In perl.git, the branch rjbs/release-v5.22.0 has been updated <http://perl5.git.perl.org/perl.git/commitdiff/4dad13159f49f2dcb57091553dff793b9d627fdb?hp=69118ad20a6b6ff961d11f96bdc209a638715c19>
- Log ----------------------------------------------------------------- commit 4dad13159f49f2dcb57091553dff793b9d627fdb Author: Ricardo Signes <[email protected]> Date: Wed May 6 08:13:30 2015 -0400 perldelta/perldiag: make a pod cross-reference pass tests Why is this change needed? M pod/perldelta.pod M pod/perldiag.pod commit 1f9749211ef612e18435739b03344a4e743462cc Author: Ricardo Signes <[email protected]> Date: Wed May 6 08:12:58 2015 -0400 describe errors with no description, delete obsolete warnings M pod/perldelta.pod commit 6732127e15f9e18944287cb49959e67f799e0f80 Author: Ricardo Signes <[email protected]> Date: Wed May 6 07:42:32 2015 -0400 perldelta is now the perl5220delta M Makefile.SH M pod/.gitignore M pod/perldelta.pod M vms/descrip_mms.template M win32/Makefile M win32/makefile.mk M win32/pod.mak ----------------------------------------------------------------------- Summary of changes: Makefile.SH | 8 +- pod/.gitignore | 2 +- pod/perldelta.pod | 3162 +++++++++++++++++++++++++++++++++++++++++++--- pod/perldiag.pod | 3 +- vms/descrip_mms.template | 2 +- win32/Makefile | 4 +- win32/makefile.mk | 4 +- win32/pod.mak | 8 +- 8 files changed, 2996 insertions(+), 197 deletions(-) diff --git a/Makefile.SH b/Makefile.SH index 4a7a357..034d812 100755 --- a/Makefile.SH +++ b/Makefile.SH @@ -492,7 +492,7 @@ mini_obj = $(minindt_obj) $(MINIDTRACE_O) ndt_obj = $(obj0) $(obj1) $(obj2) $(obj3) $(ARCHOBJS) obj = $(ndt_obj) $(DTRACE_O) -perltoc_pod_prereqs = extra.pods pod/perl52112delta.pod pod/perlapi.pod pod/perlintern.pod pod/perlmodlib.pod pod/perluniprops.pod +perltoc_pod_prereqs = extra.pods pod/perl5220delta.pod pod/perlapi.pod pod/perlintern.pod pod/perlmodlib.pod pod/perluniprops.pod generated_pods = pod/perltoc.pod $(perltoc_pod_prereqs) generated_headers = uudmap.h bitcount.h mg_data.h @@ -1020,9 +1020,9 @@ pod/perlintern.pod: $(MINIPERL_EXE) autodoc.pl embed.fnc pod/perlmodlib.pod: $(MINIPERL_EXE) pod/perlmodlib.PL MANIFEST $(MINIPERL) pod/perlmodlib.PL -q -pod/perl52112delta.pod: pod/perldelta.pod - $(RMS) pod/perl52112delta.pod - $(LNS) perldelta.pod pod/perl52112delta.pod +pod/perl5220delta.pod: pod/perldelta.pod + $(RMS) pod/perl5220delta.pod + $(LNS) perldelta.pod pod/perl5220delta.pod extra.pods: $(MINIPERL_EXE) -@test ! -f extra.pods || rm -f `cat extra.pods` diff --git a/pod/.gitignore b/pod/.gitignore index 1ef8495..e6a3ab3 100644 --- a/pod/.gitignore +++ b/pod/.gitignore @@ -53,7 +53,7 @@ /roffitall # generated -/perl52112delta.pod +/perl5220delta.pod /perlapi.pod /perlintern.pod *.html diff --git a/pod/perldelta.pod b/pod/perldelta.pod index d1a5fc9..9b8e10f 100644 --- a/pod/perldelta.pod +++ b/pod/perldelta.pod @@ -2,224 +2,676 @@ =head1 NAME -[ this is a template for a new perldelta file. Any text flagged as XXX needs -to be processed before release. ] - -perldelta - what is new for perl v5.21.12 +perldelta - what is new for perl v5.22.0 =head1 DESCRIPTION -This document describes differences between the 5.21.11 release and the 5.21.12 +This document describes differences between the 5.22.0 release and the 5.20.0 release. -If you are upgrading from an earlier release such as 5.21.10, first read -L<perl52111delta>, which describes differences between 5.21.10 and 5.21.11. +If you are upgrading from an earlier release such as 5.18.0, first read +L<perl5200delta>, which describes differences between 5.18.0 and 5.20.0. + +=head1 Core Enhancements -=head1 Notice +=head2 New bitwise operators -XXX Any important notices here +A new experimental facility has been added that makes the four standard +bitwise operators (C<& | ^ ~>) treat their operands consistently as +numbers, and introduces four new dotted operators (C<&. |. ^. ~.>) that +treat their operands consistently as strings. The same applies to the +assignment variants (C<&= |= ^= &.= |.= ^.=>). -=head1 Core Enhancements +To use this, enable the "bitwise" feature and disable the +"experimental::bitwise" warnings category. See L<perlop/Bitwise String +Operators> for details. [rt.perl.org #123466] + +=head2 New double-diamond operator + +C<<< <<>> >>> is like C<< <> >> but uses three-argument C<open> to open +each file in @ARGV. So each element of @ARGV is an actual file name, and +"|foo" won't be treated as a pipe open. + +=head2 New \b boundaries in regular expressions + +=head3 qr/\b{gcb}/ + +C<gcb> stands for Grapheme Cluster Boundary. It is a Unicode property +that finds the boundary between sequences of characters that look like a +single character to a native speaker of a language. Perl has long had +the ability to deal with these through the C<\X> regular escape +sequence. Now, there is an alternative way of handling these. See +L<perlrebackslash/\b{}, \b, \B{}, \B> for details. + +=head3 qr/\b{wb}/ + +C<wb> stands for Word Boundary. It is a Unicode property +that finds the boundary between words. This is similar to the plain +C<\b> (without braces) but is more suitable for natural language +processing. It knows, for example that apostrophes can occur in the +middle of words. See L<perlrebackslash/\b{}, \b, \B{}, \B> for details. + +=head3 qr/\b{sb}/ + +C<sb> stands for Sentence Boundary. It is a Unicode property +to aid in parsing natural language sentences. +See L<perlrebackslash/\b{}, \b, \B{}, \B> for details. + +=head2 C<no re> covers more and is lexical + +Previously running C<no re> would only turn off a few things. Now it +turns off all the enabled things. For example, previously, you +couldn't turn off debugging, once enabled, inside the same block. + +=head2 Non-Capturing Regular Expression Flag + +Regular expressions now support a C</n> flag that disables capturing +and filling in C<$1>, C<$2>, etc... inside of groups: + + "hello" =~ /(hi|hello)/n; # $1 is not set + +This is equivalent to putting C<?:> at the beginning of every capturing group. + +See L<perlre/"n"> for more information. + +=head2 C<use re 'strict'> + +This applies stricter syntax rules to regular expression patterns +compiled within its scope, which hopefully will alert you to typos and +other unintentional behavior that backwards-compatibility issues prevent +us from doing in normal regular expression compilations. Because the +behavior of this is subject to change in future Perl releases as we gain +experience, using this pragma will raise a category +C<experimental::re_strict> warning. +See L<'strict' in re|re/'strict' mode>. + +=head2 C<qr/foo/x> now ignores any Unicode pattern white space + +The C</x> regular expression modifier allows the pattern to contain +white space and comments, both of which are ignored, for improved +readability. Until now, not all the white space characters that Unicode +designates for this purpose were handled. The additional ones now +recognized are +U+0085 NEXT LINE, +U+200E LEFT-TO-RIGHT MARK, +U+200F RIGHT-TO-LEFT MARK, +U+2028 LINE SEPARATOR, +and +U+2029 PARAGRAPH SEPARATOR. + +=head2 Unicode 7.0 is now supported + +For details on what is in this release, see +L<http://www.unicode.org/versions/Unicode7.0.0/>. + +=head2 S<C<use locale>> can restrict which locale categories are affected + +It is now possible to pass a parameter to S<C<use locale>> to specify +a subset of locale categories to be locale-aware, with the remaining +ones unaffected. See L<perllocale/The "use locale" pragma> for details. + +=head2 Perl now supports POSIX 2008 locale currency additions. + +On platforms that are able to handle POSIX.1-2008, the +hash returned by +L<C<POSIX::localeconv()>|perllocale/The localeconv function> +includes the international currency fields added by that version of the +POSIX standard. These are +C<int_n_cs_precedes>, +C<int_n_sep_by_space>, +C<int_n_sign_posn>, +C<int_p_cs_precedes>, +C<int_p_sep_by_space>, +and +C<int_p_sign_posn>. + +=head2 Better heuristics on older platforms for determining locale UTF8ness + +On platforms that implement neither the C99 standard nor the POSIX 2001 +standard, determining if the current locale is UTF8 or not depends on +heuristics. These are improved in this release. + +=head2 Aliasing via reference + +Variables and subroutines can now be aliased by assigning to a reference: + + \$c = \$d; + \&x = \&y; + +Or by using a backslash before a C<foreach> iterator variable, which is +perhaps the most useful idiom this feature provides: + + foreach \%hash (@array_of_hash_refs) { ... } + +This feature is experimental and must be enabled via C<use feature +'refaliasing'>. It will warn unless the C<experimental::refaliasing> +warnings category is disabled. + +See L<perlref/Assigning to References> + +=head2 C<prototype> with no arguments + +C<prototype()> with no arguments now infers C<$_>. [perl #123514] + +=head2 New "const" subroutine attribute + +The "const" attribute can be applied to an anonymous subroutine. It causes +it to be executed immediately when it is cloned. Its value is captured and +used to create a new constant subroutine that is returned. This feature is +experimental. See L<perlsub/Constant Functions>. + +=head2 C<fileno> now works on directory handles + +When the relevant support is available in the operating system, the +C<fileno> builtin now works on directory handles, yielding the +underlying file descriptor in the same way as for filehandles. On +operating systems without such support, C<fileno> on a directory handle +continues to return the undefined value, as before, but also sets C<$!> to +indicate that the operation is not supported. + +Currently, this uses either a C<dd_fd> member in the OS C<DIR> +structure, or a dirfd(3) function as specified by POSIX.1-2008. + +=head2 List form of pipe open implemented for Win32 + +The list form of pipe: + + open my $fh, "-|", "program", @arguments; + +is now implemented on Win32. It has the same limitations as C<system +LIST> on Win32, since the Win32 API doesn't accept program arguments +as a list. + +=head2 C<close> now sets C<$!> + +When an I/O error occurs, the fact that there has been an error is recorded +in the handle. C<close> returns false for such a handle. Previously, the +value of C<$!> would be untouched by C<close>, so the common convention of +writing C<close $fh or die $!> did not work reliably. Now the handle +records the value of C<$!>, too, and C<close> restores it. + +=head2 Assignment to list repetition + +C<(...) x ...> can now be used within a list that is assigned to, as long +as the left-hand side is a valid lvalue. This allows C<(undef,undef,$foo) += that_function()> to be written as C<((undef)x2, $foo) = that_function()>. + +=head2 Infinity and NaN (not-a-number) handling improved + +Floating point values are able to hold the special values infinity (also +-infinity), and NaN (not-a-number). Now we more robustly recognize and +propagate the value in computations, and on output normalize them to C<Inf> and +C<NaN>. + +See also the L<POSIX> enhancements. + +=head2 Floating point parsing has been improved + +Parsing and printing of floating point values has been improved. + +As a completely new feature, hexadecimal floating point literals +(like 0x1.23p-4) are now supported, and they can be output with +C<printf %a>. + +=head2 Packing infinity or not-a-number into a character is now fatal + +Before, when trying to pack infinity or not-a-number into a +(signed) character, Perl would warn, and assumed you tried to +pack C<< 0xFF >>; if you gave it as an argument to C<< chr >>, +C<< U+FFFD >> was returned. + +But now, all such actions (C<< pack >>, C<< chr >>, and C<< print '%c' >>) +result in a fatal error. + +=head2 Experimental C Backtrace API -XXX New core language features go here. Summarize user-visible core language -enhancements. Particularly prominent performance optimisations could go -here, but most should go in the L</Performance Enhancements> section. +Starting from Perl 5.21.1, on some platforms Perl supports retrieving +the C level backtrace (similar to what symbolic debuggers like gdb do). -[ List each enhancement as a =head2 entry ] +The backtrace returns the stack trace of the C call frames, +with the symbol names (function names), the object names (like "perl"), +and if it can, also the source code locations (file:line). + +The supported platforms are Linux and OS X (some *BSD might work at +least partly, but they have not yet been tested). + +The feature needs to be enabled with C<Configure -Dusecbacktrace>. + +Also included is a C API to retrieve backtraces. + +See L<perlhacktips/"C backtrace"> for more information. =head1 Security -XXX Any security-related notices go here. In particular, any security -vulnerabilities closed should be noted here rather than in the -L</Selected Bug Fixes> section. +=head2 Perl is now compiled with -fstack-protector-strong if available + +Perl has been compiled with the anti-stack-smashing option +C<-fstack-protector> since 5.10.1. Now Perl uses the newer variant +called C<-fstack-protector-strong>, if available. + +=head2 The L<Safe> module could allow outside packages to be replaced + +Critical bugfix: outside packages could be replaced. L<Safe> has +been patched to 2.38 to address this. + +=head2 Perl is now always compiled with -D_FORTIFY_SOURCE=2 if available -[ List each security issue as a =head2 entry ] +The 'code hardening' option called C<_FORTIFY_SOURCE>, available in +gcc 4.*, is now always used for compiling Perl, if available. + +Note that this isn't necessarily a huge step since in many platforms +the step had already been taken several years ago: many Linux +distributions (like Fedora) have been using this option for Perl, +and OS X has enforced the same for many years. =head1 Incompatible Changes -XXX For a release on a stable branch, this section aspires to be: +=head2 Subroutine signatures moved before attributes + +The experimental sub signatures feature, as introduced in 5.20, parsed +signatures after attributes. In this release, the positioning has been +moved such that signatures occur after the subroutine name (if any) and +before the attribute list (if any). + +=head2 C<&> and C<\&> prototypes accepts only subs + +The C<&> prototype character now accepts only anonymous subs (C<sub {...}>) +and things beginning with C<\&>. Formerly it erroneously also allowed +C<undef> and references to array, hashes, and lists. [perl #4539] +[perl #123062] + +The C<\&> prototype was allowing subroutine calls, whereas now it only +allows subroutines. C<&foo> is permitted. C<&foo()> and C<foo()> are not. +[perl #77860] + +=head2 C<use encoding> is now lexical + +The L<encoding> pragma's effect is now limited to lexical scope. This +pragma is deprecated, but in the meantime, it could adversely affect +unrelated modules that are included in the same program. + +=head2 List slices returning empty lists + +List slices return an empty list now only if the original list was empty +(or if there are no indices). Formerly, a list slice would return an empty +list if all indices fell outside the original list. [perl #114498] + +=head2 C<\N{}> with a sequence of multiple spaces is now a fatal error. + +This has been deprecated since v5.18. + +=head2 S<C<use UNIVERSAL '...'>> is now a fatal error + +Importing functions from C<UNIVERSAL> has been deprecated since v5.12, and +is now a fatal error. S<C<"use UNIVERSAL">> without any arguments is still +allowed. + +=head2 In double-quotish C<\cI<X>>, I<X> must now be a printable ASCII character + +In prior releases, failure to do this raised a deprecation warning. + +=head2 Splitting the tokens C<(?> and C<(*> in regular expressions is +now a fatal compilation error. + +These had been deprecated since v5.18. + +=head2 5 additional characters are treated as white space under C</x> in +regex patterns (unless escaped) + +The use of these characters with C</x> outside bracketed character +classes and when not preceded by a backslash has raised a deprecation +warning since v5.18. Now they will be ignored. See L</"qr/foo/x"> +for the list of the five characters. + +=head2 Comment lines within S<C<(?[ ])>> now are ended only by a C<\n> + +S<C<(?[ ])>> is an experimental feature, introduced in v5.18. It operates +as if C</x> is always enabled. But there was a difference, comment +lines (following a C<#> character) were terminated by anything matching +C<\R> which includes all vertical whitespace, such as form feeds. For +consistency, this is now changed to match what terminates comment lines +outside S<C<(?[ ])>>, namely a C<\n> (even if escaped), which is the +same as what terminates a heredoc string and formats. + +=head2 C<(?[...])> operators now follow standard Perl precedence + +This experimental feature allows set operations in regular expression patterns. +Prior to this, the intersection operator had the same precedence as the other +binary operators. Now it has higher precedence. This could lead to different +outcomes than existing code expects (though the documentation has always noted +that this change might happen, recommending fully parenthesizing the +expressions). See L<perlrecharclass/Extended Bracketed Character Classes>. + +=head2 Omitting % and @ on hash and array names is no longer permitted - There are no changes intentionally incompatible with 5.XXX.XXX - If any exist, they are bugs, and we request that you submit a - report. See L</Reporting Bugs> below. +Really old Perl let you omit the @ on array names and the % on hash +names in some spots. This has issued a deprecation warning since Perl +5.0, and is no longer permitted. -[ List each incompatible change as a =head2 entry ] +=head2 C<"$!"> text is now in English outside C<"use locale"> scope + +Previously, the text, unlike almost everything else, always came out +based on the current underlying locale of the program. (Also affected +on some systems is C<"$^E>".) For programs that are unprepared to +handle locale, this can cause garbage text to be displayed. It's better +to display text that is translatable via some tool than garbage text +which is much harder to figure out. + +=head2 C<"$!"> text will be returned in UTF-8 when appropriate + +The stringification of C<$!> and C<$^E> will have the UTF-8 flag set +when the text is actually non-ASCII UTF-8. This will enable programs +that are set up to be locale-aware to properly output messages in the +user's native language. Code that needs to continue the 5.20 and +earlier behavior can do the stringification within the scopes of both +'use bytes' and 'use locale ":messages". No other Perl operations will +be affected by locale; only C<$!> and C<$^E> stringification. The +'bytes' pragma causes the UTF-8 flag to not be set, just as in previous +Perl releases. This resolves [perl #112208]. + +=head2 Support for C<?PATTERN?> without explicit operator has been removed + +Starting regular expressions matching only once directly with the +question mark delimiter is now a syntax error, so that the question mark +can be available for use in new operators. Write C<m?PATTERN?> instead, +explicitly using the C<m> operator: the question mark delimiter still +invokes match-once behaviour. + +=head2 C<defined(@array)> and C<defined(%hash)> are now fatal errors + +These have been deprecated since v5.6.1 and have raised deprecation +warnings since v5.16. + +=head2 Using a hash or an array as a reference are now fatal errors. + +For example, C<%foo-E<gt>{"bar"}> now causes a fatal compilation +error. These have been deprecated since before v5.8, and have raised +deprecation warnings since then. + +=head2 Changes to the C<*> prototype + +The C<*> character in a subroutine's prototype used to allow barewords to take +precedence over most, but not all subroutines. It was never consistent and +exhibited buggy behaviour. + +Now it has been changed, so subroutines always take precedence over barewords, +which brings it into conformity with similarly prototyped built-in functions: + + sub splat(*) { ... } + sub foo { ... } + splat(foo); # now always splat(foo()) + splat(bar); # still splat('bar') as before + close(foo); # close(foo()) + close(bar); # close('bar') =head1 Deprecations -XXX Any deprecated features, syntax, modules etc. should be listed here. +=head2 Setting C<${^ENCODING}> to anything but C<undef> -=head2 Module removals +This variable allows Perl scripts to be written in a non-ASCII, +non-UTF-8 encoding. However, it affects all modules globally, leading +to wrong answers and segmentation faults. New scripts should be written +in UTF-8; old scripts should be converted to UTF-8, which is easily done +with the L<encoding> pragma. -XXX Remove this section if inapplicable. +=head2 C<< /\C/ >> character class -The following modules will be removed from the core distribution in a -future release, and will at that time need to be installed from CPAN. -Distributions on CPAN which require these modules will need to list them as -prerequisites. +This character class, which matches a single byte, even if it appears +in a multi-byte character has been deprecated. Matching single bytes +in a multi-byte character breaks encapsulation, and can corrupt utf8 +strings. -The core versions of these modules will now issue C<"deprecated">-category -warnings to alert you to this fact. To silence these deprecation warnings, -install the modules in question from CPAN. +=head2 Use of non-graphic characters in single-character variable names -Note that these are (with rare exceptions) fine modules that you are encouraged -to continue to use. Their disinclusion from core primarily hinges on their -necessity to bootstrapping a fully functional, CPAN-capable Perl installation, -not usually on concerns over their design. +The syntax for single-character variable names is more lenient than +for longer variable names, allowing the one-character name to be a +punctuation character or even invisible (a non-graphic). Perl v5.20 +deprecated the ASCII-range controls as such a name. Now, all +non-graphic characters that formerly were allowed are deprecated. +The practical effect of this occurs only when not under C<S<"use +utf8">>, and affects just the C1 controls (code points 0x80 through +0xFF), NO-BREAK SPACE, and SOFT HYPHEN. -=over +=head2 Inlining of C<sub () { $var }> with observable side-effects -=item XXX +In many cases Perl makes sub () { $var } into an inlinable constant +subroutine, capturing the value of $var at the time the C<sub> expression +is evaluated. This can break the closure behaviour in those cases where +$var is subsequently modified. The subroutine won't return the new value. -XXX Note that deprecated modules should be listed here even if they are listed -as an updated module in the L</Modules and Pragmata> section. +This usage is now deprecated in those cases where the variable could be +modified elsewhere. Perl detects those cases and emits a deprecation +warning. Such code will likely change in the future and stop producing a +constant. -=back +If your variable is only modified in the place where it is declared, then +Perl will continue to make the sub inlinable with no warnings. -[ List each other deprecation as a =head2 entry ] + sub make_constant { + my $var = shift; + return sub () { $var }; # fine + } -=head1 Performance Enhancements + sub make_constant_deprecated { + my $var; + $var = shift; + return sub () { $var }; # deprecated + } -XXX Changes which enhance performance without changing behaviour go here. -There may well be none in a stable release. + sub make_constant_deprecated2 { + my $var = shift; + log_that_value($var); # could modify $var + return sub () { $var }; # deprecated + } -[ List each enhancement as a =item entry ] +In the second example above, detecting that $var is assigned to only once +is too hard to detect. That it happens in a spot other than the C<my> +declaration is enough for Perl to find it suspicious. -=over 4 +This deprecation warning happens only for a simple variable for the body of +the sub. (A C<BEGIN> block or C<use> statement inside the sub is ignored, +because it does not become part of the sub's body.) For more complex +cases, such as C<sub () { do_something() if 0; $var }> the behaviour has +changed such that inlining does not happen if the variable is modifiable +elsewhere. Such cases should be rare. -=item * +=head2 Use of multiple /x regexp modifiers -XXX +It is now deprecated to say something like any of the following: -=back + qr/foo/xx; + /(?xax:foo)/; + use re qw(/amxx); -=head1 Modules and Pragmata +That is, now C<x> should only occur once in any string of contiguous +regular expression pattern modifiers. We do not believe there are any +occurrences of this in all of CPAN. This is in preparation for a future +Perl release having C</xx> mean to allow white-space for readability in +bracketed character classes (those enclosed in square brackets: +C<[...]>). -XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/> -go here. If Module::CoreList is updated, generate an initial draft of the -following sections using F<Porting/corelist-perldelta.pl>. A paragraph summary -for important changes should then be added by hand. In an ideal world, -dual-life modules would have a F<Changes> file that could be cribbed. +=head2 Using a NO-BREAK space in a character alias for C<\N{...}> is now +deprecated -[ Within each section, list entries as a =item entry ] +This non-graphic character is essentially indistinguishable from a +regular space, and so should not be allowed. See +L<charnames/CUSTOM ALIASES>. -=head2 New Modules and Pragmata +=head2 A literal C<"{"> should now be escaped in a pattern + +If you want a literal left curly bracket (also called a left brace) in a +regular expression pattern, you should now escape it by either +preceding it with a backslash (C<"\{">) or enclosing it within square +brackets C<"[{]">, or by using C<\Q>; otherwise a deprecation warning +will be raised. This was first announced as forthcoming in the v5.16 +release; it will allow future extensions to the language to happen. + +=head2 Making all warnings fatal is discouraged + +The documentation for L<fatal warnings|warnings/Fatal Warnings> notes that +C<< use warnings FATAL => 'all' >> is discouraged and provides stronger +language about the risks of fatal warnings in general. + +=head1 Performance Enhancements =over 4 =item * -XXX - -=back +If method and class names are known at compile time, hashes are precomputed +to speed up run-time method lookup. Also, compound method names like +C<SUPER::new> are parsed at compile time, to save having to parse them at +run time. -=head2 Updated Modules and Pragmata +=item * -=over 4 +Array and hash lookups (especially nested ones) that use only constants +or simple variables as keys, are now considerably faster. See +L</Internal Changes> for more details. =item * -L<Module::CoreList> has been upgraded from version 5.20150420 to 5.20150520. +C<(...)x1>, C<("constant")x0> and C<($scalar)x0> are now optimised in list +context. If the right-hand argument is a constant 1, the repetition +operator disappears. If the right-hand argument is a constant 0, the whole +expressions is optimised to the empty list, so long as the left-hand +argument is a simple scalar or constant. C<(foo())x0> is not optimised. -Updated to cover the latest releases of Perl. +=item * -=back +C<substr> assignment is now optimised into 4-argument C<substr> at the end +of a subroutine (or as the argument to C<return>). Previously, this +optimisation only happened in void context. -=head2 Removed Modules and Pragmata +=item * -=over 4 +Assignment to lexical variables is often optimised away. For instance, in +C<$lexical = chr $foo>, the C<chr> operator writes directly to the lexical +variable instead of returning a value that gets copied. This optimisation +has been extended to C<split>, C<x> and C<vec> on the right-hand side. It +has also been made to work with state variable initialization. =item * -XXX +In "\L...", "\Q...", etc., the extra "stringify" op is now optimised away, +making these just as fast as C<lcfirst>, C<quotemeta>, etc. -=back +=item * -=head1 Documentation +Assignment to an empty list is now sometimes faster. In particular, it +never calls C<FETCH> on tied arguments on the right-hand side, whereas it +used to sometimes. + +=item * -XXX Changes to files in F<pod/> go here. Consider grouping entries by -file and be sure to link to the appropriate page, e.g. L<perlfunc>. +C<length> is up to 20% faster for non-magical/non-tied scalars containing a +string if it is a non-utf8 string or if C<use bytes;> is in scope. -=head2 New Documentation +=item * -XXX Changes which create B<new> files in F<pod/> go here. +Non-magical/non-tied scalars that contain only a floating point value and are +on most Perl builds with 64 bit integers now use 8-32 less bytes of memory +depending on OS. -=head3 L<XXX> +=item * -XXX Description of the purpose of the new file here +In C<@array = split>, the assignment can be optimized away with C<split> +writing directly to the array. This optimisation was happening only for +package arrays other than @_ and only +sometimes. Now this optimisation happens +almost all the time. -=head2 Changes to Existing Documentation +=item * -XXX Changes which significantly change existing files in F<pod/> go here. -However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics> -section. +C<join> is now subject to constant folding. Moreover, C<join> with a +scalar or constant for the separator and a single-item list to join is +simplified to a stringification. The separator doesn't even get evaluated. -=head3 L<XXX> +=item * -=over 4 +C<qq(@array)> is implemented using two ops: a stringify op and a join op. +If the qq contains nothing but a single array, the stringification is +optimized away. =item * -XXX Description of the change here +C<our $var> and C<our($s,@a,%h)> in void context are no longer evaluated at +run time. Even a whole sequence of C<our $foo;> statements will simply be +skipped over. The same applies to C<state> variables. -=back +=item * -=head1 Diagnostics +Many internal functions have been refactored to improve performance and reduce +their memory footprints. -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 L<perldiag>. +L<[perl #121436]|https://rt.perl.org/Ticket/Display.html?id=121436> +L<[perl #121906]|https://rt.perl.org/Ticket/Display.html?id=121906> +L<[perl #121969]|https://rt.perl.org/Ticket/Display.html?id=121969> -XXX New or changed warnings emitted by the core's C<C> code go here. Also -include any changes in L<perldiag> that reconcile it to the C<C> code. +=item * -=head2 New Diagnostics +C<-T> and C<-B> filetests will return sooner when an empty file is detected. -XXX Newly added diagnostic messages go under here, separated into New Errors -and New Warnings +L<perl #121489|https://rt.perl.org/Ticket/Display.html?id=121489> -=head3 New Errors +=item * -=over 4 +Refactoring of C<< pp_tied >> and CC<< pp_ref >> for small improvements. =item * -XXX L<message|perldiag/"message"> +Pathtools don't try to load XS on miniperl. -=back +=item * -=head3 New Warnings +A typo fix reduces the size of the C<< OP >> structure. -=over 4 +=item * + +Hash lookups where the key is a constant is faster. =item * -XXX L<message|perldiag/"message"> +Subroutines with an empty prototype and bodies containing just C<undef> are now +eligible for inlining. +L<[perl #122728]|https://rt.perl.org/Ticket/Display.html?id=122728> -=back +=item * -=head2 Changes to Existing Diagnostics +Subroutines in packages no longer need to carry typeglobs around with them. +Declaring a subroutine will now put a simple sub reference in the stash if +possible, saving memory. The typeglobs still notionally exist, so accessing +them will cause the subroutine reference to be upgraded to a typeglob. This +optimization does not currently apply to XSUBs or exported subroutines, and +method calls will undo it, since they cache things in typeglobs. +L<[perl #120441]|https://rt.perl.org/Ticket/Display.html?id=120441> -XXX Changes (i.e. rewording) of diagnostic messages go here +=item * -=over 4 +The functions C<utf8::native_to_unicode()> and C<utf8::unicode_to_native()> +(see L<utf8>) are now optimized out on ASCII platforms. There is now not even +a minimal performance hit in writing code portable between ASCII and EBCDIC +platforms. =item * -XXX Describe change here +Win32 Perl uses 8 KB less of per-process memory than before for every perl +process of this version. This data is now memory mapped from disk and shared +between perl processes from the same perl binary. =back -=head1 Utility Changes +=head1 Modules and Pragmata -XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go here. -Most of these are built within the directory F<utils>. +XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/> +go here. If Module::CoreList is updated, generate an initial draft of the +following sections using F<Porting/corelist-perldelta.pl>. A paragraph summary +for important changes should then be added by hand. In an ideal world, +dual-life modules would have a F<Changes> file that could be cribbed. -[ List utility changes as a =head2 entry for each utility and =item -entries for each change -Use L<XXX> with program names to get proper documentation linking. ] +[ Within each section, list entries as a =item entry ] -=head2 L<XXX> +=head2 New Modules and Pragmata =over 4 @@ -229,14 +681,17 @@ XXX =back -=head1 Configuration and Compilation +=head2 Updated Modules and Pragmata + +=over 4 + +=item * + +L<XXX> has been upgraded from version A.xx to B.yy. -XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools -go here. Any other changes to the Perl build process should be listed here. -However, any platform-specific changes should be listed in the -L</Platform Support> section, instead. +=back -[ List changes as a =item entry ]. +=head2 Removed Modules and Pragmata =over 4 @@ -246,141 +701,2486 @@ XXX =back -=head1 Testing +=head1 Documentation + +=head2 New Documentation -XXX Any significant changes to the testing of a freshly built perl should be -listed here. Changes which create B<new> files in F<t/> go here as do any -large changes to the testing harness (e.g. when parallel testing was added). -Changes to existing files in F<t/> aren't worth summarizing, although the bugs -that they represent may be covered elsewhere. +=head3 L<perlunicook> -[ List each test improvement as a =item entry ] +This document, by Tom Christiansen, provides examples of handling Unicode in +Perl. + +=head2 Changes to Existing Documentation + +=head3 L<perlapi> =over 4 =item * -XXX +Note that C<SvSetSV> doesn't do set magic. -=back +=item * -=head1 Platform Support +C<sv_usepvn_flags> - Fix documentation to mention the use of C<NewX> instead of +C<malloc>. -XXX Any changes to platform support should be listed in the sections below. +L<[perl #121869]|https://rt.perl.org/Ticket/Display.html?id=121869> -[ Within the sections, list each platform as a =item entry with specific -changes as paragraphs below it. ] +=item * -=head2 New Platforms +Clarify where C<NUL> may be embedded or is required to terminate a string. -XXX List any platforms that this version of perl compiles on, that previous -versions did not. These will either be enabled by new files in the F<hints/> -directories, or new subdirectories and F<README> files at the top level of the -source tree. +=item * -=over 4 +Previously missing documentation due to formatting errors are now included. -=item XXX-some-platform +=item * -XXX +Entries are now organized into groups rather than by file where they are found. -=back +=item * -=head2 Discontinued Platforms +Alphabetical sorting of entries is now handled by the POD generator to make +entries easier to find when scanning. + +=back -XXX List any platforms that this version of perl no longer compiles on. +=head3 L<perldata> =over 4 -=item XXX-some-platform +=item * -XXX +The syntax of single-character variable names has been brought +up-to-date and more fully explained. =back -=head2 Platform-Specific Notes - -XXX List any changes for specific platforms. This could include configuration -and compilation changes or changes in portability/compatibility. However, -changes within modules for platforms should generally be listed in the -L</Modules and Pragmata> section. +=head3 L<perlebcdic> =over 4 -=item XXX-some-platform +=item * -XXX +This document has been significantly updated in the light of recent +improvements to EBCDIC support. =back -=head1 Internal Changes +=head3 L<perlfunc> -XXX Changes which affect the interface available to C<XS> code go here. Other -significant internal changes for future core maintainers should be noted as -well. +=over 4 -[ List each change as a =item entry ] +=item * -=over 4 +Mention that C<study()> is currently a no-op. =item * -XXX +Calling C<delete> or C<exists> on array values is now described as "strongly +discouraged" rather than "deprecated". -=back +=item * -=head1 Selected Bug Fixes +Improve documentation of C<< our >>. -XXX Important bug fixes in the core language are summarized here. Bug fixes in -files in F<ext/> and F<lib/> are best summarized in L</Modules and Pragmata>. +=item * -[ List each fix as a =item entry ] +C<-l> now notes that it will return false if symlinks aren't supported by the +file system. -=over 4 +L<[perl #121523]|https://rt.perl.org/Ticket/Display.html?id=121523> =item * -XXX +Note that C<exec LIST> and C<system LIST> may fall back to the shell on +Win32. Only C<exec PROGRAM LIST> and C<system PROGRAM LIST> indirect object +syntax will reliably avoid using the shell. + +This has also been noted in L<perlport>. + +L<[perl #122046]|https://rt.perl.org/Ticket/Display.html?id=122046> =back -=head1 Known Problems +=head3 L<perlguts> + +=over 4 + +=item * + +The OOK example has been updated to account for COW changes and a change in the +storage of the offset. + +=item * -XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any -tests that had to be C<TODO>ed for the release would be noted here. Unfixed -platform specific bugs also go here. +Details on C level symbols and libperl.t added. -[ List each fix as a =item entry ] +=back + +=head3 L<perlhacktips> =over 4 =item * -XXX +Documentation has been added illustrating the perils of assuming the contents +of static memory pointed to by the return values of Perl wrappers for C library +functions doesn't change. + +=item * + +Recommended replacements for tmpfile, atoi, strtol, and strtoul added. + +=item * + +Updated documentation for the C<test.valgrind> C<make> target. + +L<[perl #121431]|https://rt.perl.org/Ticket/Display.html?id=121431> =back -=head1 Errata From Previous Releases +=head3 L<perlmodstyle> =over 4 =item * -XXX Add anything here that we forgot to add, or were mistaken about, in -the perldelta of a previous release. +Instead of pointing to the module list, we are now pointing to +L<PrePAN|http://prepan.org/>. =back -=head1 Obituary +=head3 L<perlpolicy> + +=over 4 + +=item * + +We now have a code of conduct for the I<< p5p >> mailing list, as documented +in L<< perlpolicy/STANDARDS OF CONDUCT >>. -XXX If any significant core contributor has died, we've added a short obituary -here. +=item * + +The conditions for marking an experimental feature as non-experimental are now +set out. + +=back + +=head3 L<perlport> + +=over 4 + +=item * + +Out-of-date VMS-specific information has been fixed/simplified. + +=back + +=head3 L<perlre> + +=over 4 + +=item * + +The C</x> modifier has been clarified to note that comments cannot be continued +onto the next line by escaping them. + +=back + +=head3 L<perlrebackslash> + +=over 4 + +=item * + +Added documentation of C<\b{sb}>, C<\b{wb}>, C<\b{gcb}>, and C<\b{g}>. + +=back + +=head3 L<perlrecharclass> + +=over 4 + +=item * + +Clarifications have been added to L<perlrecharclass/Character Ranges> +to the effect that Perl guarantees that C<[A-Z]>, C<[a-z]>, C<[0-9]> and +any subranges thereof in regular expression bracketed character classes +are guaranteed to match exactly what a naive English speaker would +expect them to match, even on platforms (such as EBCDIC) where special +handling is required to accomplish this. + +=item * + +The documentation of Bracketed Character Classes has been expanded to cover the +improvements in C<qr/[\N{named sequence}]/> (see under L</Selected Bug Fixes>). + +=back + +=head3 L<perlsec> + +=over 4 + +=item * + +Comments added on algorithmic complexity and tied hashes. + +=back + +=head3 L<perlsyn> + +=over 4 + +=item * + +An ambiguity in the documentation of the C<...> statement has been corrected. +L<[perl #122661]|https://rt.perl.org/Ticket/Display.html?id=122661> + +=item * + +The empty conditional in C<< for >> and C<< while >> is now documented +in L<< perlsyn >>. + +=back + +=head3 L<perlunicode> + +=over 4 + +=item * + +Update B<Default Word Boundaries> under +L<perlunicode/"Unicode Regular Expression Support Level">'s +B<Extended Unicode Support>. + +=back + +=head3 L<perluniintro> + +=over 4 + +=item * + +Advice for how to make sure your strings and regular expression patterns are +interpreted as Unicode has been revised to account for the new Perl 5.22 EBCDIC +handling. + +=back + +=head3 L<perlvar> + +=over 4 + +=item * + +Further clarify version number representations and usage. + +=back + +=head3 L<perlvms> + +=over 4 + +=item * + +Out-of-date and/or incorrect material has been removed. + +=item * + +Updated documentation on environment and shell interaction in VMS. + +=back + +=head3 L<perlxs> + +=over 4 + +=item * + +Added a discussion of locale issues in XS code. + +=back + +=head1 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 L<perldiag>. + +=head2 New Diagnostics + +=head3 New Errors + +=over 4 + +=item * + +L<Bad symbol for scalar|perldiag/"Bad symbol for scalar"> + +(P) An internal request asked to add a scalar entry to something that +wasn't a symbol table entry. + +=item * + +L<Can't use a hash as a reference|perldiag/"Can't use a hash as a reference"> + +(F) You tried to use a hash as a reference, as in +C<< %foo->{"bar"} >> or C<< %$ref->{"hello"} >>. Versions of perl E<lt>= 5.6.1 +used to allow this syntax, but shouldn't have. + +=item * + +L<Can't use an array as a reference|perldiag/"Can't use an array as a reference"> + +(F) You tried to use an array as a reference, as in +C<< @foo->[23] >> or C<< @$ref->[99] >>. Versions of perl E<lt>= 5.6.1 used to +allow this syntax, but shouldn't have. + +=item * + +L<Can't use 'defined(@array)' (Maybe you should just omit the defined()?)|perldiag/"Can't use 'defined(@array)' (Maybe you should just omit the defined()?)"> + +(F) defined() is not useful on arrays because it +checks for an undefined I<scalar> value. If you want to see if the +array is empty, just use C<if (@array) { # not empty }> for example. + +=item * + +L<Can't use 'defined(%hash)' (Maybe you should just omit the defined()?)|perldiag/"Can't use 'defined(%hash)' (Maybe you should just omit the defined()?)"> + +(F) C<defined()> is not usually right on hashes. + +Although C<defined %hash> is false on a plain not-yet-used hash, it +becomes true in several non-obvious circumstances, including iterators, +weak references, stash names, even remaining true after C<undef %hash>. +These things make C<defined %hash> fairly useless in practice, so it now +generates a fatal error. + +If a check for non-empty is what you wanted then just put it in boolean +context (see L<perldata/Scalar values>): + + if (%hash) { + # not empty + } + +If you had C<defined %Foo::Bar::QUUX> to check whether such a package +variable exists then that's never really been reliable, and isn't +a good way to enquire about the features of a package, or whether +it's loaded, etc. + +=item * + +L<Cannot chr %f|perldiag/"Cannot chr %f"> + +(F) You passed an invalid number (like an infinity or not-a-number) to +C<chr>. + +=item * + +L<Cannot compress %f in pack|perldiag/"Cannot compress %f in pack"> + +(F) You tried converting an infinity or not-a-number to an unsigned +character, which makes no sense. + +=item * + +L<Cannot pack %f with '%c'|perldiag/"Cannot pack %f with '%c'"> + +(F) You tried converting an infinity or not-a-number to a character, +which makes no sense. + +=item * + +L<Cannot print %f with '%c'|perldiag/"Cannot printf %f with '%c'"> + +(F) You tried printing an infinity or not-a-number as a character (%c), +which makes no sense. Maybe you meant '%s', or just stringifying it? + +=item * + +L<charnames alias definitions may not contain a sequence of multiple spaces|perldiag/"charnames alias definitions may not contain a sequence of multiple spaces"> + +(F) You defined a character name which had multiple space +characters in a row. Change them to single spaces. Usually these +names are defined in the C<:alias> import argument to C<use charnames>, but +they could be defined by a translator installed into C<$^H{charnames}>. +See L<charnames/CUSTOM ALIASES>. + +=item * + +L<charnames alias definitions may not contain trailing white-space|perldiag/"charnames alias definitions may not contain trailing white-space"> + +(F) You defined a character name which ended in a space +character. Remove the trailing space(s). Usually these names are +defined in the C<:alias> import argument to C<use charnames>, but they +could be defined by a translator installed into C<$^H{charnames}>. +See L<charnames/CUSTOM ALIASES>. + +=item * + +L<:const is not permitted on named subroutines|perldiag/":const is not permitted on named subroutines"> + +(F) The "const" attribute causes an anonymous subroutine to be run and +its value captured at the time that it is cloned. Names subroutines are +not cloned like this, so the attribute does not make sense on them. + +=item * + +L<Hexadecimal float: internal error|perldiag/"Hexadecimal float: internal error"> + +(F) Something went horribly bad in hexadecimal float handling. + +=item * + +L<Hexadecimal float: unsupported long double format|perldiag/"Hexadecimal float: unsupported long double format"> + +(F) You have configured Perl to use long doubles but +the internals of the long double format are unknown, +therefore the hexadecimal float output is impossible. + +=item * + +L<Illegal suidscript|perldiag/"Illegal suidscript"> + +(F) The script run under suidperl was somehow illegal. + +=item * + +L<In '(?...)', the '(' and '?' must be adjacent in regex; marked by S<<-- HERE> in mE<sol>%sE<sol>|perldiag/"In '(?...)', the '(' and '?' must be adjacent in regex; marked by <-- HERE in m/%s/"> + +(F) The two-character sequence C<"(?"> in +this context in a regular expression pattern should be an +indivisible token, with nothing intervening between the C<"("> +and the C<"?">, but you separated them. + +=item * + +L<In '(*VERB...)', the '(' and '*' must be adjacent in regex; marked by S<<-- HERE> in mE<sol>%sE<sol>|perldiag/"In '(*VERB...)', the '(' and '*' must be adjacent in regex; marked by <-- HERE in m/%s ... [3 chars truncated] + +(F) The two-character sequence C<"(*"> in +this context in a regular expression pattern should be an +indivisible token, with nothing intervening between the C<"("> +and the C<"*">, but you separated them. + +=item * + +L<Invalid quantifier in {,} in regex; marked by <-- HERE in mE<sol>%sE<sol>|perldiag/"Invalid quantifier in {,} in regex; marked by <-- HERE in m/%s/"> + +(F) The pattern looks like a {min,max} quantifier, but the min or max could not +be parsed as a valid number - either it has leading zeroes, or it represents +too big a number to cope with. The S<<-- HERE> shows where in the regular +expression the problem was discovered. See L<perlre>. + +=back + +=head3 New Warnings + +=over 4 + +=item * + +L<'%s' is an unknown bound type in regex|perldiag/"'%s' is an unknown bound type in regex; marked by <-- HERE in m/%s/"> + +You used C<\b{...}> or C<\B{...}> and the C<...> is not known to +Perl. The current valid ones are given in +L<perlrebackslash/\b{}, \b, \B{}, \B>. + +=item * + +L<"%s" is more clearly written simply as "%s" in regex; marked by E<lt>-- HERE in mE<sol>%sE<sol>|perldiag/"%s" is more clearly written simply as "%s" in regex; marked by <-- HERE in mE<sol>%sE<sol>> + +(W regexp) (only under C<S<use re 'strict'>> or within C<(?[...])>) + +You specified a character that has the given plainer way of writing it, +and which is also portable to platforms running with different character +sets. + +=item * + +L<Argument "%s" treated as 0 in increment (++)|perldiag/"Argument "%s" treated +as 0 in increment (++)"> + +(W numeric) The indicated string was fed as an argument to the C<++> operator +which expects either a number or a string matching C</^[a-zA-Z]*[0-9]*\z/>. +See L<perlop/Auto-increment and Auto-decrement> for details. + +=item * + +L<Both or neither range ends should be Unicode in regex; marked by E<lt>-- HERE in mE<sol>%sE<sol>|perldiag/"Both or neither range ends should be Unicode in regex; marked by <-- HERE in m/%s/"> + +(W regexp) (only under C<S<use re 'strict'>> or within C<(?[...])>) + +In a bracketed character class in a regular expression pattern, you +had a range which has exactly one end of it specified using C<\N{}>, and +the other end is specified using a non-portable mechanism. Perl treats +the range as a Unicode range, that is, all the characters in it are +considered to be the Unicode characters, and which may be different code +points on some platforms Perl runs on. For example, C<[\N{U+06}-\x08]> +is treated as if you had instead said C<[\N{U+06}-\N{U+08}]>, that is it +matches the characters whose code points in Unicode are 6, 7, and 8. +But that C<\x08> might indicate that you meant something different, so +the warning gets raised. + +=item * + +L<:const is experimental|perldiag/":const is experimental"> + +(S experimental::const_attr) The "const" attribute is experimental. +If you want to use the feature, disable the warning with C<no warnings +'experimental::const_attr'>, but know that in doing so you are taking +the risk that your code may break in a future Perl version. + +=item * + +L<gmtime(%f) failed|perldiag/"gmtime(%f) failed"> + +(W overflow) You called C<gmtime> with a number that it could not handle: +too large, too small, or NaN. The returned value is C<undef>. + +=item * + +L<Hexadecimal float: exponent overflow|perldiag/"Hexadecimal float: exponent overflow"> + +(W overflow) The hexadecimal floating point has larger exponent +than the floating point supports. + +=item * + +L<Hexadecimal float: exponent underflow|perldiag/"Hexadecimal float: exponent underflow"> + +(W overflow) The hexadecimal floating point has smaller exponent +than the floating point supports. + +=item * + +L<Hexadecimal float: mantissa overflow|perldiag/"Hexadecimal float: mantissa overflow"> + +(W overflow) The hexadecimal floating point literal had more bits in +the mantissa (the part between the 0x and the exponent, also known as +the fraction or the significand) than the floating point supports. + +=item * + +L<Hexadecimal float: precision loss|perldiag/"Hexadecimal float: precision loss"> + +(W overflow) The hexadecimal floating point had internally more +digits than could be output. This can be caused by unsupported +long double formats, or by 64-bit integers not being available +(needed to retrieve the digits under some configurations). + +=item * + +L<localtime(%f) failed|perldiag/"localtime(%f) failed"> + +(W overflow) You called C<localtime> with a number that it could not handle: +too large, too small, or NaN. The returned value is C<undef>. + +=item * + +L<Negative repeat count does nothing|perldiag/"Negative repeat count does nothing"> + +(W numeric) You tried to execute the +L<C<x>|perlop/Multiplicative Operators> repetition operator fewer than 0 +times, which doesn't make sense. + +=item * + +L<NO-BREAK SPACE in a charnames alias definition is deprecated|perldiag/"NO-BREAK SPACE in a charnames alias definition is deprecated"> + +(D deprecated) You defined a character name which contained a no-break +space character. Change it to a regular space. Usually these names are +defined in the C<:alias> import argument to C<use charnames>, but they +could be defined by a translator installed into C<$^H{charnames}>. See +L<charnames/CUSTOM ALIASES>. + +=item * + +L<Non-finite repeat count does nothing|perldiag/"Non-finite repeat count does nothing"> + +(W numeric) You tried to execute the +L<C<x>|perlop/Multiplicative Operators> repetition operator C<Inf> (or +C<-Inf>) or C<NaN> times, which doesn't make sense. + +=item * + +L<PerlIO layer ':win32' is experimental|perldiag/"PerlIO layer ':win32' is experimental"> + +(S experimental::win32_perlio) The C<:win32> PerlIO layer is +experimental. If you want to take the risk of using this layer, +simply disable this warning: + + no warnings "experimental::win32_perlio"; + +=item * + +L<Ranges of ASCII printables should be some subset of "0-9", "A-Z", or "a-z" in regex; marked by E<lt>-- HERE in mE<sol>%sE<sol>|perldiag/"Ranges of ASCII printables should be some subset of "0-9", " ... [64 chars truncated] + +(W regexp) (only under C<S<use re 'strict'>> or within C<(?[...])>) + +Stricter rules help to find typos and other errors. Perhaps you didn't +even intend a range here, if the C<"-"> was meant to be some other +character, or should have been escaped (like C<"\-">). If you did +intend a range, the one that was used is not portable between ASCII and +EBCDIC platforms, and doesn't have an obvious meaning to a casual +reader. + + [3-7] # OK; Obvious and portable + [d-g] # OK; Obvious and portable + [A-Y] # OK; Obvious and portable + [A-z] # WRONG; Not portable; not clear what is meant + [a-Z] # WRONG; Not portable; not clear what is meant + [%-.] # WRONG; Not portable; not clear what is meant + [\x41-Z] # WRONG; Not portable; not obvious to non-geek + +(You can force portability by specifying a Unicode range, which means that +the endpoints are specified by +L<C<\N{...}>|perlrecharclass/Character Ranges>, but the meaning may +still not be obvious.) +The stricter rules require that ranges that start or stop with an ASCII +character that is not a control have all their endpoints be the literal +character, and not some escape sequence (like C<"\x41">), and the ranges +must be all digits, or all uppercase letters, or all lowercase letters. + +=item * + +L<Ranges of digits should be from the same group in regex; marked by E<lt>-- HERE in mE<sol>%sE<sol>|perldiag/"Ranges of digits should be from the same group in regex; marked by <-- HERE in m/%s/"> + +(W regexp) (only under C<S<use re 'strict'>> or within C<(?[...])>) + +Stricter rules help to find typos and other errors. You included a +range, and at least one of the end points is a decimal digit. Under the +stricter rules, when this happens, both end points should be digits in +the same group of 10 consecutive digits. + +=item * + +L<Redundant argument in %s|perldiag/Redundant argument in %s> + +(W redundant) You called a function with more arguments than other +arguments you supplied indicated would be needed. Currently only +emitted when a printf-type format required fewer arguments than were +supplied, but might be used in the future for e.g. L<perlfunc/pack>. + +The warnings category C<< redundant >> is new. See also [RT #121025] + +=item * + +L<Use of \b{} for non-UTF-8 locale is wrong. Assuming a UTF-8 locale|perldiag/"Use of \b{} for non-UTF-8 locale is wrong. Assuming a UTF-8 locale"> + +You are matching a regular expression using locale rules, +and a Unicode boundary is being matched, but the locale is not a Unicode +one. This doesn't make sense. Perl will continue, assuming a Unicode +(UTF-8) locale, but the results could well be wrong except if the locale +happens to be ISO-8859-1 (Latin1) where this message is spurious and can +be ignored. + +=item * + +L<< Using E<sol>u for '%s' instead of E<sol>%s in regex; marked by E<lt>-- HERE in mE<sol>%sE<sol>|perldiag/"Using E<sol>u for '%s' instead of E<sol>%s in regex; marked by <-- HERE in mE<sol>%sE<sol> ... [4 chars truncated] + +You used a Unicode boundary (C<\b{...}> or C<\B{...}>) in a +portion of a regular expression where the character set modifiers C</a> +or C</aa> are in effect. These two modifiers indicate an ASCII +interpretation, and this doesn't make sense for a Unicode definition. +The generated regular expression will compile so that the boundary uses +all of Unicode. No other portion of the regular expression is affected. + +=item * + +L<The bitwise feature is experimental|perldiag/"The bitwise feature is experimental"> + +This warning is emitted if you use bitwise +operators (C<& | ^ ~ &. |. ^. ~.>) with the "bitwise" feature enabled. +Simply suppress the warning if you want to use the feature, but know +that in doing so you are taking the risk of using an experimental +feature which may change or be removed in a future Perl version: + + no warnings "experimental::bitwise"; + use feature "bitwise"; + $x |.= $y; + +=item * + +L<Unescaped left brace in regex is deprecated, passed through in regex; marked by <-- HERE in mE<sol>%sE<sol>|perldiag/"Unescaped left brace in regex is deprecated, passed through in regex; marked by ... [20 chars truncated] + +(D deprecated, regexp) You used a literal C<"{"> character in a regular +expression pattern. You should change to use C<"\{"> instead, because a future +version of Perl (tentatively v5.26) will consider this to be a syntax error. If +the pattern delimiters are also braces, any matching right brace +(C<"}">) should also be escaped to avoid confusing the parser, for +example, + + qr{abc\{def\}ghi} + +=item * + +L<Use of literal non-graphic characters in variable names is deprecated|perldiag/"Use of literal non-graphic characters in variable names is deprecated"> + +=item * + +L<Useless use of attribute "const"|perldiag/Useless use of attribute "const"> + +(W misc) The "const" attribute has no effect except +on anonymous closure prototypes. You applied it to +a subroutine via L<attributes.pm|attributes>. This is only useful +inside an attribute handler for an anonymous subroutine. + +=item * + +L<E<quot>use re 'strict'E<quot> is experimental|perldiag/"use re 'strict'" is experimental> + +(S experimental::re_strict) The things that are different when a regular +expression pattern is compiled under C<'strict'> are subject to change +in future Perl releases in incompatible ways. This means that a pattern +that compiles today may not in a future Perl release. This warning is +to alert you to that risk. + +=item * + +L<Warning: unable to close filehandle %s properly: %s|perldiag/"Warning: unable to close filehandle %s properly: %s"> + +=item * + +L<Wide character (U+%X) in %s|perldiag/"Wide character (U+%X) in %s"> + +(W locale) While in a single-byte locale (I<i.e.>, a non-UTF-8 +one), a multi-byte character was encountered. Perl considers this +character to be the specified Unicode code point. Combining non-UTF8 +locales and Unicode is dangerous. Almost certainly some characters +will have two different representations. For example, in the ISO 8859-7 +(Greek) locale, the code point 0xC3 represents a Capital Gamma. But so +also does 0x393. This will make string comparisons unreliable. + +You likely need to figure out how this multi-byte character got mixed up +with your single-byte locale (or perhaps you thought you had a UTF-8 +locale, but Perl disagrees). + +=item * + +The following two warnings for C<tr///> used to be skipped if the +transliteration contained wide characters, but now they occur regardless of +whether there are wide characters or not: + +L<Useless use of E<sol>d modifier in transliteration operator|perldiag/"Useless use of /d modifier in transliteration operator"> + +L<Replacement list is longer than search list|perldiag/Replacement list is longer than search list> + +=item * + +A new C<locale> warning category has been created, with the following warning +messages currently in it: + +=over 4 + +=item * + +L<Locale '%s' may not work well.%s|perldiag/Locale '%s' may not work well.%s> + +=item * + +L<Can't do %s("%s") on non-UTF-8 locale; resolved to "%s".|perldiag/Can't do %s("%s") on non-UTF-8 locale; resolved to "%s".> + +=back + +=back + +=head2 Changes to Existing Diagnostics + +=over 4 + +=item * + +<> should be quotes + +This warning has been changed to +L<< <> at require-statement should be quotes|perldiag/"<> at require-statement should be quotes" >> +to make the issue more identifiable. + +=item * + +L<Argument "%s" isn't numeric%s|perldiag/"Argument "%s" isn't numeric%s"> +now adds the following note: + + Note that for the C<Inf> and C<NaN> (infinity and not-a-number) the + definition of "numeric" is somewhat unusual: the strings themselves + (like "Inf") are considered numeric, and anything following them is + considered non-numeric. + +=item * + +L<Global symbol "%s" requires explicit package name|perldiag/"Global symbol "%s" requires explicit package name (did you forget to declare "my %s"?)"> + +This message has had '(did you forget to declare "my %s"?)' appended to it, to +make it more helpful to new Perl programmers. +L<[perl #121638]|https://rt.perl.org/Ticket/Display.html?id=121638> + +=item * + +'"my" variable &foo::bar can't be in a package' has been reworded to say +'subroutine' instead of 'variable'. + +=item * + +L<\N{} in character class restricted to one character in regex; marked by S<<-- HERE> in mE<sol>%sE<sol>|perldiag/"\N{} in inverted character class or as a range end-point is restricted to one charac ... [43 chars truncated] + +This message has had 'character class' changed to 'inverted character class or +as a range end-point is' to reflect improvements in C<qr/[\N{named sequence}]/> +(see under L</Selected Bug Fixes>). + +=item * + +L<panic: frexp|perldiag/"panic: frexp: %f"> + +This message has had ': %f' appended to it, to show what the offending floating +point number is. + +=item * + +B<Possible precedence problem on bitwise %c operator> reworded as +L<Possible precedence problem on bitwise %s operator|perldiag/"Possible precedence problem on bitwise %s operator">. + +=item * + +C<require> with no argument or undef used to warn about a Null filename; now +it dies with C<Missing or undefined argument to require>. + +=item * + +L<Unsuccessful %s on filename containing newline|perldiag/"Unsuccessful %s on filename containing newline"> + +This warning is now only produced when the newline is at the end of +the filename. + +=item * + +"Variable %s will not stay shared" has been changed to say "Subroutine" +when it is actually a lexical sub that will not stay shared. + +=item * + +L<Variable length lookbehind not implemented in regex mE<sol>%sE<sol>|perldiag/"Variable length lookbehind not implemented in regex m/%s/"> + +Information about Unicode behaviour has been added. + +=back + +=head2 Diagnostic Removals + +=over + +=item * + +"Ambiguous use of -foo resolved as -&foo()" + +There is actually no ambiguity here, and this impedes the use of negated +constants; e.g., C<-Inf>. + +=item * + +"Constant is not a FOO reference" + +Compile-time checking of constant dereferencing (e.g., C<< my_constant->() >>) +has been removed, since it was not taking overloading into account. +L<[perl #69456]|https://rt.perl.org/Ticket/Display.html?id=69456> +L<[perl #122607]|https://rt.perl.org/Ticket/Display.html?id=122607> + +=back + +=head1 Utility Changes + +=head2 F<x2p/> + +=over 4 + +=item * + +The F<x2p/> directory has been removed from the Perl core. + +This removes find2perl, s2p and a2p. They have all been released to CPAN as +separate distributions (App::find2perl, App::s2p, App::a2p). + +=back + +=head2 L<h2ph> + +=over 4 + +=item * + +F<h2ph> now handles hexadecimal constants in the compiler's predefined +macro definitions, as visible in C<$Config{cppsymbols}>. [rt.perl.org +#123784] + +=back + +=head2 L<encguess> + +=over 4 + +=item * + +No longer depends on non-core module anymore. + +=back + +=head1 Configuration and Compilation + +=over 4 + +=item * + +F<Configure> now checks for F<lrintl>, F<lroundl>, F<llrintl>, and F<llroundl>. + +=item * + +F<Configure> with C<-Dmksymlinks> should now be faster. [perl #122002] + +=item * + +pthreads and lcl will be linked by default if present. This allows XS modules +that require threading to work on non-threaded perls. Note that you must still +pass C<-Dusethreads> if you want a threaded perl. + +=item * + +For long doubles (to get more precision and range for floating point numbers) +one can now use the GCC quadmath library which implements the quadruple +precision floating point numbers in x86 and ia64 platforms. See F<INSTALL> for +details. + +=item * + +MurmurHash64A and MurmurHash64B can now be configured as the internal hash +function. + +=item * + +C<make test.valgrind> now supports parallel testing. + +For example: + + TEST_JOBS=9 make test.valgrind + +See L<perlhacktips/valgrind> for more information. + +L<[perl #121431]|https://rt.perl.org/Ticket/Display.html?id=121431> + +=item * + +The MAD (Misc Attribute Decoration) build option has been removed + +This was an unmaintained attempt at preserving +the Perl parse tree more faithfully so that automatic conversion of +Perl 5 to Perl 6 would have been easier. + +This build-time configuration option had been unmaintained for years, +and had probably seriously diverged on both Perl 5 and Perl 6 sides. + +=item * + +A new compilation flag, C<< -DPERL_OP_PARENT >> is available. For details, +see the discussion below at L<< /Internal Changes >>. + +=back + +=head1 Testing + +=over 4 + +=item * + +F<t/porting/re_context.t> has been added to test that L<utf8> and its +dependencies only use the subset of the C<$1..$n> capture vars that +Perl_save_re_context() is hard-coded to localize, because that function has no +efficient way of determining at runtime what vars to localize. + +=item * + +Tests for performance issues have been added in the file F<t/perf/taint.t>. + +=item * + +Some regular expression tests are written in such a way that they will +run very slowly if certain optimizations break. These tests have been +moved into new files, F<< t/re/speed.t >> and F<< t/re/speed_thr.t >>, +and are run with a C<< watchdog() >>. + +=item * + +C<< test.pl >> now allows C<< plan skip_all => $reason >>, to make it +more compatible with C<< Test::More >>. + +=item * + +A new test script, F<op/infnan.t>, has been added to test if Inf and NaN are +working correctly. See L</Infinity and NaN (not-a-number) handling improved>. + +=back + +=head1 Platform Support + +=head2 Regained Platforms + +=over 4 + +=item IRIX and Tru64 platforms are working again. + +(Some C<make test> failures remain.) + +=item z/OS running EBCDIC Code Page 1047 + +Core perl now works on this EBCDIC platform. Earlier perls also worked, but, +even though support wasn't officially withdrawn, recent perls would not compile +and run well. Perl 5.20 would work, but had many bugs which have now been +fixed. Many CPAN modules that ship with Perl still fail tests, including +Pod::Simple. However the version of Pod::Simple currently on CPAN should work; +it was fixed too late to include in Perl 5.22. Work is under way to fix many +of the still-broken CPAN modules, which likely will be installed on CPAN when +completed, so that you may not have to wait until Perl 5.24 to get a working +version. + +=back + +=head2 Discontinued Platforms + +=over 4 + +=item NeXTSTEP/OPENSTEP + +NeXTSTEP was proprietary OS bundled with NeXT's workstations in the early +to mid 90's; OPENSTEP was an API specification that provided a NeXTSTEP-like +environment on a non-NeXTSTEP system. Both are now long dead, so support +for building Perl on them has been removed. + +=back + +=head2 Platform-Specific Notes + +=over 4 + +=item EBCDIC + +Special handling is required on EBCDIC platforms to get C<qr/[i-j]/> to +match only C<"i"> and C<"j">, since there are 7 characters between the +code points for C<"i"> and C<"j">. This special handling had only been +invoked when both ends of the range are literals. Now it is also +invoked if any of the C<\N{...}> forms for specifying a character by +name or Unicode code point is used instead of a literal. See +L<perlrecharclass/Character Ranges>. + +=item HP-UX + +The archname now distinguishes use64bitint from use64bitall. + +=item Android + +Build support has been improved for cross-compiling in general and for +Android in particular. + **** PATCH TRUNCATED AT 2000 LINES -- 1545 NOT SHOWN **** -- Perl5 Master Repository
