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Perl 5.18


A new perl 5.18 version brings a lot of changes done over a year of development. See 5.18.0 perldelta and 5.18.1 perldelta for more details.


Current status

Completed items

  • Get dedicated build-root from rel-engs (f20-perl). Rel-engs gave us only 7 days. The build-root will be merged on 2013-07-19.
  • Patch perl to link XS modules to explicitly
  • Rebase perl to 5.18.0
  • Define perl_bootstrap in perl-srpm-macros
  • Build new perl 5.18 keeping old COMPAT Provides
  • Rebuild packages needed for minimal build-root
  • Rebuild dual-lived packages (otherwise yum recommends --skip-broken and fails)
  • Rebuild packages needed for building source packages from git repository
  • Remove old perl(:MODULE_COMPAT_5.16.*) from perl
  • Merge dedicated build-root to rawhide and remove the dedicated one by rel-engs [1]. The build-root has been merged on 2013-08-03.
  • Synchronize packages upgraded in f20 build root
  • Undefine perl_bootstrap
  • Rebuild packages having perl_bootstrap condition in spec file
  • perl-MongoDB and zfs-fuse - fixed by ExcludeArch arm

Items in progress

  • Rebuilt Perl packages: 2750 of 2757 done (99.75 %)
  • Rebuild other packages: Use Fedora::Rebuild dependency solver or ordered sets computed by Paul

Items to be done

  • Failed rebuilds (7 including intermittent failures):
    • geoqo – tests fail due to random hashes [2]
    • ltsp – flex incompatibilty [3]
    • nesc – does not halt [4]
    • perl-DBD-AnyData – tests fail, not compatible with DBI > 1.622, remove it from distribution. [5]
    • perl-Language-Expr - tests fail - Regexp::Grammars is unsupported under Perl 5.18 [6]
    • racoon2 – yacc incompatibility [7]
  • Need to be investigated
    • perl-CGI-FormBuilder – test fail due to hash randomization [8] - fixed by skipping the failing tests
    • perl-Encode-JP-Mobile – tests fail [9] – built, some tests fixed, one test disabled
    • perl-Net-DNS-SEC – a test fails [10] - built, but the test was not fixed
    • scsi-target-utils – build fails on XSLT transformation [11] - built, but needs investigation
  • Were not built due dependency
    • perl-Bio-SamTools

Detailed Description

New perl is released every year and updates containing mainly bug fixes follow during the year. The 5.18.0 version is stable release this year and 5.18.1 and subsequent revisions will follow during the year to fix issues introduced in 5.18.0.

Because of change in dlopen(3) from RTLD_GLOBAL to RTLD_LOCAL (bug #960048), we will try to link all native perl module DSOs to explicitly. This item needs discussion. Current status does not allow to use perl interpreter via dlopen() from other programs (like slapd, snmpd), but proposed change can bring other unforeseen difficulties (like double-linking).

Benefit to Fedora

Up-to-date and latest perl release will be delivered to Fedora users.


Every Perl package will be rebuilt in a dedicated f20-perl build-root against perl 5.18.0 and then if no major problem emerges the packages will be merged back to f20 build-root.

  • Proposal owners:

New perl and all packages requiring perl or a Perl module will be rebuilt into f20-perl build-root.

  • Other developers:

Owners of packages that fail to rebuild, mainly perl-sig users, will be asked using Bugzilla to fix or remove their packages from the distribution.

  • Release engineering:

Release engineers will be asked for new f20-perl build-root inheriting from f20 build-root. After successful finishing the rebuild, they will be asked to merge f20-perl packages back to f20 build-root.

  • Policies and guidelines:

No policies have to be modified to complete this change.

Upgrade/compatibility impact

Vast majority of functionality will be preserved. Only the packages that failed to build against perl 5.18 will be removed from the distribution. That will require to remove those packages from existing systems otherwise package manager will encounter unsatisfied dependencies.

How To Test

Try upgrading from Fedora 19 to 20. Try some Perl application to verify they work as expected. Try embedded perl in slapd or snmpd.

User Experience

There should not be any remarkable change in user experience. Though developers can hit some changes in perl interpreter behavior like a hash key randomization.


There is more than 2000 packages depending on perl. Most of them are expected not to break. Finishing this change can be endangered only by critical changes in a toolchain.

Contingency Plan

If we find perl 5.18 is not suitable for Fedora 20, we will revert back to perl 5.16 and we drop the temporary build-root with already rebuilt packages.

  • Contingency deadline: branching Fedora 20 from Rawhide.
  • Blocks release? No.


Release Notes

  • New features:
    • Unicode 6.2 is supported.
    • Matching Unicode properties is faster now.
    • Operators next, last, redo, and dump supports labels computed at run-time.
    • The kill function allows to send a signal to a process group by symbolic name.
    • Experimental support for lexical subroutines has been added.
    • Config::Perl::V module to access perl -V data in structured way has been added into core modules.
    • DTrace/SystemTap provides new probes op-entry, loading-file, and loaded-file.
  • Changes:
    • Hashes are randomized by default now. That means the order in which keys and values are returned from a hash changes on each perl run. One can disable the randomization by setting PERL_PERTURB_KEYS environment variable to 0.
    • qw() operator does not imply surrounding parentheses any more.
    • Unknown character names specified using \N{} syntax are processed at compile time and trigger a syntax error now.
    • Vertical tab is considered as a white space now.
    • Values stored into environment variables are byte strings by default.
    • readline function on I/O reads given number of characters instead of bytes now.
    • Here-document delimited with quoted marker starts always on line following the marker now.
    • Alpha-numeric operators must always be separated from a regular expression delimiter now.
    • Smart-match and lexical $_ became experimental because they proved being problematic.
    • Swapping $< and $> variables can cause undesired effects. Localizing changed variable is recommended.
  • Removed features:
    • PL_sv_objcount XS variable is deprecated.
    • All character classifying XS functions are deprecated.
    • to_uni_lower_lc, to_uni_title_lc, and to_uni_upper_lc XS functions are deprecated.