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perl-5.23.9
River stage five • 11292 direct dependents • 32664 total dependents
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/ perl5238delta

NAME

perl5238delta - what is new for perl v5.23.8

DESCRIPTION

This document describes differences between the 5.23.7 release and the 5.23.8 release.

If you are upgrading from an earlier release such as 5.23.6, first read perl5237delta, which describes differences between 5.23.6 and 5.23.7.

Core Enhancements

More fields provided to sigaction callback with SA_SIGINFO

When passing the SA_SIGINFO flag to sigaction, the errno, status, uid, pid, addr and band fields are now included in the hash passed to the handler, if supported by the platform.

Security

Set proper umask before calling mkstemp(3)

In 5.22 perl started setting umask to 0600 before calling mkstemp(3) and restoring it afterwards. This wrongfully tells open(2) to strip the owner read and write bits from the given mode before applying it, rather than the intended negation of leaving only those bits in place.

Systems that use mode 0666 in mkstemp(3) (like old versions of glibc) create a file with permissions 0066, leaving world read and write permissions regardless of current umask.

This has been fixed by using umask 0177 instead. [perl #127322]

Incompatible Changes

qr/\N{}/ now disallowed under use re "strict"

An empty \N{} makes no sense, but for backwards compatibility is silently accepted as doing nothing. But now this is a fatal error under the experimental feature "'strict' mode" in re.

Performance Enhancements

  • The overhead of scope entry and exit has been considerably reduced, so for example subroutine calls, loops and basic blocks are all faster now. This empty function call now takes about a third less time to execute:

        sub f{} f();

  • On Win32, stating or -Xing a path, if the file or directory does not exist, is now 3.5x faster on a SSD (or any drive) than before.

Modules and Pragmata

Updated Modules and Pragmata

  • cpan/podlators/ has been upgraded from version 4.04 to 4.06.

  • The PathTools module collection has been upgraded from version 3.62 to 3.63.

  • DynaLoader has been upgraded from version 1.37 to 1.38.

    DynaLoader now always looks for bootstrap files having the same base name as the module for which the bootstrap code is being run. Previously, and only on platforms that use mod2fname to produce unique loadable library names, DynaLoader would look for the bootstrap file using a base name that matched the loadable library and not find it.

  • Encode has been upgraded from version 2.78 to 2.80.

  • ExtUtils::CBuilder has been upgraded from version 0.280224 to 0.280225.

  • ExtUtils::MakeMaker has been upgraded from version 7.10 to 7.10_01.

  • File::Spec has been upgraded from version 3.62 to 3.63.

  • IPC::SysV has been upgraded from version 2.04 to 2.05.

  • Module::CoreList has been upgraded from version 5.20160120 to 5.20160121.

  • ODBM_File has been upgraded from version 1.12 to 1.13.

  • PerlIO::encoding has been upgraded from version 0.23 to 0.24.

  • POSIX has been upgraded from version 1.59 to 1.63.

    It can now export constants for the code value in the hash passed to the sigaction handler when using the SA_SIGINFO flag.

    These previously deprecated functions are now removed: isalnum, isalpha, iscntrl, isdigit, isgraph, islower, isprint, ispunct, isspace, isupper, and isxdigit.

  • Storable has been upgraded from version 2.54 to 2.55.

  • Time::HiRes has been upgraded from version 1.9728 to 1.9730.

    It can now export Linux-specific and FreeBSD-specific clock_gettime() constants. It also now has emulation for OS X clock_nanosleep(), clock_gettime(), and clock_getres().

Documentation

Changes to Existing Documentation

perlguts

perlmodlib

  • We now recommend contacting the module-authors list or PAUSE in seeking guidance on the naming of modules.

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

New Warnings

Configuration and Compilation

  • The GNU Make makefile for Win32 now supports parallel builds. [perl #126632]

  • You can now build perl with MSVC++ on Win32 using GNU Make. [perl #126632]

  • Bison 3.0 is now supported.

Platform Support

Platform-Specific Notes

VMS

  • For those %ENV elements based on the CRTL environ array, we've always preserved case when setting them but did look-ups only after upcasing the key first, which made lower- or mixed-case entries go missing. This problem has been corrected by making %ENV elements derived from the environ array case-sensitive on look-up as well as case-preserving on store.

  • Environment look-ups for PERL5LIB and PERLLIB previously only considered logical names, but now consider all sources of %ENV as determined by PERL_ENV_TABLES and as documented in "%ENV" in perlvms.

Win32

Builds using Microsoft Visual C++ 2003 and earlier no longer produce an "INTERNAL COMPILER ERROR" message. [perl #126045]

Internal Changes

  • The implementation of perl's context stack system, and its internal API, have been heavily reworked. Note that no significant changes have been made to any external APIs, but XS code which relies on such internal details may need to be fixed. The main changes are:

    • The PUSHBLOCK(), POPSUB() etc. macros have been replaced with static inline functions such as cx_pushblock(), cx_popsub() etc. These use function args rather than implicitly relying on local vars such as gimme and newsp being available. Also their functionality has changed: in particular, cx_popblock() no longer decrements cxstack_ix. The ordering of the steps in the pp_leave* functions involving cx_popblock(), cx_popsub() etc. has changed. See the new documentation, "Dynamic Scope and the Context Stack" in perlguts, for details on how to use them.

    • Various macros, which now consistently have a CX_ prefix, have been added:

        CX_CUR(), CX_LEAVE_SCOPE(), CX_POP()

      or renamed:

        CX_POP_SAVEARRAY(), CX_DEBUG(), CX_PUSHSUBST(), CX_POPSUBST()

    • cx_pushblock() now saves PL_savestack_ix and PL_tmps_floor, so pp_enter* and pp_leave* no longer do

        ENTER; SAVETMPS; ....; LEAVE

    • cx_popblock() now also restores PL_curpm.

    • In dounwind() for every context type, the current savestack frame is now processed before each context is popped; formerly this was only done for sub-like context frames. This action has been removed from cx_popsub() and placed into its own macro, CX_LEAVE_SCOPE(cx), which must be called before cx_popsub() etc.

      dounwind() now also does a cx_popblock() on the last popped frame (formerly it only did the cx_popsub() etc. actions on each frame).

    • The temps stack is now freed on scope exit; previously, temps created during the last statement of a block wouldn't be freed until the next nextstate following the block (apart from an existing hack that did this for recursive subs in scalar context); and in something like f(g()), the temps created by the last statement in g() would formerly not be freed until the statement following the return from f().

    • Most values that were saved on the savestack on scope entry are now saved in suitable new fields in the context struct, and saved and restored directly by cx_pushfoo() and cx_popfoo(), which is much faster.

    • Various context struct fields have been added, removed or modified.

    • The handling of @_ in cx_pushsub() and cx_popsub() has been considerably tidied up, including removing the argarray field from the context struct, and extracting out some common (but rarely used) code into a separate function, clear_defarray(). Also, useful subsets of cx_popsub() which had been unrolled in places like pp_goto have been gathered into the new functions cx_popsub_args() and cx_popsub_common().

    • pp_leavesub and pp_leavesublv now use the same function as the rest of the pp_leave*'s to process return args.

    • CXp_FOR_PAD and CXp_FOR_GV flags have been added, and CXt_LOOP_FOR has been split into CXt_LOOP_LIST, CXt_LOOP_ARY.

    • Some variables formerly declared by dMULTICALL (but not documented) have been removed.

Selected Bug Fixes

  • Line numbers larger than 2**31-1 but less than 2**32 are no longer returned by caller() as negative numbers. [perl #126991]

  • unless ( assignment ) now properly warns when syntax warnings are enabled. [perl #127122]

  • Setting an ISA glob to an array reference now properly adds isaelem magic to any existing elements. Previously modifying such an element would not update the ISA cache, so method calls would call the wrong function. Perl would also crash if the ISA glob was destroyed, since new code added in 5.23.7 would try to release the isaelem magic from the elements. [perl #127351]

  • If a here-doc was found while parsing another operator, the parser had already read end of file, and the here-doc was not terminated, perl could produce an assertion or a segmentation fault. This now reliably complains about the unterminated here-doc. [perl #125540]

  • untie() would sometimes return the last value returned by the UNTIE() handler as well as it's normal value, messing up the stack. [perl #126621]

  • Fixed an operator precedence problem when castflags & 2 is true. [perl #127474]

  • Caching of DESTROY methods could result in a non-pointer or a non-STASH stored in the SvSTASH() slot of a stash, breaking the B STASH() method. The DESTROY method is now cached in the MRO metadata for the stash. [perl #126410]

  • The AUTOLOAD method is now called when searching for a DESTROY method, and correctly sets $AUTOLOAD too. [perl #124387] [perl #127494]

  • Avoid parsing beyond the end of the buffer when processing a #line directive with no filename. [perl #127334]

  • Perl now raises a warning when a regular expression pattern looks like it was supposed to contain a POSIX class, like qr/[[:alpha:]]/, but there was some slight defect in its specification which causes it to instead be treated as a regular bracketed character class. An example would be missing the second colon in the above like this: qr/[[:alpha]]/. This compiles to match a sequence of two characters. The second is "]", and the first is any of: "[", ":", "a", "h", "l", or "p". This is unlikely to be the intended meaning, and now a warning is raised. No warning is raised unless the specification is very close to one of the 14 legal POSIX classes. (See "POSIX Character Classes" in perlrecharclass.) [perl #8904]

  • Certain regex patterns involving a complemented POSIX class in an inverted bracketed character class, and matching something else optionally would improperly fail to match. An example of one that could fail is /qr/_?[^\Wbar]\x{100}/. This has been fixed. [perl #127537]

  • Perl 5.22 added support to the C99 hexadecimal floating point notation, but sometimes misparses hex floats. This had been fixed. [perl #127183]

Acknowledgements

Perl 5.23.8 represents approximately 4 weeks of development since Perl 5.23.7 and contains approximately 30,000 lines of changes across 350 files from 23 authors.

Excluding auto-generated files, documentation and release tools, there were approximately 14,000 lines of changes to 210 .pm, .t, .c and .h files.

Perl continues to flourish into its third decade thanks to a vibrant community of users and developers. The following people are known to have contributed the improvements that became Perl 5.23.8:

Aaron Crane, Chris 'BinGOs' Williams, Craig A. Berry, Dagfinn Ilmari Mannsåker, Daniel Dragan, David Mitchell, Ed J, Herbert Breunung, H.Merijn Brand, James E Keenan, Jarkko Hietaniemi, Karl Williamson, Lukas Mai, Niko Tyni, Pip Cet, Ricardo Signes, Sawyer X, Sisyphus, Stevan Little, Steve Hay, Todd Rinaldo, Tom Hukins, Tony Cook.

The list above is almost certainly incomplete as it is automatically generated from version control history. In particular, it does not include the names of the (very much appreciated) contributors who reported issues to the Perl bug tracker.

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

For a more complete list of all of Perl's historical contributors, please see the AUTHORS file in the Perl source distribution.

Reporting Bugs

If you find what you think is a bug, you might check the articles recently posted to the comp.lang.perl.misc newsgroup and the perl bug database at 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.

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.