[perl5.git] / pod / perl5255delta.pod

=encoding utf8

=head1 NAME

perl5255delta - what is new for perl v5.25.5

=head1 DESCRIPTION

This document describes differences between the 5.25.4 release and the 5.25.5
release.

If you are upgrading from an earlier release such as 5.25.3, first read
L<perl5254delta>, which describes differences between 5.25.3 and 5.25.4.

=head1 Security

=head2 "Escaped" colons and relative paths in PATH

On Unix systems, Perl treats any relative paths in the PATH environment
variable as tainted when starting a new process.  Previously, it was
allowing a backslash to escape a colon (unlike the OS), consequently
allowing relative paths to be considered safe if the PATH was set to
something like C</\:.>.  The check has been fixed to treat C<.> as tainted
in that example.

=head1 Modules and Pragmata

=head2 Updated Modules and Pragmata

=over 4

=item *

L<Filter::Simple> has been upgraded from version 0.92 to 0.93.

It no longer treats C<no MyFilter> immediately following C<use MyFilter> as
end-of-file.  [perl #107726]

=item *

L<Locale::Codes> has been upgraded from 3.39 to 3.40.

=item *

L<Module::CoreList> has been upgraded from version 5.20160820 to 5.20160920.

=item *

L<POSIX> has been upgraded from version 1.71 to 1.72.

=item *

L<Sys::Syslog> has been upgraded from version 0.34_01 to 0.35.

=item *

L<Test::Simple> has been upgraded from version 1.302052 to 1.302056.

=item *

L<Thread::Semaphore> has been upgraded from 2.12 to 2.13.

Added the C<down_timed> method.

=item *

L<XSLoader> has been upgraded from version 0.22 to 0.24.

=back

=head1 Documentation

=head2 Changes to Existing Documentation

=head3 L<perlinterp>

=over 4

=item *

L<perlinterp> has been expanded to give a more detailed example of how to
hunt around in the parser for how a given operator is handled.

=back

=head1 Testing

=over 4

=item *

F<t/re/regexp_nonull.t> has been added to test that the regular expression
engine can handle scalars that do not have a null byte just past the end of
the string.

=back

=head1 Platform Support

=head2 Platform-Specific Notes

=over 4

=item VMS

=over 4

=item *

The path separator for the C<PERL5LIB> and C<PERLLIB> environment entries is
now a colon (C<:>) when running under a Unix shell. There is no change when
running under DCL (it's still C<|>).

=item *

Remove some VMS-specific hacks from C<showlex.t>. These were added 15 years
ago, and are no longer necessary for any VMS version now supported.

=back

=back

=over 4

=item Win32

=over 4

=item *

Tweaks for Win32 VC vs GCC detection makefile code. This fixes issue that CCHOME
depends on CCTYPE, which in auto detect mode is set after CCHOME, so CCHOME uses
the uninit CCTYPE var. Also fix else vs .ELSE in makefile.mk

=back

=back

=head1 Internal Changes

=over 4

=item *

Several macros and functions have been added to the public API for
dealing with Unicode and UTF-8-encoded strings.  See
L<perlapi/Unicode Support>.

=item *

Use C<my_strlcat()> in C<locale.c>. While C<strcat()> is safe in this context,
some compilers were optimizing this to C<strcpy()> causing a porting test to
fail that looks for unsafe code. Rather than fighting this, we just use
C<my_strlcat()> instead.

=back

=head1 Selected Bug Fixes

=over 4

=item *

Invalid assignments to a reference constructor (e.g., C<\eval=time>) could
sometimes crash in addition to giving a syntax error.  [perl #125679]

=item *

The parser could sometimes crash if a bareword came after C<evalbytes>.
[perl #129196]

=item *

Autoloading via a method call would warn erroneously ("Use of inherited
AUTOLOAD for non-method") if there was a stub present in the package into
which the invocant had been blessed.  The warning is no longer emitted in
such circumstances.  [perl #47047]

=item *

A sub containing with a "forward" declaration with the same name (e.g.,
C<sub c { sub c; }>) could sometimes crash or loop infinitely.  [perl
#129090]

=item *

The use of C<splice> on arrays with nonexistent elements could cause other
operators to crash.  [perl #129164]

=item *

Fixed case where C<re_untuit_start> will overshoot the length of a utf8
string. [perl #129012]

=item *

Handle C<CXt_SUBST> better in C<Perl_deb_stack_all>, previously it wasn't
checking that the I<current> C<cx> is the right type, and instead was always
checking the base C<cx> (effectively a noop). [perl #129029]

=item *

Fixed two possible use-after-free bugs in C<Perl_yylex>. C<Perl_yylex>
maintains up to two pointers into the parser buffer, one of which can
become stale under the right conditions. [perl #129069]

=item *

Fixed a crash with C<s///l> where it thought it was dealing with UTF-8
when it wasn't. [perl #129038]

=item *

Fixed place where regex was not setting the syntax error correctly.
[perl #129122]

=item *

The C<&.> operator (and the C<&> operator, when it treats its arguments as
strings) were failing to append a trailing null byte if at least one string
was marked as utf8 internally.  Many code paths (system calls, regexp
compilation) still expect there to be a null byte in the string buffer
just past the end of the logical string.  An assertion failure was the
result.  [perl #129287]

=item *

Check C<pack_sockaddr_un()>'s return value because C<pack_sockaddr_un()>
silently truncates the supplied path if it won't fit into the C<sun_path>
member of C<sockaddr_un>. This may change in the future, but for now
check the path in theC<sockaddr> matches the desired path, and skip if
it doesn't. [perl #128095]

=item *

Make sure C<PL_oldoldbufptr> is preserved in C<scan_heredoc()>. In some
cases this is used in building error messages. [perl #128988]

=item *

Check for null PL_curcop in IN_LC() [perl #129106]

=item *

Fixed the parser error handling for an 'C<:attr(foo>' that does not have
an ending 'C<)>'.

=item *

Fix C<Perl_delimcpy()> to handle a backslash as last char, this
actually fixed two bugs, [perl #129064] and [perl #129176].

=item *

[perl #129267] rework gv_fetchmethod_pvn_flags separator parsing to
prevent possible string overrun with invalid len in gv.c

=back

=head1 Obituary

Jon Portnoy (AVENJ), a prolific Perl author and admired Gentoo community
member, has passed away on August 10, 2016. He will be remembered and
missed by all those with which he came in contact and enriched with his
intellect, wit, and spirit.

=head1 Acknowledgements

Perl 5.25.5 represents approximately 4 weeks of development since Perl 5.25.4
and contains approximately 67,000 lines of changes across 230 files from 25
authors.

Excluding auto-generated files, documentation and release tools, there were
approximately 62,000 lines of changes to 160 .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 5.25.5:

Aaron Crane, Aristotle Pagaltzis, Chris 'BinGOs' Williams, Craig A. Berry,
Dagfinn Ilmari Mannsåker, Dan Collins, Daniel Dragan, Dave Cross, David
Mitchell, E. Choroba, Father Chrysostomos, James E Keenan, Jerry D. Hedden,
Karl Williamson, Lukas Mai, Ricardo Signes, Rick Delaney, Sawyer X, Stevan
Little, Steve Hay, Sullivan Beck, Theo Buehler, Tony Cook, Yaroslav Kuzmin,
Yves Orton.

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 F<AUTHORS> file in the Perl source distribution.

=head1 Reporting Bugs

If you find what you think is a bug, you might check the perl bug database
at L<https://rt.perl.org/> .  There may also be information at
L<http://www.perl.org/> , the Perl Home Page.

If you believe you have an unreported bug, please run the L<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 C<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 see
L<perlsec/SECURITY VULNERABILITY CONTACT INFORMATION>
for details of how to report the issue.

=head1 SEE ALSO

The F<Changes> file for an explanation of how to view exhaustive details on
what changed.

The F<INSTALL> file for how to build Perl.

The F<README> file for general stuff.

The F<Artistic> and F<Copying> files for copyright information.

=cut
Commit	Line	Data
262514fd SL	1	=encoding utf8
	2
	3	=head1 NAME
	4
	5	perl5255delta - what is new for perl v5.25.5
	6
	7	=head1 DESCRIPTION
	8
	9	This document describes differences between the 5.25.4 release and the 5.25.5
	10	release.
	11
	12	If you are upgrading from an earlier release such as 5.25.3, first read
	13	L<perl5254delta>, which describes differences between 5.25.3 and 5.25.4.
	14
	15	=head1 Security
	16
	17	=head2 "Escaped" colons and relative paths in PATH
	18
	19	On Unix systems, Perl treats any relative paths in the PATH environment
	20	variable as tainted when starting a new process. Previously, it was
	21	allowing a backslash to escape a colon (unlike the OS), consequently
	22	allowing relative paths to be considered safe if the PATH was set to
	23	something like C</\:.>. The check has been fixed to treat C<.> as tainted
	24	in that example.
	25
	26	=head1 Modules and Pragmata
	27
	28	=head2 Updated Modules and Pragmata
	29
	30	=over 4
	31
	32	=item *
	33
	34	L<Filter::Simple> has been upgraded from version 0.92 to 0.93.
	35
	36	It no longer treats C<no MyFilter> immediately following C<use MyFilter> as
	37	end-of-file. [perl #107726]
	38
	39	=item *
	40
	41	L<Locale::Codes> has been upgraded from 3.39 to 3.40.
	42
	43	=item *
	44
	45	L<Module::CoreList> has been upgraded from version 5.20160820 to 5.20160920.
	46
	47	=item *
	48
	49	L<POSIX> has been upgraded from version 1.71 to 1.72.
	50
	51	=item *
	52
	53	L<Sys::Syslog> has been upgraded from version 0.34_01 to 0.35.
	54
	55	=item *
	56
	57	L<Test::Simple> has been upgraded from version 1.302052 to 1.302056.
	58
	59	=item *
	60
	61	L<Thread::Semaphore> has been upgraded from 2.12 to 2.13.
	62
	63	Added the C<down_timed> method.
	64
65	=item *
66
67	L<XSLoader> has been upgraded from version 0.22 to 0.24.
68
69	=back
70
71	=head1 Documentation
72
73	=head2 Changes to Existing Documentation
74
75	=head3 L<perlinterp>
76
77	=over 4
78
79	=item *
80
81	L<perlinterp> has been expanded to give a more detailed example of how to
82	hunt around in the parser for how a given operator is handled.
83
84	=back
85
86	=head1 Testing
87
88	=over 4
89
90	=item *
91
92	F<t/re/regexp_nonull.t> has been added to test that the regular expression
93	engine can handle scalars that do not have a null byte just past the end of
94	the string.
95
96	=back
97
98	=head1 Platform Support
99
100	=head2 Platform-Specific Notes
101
102	=over 4
103
104	=item VMS
105
106	=over 4
107
108	=item *
109
110	The path separator for the C<PERL5LIB> and C<PERLLIB> environment entries is
111	now a colon (C<:>) when running under a Unix shell. There is no change when
112	running under DCL (it's still C<\|>).
113
114	=item *
115
116	Remove some VMS-specific hacks from C<showlex.t>. These were added 15 years
117	ago, and are no longer necessary for any VMS version now supported.
118
119	=back
120
121	=back
122
123	=over 4
124
125	=item Win32
126
127	=over 4
128
129	=item *
130
131	Tweaks for Win32 VC vs GCC detection makefile code. This fixes issue that CCHOME
132	depends on CCTYPE, which in auto detect mode is set after CCHOME, so CCHOME uses
133	the uninit CCTYPE var. Also fix else vs .ELSE in makefile.mk
134
135	=back
136
137	=back
138
139	=head1 Internal Changes
140
141	=over 4
142
143	=item *
144
145	Several macros and functions have been added to the public API for
146	dealing with Unicode and UTF-8-encoded strings. See
147	L<perlapi/Unicode Support>.
148
149	=item *
150
151	Use C<my_strlcat()> in C<locale.c>. While C<strcat()> is safe in this context,
152	some compilers were optimizing this to C<strcpy()> causing a porting test to
153	fail that looks for unsafe code. Rather than fighting this, we just use
154	C<my_strlcat()> instead.
155
156	=back
157
158	=head1 Selected Bug Fixes
159
160	=over 4
161
162	=item *
163
164	Invalid assignments to a reference constructor (e.g., C<\eval=time>) could
165	sometimes crash in addition to giving a syntax error. [perl #125679]
166
167	=item *
168
169	The parser could sometimes crash if a bareword came after C<evalbytes>.
170	[perl #129196]
171
172	=item *
173
174	Autoloading via a method call would warn erroneously ("Use of inherited
175	AUTOLOAD for non-method") if there was a stub present in the package into
176	which the invocant had been blessed. The warning is no longer emitted in
177	such circumstances. [perl #47047]
178
179	=item *
180
181	A sub containing with a "forward" declaration with the same name (e.g.,
182	C<sub c { sub c; }>) could sometimes crash or loop infinitely. [perl
183	#129090]
184
185	=item *
186
187	The use of C<splice> on arrays with nonexistent elements could cause other
188	operators to crash. [perl #129164]
189
190	=item *
191
192	Fixed case where C<re_untuit_start> will overshoot the length of a utf8
193	string. [perl #129012]
194
195	=item *
196
197	Handle C<CXt_SUBST> better in C<Perl_deb_stack_all>, previously it wasn't
198	checking that the I<current> C<cx> is the right type, and instead was always
199	checking the base C<cx> (effectively a noop). [perl #129029]
200
201	=item *
202
203	Fixed two possible use-after-free bugs in C<Perl_yylex>. C<Perl_yylex>
204	maintains up to two pointers into the parser buffer, one of which can
205	become stale under the right conditions. [perl #129069]
206
207	=item *
208
209	Fixed a crash with C<s///l> where it thought it was dealing with UTF-8
210	when it wasn't. [perl #129038]
211
212	=item *
213
214	Fixed place where regex was not setting the syntax error correctly.
215	[perl #129122]
216
217	=item *
218
219	The C<&.> operator (and the C<&> operator, when it treats its arguments as
220	strings) were failing to append a trailing null byte if at least one string
221	was marked as utf8 internally. Many code paths (system calls, regexp
222	compilation) still expect there to be a null byte in the string buffer
223	just past the end of the logical string. An assertion failure was the
224	result. [perl #129287]
225
226	=item *
227
228	Check C<pack_sockaddr_un()>'s return value because C<pack_sockaddr_un()>
229	silently truncates the supplied path if it won't fit into the C<sun_path>
230	member of C<sockaddr_un>. This may change in the future, but for now
231	check the path in theC<sockaddr> matches the desired path, and skip if
232	it doesn't. [perl #128095]
233
234	=item *
235
236	Make sure C<PL_oldoldbufptr> is preserved in C<scan_heredoc()>. In some
237	cases this is used in building error messages. [perl #128988]
238
239	=item *
240
241	Check for null PL_curcop in IN_LC() [perl #129106]
242
243	=item *
244
245	Fixed the parser error handling for an 'C<:attr(foo>' that does not have
246	an ending 'C<)>'.
247
248	=item *
249
250	Fix C<Perl_delimcpy()> to handle a backslash as last char, this
251	actually fixed two bugs, [perl #129064] and [perl #129176].
252
253	=item *
254
255	[perl #129267] rework gv_fetchmethod_pvn_flags separator parsing to
256	prevent possible string overrun with invalid len in gv.c
257
258	=back
259
260	=head1 Obituary
261
262	Jon Portnoy (AVENJ), a prolific Perl author and admired Gentoo community
263	member, has passed away on August 10, 2016. He will be remembered and
264	missed by all those with which he came in contact and enriched with his
265	intellect, wit, and spirit.
266
267	=head1 Acknowledgements
268
269	Perl 5.25.5 represents approximately 4 weeks of development since Perl 5.25.4
270	and contains approximately 67,000 lines of changes across 230 files from 25
271	authors.
272
273	Excluding auto-generated files, documentation and release tools, there were
274	approximately 62,000 lines of changes to 160 .pm, .t, .c and .h files.
275
276	Perl continues to flourish into its third decade thanks to a vibrant community
277	of users and developers. The following people are known to have contributed the
278	improvements that became Perl 5.25.5:
279
280	Aaron Crane, Aristotle Pagaltzis, Chris 'BinGOs' Williams, Craig A. Berry,
281	Dagfinn Ilmari Mannsåker, Dan Collins, Daniel Dragan, Dave Cross, David
282	Mitchell, E. Choroba, Father Chrysostomos, James E Keenan, Jerry D. Hedden,
283	Karl Williamson, Lukas Mai, Ricardo Signes, Rick Delaney, Sawyer X, Stevan
284	Little, Steve Hay, Sullivan Beck, Theo Buehler, Tony Cook, Yaroslav Kuzmin,
285	Yves Orton.
286
287	The list above is almost certainly incomplete as it is automatically generated
288	from version control history. In particular, it does not include the names of
289	the (very much appreciated) contributors who reported issues to the Perl bug
290	tracker.
291
292	Many of the changes included in this version originated in the CPAN modules
293	included in Perl's core. We're grateful to the entire CPAN community for
294	helping Perl to flourish.
295
296	For a more complete list of all of Perl's historical contributors, please see
297	the F<AUTHORS> file in the Perl source distribution.
298
299	=head1 Reporting Bugs
300
301	If you find what you think is a bug, you might check the perl bug database
302	at L<https://rt.perl.org/> . There may also be information at
303	L<http://www.perl.org/> , the Perl Home Page.
304
305	If you believe you have an unreported bug, please run the L<perlbug> program
306	included with your release. Be sure to trim your bug down to a tiny but
307	sufficient test case. Your bug report, along with the output of C<perl -V>,
308	will be sent off to perlbug@perl.org to be analysed by the Perl porting team.
309
310	If the bug you are reporting has security implications which make it
311	inappropriate to send to a publicly archived mailing list, then see
312	L<perlsec/SECURITY VULNERABILITY CONTACT INFORMATION>
313	for details of how to report the issue.
314
315	=head1 SEE ALSO
316
317	The F<Changes> file for an explanation of how to view exhaustive details on
318	what changed.
319
320	The F<INSTALL> file for how to build Perl.
321
322	The F<README> file for general stuff.
323
324	The F<Artistic> and F<Copying> files for copyright information.
325
326	=cut