5 perl5241delta - what is new for perl v5.24.1
9 This document describes differences between the 5.24.0 release and the 5.24.1
12 If you are upgrading from an earlier release such as 5.22.0, first read
13 L<perl5240delta>, which describes differences between 5.22.0 and 5.24.0.
17 =head2 B<-Di> switch is now required for PerlIO debugging output
19 Previously PerlIO debugging output would be sent to the file specified by the
20 C<PERLIO_DEBUG> environment variable if perl wasn't running setuid and the
21 B<-T> or B<-t> switches hadn't been parsed yet.
23 If perl performed output at a point where it hadn't yet parsed its switches
24 this could result in perl creating or overwriting the file named by
25 C<PERLIO_DEBUG> even when the B<-T> switch had been supplied.
27 Perl now requires the B<-Di> switch to produce PerlIO debugging output. By
28 default this is written to C<stderr>, but can optionally be redirected to a
29 file by setting the C<PERLIO_DEBUG> environment variable.
31 If perl is running setuid or the B<-T> switch was supplied C<PERLIO_DEBUG> is
32 ignored and the debugging output is sent to C<stderr> as for any other B<-D>
35 =head2 Core modules and tools no longer search F<"."> for optional modules
37 The tools and many modules supplied in core no longer search the default
38 current directory entry in L<C<@INC>|perlvar/@INC> for optional modules. For
39 example, L<Storable> will remove the final F<"."> from C<@INC> before trying to
42 This prevents an attacker injecting an optional module into a process run by
43 another user where the current directory is writable by the attacker, e.g. the
46 In most cases this removal should not cause problems, but difficulties were
47 encountered with L<base>, which treats every module name supplied as optional.
48 These difficulties have not yet been resolved, so for this release there are no
49 changes to L<base>. We hope to have a fix for L<base> in Perl 5.24.2.
51 To protect your own code from this attack, either remove the default F<".">
52 entry from C<@INC> at the start of your script, so:
61 BEGIN { pop @INC if $INC[-1] eq '.' }
65 or for modules, remove F<"."> from a localized C<@INC>, so:
67 my $can_foo = eval { require Foo; }
73 pop @INC if $INC[-1] eq '.';
77 =head1 Incompatible Changes
79 Other than the security changes above there are no changes intentionally
80 incompatible with Perl 5.24.0. If any exist, they are bugs, and we request
81 that you submit a report. See L</Reporting Bugs> below.
83 =head1 Modules and Pragmata
85 =head2 Updated Modules and Pragmata
91 L<Archive::Tar> has been upgraded from version 2.04 to 2.04_01.
95 L<bignum> has been upgraded from version 0.42 to 0.42_01.
99 L<CPAN> has been upgraded from version 2.11 to 2.11_01.
103 L<Digest> has been upgraded from version 1.17 to 1.17_01.
107 L<Digest::SHA> has been upgraded from version 5.95 to 5.95_01.
111 L<Encode> has been upgraded from version 2.80 to 2.80_01.
115 L<ExtUtils::MakeMaker> has been upgraded from version 7.10_01 to 7.10_02.
119 L<File::Fetch> has been upgraded from version 0.48 to 0.48_01.
123 L<File::Spec> has been upgraded from version 3.63 to 3.63_01.
127 L<HTTP::Tiny> has been upgraded from version 0.056 to 0.056_001.
131 L<IO> has been upgraded from version 1.36 to 1.36_01.
135 The IO-Compress modules have been upgraded from version 2.069 to 2.069_001.
139 L<IPC::Cmd> has been upgraded from version 0.92 to 0.92_01.
143 L<JSON::PP> has been upgraded from version 2.27300 to 2.27300_01.
147 L<Locale::Maketext> has been upgraded from version 1.26 to 1.26_01.
151 L<Locale::Maketext::Simple> has been upgraded from version 0.21 to 0.21_01.
155 L<Memoize> has been upgraded from version 1.03 to 1.03_01.
159 L<Module::CoreList> has been upgraded from version 5.20160506 to 5.20170114_24.
163 L<Net::Ping> has been upgraded from version 2.43 to 2.43_01.
167 L<Parse::CPAN::Meta> has been upgraded from version 1.4417 to 1.4417_001.
171 L<Pod::Html> has been upgraded from version 1.22 to 1.2201.
175 L<Pod::Perldoc> has been upgraded from version 3.25_02 to 3.25_03.
179 L<Storable> has been upgraded from version 2.56 to 2.56_01.
183 L<Sys::Syslog> has been upgraded from version 0.33 to 0.33_01.
187 L<Test> has been upgraded from version 1.28 to 1.28_01.
191 L<Test::Harness> has been upgraded from version 3.36 to 3.36_01.
195 L<XSLoader> has been upgraded from version 0.21 to 0.22, fixing a security hole
196 in which binary files could be loaded from a path outside of C<@INC>.
197 L<[perl #128528]|https://rt.perl.org/Public/Bug/Display.html?id=128528>
203 =head2 Changes to Existing Documentation
211 The documentation of C<PERLIO_DEBUG> has been updated.
221 The new B<-Di> switch has been documented, and the documentation of
222 C<PERLIO_DEBUG> has been updated.
232 A new test script, F<t/run/switchDx.t>, has been added to test that the new
233 B<-Di> switch is working correctly.
237 =head1 Selected Bug Fixes
243 The change to hashbang redirection introduced in Perl 5.24.0, whereby perl
244 would redirect to another interpreter (Perl 6) if it found a hashbang path
245 which contains "perl" followed by "6", has been reverted because it broke in
246 cases such as C<#!/opt/perl64/bin/perl>.
250 =head1 Acknowledgements
252 Perl 5.24.1 represents approximately 8 months of development since Perl 5.24.0
253 and contains approximately 8,100 lines of changes across 240 files from 18
256 Excluding auto-generated files, documentation and release tools, there were
257 approximately 2,200 lines of changes to 170 .pm, .t, .c and .h files.
259 Perl continues to flourish into its third decade thanks to a vibrant community
260 of users and developers. The following people are known to have contributed
261 the improvements that became Perl 5.24.1:
263 Aaron Crane, Alex Vandiver, Aristotle Pagaltzis, Chad Granum, Chris 'BinGOs'
264 Williams, Craig A. Berry, Father Chrysostomos, James E Keenan, Jarkko
265 Hietaniemi, Karen Etheridge, Leon Timmermans, Matthew Horsfall, Ricardo Signes,
266 Sawyer X, Sébastien Aperghis-Tramoni, Stevan Little, Steve Hay, Tony Cook.
268 The list above is almost certainly incomplete as it is automatically generated
269 from version control history. In particular, it does not include the names of
270 the (very much appreciated) contributors who reported issues to the Perl bug
273 Many of the changes included in this version originated in the CPAN modules
274 included in Perl's core. We're grateful to the entire CPAN community for
275 helping Perl to flourish.
277 For a more complete list of all of Perl's historical contributors, please see
278 the F<AUTHORS> file in the Perl source distribution.
280 =head1 Reporting Bugs
282 If you find what you think is a bug, you might check the articles recently
283 posted to the comp.lang.perl.misc newsgroup and the Perl bug database at
284 L<https://rt.perl.org/> . There may also be information at
285 L<http://www.perl.org/> , the Perl Home Page.
287 If you believe you have an unreported bug, please run the L<perlbug> program
288 included with your release. Be sure to trim your bug down to a tiny but
289 sufficient test case. Your bug report, along with the output of C<perl -V>,
290 will be sent off to perlbug@perl.org to be analysed by the Perl porting team.
292 If the bug you are reporting has security implications which make it
293 inappropriate to send to a publicly archived mailing list, then see
294 L<perlsec/SECURITY VULNERABILITY CONTACT INFORMATION> for details of how to
299 The F<Changes> file for an explanation of how to view exhaustive details on
302 The F<INSTALL> file for how to build Perl.
304 The F<README> file for general stuff.
306 The F<Artistic> and F<Copying> files for copyright information.