=encoding utf8
+=for comment
+This has been completed up to 5dca8ed9d28, except for
+b0f2e9e nwclark Fix two bugs related to pod files outside of pod/ (important enough?)
+9b9f19d craigb Another vms bug
+cc5de3b craigb " " "
+43d9ecf jpeacock Set all version object math ops to noop
+f300909 smueller EU::ParseXS: Silence warning (probably unnecessary)
+
=head1 NAME
[ this is a template for a new perldelta file. Any text flagged as
[ List each enhancement as a =head2 entry ]
+=head2 C<__SUB__>
+
+The new C<__SUB__> token, available under the "current_sub" feature (see
+L<feature>) or C<use v5.15>, returns a reference to the current subroutine,
+making it easier to write recursive closures.
+
+=head2 New option for the debugger's B<t> command
+
+The B<t> command in the debugger, which toggles tracing mode, now accepts a
+numerical argument that determines how many levels of subroutine calls to
+trace.
+
+=head2 Return value of C<tied>
+
+The value returned by C<tied> on a tied variable is now the actual scalar
+that holds the object to which the variable is tied. This allows ties to
+be weakened with C<Scalar::Util::weaken(tied $tied_variable)>.
+
+=head2 Lvalue C<scalar>
+
+C<scalar> can now be used as an lvalue. You might consider this a new
+feature (which is why it is listed in this section), but the author of
+the change considered it a bug fix, since C<scalar> is only supposed to be
+setting scalar context, not changing lvalueness [perl #24346].
+
=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.
-[ List each security issue as a =head2 entry ]
+=head2 C<is_utf8_char()>
+
+The XS-callable function C<is_utf8_char()> when presented with malformed
+UTF-8 input can read up to 12 bytes beyond the end of the string. This
+cannot be fixed without changing its API. It is not called from CPAN.
+The documentation for it now describes how to use it safely.
+
+=head2 Other C<is_utf8_foo()> functions, as well as C<utf8_to_foo()>, etc.
+
+Most of the other XS-callable functions that take UTF-8 encoded input
+implicitly assume that the UTF-8 is valid (not malformed) in regards to
+buffer length. Do not do things such as change a character's case or
+see if it is alphanumeric without first being sure that it is valid
+UTF-8. This can be safely done for a whole string by using one of the
+functions C<is_utf8_string()>, C<is_utf8_string_loc()>, and
+C<is_utf8_string_loclen()>.
=head1 Incompatible Changes
[ List each incompatible change as a =head2 entry ]
+=head2 C<use I<VERSION>>
+
+As of this release, version declarations like C<use v5.16> now disable all
+features before enabling the new feature bundle. This means that the
+following holds true:
+
+ use 5.016;
+ # 5.16 features enabled here
+ use 5.014;
+ # 5.16 features disabled here
+
+C<use v5.12> and higher continue to enable strict, but explicit
+C<use strict> and C<no strict> now override the version declaration, even
+when they come first:
+
+ no strict;
+ use 5.012;
+ # no strict here
+
+There is a new ":default" feature bundle, that represents the set of
+features enabled before any version declaration or C<use feature> has been
+seen. Version declarations below 5.10 now enable the ":default" feature
+set. This does not actually change the behaviour of C<use v5.8>, because
+features added to the ":default" set are those that were traditionally
+enabled by default, before they could be turned off.
+
+C<$[> is now disabled under C<use v5.16>. It is part of the default
+feature set and can be turned on or off explicitly
+with C<use feature 'array_base'>.
+
+=head2 C<UNIVERSAL::VERSION>
+
+The change to C<UNIVERSAL::VERSION> in 5.15.2 has been reverted. It now
+returns a stringified version object once more.
+
+=head2 C<substr> lvalue revamp
+
+When C<substr> is called in lvalue or potential lvalue context with two or
+three arguments, a special lvalue scalar is returned that modifies the
+original string (the first argument) when assigned to.
+
+Previously, the offsets (the second and third arguments) passed to
+C<substr> would be converted immediately to match the string, negative
+offsets being translated to positive and offsets beyond the end of the
+string being truncated.
+
+Now, the offsets are recorded without modification in the special lvalue
+scalar that is returned, and the original string is not even looked at by
+C<substr> itself, but only when the returned lvalue is read or modified.
+
+These changes result in several incompatible changes and bug fixes:
+
+=over
+
+=item *
+
+If the original string changes length after the call to C<substr> but
+before assignment to its return value, negative offsets will remember
+their position from the end of the string, affecting code like this:
+
+ my $string = "string";
+ my $lvalue = \substr $string, -4, 2;
+ print $lvalue, "\n"; # prints "ri"
+ $string = "bailing twine";
+ print $lvalue, "\n"; # prints "wi"; used to print "il"
+
+The same thing happens with an omitted third argument. The returned lvalue
+will always extend to the end of the string, even if the string becomes
+longer.
+
+=item *
+
+Tied (and otherwise magical) variables are no longer exempt from the
+"Attempt ot use reference as lvalue in substr" warning.
+
+=item *
+
+That warning now occurs when the returned lvalue is assigned to, not when
+C<substr> itself is called. This only makes a difference if the return
+value of C<substr> is referenced and assigned to later.
+
+=item *
+
+The order in which "uninitialized" warnings occur for arguments to
+C<substr> has changed.
+
+=item *
+
+Passing a substring of a read-only value or a typeglob to a function (potential lvalue context) no longer causes an immediate "Can't coerce" or "Modification of a read-only value" error. That error only occurs if and
+when the value passed is assigned to.
+
+The same thing happens with the "substr outside of string" error. If the
+lvalue is only read, not written to, it is now just a warning, as with
+rvalue C<substr>.
+
+=item *
+
+C<substr> assignments no longer call FETCH twice if the first argument is a
+tied variable, but just once.
+
+=back
+
+It was impossible to fix all the bugs without an incompatible change, and
+the behaviour of negative offsets was never specified, so the change was
+deemed acceptable.
+
+=head2 Return value of C<eval>
+
+C<eval> returns C<undef> in scalar context or an empty list in list context
+when there is a run-time error. For syntax errors (when C<eval> is passed
+a string), in list context it used to return a list containing a single
+undefined element. Now it returns an empty list in list context for all
+errors [perl #80630].
+
+=head2 Anonymous handles
+
+Automatically generated file handles are now named __ANONIO__ when the
+variable name cannot be determined, rather than $__ANONIO__.
+
+=head2 XS API tweak
+
+The C<newCONSTSUB_flags> C-level function, added in 5.15.4, now has a
+C<len> parameter.
+
=head1 Deprecations
XXX Any deprecated features, syntax, modules etc. should be listed here.
=item *
-XXX
+Perl 5.12.0 sped up the destruction of objects whose classes define empty
+C<DESTROY> methods (to prevent autoloading), simply by not calling such
+empty methods. This release takes this optimisation a step further, by not
+calling any C<DESTROY> method that begins with an C<return> statement.
+This can be useful for destructors that are only used for debugging:
+
+ use constant DEBUG => 1;
+ sub DESTROY { return unless DEBUG; ... }
+
+Constant-folding will reduce the first statement to C<return;> if DEBUG is
+set to 0, triggering this optimisation.
+
+=item *
+
+Assign to a variable that holds a typeglob or copy-on-write scalar is now
+much faster. Previously the typeglob would be stringified or the
+copy-on-write scalar would be copied before being clobbered.
+
+=item *
+
+Assignment to a substring in void context is now more than twice its
+previous speed. Instead of creating and returning a special lvalue scalar
+that is then assigned to, C<substr> modifies the original string itself.
=back
=item *
-L<Compress::Raw::Zlib> has been upgraded from version 2.042 to version 2.043.
+L<AutoLoader> has been upgraded from version 5.71 to version 5.72.
=item *
-L<Compress::Raw::Bzip2> has been upgraded from version 2.042 to version 2.043.
+L<B::Debug> has been upgraded from version 1.16 to version 1.17.
=item *
-L<IO::Compress::Base> has been upgraded from version 2.042 to version 2.043.
+L<B::Deparse> has been upgraded from version 1.09 to version 1.10.
+
+Various constructs that used to be deparsed incorrectly have been fixed:
+
+=over
+
+=item C<sort(foo(bar))>
+
+C<sort foo(bar)>, how it used to deparse, makes foo the sort routine,
+rather than a regular function call.
+
+=item Keys and values in C<%^H>
+
+Undefined values in the hint hash were being deparsed as empty strings.
+Whenever the hint hash changed, all undefined values, even those
+unmodified, were being printed.
+
+Special characters, such as quotation marks, were not being escaped
+properly.
+
+Some values used to be omitted if, for instance, a key was the same as a
+previous value and vice versa.
+
+=item "method BLOCK" syntax
+
+C<method { $expr }> used to be deparsed as something like
+C<< do{ $expr }->method >>, but the latter puts the $expr in scalar
+context, whereas the former puts in list context.
+
+=item C<do +{}> and C<do({})>
+
+These are both variants of do-file syntax, but were being deparsed as
+do-blocks.
+
+=item Keywords that do not follow the llafr
+
+Keywords like C<return> and C<last> that do not follow the
+looks-like-a-function rule are now deparsed correctly with parentheses in
+the right place.
+
+Similarly, C<not>, which I<does> follow the llafr, was being deparsed as
+though it does not.
+
+=item C<=~>
+
+In various cases, B::Deparse started adding a spurious C<$_ =~> before the
+right-hand side in Perl 5.14; e.g., C<< "" =~ <$a> >> would become
+C<< "" =~ ($_ =~ <$a>) >>.
+
+=item C<open local *FH>
+
+C<open>, C<pipe> and other functions that autovivify handles used to omit
+C<local *> from C<local *FH>.
+
+=item Negated single-letter subroutine calls
+
+Negated subroutine calls like C<- f()> and C<-(f())> were being deparsed
+as file test operators.
+
+=item C<&{&}>
+
+C<&{&}> and C<& &>, which are calls to the subroutine named "&", believe it
+or not, were being deparsed as C<&&>.
+
+=back
+
+=item *
+
+L<Compress::Raw::Zlib> has been upgraded from version 2.042 to version 2.045.
+
+=item *
+
+L<Compress::Raw::Bzip2> has been upgraded from version 2.042 to version 2.045.
+
+=item *
+
+L<CPAN::Meta::YAML> has been upgraded from version 0.004 to version 0.005.
+
+=item *
+
+L<CPANPLUS> has been upgraded from version 0.9112 to version 0.9113.
+
+=item *
+
+L<Data::Dumper> has been upgraded from version 2.134 to version 2.135.
+
+The XS implementation has been updated to account for the Unicode symbol
+changes in Perl 5.15.4. It also knows how to output typeglobs with nulls
+in their names.
+
+=item *
+
+L<Digest::SHA> has been upgraded from version 5.63 to version 5.70.
+
+Added BITS mode to addfile method and shasum which makes partial-byte inputs
+now possible via files/STDIN and allows shasum to check all 8074 NIST Msg vectors,
+where previously special programming was required to do this.
+
+=item *
+
+L<Exporter> has been upgraded from version 5.65 to version 5.66.
+
+It no longer tries to localise C<$_> unnecessarily.
+
+=item *
+
+L<ExtUtils::ParseXS> has been upgraded from version 3.05 to version 3.07.
+
+=item *
+
+L<IO::Compress::Base> has been upgraded from version 2.042 to version 2.045.
+
+Added zipdetails utility.
+
+=item *
+
+L<Locale::Codes> has been upgraded from version 3.18 to version 3.20.
+
+The code2XXX, XXX2code, all_XXX_codes, and all_XXX_names functions now support retired codes.
+All codesets may be specified by a constant or by their name now. Previously,
+they were specified only by a constant.
+The alias_code function exists for backward compatibility. It has been replaced by rename_country_code.
+The alias_code function will be removed sometime after September, 2013.
+All work is now done in the central module (Locale::Codes). Previously, some was still done in the
+wrapper modules (Locale::Codes::*) but that is gone now.
+Added Language Family codes (langfam) as defined in ISO 639-5.
+
+=item *
+
+L<Module::Loaded> has been uprgaded from version 0.06 to version 0.08.
=item *
=item *
-L<Unicode::Collate> has been upgraded from version 0.85 to version 0.86.
+L<POSIX> has been upgraded from version 1.26 to version 1.27.
+
+It no longer produces a "Constant subroutine TCSANOW redefined" warning on
+Windows.
+
+XXX When did it start producing that warning? Was it post-5.15.5? Even if
+it was not, adding a note will help whoever compiles perl5160delta.
+
+=item *
+
+L<Socket> has been upgraded from version 1.94_02 to version 1.96.
+
+=item *
+
+L<threads> has been upgraded from version 1.85 to version 1.86.
+
+=item *
+
+L<Unicode::Collate> has been upgraded from version 0.85 to version 0.87.
Tailored compatibility ideographs as well as unified ideographs for
the locales: ja, ko, zh__big5han, zh__gb2312han, zh__pinyin, zh__stroke.
+Now Locale/*.pl files are searched in @INC.
+
+=item *
+
+L<UNIVERSAL> has been upgraded from version 1.10 to version 1.11.
+
+Documentation change clarifies return values from UNIVERSAL::VERSION.
+
=back
=head2 Removed Modules and Pragmata
=item *
-XXX
+Changing the case of a UTF-8 encoded string under C<use locale> now
+gives better, but still imperfect, results. Previously, such a string
+would entirely lose locale semantics and silently be treated as Unicode.
+Now, the code points that are less than 256 are treated with locale
+rules, while those above 255 are, of course, treated as Unicode. See
+L<perlfunc/lc> for more details, including the deficiencies of this
+scheme.
=back
However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics>
section.
-=head3 L<XXX>
+=head3 L<perlsec/Laundering and Detecting Tainted Data>
=over 4
=item *
-XXX Description of the change here
+The example function for checking for taintedness contained a subtle
+error. C<$@> needs to be localized to prevent its changing this
+global's value outside the function. The preferred method to check for
+this, though, remains to use L<Scalar::Util/tainted>.
=back
=item *
-XXX Describe change here
+Redefinition warnings for constant subroutines used to be mandatory, even
+occurring under C<no warnings>. Now they respect the L<warnings> pragma.
+
+=item *
+
+The "Attempt to free non-existent shared string" has had the spelling of
+"non-existent" corrected to "nonexistent". It was already listed with the
+correct spelling in L<perldiag>.
+
+=item *
+
+The 'Use of "foo" without parentheses is ambiguous' warning has been
+extended to apply also to user-defined subroutines with a (;$) prototype,
+and not just to built-in functions.
=back
entries for each change
Use L<XXX> with program names to get proper documentation linking. ]
-=head3 L<XXX>
+=head3 L<zipdetails>
=over 4
=item *
-XXX
+L<zipdetails> displays information about the internal record structure of the zip file.
+It is not concerned with displaying any details of the compressed data stored in the zip file.
=back
=item *
-XXX
+F<pod/roffitall> is now build by F<pod/buildtoc>, instead of being shipped
+with the distribution. Its list of manpages is now generated (and therefore
+current). See also RT #103202 for an unresolved related issue.
+
+=item *
+
+Perl 5.15.5 had a bug in its installation script, which did not install
+F<unicore/Name.pm>. This has been corrected [perl #104226].
+
+XXX Is that Perl version correct? Is the file path correct?
+
+=item *
+
+The -Dusesitecustomize and -Duserelocatableinc options now work together
+properly.
=back
=item *
-XXX
+The F<substr.t> and F<substr_thr.t> scripts for testing C<substr> have been
+moved under F<t/op/>, where they were originally. They had been moved
+under F<t/re/> along with the substitution tests when that directory was
+created.
=back
changes within modules for platforms should generally be listed in the
L</Modules and Pragmata> section.
+=head3 VMS
+
=over 4
-=item XXX-some-platform
+=item *
-XXX
+Fixed a bug that caused a link error on older versions of VMS.
+
+=item *
+
+Perl no longer supports pre-7.0 VMS or pre-6.0 DEC C.
=back
=item *
-XXX
+RT #78266: The regex engine has been leaking memory when accessing
+named captures that weren't matched as part of a regex ever since 5.10
+when they were introduced, e.g. this would consume over a hundred MB
+of memory:
+
+ for (1..10_000_000) {
+ if ("foo" =~ /(foo|(?<capture>bar))?/) {
+ my $capture = $+{capture}
+ }
+ }
+ system "ps -o rss $$"'
+
+=item *
+
+A constant subroutine assigned to a glob whose name contains a null will no
+longer cause extra globs to pop into existence when the constant is
+referenced under its new name.
+
+=item *
+
+C<sort> was not treating C<sub {}> and C<sub {()}> as equivalent when such
+a sub was provided as the comparison routine. It used to croak on
+C<sub {()}>.
+
+=item *
+
+Subroutines from the C<autouse> namespace are once more exempt from
+redefinition warnings. This used to work in 5.005, but was broken in 5.6
+for most subroutines. For subs created via XS that redefine subroutines
+from the C<autouse> package, this stopped working in 5.10.
+
+=item *
+
+New XSUBs now produce redefinition warnings if they overwrite existing
+subs, as they did in 5.8.x. (The C<autouse> logic was reversed in 5.10-14.
+Only subroutines from the C<autouse> namespace would warn when clobbered.)
+
+=item *
+
+Redefinition warnings triggered by the creation of XSUBs now respect
+Unicode glob names, instead of using the internal representation. This was
+missed in 5.15.4, partly because this warning was so hard to trigger. (See
+the previous item.)
+
+=item *
+
+C<newCONSTSUB> used to use compile-time warning hints, instead of run-time
+hints. The following code should never produce a redefinition warning, but
+it used to, if C<newCONSTSUB> redefine and existing subroutine:
+
+ use warnings;
+ BEGIN {
+ no warnings;
+ some_XS_function_that_calls_new_CONSTSUB();
+ }
+
+=item *
+
+Redefinition warnings for constant subroutines are on by default (what are
+known as severe warnings in L<perldiag>). This was only the case when it
+was a glob assignment or declaration of a Perl subroutine that caused the
+warning. If the creation of XSUBs triggered the warning, it was not a
+default warning. This has been corrected.
+
+=item *
+
+The internal check to see whether a redefinition warning should occur used
+to emit "uninitialized" warnings in cases like this:
+
+ use warnings "uninitialized";
+ use constant {u=>undef,v=>undef};
+ sub foo(){u} sub foo(){v}
+
+=item *
+
+A bug fix in Perl 5.14 introduced a new bug, causing "uninitialized"
+warnings to report the wrong variable if the operator in question has
+two operands and one is C<%{...}> or C<@{...}>. This has been fixed
+[perl #103766].
+
+=item *
+
+C<< version->new("version") >> and C<printf "%vd", "version"> no longer
+crash [perl #102586].
+
+=item *
+
+C<$tied =~ y/a/b/>, C<chop $tied> and C<chomp $tied> now call FETCH just
+once when $tied holds a reference.
+
+=item *
+
+Four-argument C<select> now always calls FETCH on tied arguments. It used
+to skip the call if the tied argument happened to hold C<undef> or a
+typeglob.
+
+=item *
+
+Four-argument C<select> no longer produces its "Non-string passed as
+bitmask" warning on tied or tainted variables that are strings.
+
+=item *
+
+C<sysread> now always calls FETCH on the buffer passed to it if it is tied.
+It used to skip the call if the tied variable happened to hold a typeglob.
+
+=item *
+
+C<< $tied .= <> >> now calls FETCH once on C<$tied>. It used to call it
+multiple times if the last value assigned to or returned from the tied
+variable was anything other than a string or typeglob.
+
+=item *
+
+The C<evalbytes> keyword added in 5.15.5 was respecting C<use utf8>
+declarations from the outer scope, when it should have been ignoring them.
+
+=item *
+
+C<goto &func> no longers crashes, but produces an error message, when the
+unwinding of the current subroutine's scope fires a destructor that
+undefines the subroutine being "goneto" [perl #99850].
+
+=item *
+
+Arithmetic assignment (C<$left += $right>) involving overloaded objects that
+rely on the 'nomethod' override no longer segfault when the left operand is not
+overloaded.
+
+=item *
+
+Assigning C<__PACKAGE__> or any other shared hash key scalar to a stash
+element no longer causes a double free. Regardless of this change, the
+results of such assignments are still undefined.
+
+=item *
+
+Creating a C<UNIVERSAL::AUTOLOAD> sub no longer stops C<%+>, C<%-> and
+C<%!> from working some of the time [perl #105024].
+
+=item *
+
+Assigning C<__PACKAGE__> or another shared hash key string to a variable no
+longer stops that variable from being tied if it happens to be a PVMG or
+PVLV internally.
+
+=item *
+
+When presented with malformed UTF-8 input, the XS-callable functions
+C<is_utf8_string()>, C<is_utf8_string_loc()>, and
+C<is_utf8_string_loclen()> could read beyond the end of the input
+string by up to 12 bytes. This no longer happens. [perl #32080].
+However, currently, C<is_utf8_char()> still has this defect,
+see L</is_utf8_char()> above.
+
+=item *
+
+Doing a substitution on a tied variable returning a copy-on-write scalar
+used to cause an assertion failure or an "Attempt to free nonexistent
+shared string" warning.
+
+=item *
+
+A change in perl 5.15.4 caused C<caller()> to produce malloc errors and a
+crash with Perl's own malloc, and possibly with other malloc
+implementations, too [perl #104034].
+
+=item *
+
+A bug fix in 5.15.5 could sometimes result in assertion failures under
+debugging builds of perl for certain syntax errors in C<eval>, such as
+C<eval(q|""!=!~//|);>
+
+=item *
+
+The "c [line num]" debugger command was broken by other debugger changes
+release in 5.15.3. This is now fixed.
+
+=item *
+
+Breakpoints were not properly restored after a debugger restart using the
+"R" command in 5.15.3. This is now fixed.
+
+=item *
+
+The debugger prompt did not display the current line in 5.15.3. This is now
+fixed.
=back
https://perl5.git.perl.org / perl5.git / blobdiff