Changes/perl5.26

Perl 5.26

Summary

A new perl 5.26 version brings a lot of changes done over a year of development. Perl 5.26 was released 5/31/2017. See 5.26.0 perldelta for more details about preparing release.

Owner

• Name: Jitka Plesníková
• Email: <jplesnik@redhat.com>
• Name: Petr Písař
• Email: <ppisar@redhat.com>
• Release notes owner: Simon Clark (sclark)

Current status

• Targeted release: Fedora 27
• Last updated: 2017-08-28
• Tracker bug: #1453004

Completed items

• Get dedicated build-root from rel-engs (f27-perl)
• Define perl_bootstrap in perl-srpm-macros
• Rebase perl to 5.26.0
• Build new perl 5.26 keeping old COMPAT Provides
• Rebuild dual-lived packages (otherwise yum recommends --skip-broken and fails)
• Rebuild packages needed for minimal build-root
• Rebuild packages needed for building source packages from git repository
• Remove old perl(:MODULE_COMPAT_5.24.*) from perl
• Undefine perl_bootstrap
• Rebuild other packages: Use Fedora::Rebuild dependency solver
• Rebuild packages having perl_bootstrap condition in spec file
• Rebuild all updated packages
• Merge dedicated build-root to rawhide and remove the dedicated one by rel-engs
• Synchronize packages upgraded in f27 build root
• Rebuilt Perl packages: 3006 of 3011 done (99.83 %)
• Unfixable packages retired (3):
  • obexftp - openobex-devel is missing on s390x
  • perl-Algorithm-CurveFit - build failed BZ#1242769
  • perl-PDL-Graphics-PLplot - tests failed BZ#1459590

Items in progress

• Failed builds (2):
  • dnssec-tools - build failed BZ#1381613
  • perl-OpenOffice-UNO - test fail randomly BZ#1106166

Detailed Description

New perl is released every year and updates containing mainly bug fixes follow during the year. The 5.26.0 version is stable release this year.

Benefit to Fedora

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

Scope

Every Perl package will be rebuilt in a dedicated f27-perl build-root against perl 5.26.0 and then if no major problem emerges the packages will be merged back to f27 build-root.

• Proposal owners:

New perl and all packages requiring perl or a Perl module will be rebuilt into f27-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 f27-perl build-root inheriting from f27 build-root. After successful finishing the rebuild, they will be asked to merge f27-perl packages back to f27 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 5.26 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 26 to 27. 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.

Dependencies

There is more than 3000 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 5.26 is not suitable for Fedora 27, we will revert back to perl 5.24 and we drop the temporary build-root with already rebuilt packages.

• Contingency deadline: branching Fedora 27 from Rawhide.
• Blocks release? No.

Documentation

• 5.26.0 perldelta

Release Notes

• Main changes with widespread effects:
  • Removal of the current directory (".") from @INC for security reason (more info).
  • do now gives a deprecation warning when it fails to load a file which it would have loaded had "." been in @INC.
  • Unescaped literal { characters in regular expression patterns are no longer permissible.

• Other changes:
  • Lexical subroutines (lexical_subs) are no longer experimental.
  • It is possible to indented here-documents. The ~ modifier will strip, from each line in the here-doc, the same whitespace that appears before the delimiter.
  • There is a new regular expression modifier /xx. It does everything that a single x does, but additionally TAB and SPACE characters within a bracketed character class are generally ignored.
  • Unicode 9.0 is now supported.
  • Use of \p{script} uses the improved Script_Extensions property.
  • The hash and array functions in the CORE namespace (keys, each, values, push, pop, shift, unshift and splice) can be called with ampersand syntax (&CORE::keys(\%hash) and via reference (my $k = \&CORE::keys; $k->(\%hash)).
  • New -Di switch is now required for PerlIO debugging output/
  • scalar(%hash) returns the count of used keys instead of information about the buckets allocated in the hash.
  • keys returned from an lvalue subroutine can no longer be assigned to in list context.
  • require ::Foo::Bar is now illegal. Now any bareword require which starts with a double colon dies.
  • New documentation perldeprecation describe all upcoming deprecations and some of the deprecations which already have been removed.

• Removed features:
  • The ${^ENCODING} facility has been removed. The encoding pragma's default mode is no longer supported. If you need to write your source code in encoding other than UTF-8, use a source filter such as Filter::Encoding on CPAN or encoding's Filter option.
  • The old utilities c2ph and pstruct were removed.