directory utils.
[ List utility changes as a =head2 entry for each utility and =item entries for each change Use XXX with program names to get proper documentation linking. ]
The x2p/ directory has been removed from the Perl core.
This removes find2perl, s2p and a2p. They have all been released to CPAN as separate distributions (App::find2perl, App::s2p, App::a2p).
XXX Changes to Configure, installperl, installman, and analogous tools go here. Any other changes to the Perl build process should be listed here. However, any platform-specific changes should be listed in the "Platform Support" section, instead.
[ List changes as a =item entry ].
make test.valgrindnow supports parallel testing.For example:
TEST_JOBS=9 make test.valgrindSee "valgrind" in perlhacktips for more information.
XXX Any significant changes to the testing of a freshly built perl should be listed here. Changes which create new files in t/ go here as do any large changes to the testing harness (e.g. when parallel testing was added). Changes to existing files in t/ aren't worth summarizing, although the bugs that they represent may be covered elsewhere.
[ List each test improvement as a =item entry ]
XXX
XXX Any changes to platform support should be listed in the sections below.
[ Within the sections, list each platform as a =item entry with specific changes as paragraphs below it. ]
XXX List any platforms that this version of perl compiles on, that previous versions did not. These will either be enabled by new files in the hints/ directories, or new subdirectories and README files at the top level of the source tree.
- XXX-some-platform
-
XXX
XXX List any platforms that this version of perl no longer compiles on.
- NeXTSTEP/OPENSTEP
-
NeXTSTEP was proprietary OS bundled with NeXT's workstations in the early to mid 90's; OPENSTEP was an API specification that provided a NeXTSTEP-like environment on a non-NeXTSTEP system. Both are now long dead, so support for building Perl on them has been removed.
XXX List any changes for specific platforms. This could include configuration and compilation changes or changes in portability/compatibility. However, changes within modules for platforms should generally be listed in the "Modules and Pragmata" section.
- XXX-some-platform
-
XXX
- OpenBSD
-
On OpenBSD, Perl will now default to using the system
mallocdue to the security features it provides. Perl's own malloc wrapper has been in use since v5.14 due to performance reasons, but the OpenBSD project believes the tradeoff is worth it and would prefer that users who need the speed specifically ask for it.
XXX Changes which affect the interface available to XS code go here. Other significant internal changes for future core maintainers should be noted as well.
The deprecated variable
PL_sv_objcounthas been removed.Perl now tries to keep the locale category
LC_NUMERICset to "C" except around operations that need it to be set to the program's underlying locale. This protects the many XS modules that cannot cope with the decimal radix character not being a dot. Prior to this release, Perl initialized this category to "C", but a call toPOSIX::setlocale()would change it. Now such a call will change the underlying locale of theLC_NUMERICcategory for the program, but the locale exposed to XS code will remain "C". There is an API under development for those relatively few modules that need to use the underlying locale. This API will be nailed down during the course of developing v5.21. Send email to mailto:perl5-porters@perl.org for guidance.
XXX Important bug fixes in the core language are summarized here. Bug fixes in files in ext/ and lib/ are best summarized in "Modules and Pragmata".
[ List each fix as a =item entry ]
index() and rindex() no longer crash when used on strings over 2GB in size. [perl #121562].
A small previously intentional memory leak in PERL_SYS_INIT/PERL_SYS_INIT3 on Win32 builds was fixed. This might affect embedders who repeatedly create and destroy perl engines within the same process.
POSIX::localeconv()now returns the data for the program's underlying locale even when called from outside the scope ofuse locale.POSIX::localeconv()now works properly on platforms which don't haveLC_NUMERICand/orLC_MONETARY, or for which Perl has been compiled to disregard either or both of these locale categories. In such circumstances, there are now no entries for the corresponding values in the hash returned bylocaleconv().POSIX::localeconv()now marks appropriately the values it returns as UTF-8 or not. Previously they were always returned as a bytes, even if they were supposed to be encoded as UTF-8.On Microsoft Windows, within the scope of
use locale, the following POSIX character classes gave results for many locales that did not conform to the POSIX standard:[[:alnum:]],[[:alpha:]],[[:blank:]],[[:digit:]],[[:graph:]],[[:lower:]],[[:print:]],[[:punct:]],[[:upper:]],[[:word:]], and[[:xdigit:]]. These are because the underlying Microsoft implementation does not follow the standard. Perl now takes special precautions to correct for this.Many issues have been detected by Coverity and fixed.
system() and friends should now work properly on more Android builds.
Due to an oversight, the value specified through -Dtargetsh to Configure would end up being ignored by some of the build process. This caused perls cross-compiled for Android to end up with defective versions of system(), exec() and backticks: the commands would end up looking for
/bin/shinstead of/system/bin/sh, and so would fail for the vast majority of devices, leaving$!asENOENT.
XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any tests that had to be TODOed for the release would be noted here. Unfixed platform specific bugs also go here.
[ List each fix as a =item entry ]
XXX
XXX Add anything here that we forgot to add, or were mistaken about, in the perldelta of a previous release.
XXX If any significant core contributor has died, we've added a short obituary here.
XXX Generate this with:
perl Porting/acknowledgements.pl v5.21.1..HEADIf you find what you think is a bug, you might check the articles recently posted to the comp.lang.perl.misc newsgroup and the perl bug database at 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 please send it to perl5-security-report@perl.org. This points to a closed subscription unarchived mailing list, which includes all the core committers, who will be able to help assess the impact of issues, figure out a resolution, and help co-ordinate the release of patches to mitigate or fix the problem across all platforms on which Perl is supported. Please only use this address for security issues in the Perl core, not for modules independently distributed on CPAN.
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.