[ this is a template for a new perldelta file. Any text flagged as
XXX needs to be processed before release. ]
-perldelta - what is new for perl v5.17.1
+perldelta - what is new for perl v5.17.2
=head1 DESCRIPTION
-This document describes differences between the 5.17.0 release and
-the 5.17.1 release.
+This document describes differences between the 5.17.1 release and
+the 5.17.2 release.
-If you are upgrading from an earlier release such as 5.16.0, first read
-L<perl5170delta>, which describes differences between 5.16.0 and
-5.17.0.
+If you are upgrading from an earlier release such as 5.17.0, first read
+L<perl5171delta>, which describes differences between 5.17.0 and
+5.17.1.
=head1 Notice
[ List each enhancement as a =head2 entry ]
-=head2 More CORE:: subs
-
-Several more built-in functions have been added as subroutines to the
-CORE:: namespace, namely, those non-overridable keywords that can be
-implemented without custom parsers: C<defined>, C<delete>, C<exists>,
-C<glob>, C<pos>, C<protoytpe>, C<scalar>, C<split>, C<study>, C<undef>,
-
-As some of these have prototypes, C<prototype('CORE::...')> has been
-changed not to make a distinction between overridable and non-overridable
-keywords. This is to make C<prototype('CORE::pos')> consistent with
-C<prototype(&CORE::pos)>.
-
=head1 Security
XXX Any security-related notices go here. In particular, any security
If any exist, they are bugs, and we request that you submit a
report. See L</Reporting Bugs> below.
-=head2 C</(?{})/> and C</(??{}> have been heavily reworked.
-
-The implementation of this feature has been almost completely written.
-Although its main intent is is to fix bugs, some behaviours, especially
-related to the scope of lexical variables, will have changed. This is
-described more fully in the L</Selected Bug Fixes> section.
-
-=head2 C<\N{BELL}> now refers to U+1F514 instead of U+0007
-
-Unicode 6.0 reused the name "BELL" for a different code point than it
-traditionally had meant. Since Perl v5.14, use of this name still
-referred to U+0007, but would raise a deprecated warning. Now, "BELL"
-refers to U+1F514, and the name for U+0007 is "ALERT". All the
-functions in L<charnames> have been correspondingly updated.
-
-=head2 Alphanumeric operators must now be separated from the closing
-delimter of regular expressions
-
-You may no longer write something like:
-
- m/a/and 1
-
-Instead you must write
-
- m/a/ and 1
-
-with whitespace separating the operator from the closing delimiter of
-the regular expression. Not having whitespace has resulted in a
-deprecated warning since Perl v5.14.0.
+[ List each incompatible change as a =head2 entry ]
=head1 Deprecations
=item *
-L<ExtUtils::CBuilder> has been upgraded from version 0.280206 to 0.280208.
-
-Manifest files are now correctly embedded for those versions of VC++ which
-make use of them.
-
-=item *
-
-L<B> has been upgraded from version 1.35 to 1.36.
-
-C<B::COP::stashlen> has been replaced with C<B::COP::stashoff>.
-
-C<B::COP::stashpv> now supports UTF8 package names and embedded nulls.
-
-=item *
-
-L<ExtUtils::CBuilder> has been upgraded from version 0.280206 to 0.280208.
-
-It no longer fails when trying to embed manifests on Windows
-[perl #111782, #111798].
-
-=item *
-
-L<File::DosGlob> has been upgraded from version 1.07 to 1.08.
-
-There are no visible changes, only minor internal refactorings.
-
-=item *
-
-L<File::Spec::Unix> has been upgraded from version 3.39_02 to 3.39_03.
-
-C<abs2rel> could produce incorrect results when given two relative paths or
-the root directory twice [perl #111510].
-
-=item *
-
-L<IO> has been upgraded from version 1.25_06 to 1.25_07.
-
-C<sync()> can now be called on read-only file handles [perl #64772].
-
-=item *
-
-L<Pod::Html> has been upgraded from version 1.15_02 to 1.16.
-
-The option C<--libpods> has been re-instated. It is deprecated, and its use
-does nothing other than issue a warning that it is no longer supported.
-
-=item *
-
-L<Unicode::UCD> has been upgraded from version 0.43 to 0.44.
+L<File::stat> has been upgraded from version 1.06 to 1.07.
-This adds a function L<all_casefolds()|Unicode::UCD/all_casefolds()>
-that returns all the casefolds.
-
-=item *
-
-L<Scalar::Util> has been upgraded from version 1.23 to version 1.25.
+Previously C<File::stat>'s overloaded C<-x> and C<-X> operators did not give
+the correct results for directories or executable files when running as
+root. They had been treating executable permissions for root just like for
+any other user, performing group membership tests I<etc> for files not owned
+by root. They now follow the correct Unix behaviour - for a directory they
+are always true, and for a file if any of the three execute permission bits
+are set then they report that root can execute the file. Perl's builtin
+C<-x> and C<-X> operators have always been correct.
=back
However, any changes to F<pod/perldiag.pod> should go in the L</Diagnostics>
section.
-=head3 L<perlfaq>
+=head3 L<XXX>
=over 4
=item *
-L<perlfaq> has been synchronised with version 5.0150040 from C<CPAN>.
+XXX Description of the change here
=back
=item *
-XXX L<message|perldiag/"message">
+C<chr()> now warns when passed a negative value [perl #83048].
+
+=item *
+
+C<srand()> now warns when passed a value that doesn't fit in a C<UV> (since the
+value will be truncated rather than overflowing) [perl #40605].
=back
=back
-=head2 Removals of Diagnostics
-
-=over 4
-
-=item *
-
-The "Runaway prototype" warning that occurs in bizarre cases has been
-removed as being unhelpful and inconsistent.
-
-=item *
-
-The "Not a format reference" error has been removed, as the only case in
-which it could be triggered was a bug.
-
-=back
-
=head1 Utility Changes
XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go
=over 4
-=item Win32
+=item XXX-some-platform
-C<link> on Win32 now attempts to set C<$!> to more appropriate values
-based on the Win32 API error code. [perl #112272]
+XXX
=back
=item *
-The C<study> function was made a no-op in 5.16. It was simply disabled via
-a C<return> statement; the code was left in place. Now the code supporting
-what C<study> used to do has been removed.
-
-=item *
-
-Under threaded perls, there is no longer a separate PV allocated for every
-COP to store its package name (C<< cop->stashpv >>). Instead, there is an
-offset (C<< cop->stashoff >>) into the new C<PL_stashpad> array, which
-holds stash pointers.
-
-=item *
-
-In the pluggable regex API, the C<regexp_engine> struct has acquired a new
-field C<op_comp>, which is currently just for perl's internal use, and
-should be initialised to NULL by other regexp plugin modules.
+XXX
=back
=item *
-The implementation of code blocks in regular expressions, such as C<(?{})>
-and C<(??{})> has been heavily reworked to eliminate a whole slew of bugs.
-The main user-visible changes are:
-
-=over 4
-
-=item *
-
-Code blocks within patterns are now parsed in the same pass as the
-surrounding code; in particular it is no longer necessary to have balanced
-braces: this now works:
-
- /(?{ $x='{' })/
-
-This means that this error message is longer generated:
-
- Sequence (?{...}) not terminated or not {}-balanced in regex
-
-but a new error may be seen:
-
- Sequence (?{...}) not terminated with ')'
-
-In addition, literal code blocks within run-time patterns are only
-compiled once, at perl compile-time:
-
- for my $p (...) {
- # this 'FOO' block of code is compiled once,
- # at the same time as the surrounding 'for' loop
- /$p{(?{FOO;})/;
- }
-
-=item *
-
-Lexical variables are now sane as regards scope, recursion and closure
-behaviour. In particular, C</A(?{B})C/> behaves (from a closure viewpoint)
-exactly like C</A/ && do { B } && /C/>, while C<qr/A(?{B})C/> is like
-C<sub {/A/ && do { B } && /C/}>. So this code now works how you might
-expect, creating three regexes that match 1,2, and 3:
-
- for my $i (0..2) {
- push @r, qr/^(??{$i})$/;
- }
- "1" =~ $r[1]; # matches
-
-=item *
-
-The C<use re 'eval'> pragma is now only required for code blocks defined
-at runtime; in particular in the following, the text of the $r pattern is
-still interpolated into the new pattern and recompiled, but the individual
-compiled code-blocks within $r are reused rather than being recompiled,
-and C<use re 'eval'> isn't needed any more:
-
- my $r = qr/abc(?{....})def/;
- /xyz$r/;
-
-=item *
-
-Flow control operators no longer crash. Each code block runs in a new
-dynamic scope, so C<next> etc. will not see any enclosing loops and
-C<caller> will not see any calling subroutines. C<return> returns a value
-from the code block, not from any enclosing subroutine.
-
-=item *
-
-Perl normally caches the compilation of run-time patterns, and doesn't
-recompile if the pattern hasn't changed; but this is now disabled if
-required for the correct behaviour of closures; for example:
-
- my $code = '(??{$x})';
- for my $x (1..3) {
- # recompile to see fresh value of $x each time
- $x =~ /$code/;
- }
-
-
-=item *
-
-The C</msix> and C<(?msix)> etc. flags are now propagated into the return
-value from C<(??{})>; this now works:
-
- "AB" =~ /a(??{'b'})/i;
-
-=item *
-
-Warnings and errors will appear to come from the surrounding code (or for
-run-time code blocks, from an eval) rather than from an C<re_eval>:
-
- use re 'eval'; $c = '(?{ warn "foo" })'; /$c/;
- /(?{ warn "foo" })/;
-
-formerly gave:
-
- foo at (re_eval 1) line 1.
- foo at (re_eval 2) line 1.
-
-and now gives:
-
- foo at (eval 1) line 1.
- foo at /some/prog line 2.
-
-=back
-
-=item *
-
-Perl now works as well as can be expected on all releases of Unicode so
-far. In v5.16, it worked on Unicodes 6.0 and 6.1, but there were
-various bugs for earlier releases; the older the release the more
-problems.
-
-=item *
-
-C<vec> no longer produces "uninitialized" warnings in lvalue context
-[perl #9423].
-
-=item *
-
-An optimisation involving fixed strings in regular expressions could cause
-a severe performance penalty in edge cases. This has been fixed
-[perl #76546].
-
-=item *
-
-The "Can't find an opnumber" message that C<prototype> produces when passed
-a string like "CORE::nonexistent_keyword" is now passes UTF8 and embedded
-nulls through unchanged [perl #97478].
-
-=item *
-
-C<prototype> now treats magical variables like C<$1> the same way as
-non-magical variables when checking for the CORE:: prefix, instead of
-treating them as subroutine names.
+A regression introduced in v5.14.0 has been fixed, in which some calls
+to the C<re> module would clobber C<$_>.
=item *
-Under threaded perls, a run-time code block in a regular expression could
-corrupt the package name stored in the op tree, resulting in bad reads
-in C<caller>, and possibly crashes [perl #113060].
+C<do FILE> now always either sets or clears C<$@>, even when the file can't be
+read. This ensures that testing C<$@> first (as recommended by the
+documentation) always returns the correct result.
=item *
-Referencing a closure prototype (C<\&{$_[1]}> in an attribute handler for a
-closure) no longer results in a copy of the subroutine (or assertion
-failures on debugging builds).
+The array iterator used for the C<each @array> construct is now correctly
+reset when C<@array> is cleared (RT #75596). This happens for example when the
+array is globally assigned to, as in C<@array = (...)>, but not when its
+B<values> are assigned to. In terms of the XS API, it means that C<av_clear()>
+will now reset the iterator.
-=item *
-
-C<eval '__PACKAGE__'> now returns the right answer on threaded builds if
-the current package has been assigned over (as in
-C<*ThisPackage:: = *ThatPackage::>) [perl #78742].
-
-=item *
-
-If a package is deleted by code that it calls, it is possible for C<caller>
-to see a stack frame belonging to that deleted package. C<caller> could
-crash if the stash's memory address was reused for a scalar and a
-substitution was performed on the same scalar [perl #113486].
-
-=item *
-
-C<UNIVERSAL::can> no longer treats its first argument differently
-depending on whether it is a string or number internally.
-
-=item *
-
-C<open> with "<&" for the mode checks to see whether the third argument is
-a number, in determining whether to treat it as a file descriptor or a
-handle name. Magical variables like C<$1> were always failing the numeric
-check and being treated as handle names.
-
-=item *
-
-C<warn>'s handling of magical variables (C<$1>, ties) has undergone several
-fixes. FETCH is only called once now on a tied argument or a tied C<$@>
-[perl #97480]. Tied variables returning objects that stringify as "" are
-no longer ignored. A tied C<$@> that happened to return a reference the
-I<previous> time is was used is no longer ignored.
+This mirrors the behaviour of the hash iterator when the hash is cleared.
=item *
-C<warn ""> now treats C<$@> with a number in it the same way, regardless of
-whether it happened via C<$@=3> or C<$@="3">. It used to ignore the
-former. Now it appends "\t...caught", as it has always done with
-C<$@="3">.
+C<< $class->can >>, C<< $class->isa >>, and C<< $class->DOES >> now return
+correct results, regardless of whether that package referred to by C<$class>
+exists [perl #47113].
=item *
-Numeric operators on magical variables (e.g., S<C<$1 + 1>>) used to use
-floating point operations even where integer operations were more appropriate, resulting in loss of accuracy on 64-bit platforms
-[perl #109542].
+Arriving signals no longer clear C<$@> [perl #45173].
=item *
-Unary negation no longer treats a string as a number if the string happened
-to be used as a number some time. So, if $x contains the string "dogs",
-C<-$x> returns "-dogs" even if C<$y=0+$x> has happened at some point.
+Allow C<my ()> declarations with an empty variable list [perl #113554].
=item *
-In Perl 5.14, C<-'-10'> was fixed to return "10", not "+10". But magical
-variables (C<$1>, ties) were not fixed till now [perl #57706].
+During parsing, subs declared after errors no longer leave stubs
+[perl #113712].
=item *
-Unary negation now treats strings consistently, regardless of the internal
-UTF8 flag.
-
-=item *
-
-A regression introduced in Perl v5.16.0 involving
-C<tr/I<SEARCHLIST>/I<REPLACEMENTLIST>/> has been fixed. Only the first
-instance is supposed to be meaningful if a character appears more than
-once in C<I<SEARCHLIST>>. Under some circumstances, the final instance
-was overriding all earlier ones. [perl #113584]
+C<do $file> now clears C<$@> after an I/O error [perl #113730].
=back
=head1 Known Problems
XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
-tests that had to be C<TODO>ed for the release would be noted here, unless
-they were specific to a particular platform (see below).
-
-This is a list of some significant unfixed bugs, which are regressions
-from either 5.XXX.XXX or 5.XXX.XXX.
+tests that had to be C<TODO>ed for the release would be noted here. Unfixed
+platform specific bugs also go here.
[ List each fix as a =item entry ]
XXX Generate this with:
- perl Porting/acknowledgements.pl v5.17.0..HEAD
+ perl Porting/acknowledgements.pl v5.17.1..HEAD
=head1 Reporting Bugs
https://perl5.git.perl.org / perl5.git / blobdiff