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diff --git a/upstream/debian-unstable/man1/perl5280delta.1 b/upstream/debian-unstable/man1/perl5280delta.1 new file mode 100644 index 00000000..4b9b7774 --- /dev/null +++ b/upstream/debian-unstable/man1/perl5280delta.1 @@ -0,0 +1,1863 @@ +.\" -*- mode: troff; coding: utf-8 -*- +.\" Automatically generated by Pod::Man 5.01 (Pod::Simple 3.43) +.\" +.\" Standard preamble: +.\" ======================================================================== +.de Sp \" Vertical space (when we can't use .PP) +.if t .sp .5v +.if n .sp +.. +.de Vb \" Begin verbatim text +.ft CW +.nf +.ne \\$1 +.. +.de Ve \" End verbatim text +.ft R +.fi +.. +.\" \*(C` and \*(C' are quotes in nroff, nothing in troff, for use with C<>. +.ie n \{\ +. ds C` "" +. ds C' "" +'br\} +.el\{\ +. ds C` +. ds C' +'br\} +.\" +.\" Escape single quotes in literal strings from groff's Unicode transform. +.ie \n(.g .ds Aq \(aq +.el .ds Aq ' +.\" +.\" If the F register is >0, we'll generate index entries on stderr for +.\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index +.\" entries marked with X<> in POD. Of course, you'll have to process the +.\" output yourself in some meaningful fashion. +.\" +.\" Avoid warning from groff about undefined register 'F'. +.de IX +.. +.nr rF 0 +.if \n(.g .if rF .nr rF 1 +.if (\n(rF:(\n(.g==0)) \{\ +. if \nF \{\ +. de IX +. tm Index:\\$1\t\\n%\t"\\$2" +.. +. if !\nF==2 \{\ +. nr % 0 +. nr F 2 +. \} +. \} +.\} +.rr rF +.\" ======================================================================== +.\" +.IX Title "PERL5280DELTA 1" +.TH PERL5280DELTA 1 2024-01-12 "perl v5.38.2" "Perl Programmers Reference Guide" +.\" For nroff, turn off justification. Always turn off hyphenation; it makes +.\" way too many mistakes in technical documents. +.if n .ad l +.nh +.SH NAME +perl5280delta \- what is new for perl v5.28.0 +.SH DESCRIPTION +.IX Header "DESCRIPTION" +This document describes differences between the 5.26.0 release and the 5.28.0 +release. +.PP +If you are upgrading from an earlier release such as 5.24.0, first read +perl5260delta, which describes differences between 5.24.0 and 5.26.0. +.SH "Core Enhancements" +.IX Header "Core Enhancements" +.SS "Unicode 10.0 is supported" +.IX Subsection "Unicode 10.0 is supported" +A list of changes is at +<http://www.unicode.org/versions/Unicode10.0.0>. +.ie n .SS """delete"" on key/value hash slices" +.el .SS "\f(CWdelete\fP on key/value hash slices" +.IX Subsection "delete on key/value hash slices" +\&\f(CW\*(C`delete\*(C'\fR can now be used on +key/value hash slices, +returning the keys along with the deleted values. +[GH #15982] <https://github.com/Perl/perl5/issues/15982> +.SS "Experimentally, there are now alphabetic synonyms for some regular expression assertions" +.IX Subsection "Experimentally, there are now alphabetic synonyms for some regular expression assertions" +If you find it difficult to remember how to write certain of the pattern +assertions, there are now alphabetic synonyms. +.PP +.Vb 7 +\& CURRENT NEW SYNONYMS +\& \-\-\-\-\-\- \-\-\-\-\-\-\-\-\-\-\-\- +\& (?=...) (*pla:...) or (*positive_lookahead:...) +\& (?!...) (*nla:...) or (*negative_lookahead:...) +\& (?<=...) (*plb:...) or (*positive_lookbehind:...) +\& (?<!...) (*nlb:...) or (*negative_lookbehind:...) +\& (?>...) (*atomic:...) +.Ve +.PP +These are considered experimental, so using any of these will raise +(unless turned off) a warning in the \f(CW\*(C`experimental::alpha_assertions\*(C'\fR +category. +.SS "Mixed Unicode scripts are now detectable" +.IX Subsection "Mixed Unicode scripts are now detectable" +A mixture of scripts, such as Cyrillic and Latin, in a string is often +the sign of a spoofing attack. A new regular expression construct +now allows for easy detection of these. For example, you can say +.PP +.Vb 1 +\& qr/(*script_run: \ed+ \eb )/x +.Ve +.PP +And the digits matched will all be from the same set of 10. You won't +get a look-alike digit from a different script that has a different +value than what it appears to be. +.PP +Or: +.PP +.Vb 1 +\& qr/(*sr: \eb \ew+ \eb )/x +.Ve +.PP +makes sure that all the characters come from the same script. +.PP +You can also combine script runs with \f(CW\*(C`(?>...)\*(C'\fR (or +\&\f(CW\*(C`*atomic:...)\*(C'\fR). +.PP +Instead of writing: +.PP +.Vb 1 +\& (*sr:(?<...)) +.Ve +.PP +you can now run: +.PP +.Vb 3 +\& (*asr:...) +\& # or +\& (*atomic_script_run:...) +.Ve +.PP +This is considered experimental, so using it will raise (unless turned +off) a warning in the \f(CW\*(C`experimental::script_run\*(C'\fR category. +.PP +See "Script Runs" in perlre. +.ie n .SS "In-place editing with ""perl \-i"" is now safer" +.el .SS "In-place editing with \f(CWperl \-i\fP is now safer" +.IX Subsection "In-place editing with perl -i is now safer" +Previously in-place editing (\f(CW\*(C`perl \-i\*(C'\fR) would delete or rename the +input file as soon as you started working on a new file. +.PP +Without backups this would result in loss of data if there was an +error, such as a full disk, when writing to the output file. +.PP +This has changed so that the input file isn't replaced until the +output file has been completely written and successfully closed. +.PP +This works by creating a work file in the same directory, which is +renamed over the input file once the output file is complete. +.PP +Incompatibilities: +.IP \(bu 4 +Since this renaming needs to only happen once, if you create a thread +or child process, that renaming will only happen in the original +thread or process. +.IP \(bu 4 +If you change directories while processing a file, and your operating +system doesn't provide the \f(CWunlinkat()\fR, \f(CWrenameat()\fR and \f(CWfchmodat()\fR +functions, the final rename step may fail. +.PP +[GH #15216] <https://github.com/Perl/perl5/issues/15216> +.SS "Initialisation of aggregate state variables" +.IX Subsection "Initialisation of aggregate state variables" +A persistent lexical array or hash variable can now be initialized, +by an expression such as \f(CW\*(C`state @a = qw(x y z)\*(C'\fR. Initialization of a +list of persistent lexical variables is still not possible. +.SS "Full-size inode numbers" +.IX Subsection "Full-size inode numbers" +On platforms where inode numbers are of a type larger than perl's native +integer numerical types, stat will preserve the full +content of large inode numbers by returning them in the form of strings of +decimal digits. Exact comparison of inode numbers can thus be achieved by +comparing with \f(CW\*(C`eq\*(C'\fR rather than \f(CW\*(C`==\*(C'\fR. Comparison with \f(CW\*(C`==\*(C'\fR, and other +numerical operations (which are usually meaningless on inode numbers), +work as well as they did before, which is to say they fall back to +floating point, and ultimately operate on a fairly useless rounded inode +number if the real inode number is too big for the floating point format. +.ie n .SS "The ""sprintf"" %j format size modifier is now available with pre\-C99 compilers" +.el .SS "The \f(CWsprintf\fP \f(CW%j\fP format size modifier is now available with pre\-C99 compilers" +.IX Subsection "The sprintf %j format size modifier is now available with pre-C99 compilers" +The actual size used depends on the platform, so remains unportable. +.SS "Close-on-exec flag set atomically" +.IX Subsection "Close-on-exec flag set atomically" +When opening a file descriptor, perl now generally opens it with its +close-on-exec flag already set, on platforms that support doing so. +This improves thread safety, because it means that an \f(CW\*(C`exec\*(C'\fR initiated +by one thread can no longer cause a file descriptor in the process +of being opened by another thread to be accidentally passed to the +executed program. +.PP +Additionally, perl now sets the close-on-exec flag more reliably, whether +it does so atomically or not. Most file descriptors were getting the +flag set, but some were being missed. +.SS "String\- and number-specific bitwise ops are no longer experimental" +.IX Subsection "String- and number-specific bitwise ops are no longer experimental" +The new string-specific (\f(CW\*(C`&. |. ^. ~.\*(C'\fR) and number-specific (\f(CW\*(C`& | ^ ~\*(C'\fR) +bitwise operators introduced in Perl 5.22 that are available within the +scope of \f(CW\*(C`use feature \*(Aqbitwise\*(Aq\*(C'\fR are no longer experimental. +Because the number-specific ops are spelled the same way as the existing +operators that choose their behaviour based on their operands, these +operators must still be enabled via the "bitwise" feature, in either of +these two ways: +.PP +.Vb 1 +\& use feature "bitwise"; +\& +\& use v5.28; # "bitwise" now included +.Ve +.PP +They are also now enabled by the \fB\-E\fR command-line switch. +.PP +The "bitwise" feature no longer emits a warning. Existing code that +disables the "experimental::bitwise" warning category that the feature +previously used will continue to work. +.PP +One caveat that module authors ought to be aware of is that the numeric +operators now pass a fifth TRUE argument to overload methods. Any methods +that check the number of operands may croak if they do not expect so many. +XS authors in particular should be aware that this: +.PP +.Vb 2 +\& SV * +\& bitop_handler (lobj, robj, swap) +.Ve +.PP +may need to be changed to this: +.PP +.Vb 2 +\& SV * +\& bitop_handler (lobj, robj, swap, ...) +.Ve +.SS "Locales are now thread-safe on systems that support them" +.IX Subsection "Locales are now thread-safe on systems that support them" +These systems include Windows starting with Visual Studio 2005, and in +POSIX 2008 systems. +.PP +The implication is that you are now free to use locales and change them +in a threaded environment. Your changes affect only your thread. +See "Multi-threaded operation" in perllocale +.ie n .SS "New read-only predefined variable ""${^SAFE_LOCALES}""" +.el .SS "New read-only predefined variable \f(CW${^SAFE_LOCALES}\fP" +.IX Subsection "New read-only predefined variable ${^SAFE_LOCALES}" +This variable is 1 if the Perl interpreter is operating in an +environment where it is safe to use and change locales (see +perllocale.) This variable is true when the perl is +unthreaded, or compiled in a platform that supports thread-safe locale +operation (see previous item). +.SH Security +.IX Header "Security" +.SS "[CVE\-2017\-12837] Heap buffer overflow in regular expression compiler" +.IX Subsection "[CVE-2017-12837] Heap buffer overflow in regular expression compiler" +Compiling certain regular expression patterns with the case-insensitive +modifier could cause a heap buffer overflow and crash perl. This has now been +fixed. +[GH #16021] <https://github.com/Perl/perl5/issues/16021> +.SS "[CVE\-2017\-12883] Buffer over-read in regular expression parser" +.IX Subsection "[CVE-2017-12883] Buffer over-read in regular expression parser" +For certain types of syntax error in a regular expression pattern, the error +message could either contain the contents of a random, possibly large, chunk of +memory, or could crash perl. This has now been fixed. +[GH #16025] <https://github.com/Perl/perl5/issues/16025> +.ie n .SS "[CVE\-2017\-12814] $ENV{$key} stack buffer overflow on Windows" +.el .SS "[CVE\-2017\-12814] \f(CW$ENV{$key}\fP stack buffer overflow on Windows" +.IX Subsection "[CVE-2017-12814] $ENV{$key} stack buffer overflow on Windows" +A possible stack buffer overflow in the \f(CW%ENV\fR code on Windows has been fixed +by removing the buffer completely since it was superfluous anyway. +[GH #16051] <https://github.com/Perl/perl5/issues/16051> +.SS "Default Hash Function Change" +.IX Subsection "Default Hash Function Change" +Perl 5.28.0 retires various older hash functions which are not viewed as +sufficiently secure for use in Perl. We now support four general purpose +hash functions, Siphash (2\-4 and 1\-3 variants), and Zaphod32, and StadtX +hash. In addition we support SBOX32 (a form of tabular hashing) for hashing +short strings, in conjunction with any of the other hash functions provided. +.PP +By default Perl is configured to support SBOX hashing of strings up to 24 +characters, in conjunction with StadtX hashing on 64 bit builds, and +Zaphod32 hashing for 32 bit builds. +.PP +You may control these settings with the following options to Configure: +.PP +.Vb 4 +\& \-DPERL_HASH_FUNC_SIPHASH +\& \-DPERL_HASH_FUNC_SIPHASH13 +\& \-DPERL_HASH_FUNC_STADTX +\& \-DPERL_HASH_FUNC_ZAPHOD32 +.Ve +.PP +To disable SBOX hashing you can use +.PP +.Vb 1 +\& \-DPERL_HASH_USE_SBOX32_ALSO=0 +.Ve +.PP +And to set the maximum length to use SBOX32 hashing on with: +.PP +.Vb 1 +\& \-DSBOX32_MAX_LEN=16 +.Ve +.PP +The maximum length allowed is 256. There probably isn't much point +in setting it higher than the default. +.SH "Incompatible Changes" +.IX Header "Incompatible Changes" +.SS "Subroutine attribute and signature order" +.IX Subsection "Subroutine attribute and signature order" +The experimental subroutine signatures feature has been changed so that +subroutine attributes must now come before the signature rather than +after. This is because attributes like \f(CW\*(C`:lvalue\*(C'\fR can affect the +compilation of code within the signature, for example: +.PP +.Vb 1 +\& sub f :lvalue ($a = do { $x = "abc"; return substr($x,0,1)}) { ...} +.Ve +.PP +Note that this the second time they have been flipped: +.PP +.Vb 2 +\& sub f :lvalue ($a, $b) { ... }; # 5.20; 5.28 onwards +\& sub f ($a, $b) :lvalue { ... }; # 5.22 \- 5.26 +.Ve +.SS "Comma-less variable lists in formats are no longer allowed" +.IX Subsection "Comma-less variable lists in formats are no longer allowed" +Omitting the commas between variables passed to formats is no longer +allowed. This has been deprecated since Perl 5.000. +.ie n .SS "The "":locked"" and "":unique"" attributes have been removed" +.el .SS "The \f(CW:locked\fP and \f(CW:unique\fP attributes have been removed" +.IX Subsection "The :locked and :unique attributes have been removed" +These have been no-ops and deprecated since Perl 5.12 and 5.10, +respectively. +.ie n .SS """\eN{}"" with nothing between the braces is now illegal" +.el .SS "\f(CW\eN{}\fP with nothing between the braces is now illegal" +.IX Subsection "N{} with nothing between the braces is now illegal" +This has been deprecated since Perl 5.24. +.SS "Opening the same symbol as both a file and directory handle is no longer allowed" +.IX Subsection "Opening the same symbol as both a file and directory handle is no longer allowed" +Using \f(CWopen()\fR and \f(CWopendir()\fR to associate both a filehandle and a dirhandle +to the same symbol (glob or scalar) has been deprecated since Perl 5.10. +.ie n .SS "Use of bare ""<<"" to mean ""<<"""""" is no longer allowed" +.el .SS "Use of bare \f(CW<<\fP to mean \f(CW<<""""\fP is no longer allowed" +.IX Subsection "Use of bare << to mean <<"""" is no longer allowed" +Use of a bare terminator has been deprecated since Perl 5.000. +.SS "Setting $/ to a reference to a non-positive integer no longer allowed" +.IX Subsection "Setting $/ to a reference to a non-positive integer no longer allowed" +This used to work like setting it to \f(CW\*(C`undef\*(C'\fR, but has been deprecated +since Perl 5.20. +.ie n .SS "Unicode code points with values exceeding ""IV_MAX"" are now fatal" +.el .SS "Unicode code points with values exceeding \f(CWIV_MAX\fP are now fatal" +.IX Subsection "Unicode code points with values exceeding IV_MAX are now fatal" +This was deprecated since Perl 5.24. +.ie n .SS "The ""B::OP::terse"" method has been removed" +.el .SS "The \f(CWB::OP::terse\fP method has been removed" +.IX Subsection "The B::OP::terse method has been removed" +Use \f(CW\*(C`B::Concise::b_terse\*(C'\fR instead. +.SS "Use of inherited AUTOLOAD for non-methods is no longer allowed" +.IX Subsection "Use of inherited AUTOLOAD for non-methods is no longer allowed" +This was deprecated in Perl 5.004. +.SS "Use of strings with code points over 0xFF is not allowed for bitwise string operators" +.IX Subsection "Use of strings with code points over 0xFF is not allowed for bitwise string operators" +Code points over \f(CW0xFF\fR do not make sense for bitwise operators and such +an operation will now croak, except for a few remaining cases. See +perldeprecation. +.PP +This was deprecated in Perl 5.24. +.ie n .SS "Setting ""${^ENCODING}"" to a defined value is now illegal" +.el .SS "Setting \f(CW${^ENCODING}\fP to a defined value is now illegal" +.IX Subsection "Setting ${^ENCODING} to a defined value is now illegal" +This has been deprecated since Perl 5.22 and a no-op since Perl 5.26. +.ie n .SS "Backslash no longer escapes colon in PATH for the ""\-S"" switch" +.el .SS "Backslash no longer escapes colon in PATH for the \f(CW\-S\fP switch" +.IX Subsection "Backslash no longer escapes colon in PATH for the -S switch" +Previously the \f(CW\*(C`\-S\*(C'\fR switch incorrectly treated backslash ("\e") as an +escape for colon when traversing the \f(CW\*(C`PATH\*(C'\fR environment variable. +[GH #15584] <https://github.com/Perl/perl5/issues/15584> +.SS "the \-DH (DEBUG_H) misfeature has been removed" +.IX Subsection "the -DH (DEBUG_H) misfeature has been removed" +On a perl built with debugging support, the \f(CW\*(C`H\*(C'\fR flag to the \f(CW\*(C`\-D\*(C'\fR +debugging option has been removed. This was supposed to dump hash values, +but has been broken for many years. +.SS "Yada-yada is now strictly a statement" +.IX Subsection "Yada-yada is now strictly a statement" +By the time of its initial stable release in Perl 5.12, the \f(CW\*(C`...\*(C'\fR +(yada-yada) operator was explicitly intended to serve as a statement, +not an expression. However, the original implementation was confused +on this point, leading to inconsistent parsing. The operator was +accidentally accepted in a few situations where it did not serve as a +complete statement, such as +.PP +.Vb 2 +\& ... . "foo"; +\& ... if $a < $b; +.Ve +.PP +The parsing has now been made consistent, permitting yada-yada only as +a statement. Affected code can use \f(CW\*(C`do{...}\*(C'\fR to put a yada-yada into +an arbitrary expression context. +.SS "Sort algorithm can no longer be specified" +.IX Subsection "Sort algorithm can no longer be specified" +Since Perl 5.8, the sort pragma has had subpragmata \f(CW\*(C`_mergesort\*(C'\fR, +\&\f(CW\*(C`_quicksort\*(C'\fR, and \f(CW\*(C`_qsort\*(C'\fR that can be used to specify which algorithm +perl should use to implement the sort builtin. +This was always considered a dubious feature that might not last, +hence the underscore spellings, and they were documented as not being +portable beyond Perl 5.8. These subpragmata have now been deleted, +and any attempt to use them is an error. The sort pragma otherwise +remains, and the algorithm-neutral \f(CW\*(C`stable\*(C'\fR subpragma can be used to +control sorting behaviour. +[GH #13234] <https://github.com/Perl/perl5/issues/13234> +.SS "Over-radix digits in floating point literals" +.IX Subsection "Over-radix digits in floating point literals" +Octal and binary floating point literals used to permit any hexadecimal +digit to appear after the radix point. The digits are now restricted +to those appropriate for the radix, as digits before the radix point +always were. +.ie n .SS "Return type of unpackstring()" +.el .SS "Return type of \f(CWunpackstring()\fP" +.IX Subsection "Return type of unpackstring()" +The return types of the C API functions \f(CWunpackstring()\fR and +\&\f(CWunpack_str()\fR have changed from \f(CW\*(C`I32\*(C'\fR to \f(CW\*(C`SSize_t\*(C'\fR, in order to +accommodate datasets of more than two billion items. +.SH Deprecations +.IX Header "Deprecations" +.ie n .SS "Use of ""vec"" on strings with code points above 0xFF is deprecated" +.el .SS "Use of \f(CWvec\fP on strings with code points above 0xFF is deprecated" +.IX Subsection "Use of vec on strings with code points above 0xFF is deprecated" +Such strings are represented internally in UTF\-8, and \f(CW\*(C`vec\*(C'\fR is a +bit-oriented operation that will likely give unexpected results on those +strings. +.ie n .SS "Some uses of unescaped ""{"" in regexes are no longer fatal" +.el .SS "Some uses of unescaped \f(CW""{""\fP in regexes are no longer fatal" +.IX Subsection "Some uses of unescaped ""{"" in regexes are no longer fatal" +Perl 5.26.0 fatalized some uses of an unescaped left brace, but an +exception was made at the last minute, specifically crafted to be a +minimal change to allow GNU Autoconf to work. That tool is heavily +depended upon, and continues to use the deprecated usage. Its use of an +unescaped left brace is one where we have no intention of repurposing +\&\f(CW"{"\fR to be something other than itself. +.PP +That exception is now generalized to include various other such cases +where the \f(CW"{"\fR will not be repurposed. +.PP +Note that these uses continue to raise a deprecation message. +.ie n .SS "Use of unescaped ""{"" immediately after a ""("" in regular expression patterns is deprecated" +.el .SS "Use of unescaped \f(CW""{""\fP immediately after a \f(CW""(""\fP in regular expression patterns is deprecated" +.IX Subsection "Use of unescaped ""{"" immediately after a ""("" in regular expression patterns is deprecated" +Using unescaped left braces is officially deprecated everywhere, but it +is not enforced in contexts where their use does not interfere with +expected extensions to the language. A deprecation is added in this +release when the brace appears immediately after an opening parenthesis. +Before this, even if the brace was part of a legal quantifier, it was +not interpreted as such, but as the literal characters, unlike other +quantifiers that follow a \f(CW"("\fR which are considered errors. Now, +their use will raise a deprecation message, unless turned off. +.ie n .SS "Assignment to $[ will be fatal in Perl 5.30" +.el .SS "Assignment to \f(CW$[\fP will be fatal in Perl 5.30" +.IX Subsection "Assignment to $[ will be fatal in Perl 5.30" +Assigning a non-zero value to \f(CW$[\fR has been deprecated +since Perl 5.12, but was never given a deadline for removal. This has +now been scheduled for Perl 5.30. +.SS "\fBhostname()\fP won't accept arguments in Perl 5.32" +.IX Subsection "hostname() won't accept arguments in Perl 5.32" +Passing arguments to \f(CWSys::Hostname::hostname()\fR was already deprecated, +but didn't have a removal date. This has now been scheduled for Perl +5.32. [GH #14662] <https://github.com/Perl/perl5/issues/14662> +.SS "Module removals" +.IX Subsection "Module removals" +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. +.PP +The core versions of these modules will now issue \f(CW"deprecated"\fR\-category +warnings to alert you to this fact. To silence these deprecation warnings, +install the modules in question from CPAN. +.PP +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. +.IP B::Debug 4 +.IX Item "B::Debug" +.PD 0 +.IP "Locale::Codes and its associated Country, Currency and Language modules" 4 +.IX Item "Locale::Codes and its associated Country, Currency and Language modules" +.PD +.SH "Performance Enhancements" +.IX Header "Performance Enhancements" +.IP \(bu 4 +The start up overhead for creating regular expression patterns with +Unicode properties (\f(CW\*(C`\ep{...}\*(C'\fR) has been greatly reduced in most cases. +.IP \(bu 4 +Many string concatenation expressions are now considerably faster, due +to the introduction internally of a \f(CW\*(C`multiconcat\*(C'\fR opcode which combines +multiple concatenations, and optionally a \f(CW\*(C`=\*(C'\fR or \f(CW\*(C`.=\*(C'\fR, into a single +action. For example, apart from retrieving \f(CW$s\fR, \f(CW$a\fR and \f(CW$b\fR, this +whole expression is now handled as a single op: +.Sp +.Vb 1 +\& $s .= "a=$a b=$b\en" +.Ve +.Sp +As a special case, if the LHS of an assignment is a lexical variable or +\&\f(CW\*(C`my $s\*(C'\fR, the op itself handles retrieving the lexical variable, which +is faster. +.Sp +In general, the more the expression includes a mix of constant strings and +variable expressions, the longer the expression, and the more it mixes +together non\-utf8 and utf8 strings, the more marked the performance +improvement. For example on a \f(CW\*(C`x86_64\*(C'\fR system, this code has been +benchmarked running four times faster: +.Sp +.Vb 4 +\& my $s; +\& my $a = "ab\ex{100}cde"; +\& my $b = "fghij"; +\& my $c = "\ex{101}klmn"; +\& +\& for my $i (1..10_000_000) { +\& $s = "\ex{100}wxyz"; +\& $s .= "foo=$a bar=$b baz=$c"; +\& } +.Ve +.Sp +In addition, \f(CW\*(C`sprintf\*(C'\fR expressions which have a constant format +containing only \f(CW%s\fR and \f(CW\*(C`%%\*(C'\fR format elements, and which have a fixed +number of arguments, are now also optimised into a \f(CW\*(C`multiconcat\*(C'\fR op. +.IP \(bu 4 +The \f(CWref()\fR builtin is now much faster in boolean context, since it no +longer bothers to construct a temporary string like \f(CW\*(C`Foo=ARRAY(0x134af48)\*(C'\fR. +.IP \(bu 4 +\&\f(CWkeys()\fR in void and scalar contexts is now more efficient. +.IP \(bu 4 +The common idiom of comparing the result of \fBindex()\fR with \-1 is now +specifically optimised, e.g. +.Sp +.Vb 1 +\& if (index(...) != \-1) { ... } +.Ve +.IP \(bu 4 +\&\f(CWfor()\fR loops and similar constructs are now more efficient in most cases. +.IP \(bu 4 +File::Glob has been modified to remove unnecessary backtracking and +recursion, thanks to Russ Cox. See <https://research.swtch.com/glob> +for more details. +.IP \(bu 4 +The XS-level \f(CWSvTRUE()\fR API function is now more efficient. +.IP \(bu 4 +Various integer-returning ops are now more efficient in scalar/boolean context. +.IP \(bu 4 +Slightly improved performance when parsing stash names. +[GH #15689] <https://github.com/Perl/perl5/issues/15689> +.IP \(bu 4 +Calls to \f(CW\*(C`require\*(C'\fR for an already loaded module are now slightly faster. +[GH #16175] <https://github.com/Perl/perl5/issues/16175> +.IP \(bu 4 +The performance of pattern matching \f(CW\*(C`[[:ascii:]]\*(C'\fR and \f(CW\*(C`[[:^ascii:]]\*(C'\fR +has been improved significantly except on EBCDIC platforms. +.IP \(bu 4 +Various optimizations have been applied to matching regular expression +patterns, so under the right circumstances, significant performance +gains may be noticed. But in an application with many varied patterns, +little overall improvement likely will be seen. +.IP \(bu 4 +Other optimizations have been applied to UTF\-8 handling, but these are +not typically a major factor in most applications. +.SH "Modules and Pragmata" +.IX Header "Modules and Pragmata" +Key highlights in this release across several modules: +.SS "Removal of use vars" +.IX Subsection "Removal of use vars" +The usage of \f(CW\*(C`use vars\*(C'\fR has been discouraged since the introduction of +\&\f(CW\*(C`our\*(C'\fR in Perl 5.6.0. Where possible the usage of this pragma has now been +removed from the Perl source code. +.PP +This had a slight effect (for the better) on the output of WARNING_BITS in +B::Deparse. +.SS "Use of DynaLoader changed to XSLoader in many modules" +.IX Subsection "Use of DynaLoader changed to XSLoader in many modules" +XSLoader is more modern, and most modules already require perl 5.6 or +greater, so no functionality is lost by switching. In some cases, we have +also made changes to the local implementation that may not be reflected in +the version on CPAN due to a desire to maintain more backwards +compatibility. +.SS "Updated Modules and Pragmata" +.IX Subsection "Updated Modules and Pragmata" +.IP \(bu 4 +Archive::Tar has been upgraded from version 2.24 to 2.30. +.Sp +This update also handled CVE\-2018\-12015: directory traversal +vulnerability. +[cpan #125523] <https://rt.cpan.org/Ticket/Display.html?id=125523> +.IP \(bu 4 +arybase has been upgraded from version 0.12 to 0.15. +.IP \(bu 4 +Attribute::Handlers has been upgraded from version 0.99 to 1.01. +.IP \(bu 4 +attributes has been upgraded from version 0.29 to 0.33. +.IP \(bu 4 +B has been upgraded from version 1.68 to 1.74. +.IP \(bu 4 +B::Concise has been upgraded from version 0.999 to 1.003. +.IP \(bu 4 +B::Debug has been upgraded from version 1.24 to 1.26. +.Sp +NOTE: B::Debug is deprecated and may be removed from a future version +of Perl. +.IP \(bu 4 +B::Deparse has been upgraded from version 1.40 to 1.48. +.Sp +It includes many bug fixes, and in particular, it now deparses variable +attributes correctly: +.Sp +.Vb 2 +\& my $x :foo; # used to deparse as +\& # \*(Aqattributes\*(Aq\->import(\*(Aqmain\*(Aq, \e$x, \*(Aqfoo\*(Aq), my $x; +.Ve +.IP \(bu 4 +base has been upgraded from version 2.25 to 2.27. +.IP \(bu 4 +bignum has been upgraded from version 0.47 to 0.49. +.IP \(bu 4 +blib has been upgraded from version 1.06 to 1.07. +.IP \(bu 4 +bytes has been upgraded from version 1.05 to 1.06. +.IP \(bu 4 +Carp has been upgraded from version 1.42 to 1.50. +.Sp +If a package on the call stack contains a constant named \f(CW\*(C`ISA\*(C'\fR, Carp no +longer throws a "Not a GLOB reference" error. +.Sp +Carp, when generating stack traces, now attempts to work around +longstanding bugs resulting from Perl's non-reference-counted stack. +[GH #9282] <https://github.com/Perl/perl5/issues/9282> +.Sp +Carp has been modified to avoid assuming that objects cannot be +overloaded without the overload module loaded (this can happen with +objects created by XS modules). Previously, infinite recursion would +result if an XS-defined overload method itself called Carp. +[GH #16407] <https://github.com/Perl/perl5/issues/16407> +.Sp +Carp now avoids using \f(CW\*(C`overload::StrVal\*(C'\fR, partly because older versions +of overload (included with perl 5.14 and earlier) load Scalar::Util +at run time, which will fail if Carp has been invoked after a syntax error. +.IP \(bu 4 +charnames has been upgraded from version 1.44 to 1.45. +.IP \(bu 4 +Compress::Raw::Zlib has been upgraded from version 2.074 to 2.076. +.Sp +This addresses a security vulnerability in older versions of the 'zlib' library +(which is bundled with Compress-Raw-Zlib). +.IP \(bu 4 +Config::Extensions has been upgraded from version 0.01 to 0.02. +.IP \(bu 4 +Config::Perl::V has been upgraded from version 0.28 to 0.29. +.IP \(bu 4 +CPAN has been upgraded from version 2.18 to 2.20. +.IP \(bu 4 +Data::Dumper has been upgraded from version 2.167 to 2.170. +.Sp +Quoting of glob names now obeys the Useqq option +[GH #13274] <https://github.com/Perl/perl5/issues/13274>. +.Sp +Attempts to set an option to \f(CW\*(C`undef\*(C'\fR through a combined getter/setter +method are no longer mistaken for getter calls +[GH #12135] <https://github.com/Perl/perl5/issues/12135>. +.IP \(bu 4 +Devel::Peek has been upgraded from version 1.26 to 1.27. +.IP \(bu 4 +Devel::PPPort has been upgraded from version 3.35 to 3.40. +.Sp +Devel::PPPort has moved from cpan-first to perl-first maintenance +.Sp +Primary responsibility for the code in Devel::PPPort has moved into core perl. +In a practical sense there should be no change except that hopefully it will +stay more up to date with changes made to symbols in perl, rather than needing +to be updated after the fact. +.IP \(bu 4 +Digest::SHA has been upgraded from version 5.96 to 6.01. +.IP \(bu 4 +DirHandle has been upgraded from version 1.04 to 1.05. +.IP \(bu 4 +DynaLoader has been upgraded from version 1.42 to 1.45. +.Sp +Its documentation now shows the use of \f(CW\*(C`_\|_PACKAGE_\|_\*(C'\fR and direct object +syntax +[GH #16190] <https://github.com/Perl/perl5/issues/16190>. +.IP \(bu 4 +Encode has been upgraded from version 2.88 to 2.97. +.IP \(bu 4 +encoding has been upgraded from version 2.19 to 2.22. +.IP \(bu 4 +Errno has been upgraded from version 1.28 to 1.29. +.IP \(bu 4 +experimental has been upgraded from version 0.016 to 0.019. +.IP \(bu 4 +Exporter has been upgraded from version 5.72 to 5.73. +.IP \(bu 4 +ExtUtils::CBuilder has been upgraded from version 0.280225 to 0.280230. +.IP \(bu 4 +ExtUtils::Constant has been upgraded from version 0.23 to 0.25. +.IP \(bu 4 +ExtUtils::Embed has been upgraded from version 1.34 to 1.35. +.IP \(bu 4 +ExtUtils::Install has been upgraded from version 2.04 to 2.14. +.IP \(bu 4 +ExtUtils::MakeMaker has been upgraded from version 7.24 to 7.34. +.IP \(bu 4 +ExtUtils::Miniperl has been upgraded from version 1.06 to 1.08. +.IP \(bu 4 +ExtUtils::ParseXS has been upgraded from version 3.34 to 3.39. +.IP \(bu 4 +ExtUtils::Typemaps has been upgraded from version 3.34 to 3.38. +.IP \(bu 4 +ExtUtils::XSSymSet has been upgraded from version 1.3 to 1.4. +.IP \(bu 4 +feature has been upgraded from version 1.47 to 1.52. +.IP \(bu 4 +fields has been upgraded from version 2.23 to 2.24. +.IP \(bu 4 +File::Copy has been upgraded from version 2.32 to 2.33. +.Sp +It will now use the sub-second precision variant of \fButime()\fR supplied by +Time::HiRes where available. +[GH #16225] <https://github.com/Perl/perl5/issues/16225>. +.IP \(bu 4 +File::Fetch has been upgraded from version 0.52 to 0.56. +.IP \(bu 4 +File::Glob has been upgraded from version 1.28 to 1.31. +.IP \(bu 4 +File::Path has been upgraded from version 2.12_01 to 2.15. +.IP \(bu 4 +File::Spec and Cwd have been upgraded from version 3.67 to 3.74. +.IP \(bu 4 +File::stat has been upgraded from version 1.07 to 1.08. +.IP \(bu 4 +FileCache has been upgraded from version 1.09 to 1.10. +.IP \(bu 4 +Filter::Simple has been upgraded from version 0.93 to 0.95. +.IP \(bu 4 +Filter::Util::Call has been upgraded from version 1.55 to 1.58. +.IP \(bu 4 +GDBM_File has been upgraded from version 1.15 to 1.17. +.Sp +Its documentation now explains that \f(CW\*(C`each\*(C'\fR and \f(CW\*(C`delete\*(C'\fR don't mix in +hashes tied to this module +[GH #12894] <https://github.com/Perl/perl5/issues/12894>. +.Sp +It will now retry opening with an acceptable block size if asking gdbm +to default the block size failed +[GH #13232] <https://github.com/Perl/perl5/issues/13232>. +.IP \(bu 4 +Getopt::Long has been upgraded from version 2.49 to 2.5. +.IP \(bu 4 +Hash::Util::FieldHash has been upgraded from version 1.19 to 1.20. +.IP \(bu 4 +I18N::Langinfo has been upgraded from version 0.13 to 0.17. +.Sp +This module is now available on all platforms, emulating the system +\&\fBnl_langinfo\fR\|(3) on systems that lack it. Some caveats apply, as +detailed in its documentation, the most severe being +that, except for MS Windows, the \f(CW\*(C`CODESET\*(C'\fR item is not implemented on +those systems, always returning \f(CW""\fR. +.Sp +It now sets the UTF\-8 flag in its returned scalar if the string contains +legal non-ASCII UTF\-8, and the locale is UTF\-8 +[GH #15131] <https://github.com/Perl/perl5/issues/15131>. +.Sp +This update also fixes a bug in which the underlying locale was ignored +for the \f(CW\*(C`RADIXCHAR\*(C'\fR (always was returned as a dot) and the \f(CW\*(C`THOUSEP\*(C'\fR +(always empty). Now the locale-appropriate values are returned. +.IP \(bu 4 +I18N::LangTags has been upgraded from version 0.42 to 0.43. +.IP \(bu 4 +if has been upgraded from version 0.0606 to 0.0608. +.IP \(bu 4 +IO has been upgraded from version 1.38 to 1.39. +.IP \(bu 4 +IO::Socket::IP has been upgraded from version 0.38 to 0.39. +.IP \(bu 4 +IPC::Cmd has been upgraded from version 0.96 to 1.00. +.IP \(bu 4 +JSON::PP has been upgraded from version 2.27400_02 to 2.97001. +.IP \(bu 4 +The \f(CW\*(C`libnet\*(C'\fR distribution has been upgraded from version 3.10 to 3.11. +.IP \(bu 4 +List::Util has been upgraded from version 1.46_02 to 1.49. +.IP \(bu 4 +Locale::Codes has been upgraded from version 3.42 to 3.56. +.Sp +\&\fBNOTE\fR: Locale::Codes scheduled to be removed from core in Perl 5.30. +.IP \(bu 4 +Locale::Maketext has been upgraded from version 1.28 to 1.29. +.IP \(bu 4 +Math::BigInt has been upgraded from version 1.999806 to 1.999811. +.IP \(bu 4 +Math::BigInt::FastCalc has been upgraded from version 0.5005 to 0.5006. +.IP \(bu 4 +Math::BigRat has been upgraded from version 0.2611 to 0.2613. +.IP \(bu 4 +Module::CoreList has been upgraded from version 5.20170530 to 5.20180622. +.IP \(bu 4 +mro has been upgraded from version 1.20 to 1.22. +.IP \(bu 4 +Net::Ping has been upgraded from version 2.55 to 2.62. +.IP \(bu 4 +NEXT has been upgraded from version 0.67 to 0.67_01. +.IP \(bu 4 +ODBM_File has been upgraded from version 1.14 to 1.15. +.IP \(bu 4 +Opcode has been upgraded from version 1.39 to 1.43. +.IP \(bu 4 +overload has been upgraded from version 1.28 to 1.30. +.IP \(bu 4 +PerlIO::encoding has been upgraded from version 0.25 to 0.26. +.IP \(bu 4 +PerlIO::scalar has been upgraded from version 0.26 to 0.29. +.IP \(bu 4 +PerlIO::via has been upgraded from version 0.16 to 0.17. +.IP \(bu 4 +Pod::Functions has been upgraded from version 1.11 to 1.13. +.IP \(bu 4 +Pod::Html has been upgraded from version 1.2202 to 1.24. +.Sp +A title for the HTML document will now be automatically generated by +default from a "NAME" section in the POD document, as it used to be +before the module was rewritten to use Pod::Simple::XHTML to do the +core of its job +[GH #11954] <https://github.com/Perl/perl5/issues/11954>. +.IP \(bu 4 +Pod::Perldoc has been upgraded from version 3.28 to 3.2801. +.IP \(bu 4 +The \f(CW\*(C`podlators\*(C'\fR distribution has been upgraded from version 4.09 to 4.10. +.Sp +Man page references and function names now follow the Linux man page +formatting standards, instead of the Solaris standard. +.IP \(bu 4 +POSIX has been upgraded from version 1.76 to 1.84. +.Sp +Some more cautions were added about using locale-specific functions in +threaded applications. +.IP \(bu 4 +re has been upgraded from version 0.34 to 0.36. +.IP \(bu 4 +Scalar::Util has been upgraded from version 1.46_02 to 1.50. +.IP \(bu 4 +SelfLoader has been upgraded from version 1.23 to 1.25. +.IP \(bu 4 +Socket has been upgraded from version 2.020_03 to 2.027. +.IP \(bu 4 +sort has been upgraded from version 2.02 to 2.04. +.IP \(bu 4 +Storable has been upgraded from version 2.62 to 3.08. +.IP \(bu 4 +Sub::Util has been upgraded from version 1.48 to 1.49. +.IP \(bu 4 +subs has been upgraded from version 1.02 to 1.03. +.IP \(bu 4 +Sys::Hostname has been upgraded from version 1.20 to 1.22. +.IP \(bu 4 +Term::ReadLine has been upgraded from version 1.16 to 1.17. +.IP \(bu 4 +Test has been upgraded from version 1.30 to 1.31. +.IP \(bu 4 +Test::Harness has been upgraded from version 3.38 to 3.42. +.IP \(bu 4 +Test::Simple has been upgraded from version 1.302073 to 1.302133. +.IP \(bu 4 +threads has been upgraded from version 2.15 to 2.22. +.Sp +The documentation now better describes the problems that arise when +returning values from threads, and no longer warns about creating threads +in \f(CW\*(C`BEGIN\*(C'\fR blocks. +[GH #11563] <https://github.com/Perl/perl5/issues/11563> +.IP \(bu 4 +threads::shared has been upgraded from version 1.56 to 1.58. +.IP \(bu 4 +Tie::Array has been upgraded from version 1.06 to 1.07. +.IP \(bu 4 +Tie::StdHandle has been upgraded from version 4.4 to 4.5. +.IP \(bu 4 +Time::gmtime has been upgraded from version 1.03 to 1.04. +.IP \(bu 4 +Time::HiRes has been upgraded from version 1.9741 to 1.9759. +.IP \(bu 4 +Time::localtime has been upgraded from version 1.02 to 1.03. +.IP \(bu 4 +Time::Piece has been upgraded from version 1.31 to 1.3204. +.IP \(bu 4 +Unicode::Collate has been upgraded from version 1.19 to 1.25. +.IP \(bu 4 +Unicode::Normalize has been upgraded from version 1.25 to 1.26. +.IP \(bu 4 +Unicode::UCD has been upgraded from version 0.68 to 0.70. +.Sp +The function \f(CW\*(C`num\*(C'\fR now accepts an optional parameter to help in +diagnosing error returns. +.IP \(bu 4 +User::grent has been upgraded from version 1.01 to 1.02. +.IP \(bu 4 +User::pwent has been upgraded from version 1.00 to 1.01. +.IP \(bu 4 +utf8 has been upgraded from version 1.19 to 1.21. +.IP \(bu 4 +vars has been upgraded from version 1.03 to 1.04. +.IP \(bu 4 +version has been upgraded from version 0.9917 to 0.9923. +.IP \(bu 4 +VMS::DCLsym has been upgraded from version 1.08 to 1.09. +.IP \(bu 4 +VMS::Stdio has been upgraded from version 2.41 to 2.44. +.IP \(bu 4 +warnings has been upgraded from version 1.37 to 1.42. +.Sp +It now includes new functions with names ending in \f(CW\*(C`_at_level\*(C'\fR, allowing +callers to specify the exact call frame. +[GH #16257] <https://github.com/Perl/perl5/issues/16257> +.IP \(bu 4 +XS::Typemap has been upgraded from version 0.15 to 0.16. +.IP \(bu 4 +XSLoader has been upgraded from version 0.27 to 0.30. +.Sp +Its documentation now shows the use of \f(CW\*(C`_\|_PACKAGE_\|_\*(C'\fR, and direct object +syntax for example \f(CW\*(C`DynaLoader\*(C'\fR usage +[GH #16190] <https://github.com/Perl/perl5/issues/16190>. +.Sp +Platforms that use \f(CW\*(C`mod2fname\*(C'\fR to edit the names of loadable +libraries now look for bootstrap (.bs) files under the correct, +non-edited name. +.SS "Removed Modules and Pragmata" +.IX Subsection "Removed Modules and Pragmata" +.IP \(bu 4 +The \f(CW\*(C`VMS::stdio\*(C'\fR compatibility shim has been removed. +.SH Documentation +.IX Header "Documentation" +.SS "Changes to Existing Documentation" +.IX Subsection "Changes to Existing Documentation" +We have attempted to update the documentation to reflect the changes +listed in this document. If you find any we have missed, send email +to perlbug@perl.org <mailto:perlbug@perl.org>. +.PP +Additionally, the following selected changes have been made: +.PP +\fIperlapi\fR +.IX Subsection "perlapi" +.IP \(bu 4 +The API functions \f(CWperl_parse()\fR, \f(CWperl_run()\fR, and \f(CWperl_destruct()\fR +are now documented comprehensively, where previously the only +documentation was a reference to the perlembed tutorial. +.IP \(bu 4 +The documentation of \f(CWnewGIVENOP()\fR has been belatedly updated to +account for the removal of lexical \f(CW$_\fR. +.IP \(bu 4 +The API functions \f(CWnewCONSTSUB()\fR and \f(CWnewCONSTSUB_flags()\fR are +documented much more comprehensively than before. +.PP +\fIperldata\fR +.IX Subsection "perldata" +.IP \(bu 4 +The section "Truth and Falsehood" in perlsyn has been moved into +perldata. +.PP +\fIperldebguts\fR +.IX Subsection "perldebguts" +.IP \(bu 4 +The description of the conditions under which \f(CWDB::sub()\fR will be called +has been clarified. +[GH #16055] <https://github.com/Perl/perl5/issues/16055> +.PP +\fIperldiag\fR +.IX Subsection "perldiag" +.IP \(bu 4 +"Variable length lookbehind not implemented in regex m/%s/" in perldiag +.Sp +This now gives more ideas as to workarounds to the issue that was +introduced in Perl 5.18 (but not documented explicitly in its perldelta) +for the fact that some Unicode \f(CW\*(C`/i\*(C'\fR rules cause a few sequences such as +.Sp +.Vb 1 +\& (?<!st) +.Ve +.Sp +to be considered variable length, and hence disallowed. +.IP \(bu 4 +"Use of state \f(CW$_\fR is experimental" in perldiag +.Sp +This entry has been removed, as the experimental support of this construct was +removed in perl 5.24.0. +.IP \(bu 4 +The diagnostic \f(CW\*(C`Initialization of state variables in list context +currently forbidden\*(C'\fR has changed to \f(CW\*(C`Initialization of state variables +in list currently forbidden\*(C'\fR, because list-context initialization of +single aggregate state variables is now permitted. +.PP +\fIperlembed\fR +.IX Subsection "perlembed" +.IP \(bu 4 +The examples in perlembed have been made more portable in the way +they exit, and the example that gets an exit code from the embedded Perl +interpreter now gets it from the right place. The examples that pass +a constructed argv to Perl now show the mandatory null \f(CW\*(C`argv[argc]\*(C'\fR. +.IP \(bu 4 +An example in perlembed used the string value of \f(CW\*(C`ERRSV\*(C'\fR as a +format string when calling \fBcroak()\fR. If that string contains format +codes such as \f(CW%s\fR this could crash the program. +.Sp +This has been changed to a call to \fBcroak_sv()\fR. +.Sp +An alternative could have been to supply a trivial format string: +.Sp +.Vb 1 +\& croak("%s", SvPV_nolen(ERRSV)); +.Ve +.Sp +or as a special case for \f(CW\*(C`ERRSV\*(C'\fR simply: +.Sp +.Vb 1 +\& croak(NULL); +.Ve +.PP +\fIperlfunc\fR +.IX Subsection "perlfunc" +.IP \(bu 4 +There is now a note that warnings generated by built-in functions are +documented in perldiag and warnings. +[GH #12642] <https://github.com/Perl/perl5/issues/12642> +.IP \(bu 4 +The documentation for the \f(CW\*(C`exists\*(C'\fR operator no longer says that +autovivification behaviour "may be fixed in a future release". +We've determined that we're not going to change the default behaviour. +[GH #15231] <https://github.com/Perl/perl5/issues/15231> +.IP \(bu 4 +A couple of small details in the documentation for the \f(CW\*(C`bless\*(C'\fR operator +have been clarified. +[GH #14684] <https://github.com/Perl/perl5/issues/14684> +.IP \(bu 4 +The description of \f(CW@INC\fR hooks in the documentation for \f(CW\*(C`require\*(C'\fR +has been corrected to say that filter subroutines receive a useless +first argument. +[GH #12569] <https://github.com/Perl/perl5/issues/12569> +.IP \(bu 4 +The documentation of \f(CW\*(C`ref\*(C'\fR has been rewritten for clarity. +.IP \(bu 4 +The documentation of \f(CW\*(C`use\*(C'\fR now explains what syntactically qualifies +as a version number for its module version checking feature. +.IP \(bu 4 +The documentation of \f(CW\*(C`warn\*(C'\fR has been updated to reflect that since Perl +5.14 it has treated complex exception objects in a manner equivalent +to \f(CW\*(C`die\*(C'\fR. +[GH #13641] <https://github.com/Perl/perl5/issues/13641> +.IP \(bu 4 +The documentation of \f(CW\*(C`die\*(C'\fR and \f(CW\*(C`warn\*(C'\fR has been revised for clarity. +.IP \(bu 4 +The documentation of \f(CW\*(C`each\*(C'\fR has been improved, with a slightly more +explicit description of the sharing of iterator state, and with +caveats regarding the fragility of while-each loops. +[GH #16334] <https://github.com/Perl/perl5/issues/16334> +.IP \(bu 4 +Clarification to \f(CW\*(C`require\*(C'\fR was added to explain the differences between +.Sp +.Vb 2 +\& require Foo::Bar; +\& require "Foo/Bar.pm"; +.Ve +.PP +\fIperlgit\fR +.IX Subsection "perlgit" +.IP \(bu 4 +The precise rules for identifying \f(CW\*(C`smoke\-me\*(C'\fR branches are now stated. +.PP +\fIperlguts\fR +.IX Subsection "perlguts" +.IP \(bu 4 +The section on reference counting in perlguts has been heavily revised, +to describe references in the way a programmer needs to think about them +rather than in terms of the physical data structures. +.IP \(bu 4 +Improve documentation related to UTF\-8 multibytes. +.PP +\fIperlintern\fR +.IX Subsection "perlintern" +.IP \(bu 4 +The internal functions \f(CWnewXS_len_flags()\fR and \f(CWnewATTRSUB_x()\fR are +now documented. +.PP +\fIperlobj\fR +.IX Subsection "perlobj" +.IP \(bu 4 +The documentation about \f(CW\*(C`DESTROY\*(C'\fR methods has been corrected, updated, +and revised, especially in regard to how they interact with exceptions. +[GH #14083] <https://github.com/Perl/perl5/issues/14083> +.PP +\fIperlop\fR +.IX Subsection "perlop" +.IP \(bu 4 +The description of the \f(CW\*(C`x\*(C'\fR operator in perlop has been clarified. +[GH #16253] <https://github.com/Perl/perl5/issues/16253> +.IP \(bu 4 +perlop has been updated to note that \f(CW\*(C`qw\*(C'\fR's whitespace rules differ +from that of \f(CW\*(C`split\*(C'\fR's in that only ASCII whitespace is used. +.IP \(bu 4 +The general explanation of operator precedence and associativity has +been corrected and clarified. +[GH #15153] <https://github.com/Perl/perl5/issues/15153> +.IP \(bu 4 +The documentation for the \f(CW\*(C`\e\*(C'\fR referencing operator now explains the +unusual context that it supplies to its operand. +[GH #15932] <https://github.com/Perl/perl5/issues/15932> +.PP +\fIperlrequick\fR +.IX Subsection "perlrequick" +.IP \(bu 4 +Clarifications on metacharacters and character classes +.PP +\fIperlretut\fR +.IX Subsection "perlretut" +.IP \(bu 4 +Clarify metacharacters. +.PP +\fIperlrun\fR +.IX Subsection "perlrun" +.IP \(bu 4 +Clarify the differences between \fB\-M\fR and \fB\-m\fR. +[GH #15998] <https://github.com/Perl/perl5/issues/15998> +.PP +\fIperlsec\fR +.IX Subsection "perlsec" +.IP \(bu 4 +The documentation about set-id scripts has been updated and revised. +[GH #10289] <https://github.com/Perl/perl5/issues/10289> +.IP \(bu 4 +A section about using \f(CW\*(C`sudo\*(C'\fR to run Perl scripts has been added. +.PP +\fIperlsyn\fR +.IX Subsection "perlsyn" +.IP \(bu 4 +The section "Truth and Falsehood" in perlsyn has been removed from +that document, where it didn't belong, and merged into the existing +paragraph on the same topic in perldata. +.IP \(bu 4 +The means to disambiguate between code blocks and hash constructors, +already documented in perlref, are now documented in perlsyn too. +[GH #15918] <https://github.com/Perl/perl5/issues/15918> +.PP +\fIperluniprops\fR +.IX Subsection "perluniprops" +.IP \(bu 4 +perluniprops has been updated to note that \f(CW\*(C`\ep{Word}\*(C'\fR now includes +code points matching the \f(CW\*(C`\ep{Join_Control}\*(C'\fR property. The change to +the property was made in Perl 5.18, but not documented until now. There +are currently only two code points that match this property U+200C (ZERO +WIDTH NON-JOINER) and U+200D (ZERO WIDTH JOINER). +.IP \(bu 4 +For each binary table or property, the documentation now includes which +characters in the range \f(CW\*(C`\ex00\-\exFF\*(C'\fR it matches, as well as a list of +the first few ranges of code points matched above that. +.PP +\fIperlvar\fR +.IX Subsection "perlvar" +.IP \(bu 4 +The entry for \f(CW$+\fR in perlvar has been expanded upon to describe handling of +multiply-named capturing groups. +.PP +\fIperlfunc, perlop, perlsyn\fR +.IX Subsection "perlfunc, perlop, perlsyn" +.IP \(bu 4 +In various places, improve the documentation of the special cases +in the condition expression of a while loop, such as implicit \f(CW\*(C`defined\*(C'\fR +and assignment to \f(CW$_\fR. +[GH #16334] <https://github.com/Perl/perl5/issues/16334> +.SH Diagnostics +.IX Header "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 perldiag. +.SS "New Diagnostics" +.IX Subsection "New Diagnostics" +\fINew Errors\fR +.IX Subsection "New Errors" +.IP \(bu 4 +Can't "goto" into a "given" block +.Sp +(F) A "goto" statement was executed to jump into the middle of a \f(CW\*(C`given\*(C'\fR +block. You can't get there from here. See "goto" in perlfunc. +.IP \(bu 4 +Can't "goto" into a binary or list expression +.Sp +Use of \f(CW\*(C`goto\*(C'\fR to jump into the parameter of a binary or list operator has +been prohibited, to prevent crashes and stack corruption. +[GH #15914] <https://github.com/Perl/perl5/issues/15914> +.Sp +You may only enter the \fIfirst\fR argument of an operator that takes a fixed +number of arguments, since this is a case that will not cause stack +corruption. +[GH #16415] <https://github.com/Perl/perl5/issues/16415> +.PP +\fINew Warnings\fR +.IX Subsection "New Warnings" +.IP \(bu 4 +Old package separator used in string +.Sp +(W syntax) You used the old package separator, "'", in a variable +named inside a double-quoted string; e.g., \f(CW"In $name\*(Aqs house"\fR. This +is equivalent to \f(CW"In $name::s house"\fR. If you meant the former, put +a backslash before the apostrophe (\f(CW"In $name\e\*(Aqs house"\fR). +.IP \(bu 4 +"Locale '%s' contains (at least) the following characters which +have unexpected meanings: \f(CW%s\fR The Perl program will use the expected +meanings" in perldiag +.SS "Changes to Existing Diagnostics" +.IX Subsection "Changes to Existing Diagnostics" +.IP \(bu 4 +A false-positive warning that was issued when using a +numerically-quantified sub-pattern in a recursive regex has been +silenced. [GH #16106] <https://github.com/Perl/perl5/issues/16106> +.IP \(bu 4 +The warning about useless use of a concatenation operator in void context +is now generated for expressions with multiple concatenations, such as +\&\f(CW\*(C`$a.$b.$c\*(C'\fR, which used to mistakenly not warn. +[GH #3990] <https://github.com/Perl/perl5/issues/3990> +.IP \(bu 4 +Warnings that a variable or subroutine "masks earlier declaration in same +\&...", or that an \f(CW\*(C`our\*(C'\fR variable has been redeclared, have been moved to a +new warnings category "shadow". Previously they were in category "misc". +.IP \(bu 4 +The deprecation warning from \f(CWSys::Hostname::hostname()\fR saying that +it doesn't accept arguments now states the Perl version in which the +warning will be upgraded to an error. +[GH #14662] <https://github.com/Perl/perl5/issues/14662> +.IP \(bu 4 +The perldiag entry for the error regarding a set-id script has been +expanded to make clear that the error is reporting a specific security +vulnerability, and to advise how to fix it. +.IP \(bu 4 +The \f(CW\*(C`Unable to flush stdout\*(C'\fR error message was missing a trailing +newline. [debian #875361] +.SH "Utility Changes" +.IX Header "Utility Changes" +.SS perlbug +.IX Subsection "perlbug" +.IP \(bu 4 +\&\f(CW\*(C`\-\-help\*(C'\fR and \f(CW\*(C`\-\-version\*(C'\fR options have been added. +.SH "Configuration and Compilation" +.IX Header "Configuration and Compilation" +.IP \(bu 4 +C89 requirement +.Sp +Perl has been documented as requiring a C89 compiler to build since October +1998. A variety of simplifications have now been made to Perl's internals to +rely on the features specified by the C89 standard. We believe that this +internal change hasn't altered the set of platforms that Perl builds on, but +please report a bug if Perl now has new problems building on your platform. +.IP \(bu 4 +On GCC, \f(CW\*(C`\-Werror=pointer\-arith\*(C'\fR is now enabled by default, +disallowing arithmetic on void and function pointers. +.IP \(bu 4 +Where an HTML version of the documentation is installed, the HTML +documents now use relative links to refer to each other. Links from +the index page of perlipc to the individual section documents are +now correct. +[GH #11941] <https://github.com/Perl/perl5/issues/11941> +.IP \(bu 4 +\&\fIlib/unicore/mktables\fR now correctly canonicalizes the names of the +dependencies stored in the files it generates. +.Sp +\&\fIregen/mk_invlists.pl\fR, unlike the other \fIregen/*.pl\fR scripts, used +\&\f(CW$0\fR to name itself in the dependencies stored in the files it +generates. It now uses a literal so that the path stored in the +generated files doesn't depend on how \fIregen/mk_invlists.pl\fR is +invoked. +.Sp +This lack of canonical names could cause test failures in \fIt/porting/regen.t\fR. +[GH #16446] <https://github.com/Perl/perl5/issues/16446> +.IP \(bu 4 +New probes +.RS 4 +.IP HAS_BUILTIN_ADD_OVERFLOW 2 +.IX Item "HAS_BUILTIN_ADD_OVERFLOW" +.PD 0 +.IP HAS_BUILTIN_MUL_OVERFLOW 2 +.IX Item "HAS_BUILTIN_MUL_OVERFLOW" +.IP HAS_BUILTIN_SUB_OVERFLOW 2 +.IX Item "HAS_BUILTIN_SUB_OVERFLOW" +.IP HAS_THREAD_SAFE_NL_LANGINFO_L 2 +.IX Item "HAS_THREAD_SAFE_NL_LANGINFO_L" +.IP HAS_LOCALECONV_L 2 +.IX Item "HAS_LOCALECONV_L" +.IP HAS_MBRLEN 2 +.IX Item "HAS_MBRLEN" +.IP HAS_MBRTOWC 2 +.IX Item "HAS_MBRTOWC" +.IP HAS_MEMRCHR 2 +.IX Item "HAS_MEMRCHR" +.IP HAS_NANOSLEEP 2 +.IX Item "HAS_NANOSLEEP" +.IP HAS_STRNLEN 2 +.IX Item "HAS_STRNLEN" +.IP HAS_STRTOLD_L 2 +.IX Item "HAS_STRTOLD_L" +.IP I_WCHAR 2 +.IX Item "I_WCHAR" +.RE +.RS 4 +.RE +.PD +.SH Testing +.IX Header "Testing" +.IP \(bu 4 +Testing of the XS-APItest directory is now done in parallel, where +applicable. +.IP \(bu 4 +Perl now includes a default \fI.travis.yml\fR file for Travis CI testing +on github mirrors. +[GH #14558] <https://github.com/Perl/perl5/issues/14558> +.IP \(bu 4 +The watchdog timer count in \fIre/pat_psycho.t\fR can now be overridden. +.Sp +This test can take a long time to run, so there is a timer to keep +this in check (currently, 5 minutes). This commit adds checking +the environment variable \f(CW\*(C`PERL_TEST_TIME_OUT_FACTOR\*(C'\fR; if set, +the time out setting is multiplied by its value. +.IP \(bu 4 +\&\fIharness\fR no longer waits for 30 seconds when running \fIt/io/openpid.t\fR. +[GH #13535] <https://github.com/Perl/perl5/issues/13535> +[GH #16420] <https://github.com/Perl/perl5/issues/16420> +.SH Packaging +.IX Header "Packaging" +For the past few years we have released perl using three different archive +formats: bzip (\f(CW\*(C`.bz2\*(C'\fR), LZMA2 (\f(CW\*(C`.xz\*(C'\fR) and gzip (\f(CW\*(C`.gz\*(C'\fR). Since xz compresses +better and decompresses faster, and gzip is more compatible and uses less +memory, we have dropped the \f(CW\*(C`.bz2\*(C'\fR archive format with this release. +(If this poses a problem, do let us know; see "Reporting Bugs", below.) +.SH "Platform Support" +.IX Header "Platform Support" +.SS "Discontinued Platforms" +.IX Subsection "Discontinued Platforms" +.IP "PowerUX / Power MAX OS" 4 +.IX Item "PowerUX / Power MAX OS" +Compiler hints and other support for these apparently long-defunct +platforms has been removed. +.SS "Platform-Specific Notes" +.IX Subsection "Platform-Specific Notes" +.IP CentOS 4 +.IX Item "CentOS" +Compilation on CentOS 5 is now fixed. +.IP Cygwin 4 +.IX Item "Cygwin" +A build with the quadmath library can now be done on Cygwin. +.IP Darwin 4 +.IX Item "Darwin" +Perl now correctly uses reentrant functions, like \f(CW\*(C`asctime_r\*(C'\fR, on +versions of Darwin that have support for them. +.IP FreeBSD 4 +.IX Item "FreeBSD" +FreeBSD's \fI/usr/share/mk/sys.mk\fR specifies \f(CW\*(C`\-O2\*(C'\fR for +architectures other than ARM and MIPS. By default, perl is now compiled +with the same optimization levels. +.IP VMS 4 +.IX Item "VMS" +Several fix-ups for \fIconfigure.com\fR, marking function VMS has +(or doesn't have). +.Sp +CRTL features can now be set by embedders before invoking Perl by using +the \f(CW\*(C`decc$feature_set\*(C'\fR and \f(CW\*(C`decc$feature_set_value\*(C'\fR functions. +Previously any attempt to set features after image initialization were +ignored. +.IP Windows 4 +.IX Item "Windows" +.RS 4 +.PD 0 +.IP \(bu 4 +.PD +Support for compiling perl on Windows using Microsoft Visual Studio 2017 +(containing Visual C++ 14.1) has been added. +.IP \(bu 4 +Visual C++ compiler version detection has been improved to work on non-English +language systems. +.IP \(bu 4 +We now set \f(CW$Config{libpth}\fR correctly for 64\-bit builds using Visual C++ +versions earlier than 14.1. +.RE +.RS 4 +.RE +.SH "Internal Changes" +.IX Header "Internal Changes" +.IP \(bu 4 +A new optimisation phase has been added to the compiler, +\&\f(CWoptimize_optree()\fR, which does a top-down scan of a complete optree +just before the peephole optimiser is run. This phase is not currently +hookable. +.IP \(bu 4 +An \f(CW\*(C`OP_MULTICONCAT\*(C'\fR op has been added. At \f(CWoptimize_optree()\fR time, a +chain of \f(CW\*(C`OP_CONCAT\*(C'\fR and \f(CW\*(C`OP_CONST\*(C'\fR ops, together optionally with an +\&\f(CW\*(C`OP_STRINGIFY\*(C'\fR and/or \f(CW\*(C`OP_SASSIGN\*(C'\fR, are combined into a single +\&\f(CW\*(C`OP_MULTICONCAT\*(C'\fR op. The op is of type \f(CW\*(C`UNOP_AUX\*(C'\fR, and the aux array +contains the argument count, plus a pointer to a constant string and a set +of segment lengths. For example with +.Sp +.Vb 1 +\& my $x = "foo=$foo, bar=$bar\en"; +.Ve +.Sp +the constant string would be \f(CW"foo=, bar=\en"\fR and the segment lengths +would be (4,6,1). If the string contains characters such as \f(CW\*(C`\ex80\*(C'\fR, whose +representation changes under utf8, two sets of strings plus lengths are +precomputed and stored. +.IP \(bu 4 +Direct access to \f(CW\*(C`PL_keyword_plugin\*(C'\fR is not +safe in the presence of multithreading. A new +\&\f(CW\*(C`wrap_keyword_plugin\*(C'\fR function has been +added to allow XS modules to safely define custom keywords even when +loaded from a thread, analogous to \f(CW\*(C`PL_check\*(C'\fR / +\&\f(CW\*(C`wrap_op_checker\*(C'\fR. +.IP \(bu 4 +The \f(CW\*(C`PL_statbuf\*(C'\fR interpreter variable has been removed. +.IP \(bu 4 +The deprecated function \f(CWto_utf8_case()\fR, accessible from XS code, has +been removed. +.IP \(bu 4 +A new function +\&\f(CWis_utf8_invariant_string_loc()\fR +has been added that is like +\&\f(CWis_utf8_invariant_string()\fR +but takes an extra pointer parameter into which is stored the location +of the first variant character, if any are found. +.IP \(bu 4 +A new function, \f(CWPerl_langinfo()\fR has been +added. It is an (almost) drop-in replacement for the system +\&\f(CWnl_langinfo(3)\fR, but works on platforms that lack that; as well as +being more thread-safe, and hiding some gotchas with locale handling +from the caller. Code that uses this, needn't use \f(CWlocaleconv(3)\fR +(and be affected by the gotchas) to find the decimal point, thousands +separator, or currency symbol. See "Perl_langinfo" in perlapi. +.IP \(bu 4 +A new API function \f(CWsv_rvunweaken()\fR has +been added to complement \f(CWsv_rvweaken()\fR. +The implementation was taken from "unweaken" in Scalar::Util. +.IP \(bu 4 +A new flag, \f(CW\*(C`SORTf_UNSTABLE\*(C'\fR, has been added. This will allow a +future commit to make mergesort unstable when the user specifies ‘no +sort stable’, since it has been decided that mergesort should remain +stable by default. +.IP \(bu 4 +XS modules can now automatically get reentrant versions of system +functions on threaded perls. +.Sp +By adding +.Sp +.Vb 1 +\& #define PERL_REENTRANT +.Ve +.Sp +near the beginning of an \f(CW\*(C`XS\*(C'\fR file, it will be compiled so that +whatever reentrant functions perl knows about on that system will +automatically and invisibly be used instead of the plain, non-reentrant +versions. For example, if you write \f(CWgetpwnam()\fR in your code, on a +system that has \f(CWgetpwnam_r()\fR all calls to the former will be translated +invisibly into the latter. This does not happen except on threaded +perls, as they aren't needed otherwise. Be aware that which functions +have reentrant versions varies from system to system. +.IP \(bu 4 +The \f(CW\*(C`PERL_NO_OP_PARENT\*(C'\fR build define is no longer supported, which means +that perl is now always built with \f(CW\*(C`PERL_OP_PARENT\*(C'\fR enabled. +.IP \(bu 4 +The format and content of the non\-utf8 transliteration table attached to +the \f(CW\*(C`op_pv\*(C'\fR field of \f(CW\*(C`OP_TRANS\*(C'\fR/\f(CW\*(C`OP_TRANSR\*(C'\fR ops has changed. It's now a +\&\f(CW\*(C`struct OPtrans_map\*(C'\fR. +.IP \(bu 4 +A new compiler \f(CW\*(C`#define\*(C'\fR, \f(CW\*(C`dTHX_DEBUGGING\*(C'\fR. has been added. This is +useful for XS or C code that only need the thread context because their +debugging statements that get compiled only under \f(CW\*(C`\-DDEBUGGING\*(C'\fR need +one. +.IP \(bu 4 +A new API function "Perl_setlocale" in perlapi has been added. +.IP \(bu 4 +"sync_locale" in perlapi has been revised to return a boolean as to +whether the system was using the global locale or not. +.IP \(bu 4 +A new kind of magic scalar, called a "nonelem" scalar, has been introduced. +It is stored in an array to denote a non-existent element, whenever such an +element is accessed in a potential lvalue context. It replaces the +existing "defelem" (deferred element) magic wherever this is possible, +being significantly more efficient. This means that +\&\f(CWsome_sub($sparse_array[$nonelem])\fR no longer has to create a new magic +defelem scalar each time, as long as the element is within the array. +.Sp +It partially fixes the rare bug of deferred elements getting out of synch +with their arrays when the array is shifted or unshifted. +[GH #16364] <https://github.com/Perl/perl5/issues/16364> +.SH "Selected Bug Fixes" +.IX Header "Selected Bug Fixes" +.IP \(bu 4 +List assignment (\f(CW\*(C`aassign\*(C'\fR) could in some rare cases allocate an +entry on the mortals stack and leave the entry uninitialized, leading to +possible crashes. +[GH #16017] <https://github.com/Perl/perl5/issues/16017> +.IP \(bu 4 +Attempting to apply an attribute to an \f(CW\*(C`our\*(C'\fR variable where a +function of that name already exists could result in a NULL pointer +being supplied where an SV was expected, crashing perl. +[perl #131597] <https://rt.perl.org/Ticket/Display.html?id=131597> +.IP \(bu 4 +\&\f(CW\*(C`split \*(Aq \*(Aq\*(C'\fR now correctly handles the argument being split when in the +scope of the \f(CW\*(C`unicode_strings\*(C'\fR feature. Previously, when a string using the single-byte internal +representation contained characters that are whitespace by Unicode rules but +not by ASCII rules, it treated those characters as part of fields rather +than as field separators. +[GH #15904] <https://github.com/Perl/perl5/issues/15904> +.IP \(bu 4 +Several built-in functions previously had bugs that could cause them to +write to the internal stack without allocating room for the item being +written. In rare situations, this could have led to a crash. These bugs have +now been fixed, and if any similar bugs are introduced in future, they will +be detected automatically in debugging builds. +.Sp +These internal stack usage checks introduced are also done +by the \f(CW\*(C`entersub\*(C'\fR operator when calling XSUBs. This means we can +report which XSUB failed to allocate enough stack space. +[GH #16126] <https://github.com/Perl/perl5/issues/16126> +.IP \(bu 4 +Using a symbolic ref with postderef syntax as the key in a hash lookup was +yielding an assertion failure on debugging builds. +[GH #16029] <https://github.com/Perl/perl5/issues/16029> +.IP \(bu 4 +Array and hash variables whose names begin with a caret now admit indexing +inside their curlies when interpolated into strings, as in \f(CW"${^CAPTURE[0]}"\fR to index \f(CW\*(C`@{^CAPTURE}\*(C'\fR. +[GH #16050] <https://github.com/Perl/perl5/issues/16050> +.IP \(bu 4 +Fetching the name of a glob that was previously UTF\-8 but wasn't any +longer would return that name flagged as UTF\-8. +[GH #15971] <https://github.com/Perl/perl5/issues/15971> +.IP \(bu 4 +The perl \f(CWsprintf()\fR function (via the underlying C function +\&\f(CWPerl_sv_vcatpvfn_flags()\fR) has been heavily reworked to fix many minor +bugs, including the integer wrapping of large width and precision +specifiers and potential buffer overruns. It has also been made faster in +many cases. +.IP \(bu 4 +Exiting from an \f(CW\*(C`eval\*(C'\fR, whether normally or via an exception, now always +frees temporary values (possibly calling destructors) \fIbefore\fR setting +\&\f(CW$@\fR. For example: +.Sp +.Vb 3 +\& sub DESTROY { eval { die "died in DESTROY"; } } +\& eval { bless []; }; +\& # $@ used to be equal to "died in DESTROY" here; it\*(Aqs now "". +.Ve +.IP \(bu 4 +Fixed a duplicate symbol failure with \f(CW\*(C`\-flto \-mieee\-fp\*(C'\fR builds. +\&\fIpp.c\fR defined \f(CW\*(C`_LIB_VERSION\*(C'\fR which \f(CW\*(C`\-lieee\*(C'\fR already defines. +[GH #16086] <https://github.com/Perl/perl5/issues/16086> +.IP \(bu 4 +The tokenizer no longer consumes the exponent part of a floating +point number if it's incomplete. +[GH #16073] <https://github.com/Perl/perl5/issues/16073> +.IP \(bu 4 +On non-threaded builds, for \f(CW\*(C`m/$null/\*(C'\fR where \f(CW$null\fR is an empty +string is no longer treated as if the \f(CW\*(C`/o\*(C'\fR flag was present when the +previous matching match operator included the \f(CW\*(C`/o\*(C'\fR flag. The +rewriting used to implement this behavior could confuse the +interpreter. This matches the behaviour of threaded builds. +[GH #14668] <https://github.com/Perl/perl5/issues/14668> +.IP \(bu 4 +Parsing a \f(CW\*(C`sub\*(C'\fR definition could cause a use after free if the \f(CW\*(C`sub\*(C'\fR +keyword was followed by whitespace including newlines (and comments.) +[GH #16097] <https://github.com/Perl/perl5/issues/16097> +.IP \(bu 4 +The tokenizer now correctly adjusts a parse pointer when skipping +whitespace in a \f(CW\*(C`${identifier}\*(C'\fR construct. +[perl #131949] <https://rt.perl.org/Public/Bug/Display.html?id=131949> +.IP \(bu 4 +Accesses to \f(CW\*(C`${^LAST_FH}\*(C'\fR no longer assert after using any of a +variety of I/O operations on a non-glob. +[GH #15372] <https://github.com/Perl/perl5/issues/15372> +.IP \(bu 4 +The XS-level \f(CWCopy()\fR, \f(CWMove()\fR, \f(CWZero()\fR macros and their variants now +assert if the pointers supplied are \f(CW\*(C`NULL\*(C'\fR. ISO C considers +supplying NULL pointers to the functions these macros are built upon +as undefined behaviour even when their count parameters are zero. +Based on these assertions and the original bug report three macro +calls were made conditional. +[GH #16079] <https://github.com/Perl/perl5/issues/16079> +[GH #16112] <https://github.com/Perl/perl5/issues/16112> +.IP \(bu 4 +Only the \f(CW\*(C`=\*(C'\fR operator is permitted for defining defaults for +parameters in subroutine signatures. Previously other assignment +operators, e.g. \f(CW\*(C`+=\*(C'\fR, were also accidentally permitted. +[GH #16084] <https://github.com/Perl/perl5/issues/16084> +.IP \(bu 4 +Package names are now always included in \f(CW\*(C`:prototype\*(C'\fR warnings +[perl #131833] <https://rt.perl.org/Public/Bug/Display.html?id=131833> +.IP \(bu 4 +The \f(CW\*(C`je_old_stack_hwm\*(C'\fR field, previously only found in the \f(CW\*(C`jmpenv\*(C'\fR +structure on debugging builds, has been added to non-debug builds as +well. This fixes an issue with some CPAN modules caused by the size of +this structure varying between debugging and non-debugging builds. +[GH #16122] <https://github.com/Perl/perl5/issues/16122> +.IP \(bu 4 +The arguments to the \f(CWninstr()\fR macro are now correctly parenthesized. +.IP \(bu 4 +A NULL pointer dereference in the \f(CWS_regmatch()\fR function has been +fixed. +[perl #132017] <https://rt.perl.org/Public/Bug/Display.html?id=132017> +.IP \(bu 4 +Calling exec PROGRAM LIST with an empty \f(CW\*(C`LIST\*(C'\fR +has been fixed. This should call \f(CWexecvp()\fR with an empty \f(CW\*(C`argv\*(C'\fR array +(containing only the terminating \f(CW\*(C`NULL\*(C'\fR pointer), but was instead just +returning false (and not setting \f(CW$!\fR). +[GH #16075] <https://github.com/Perl/perl5/issues/16075> +.IP \(bu 4 +The \f(CW\*(C`gv_fetchmeth_sv\*(C'\fR C function stopped working properly in Perl 5.22 when +fetching a constant with a UTF\-8 name if that constant subroutine was stored in +the stash as a simple scalar reference, rather than a full typeglob. This has +been corrected. +.IP \(bu 4 +Single-letter debugger commands followed by an argument which starts with +punctuation (e.g. \f(CW\*(C`p$^V\*(C'\fR and \f(CW\*(C`x@ARGV\*(C'\fR) now work again. They had been +wrongly requiring a space between the command and the argument. +[GH #13342] <https://github.com/Perl/perl5/issues/13342> +.IP \(bu 4 +splice now throws an exception +("Modification of a read-only value attempted") when modifying a read-only +array. Until now it had been silently modifying the array. The new behaviour +is consistent with the behaviour of push and +unshift. +[GH #15923] <https://github.com/Perl/perl5/issues/15923> +.IP \(bu 4 +\&\f(CWstat()\fR, \f(CWlstat()\fR, and file test operators now fail if given a +filename containing a nul character, in the same way that \f(CWopen()\fR +already fails. +.IP \(bu 4 +\&\f(CWstat()\fR, \f(CWlstat()\fR, and file test operators now reliably set \f(CW$!\fR when +failing due to being applied to a closed or otherwise invalid file handle. +.IP \(bu 4 +File test operators for Unix permission bits that don't exist on a +particular platform, such as \f(CW\*(C`\-k\*(C'\fR (sticky bit) on Windows, now check that +the file being tested exists before returning the blanket false result, +and yield the appropriate errors if the argument doesn't refer to a file. +.IP \(bu 4 +Fixed a 'read before buffer' overrun when parsing a range starting with +\&\f(CW\*(C`\eN{}\*(C'\fR at the beginning of the character set for the transliteration +operator. +[GH #16189] <https://github.com/Perl/perl5/issues/16189> +.IP \(bu 4 +Fixed a leaked scalar when parsing an empty \f(CW\*(C`\eN{}\*(C'\fR at compile-time. +[GH #16189] <https://github.com/Perl/perl5/issues/16189> +.IP \(bu 4 +Calling \f(CW\*(C`do $path\*(C'\fR on a directory or block device now yields a meaningful +error code in \f(CW$!\fR. +[GH #14841] <https://github.com/Perl/perl5/issues/14841> +.IP \(bu 4 +Regexp substitution using an overloaded replacement value that provides +a tainted stringification now correctly taints the resulting string. +[GH #12495] <https://github.com/Perl/perl5/issues/12495> +.IP \(bu 4 +Lexical sub declarations in \f(CW\*(C`do\*(C'\fR blocks such as \f(CW\*(C`do { my sub lex; 123 }\*(C'\fR +could corrupt the stack, erasing items already on the stack in the +enclosing statement. This has been fixed. +[GH #16243] <https://github.com/Perl/perl5/issues/16243> +.IP \(bu 4 +\&\f(CW\*(C`pack\*(C'\fR and \f(CW\*(C`unpack\*(C'\fR can now handle repeat counts and lengths that +exceed two billion. +[GH #13179] <https://github.com/Perl/perl5/issues/13179> +.IP \(bu 4 +Digits past the radix point in octal and binary floating point literals +now have the correct weight on platforms where a floating point +significand doesn't fit into an integer type. +.IP \(bu 4 +The canonical truth value no longer has a spurious special meaning as a +callable subroutine. It used to be a magic placeholder for a missing +\&\f(CW\*(C`import\*(C'\fR or \f(CW\*(C`unimport\*(C'\fR method, but is now treated like any other string +\&\f(CW1\fR. +[GH #14902] <https://github.com/Perl/perl5/issues/14902> +.IP \(bu 4 +\&\f(CW\*(C`system\*(C'\fR now reduces its arguments to strings in the parent process, so +any effects of stringifying them (such as overload methods being called +or warnings being emitted) are visible in the way the program expects. +[GH #13561] <https://github.com/Perl/perl5/issues/13561> +.IP \(bu 4 +The \f(CWreadpipe()\fR built-in function now checks at compile time that +it has only one parameter expression, and puts it in scalar context, +thus ensuring that it doesn't corrupt the stack at runtime. +[GH #2793] <https://github.com/Perl/perl5/issues/2793> +.IP \(bu 4 +\&\f(CW\*(C`sort\*(C'\fR now performs correct reference counting when aliasing \f(CW$a\fR and +\&\f(CW$b\fR, thus avoiding premature destruction and leakage of scalars if they +are re-aliased during execution of the sort comparator. +[GH #11422] <https://github.com/Perl/perl5/issues/11422> +.IP \(bu 4 +\&\f(CW\*(C`reverse\*(C'\fR with no operand, reversing \f(CW$_\fR by default, is no longer in +danger of corrupting the stack. +[GH #16291] <https://github.com/Perl/perl5/issues/16291> +.IP \(bu 4 +\&\f(CW\*(C`exec\*(C'\fR, \f(CW\*(C`system\*(C'\fR, et al are no longer liable to have their argument +lists corrupted by reentrant calls and by magic such as tied scalars. +[GH #15660] <https://github.com/Perl/perl5/issues/15660> +.IP \(bu 4 +Perl's own \f(CW\*(C`malloc\*(C'\fR no longer gets confused by attempts to allocate +more than a gigabyte on a 64\-bit platform. +[GH #13273] <https://github.com/Perl/perl5/issues/13273> +.IP \(bu 4 +Stacked file test operators in a sort comparator expression no longer +cause a crash. +[GH #15626] <https://github.com/Perl/perl5/issues/15626> +.IP \(bu 4 +An identity \f(CW\*(C`tr///\*(C'\fR transformation on a reference is no longer mistaken +for that reference for the purposes of deciding whether it can be +assigned to. +[GH #15812] <https://github.com/Perl/perl5/issues/15812> +.IP \(bu 4 +Lengthy hexadecimal, octal, or binary floating point literals no +longer cause undefined behaviour when parsing digits that are of such +low significance that they can't affect the floating point value. +[GH #16114] <https://github.com/Perl/perl5/issues/16114> +.IP \(bu 4 +\&\f(CW\*(C`open $$scalarref...\*(C'\fR and similar invocations no longer leak the file +handle. +[GH #12593] <https://github.com/Perl/perl5/issues/12593> +.IP \(bu 4 +Some convoluted kinds of regexp no longer cause an arithmetic overflow +when compiled. +[GH #16113] <https://github.com/Perl/perl5/issues/16113> +.IP \(bu 4 +The default typemap, by avoiding \f(CW\*(C`newGVgen\*(C'\fR, now no longer leaks when +XSUBs return file handles (\f(CW\*(C`PerlIO *\*(C'\fR or \f(CW\*(C`FILE *\*(C'\fR). +[GH #12593] <https://github.com/Perl/perl5/issues/12593> +.IP \(bu 4 +Creating a \f(CW\*(C`BEGIN\*(C'\fR block as an XS subroutine with a prototype no longer +crashes because of the early freeing of the subroutine. +.IP \(bu 4 +The \f(CW\*(C`printf\*(C'\fR format specifier \f(CW\*(C`%.0f\*(C'\fR no longer rounds incorrectly +[GH #9125] <https://github.com/Perl/perl5/issues/9125>, +and now shows the correct sign for a negative zero. +.IP \(bu 4 +Fixed an issue where the error \f(CW\*(C`Scalar value @arrayname[0] better +written as $arrayname\*(C'\fR would give an error \f(CW\*(C`Cannot printf Inf with \*(Aqc\*(Aq\*(C'\fR +when arrayname starts with \f(CW\*(C`Inf\*(C'\fR. +[GH #16335] <https://github.com/Perl/perl5/issues/16335> +.IP \(bu 4 +The Perl implementation of \f(CWgetcwd()\fR in \f(CW\*(C`Cwd\*(C'\fR in the PathTools +distribution now behaves the same as XS implementation on errors: it +returns an error, and sets \f(CW$!\fR. +[GH #16338] <https://github.com/Perl/perl5/issues/16338> +.IP \(bu 4 +Vivify array elements when putting them on the stack. +Fixes [GH #5310] <https://github.com/Perl/perl5/issues/5310> +(reported in April 2002). +.IP \(bu 4 +Fixed parsing of braced subscript after parens. Fixes +[GH #4688] <https://github.com/Perl/perl5/issues/4688> +(reported in December 2001). +.IP \(bu 4 +\&\f(CW\*(C`tr/non_utf8/long_non_utf8/c\*(C'\fR could give the wrong results when the +length of the replacement character list was greater than 0x7fff. +.IP \(bu 4 +\&\f(CW\*(C`tr/non_utf8/non_utf8/cd\*(C'\fR failed to add the implied +\&\f(CW\*(C`\ex{100}\-\ex{7fffffff}\*(C'\fR to the search character list. +.IP \(bu 4 +Compilation failures within "perl-within-perl" constructs, such as with +string interpolation and the right part of \f(CW\*(C`s///e\*(C'\fR, now cause +compilation to abort earlier. +.Sp +Previously compilation could continue in order to report other errors, +but the failed sub-parse could leave partly parsed constructs on the +parser shift-reduce stack, confusing the parser, leading to perl +crashes. +[GH #14739] <https://github.com/Perl/perl5/issues/14739> +.IP \(bu 4 +On threaded perls where the decimal point (radix) character is not a +dot, it has been possible for a race to occur between threads when one +needs to use the real radix character (such as with \f(CW\*(C`sprintf\*(C'\fR). This has +now been fixed by use of a mutex on systems without thread-safe locales, +and the problem just doesn't come up on those with thread-safe locales. +.IP \(bu 4 +Errors while compiling a regex character class could sometime trigger an +assertion failure. +[GH #16172] <https://github.com/Perl/perl5/issues/16172> +.SH Acknowledgements +.IX Header "Acknowledgements" +Perl 5.28.0 represents approximately 13 months of development since Perl +5.26.0 and contains approximately 730,000 lines of changes across 2,200 +files from 77 authors. +.PP +Excluding auto-generated files, documentation and release tools, there were +approximately 580,000 lines of changes to 1,300 .pm, .t, .c and .h files. +.PP +Perl continues to flourish into its fourth decade thanks to a vibrant +community of users and developers. The following people are known to have +contributed the improvements that became Perl 5.28.0: +.PP +Aaron Crane, Abigail, Ævar Arnfjörð Bjarmason, Alberto Simões, Alexandr +Savca, Andrew Fresh, Andy Dougherty, Andy Lester, Aristotle Pagaltzis, Ask +Bjørn Hansen, Chris 'BinGOs' Williams, Craig A. Berry, Dagfinn Ilmari +Mannsåker, Dan Collins, Daniel Dragan, David Cantrell, David Mitchell, +Dmitry Ulanov, Dominic Hargreaves, E. Choroba, Eric Herman, Eugen Konkov, +Father Chrysostomos, Gene Sullivan, George Hartzell, Graham Knop, Harald +Jörg, H.Merijn Brand, Hugo van der Sanden, Jacques Germishuys, James E +Keenan, Jarkko Hietaniemi, Jerry D. Hedden, J. Nick Koston, John Lightsey, +John Peacock, John P. Linderman, John SJ Anderson, Karen Etheridge, Karl +Williamson, Ken Brown, Ken Cotterill, Leon Timmermans, Lukas Mai, Marco +Fontani, Marc-Philip Werner, Matthew Horsfall, Neil Bowers, Nicholas Clark, +Nicolas R., Niko Tyni, Pali, Paul Marquess, Peter John Acklam, Reini Urban, +Renee Baecker, Ricardo Signes, Robin Barker, Sawyer X, Scott Lanning, Sergey +Aleynikov, Shirakata Kentaro, Shoichi Kaji, Slaven Rezic, Smylers, Steffen +Müller, Steve Hay, Sullivan Beck, Thomas Sibley, Todd Rinaldo, Tomasz +Konojacki, Tom Hukins, Tom Wyant, Tony Cook, Vitali Peil, Yves Orton, +Zefram. +.PP +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. +.PP +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. +.PP +For a more complete list of all of Perl's historical contributors, please +see the \fIAUTHORS\fR file in the Perl source distribution. +.SH "Reporting Bugs" +.IX Header "Reporting Bugs" +If you find what you think is a bug, you might check the perl bug database +at <https://rt.perl.org/> . There may also be information at +<http://www.perl.org/> , the Perl Home Page. +.PP +If you believe you have an unreported bug, please run the 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 \f(CW\*(C`perl \-V\*(C'\fR, +will be sent off to perlbug@perl.org to be analysed by the Perl porting team. +.PP +If the bug you are reporting has security implications which make it +inappropriate to send to a publicly archived mailing list, then see +"SECURITY VULNERABILITY CONTACT INFORMATION" in perlsec +for details of how to report the issue. +.SH "Give Thanks" +.IX Header "Give Thanks" +If you wish to thank the Perl 5 Porters for the work we had done in Perl 5, +you can do so by running the \f(CW\*(C`perlthanks\*(C'\fR program: +.PP +.Vb 1 +\& perlthanks +.Ve +.PP +This will send an email to the Perl 5 Porters list with your show of thanks. +.SH "SEE ALSO" +.IX Header "SEE ALSO" +The \fIChanges\fR file for an explanation of how to view exhaustive details on +what changed. +.PP +The \fIINSTALL\fR file for how to build Perl. +.PP +The \fIREADME\fR file for general stuff. +.PP +The \fIArtistic\fR and \fICopying\fR files for copyright information. |