The deprecated features will be grouped by the version of Perl in
which they will be removed.
-=head2 Perl 5.30
+=head2 Perl 5.32
-=head3 C<< File::Glob::glob() >> will disappear
+=head3 Constants from lexical variables potentially modified elsewhere
-C<< File::Glob >> has a function called C<< glob >>, which just calls
-C<< bsd_glob >>. However, its prototype is different from the prototype
-of C<< CORE::glob >>, and hence, C<< File::Glob::glob >> should not
-be used.
+You wrote something like
-C<< File::Glob::glob() >> was deprecated in Perl 5.8. A deprecation
-message was issued from Perl 5.26 onwards, and the function will
-disappear in Perl 5.30.
+ my $var;
+ $sub = sub () { $var };
-Code using C<< File::Glob::glob() >> should call
-C<< File::Glob::bsd_glob() >> instead.
+but $var is referenced elsewhere and could be modified after the C<sub>
+expression is evaluated. Either it is explicitly modified elsewhere
+(C<$var = 3>) or it is passed to a subroutine or to an operator like
+C<printf> or C<map>, which may or may not modify the variable.
+
+Traditionally, Perl has captured the value of the variable at that
+point and turned the subroutine into a constant eligible for inlining.
+In those cases where the variable can be modified elsewhere, this
+breaks the behavior of closures, in which the subroutine captures
+the variable itself, rather than its value, so future changes to the
+variable are reflected in the subroutine's return value.
+
+If you intended for the subroutine to be eligible for inlining, then
+make sure the variable is not referenced elsewhere, possibly by
+copying it:
+ my $var2 = $var;
+ $sub = sub () { $var2 };
+
+If you do want this subroutine to be a closure that reflects future
+changes to the variable that it closes over, add an explicit C<return>:
+
+ my $var;
+ $sub = sub () { return $var };
+
+This usage has been deprecated, and will no longer be allowed in Perl 5.32.
+
+=head3 Use of strings with code points over 0xFF as arguments to C<vec>
+
+C<vec> views its string argument as a sequence of bits. A string
+containing a code point over 0xFF is nonsensical. This usage is
+deprecated in Perl 5.28, and was removed in Perl 5.32.
+
+=head3 Use of code points over 0xFF in string bitwise operators
+
+The string bitwise operators, C<&>, C<|>, C<^>, and C<~>, treat their
+operands as strings of bytes. As such, values above 0xFF are
+nonsensical. Some instances of these have been deprecated since Perl
+5.24, and were made fatal in 5.28, but it turns out that in cases where
+the wide characters did not affect the end result, no deprecation
+notice was raised, and so remain legal. Now, all occurrences either are
+fatal or raise a deprecation warning, so that the remaining legal
+occurrences became fatal in 5.32.
+
+An example of this is
+
+ "" & "\x{100}"
+
+The wide character is not used in the C<&> operation because the left
+operand is shorter. This now throws an exception.
+
+=head3 hostname() doesn't accept any arguments
+
+The function C<hostname()> in the L<Sys::Hostname> module has always
+been documented to be called with no arguments. Historically it has not
+enforced this, and has actually accepted and ignored any arguments. As a
+result, some users have got the mistaken impression that an argument does
+something useful. To avoid these bugs, the function is being made strict.
+Passing arguments was deprecated in Perl 5.28, and will become fatal in
+Perl 5.32.
=head3 Unescaped left braces in regular expressions
language to be extended in various ways in future releases. To avoid
needlessly breaking existing code, the restriction is is not enforced in
contexts where there are unlikely to ever be extensions that could
-conflict with the use there of C<{> as a literal.
+conflict with the use there of C<{> as a literal. A non-deprecation
+warning that the left brace is being taken literally is raised in
+contexts where there could be confusion about it.
Literal uses of C<{> were deprecated in Perl 5.20, and some uses of it
started to give deprecation warnings since. These cases were made fatal
in Perl 5.26. Due to an oversight, not all cases of a use of a literal
-C<{> got a deprecation warning. These cases started warning in Perl 5.26,
-and they will be fatal by Perl 5.30.
+C<{> got a deprecation warning. Some cases started warning in Perl 5.26,
+and were made fatal in Perl 5.30. Other cases started in Perl 5.28,
+and will be made fatal in 5.32.
+
+=head3 In XS code, use of various macros dealing with UTF-8.
+
+The macros below now require an extra parameter than in versions prior
+to Perl 5.32. The final parameter in each one is a pointer into the
+string supplied by the first parameter beyond which the input will not
+be read. This prevents potential reading beyond the end of the buffer.
+C<isALPHANUMERIC_utf8>,
+C<isASCII_utf8>,
+C<isBLANK_utf8>,
+C<isCNTRL_utf8>,
+C<isDIGIT_utf8>,
+C<isIDFIRST_utf8>,
+C<isPSXSPC_utf8>,
+C<isSPACE_utf8>,
+C<isVERTWS_utf8>,
+C<isWORDCHAR_utf8>,
+C<isXDIGIT_utf8>,
+C<isALPHANUMERIC_LC_utf8>,
+C<isALPHA_LC_utf8>,
+C<isASCII_LC_utf8>,
+C<isBLANK_LC_utf8>,
+C<isCNTRL_LC_utf8>,
+C<isDIGIT_LC_utf8>,
+C<isGRAPH_LC_utf8>,
+C<isIDCONT_LC_utf8>,
+C<isIDFIRST_LC_utf8>,
+C<isLOWER_LC_utf8>,
+C<isPRINT_LC_utf8>,
+C<isPSXSPC_LC_utf8>,
+C<isPUNCT_LC_utf8>,
+C<isSPACE_LC_utf8>,
+C<isUPPER_LC_utf8>,
+C<isWORDCHAR_LC_utf8>,
+C<isXDIGIT_LC_utf8>,
+C<toFOLD_utf8>,
+C<toLOWER_utf8>,
+C<toTITLE_utf8>,
+and
+C<toUPPER_utf8>.
+
+Since Perl 5.26, this functionality with the extra parameter has been
+available by using a corresponding macro to each one of these, and whose
+name is formed by appending C<_safe> to the base name. There is no
+change to the functionality of those. For example, C<isDIGIT_utf8_safe>
+corresponds to C<isDIGIT_utf8>, and both now behave identically. All
+are documented in L<perlapi/Character case changing> and
+L<perlapi/Character classification>.
+
+This change was originally scheduled for 5.30, but was delayed.
+
+=head2 Perl 5.30
+
+=head3 C<< $* >> is no longer supported
+
+Before Perl 5.10, setting C<< $* >> to a true value globally enabled
+multi-line matching within a string. This relique from the past lost
+its special meaning in 5.10. Use of this variable will be a fatal error
+in Perl 5.30, freeing the variable up for a future special meaning.
+
+To enable multiline matching one should use the C<< /m >> regexp
+modifier (possibly in combination with C<< /s >>). This can be set
+on a per match bases, or can be enabled per lexical scope (including
+a whole file) with C<< use re '/m' >>.
+
+=head3 C<< $# >> is no longer supported
+
+This variable used to have a special meaning -- it could be used
+to control how numbers were formatted when printed. This seldom
+used functionality was removed in Perl 5.10. In order to free up
+the variable for a future special meaning, its use will be a fatal
+error in Perl 5.30.
+
+To specify how numbers are formatted when printed, one is advised
+to use C<< printf >> or C<< sprintf >> instead.
+
+=head3 Assigning non-zero to C<< $[ >> is fatal
+
+This variable (and the corresponding C<array_base> feature and
+L<arybase> module) allowed changing the base for array and string
+indexing operations.
+
+Setting this to a non-zero value has been deprecated since Perl 5.12 and
+throws a fatal error as of Perl 5.30.
+
+=head3 C<< File::Glob::glob() >> will disappear
+
+C<< File::Glob >> has a function called C<< glob >>, which just calls
+C<< bsd_glob >>. However, its prototype is different from the prototype
+of C<< CORE::glob >>, and hence, C<< File::Glob::glob >> should not
+be used.
+
+C<< File::Glob::glob() >> was deprecated in Perl 5.8. A deprecation
+message was issued from Perl 5.26 onwards, and the function will
+disappear in Perl 5.30.
+
+Code using C<< File::Glob::glob() >> should call
+C<< File::Glob::bsd_glob() >> instead.
+
+=head3 Unescaped left braces in regular expressions (for 5.30)
+
+See L</Unescaped left braces in regular expressions> above.
=head3 Unqualified C<dump()>
See L<perlfunc/dump>.
+=head3 Using my() in false conditional.
+
+There has been a long-standing bug in Perl that causes a lexical variable
+not to be cleared at scope exit when its declaration includes a false
+conditional. Some people have exploited this bug to achieve a kind of
+static variable. Since we intend to fix this bug, we don't want people
+relying on this behavior.
+
+Instead, it's recommended one uses C<state> variables to achieve the
+same effect:
+
+ use 5.10.0;
+ sub count {state $counter; return ++ $counter}
+ say count (); # Prints 1
+ say count (); # Prints 2
+
+C<state> variables were introduced in Perl 5.10.
+
+Alternatively, you can achieve a similar static effect by
+declaring the variable in a separate block outside the function, eg
+
+ sub f { my $x if 0; return $x++ }
+
+becomes
+
+ { my $x; sub f { return $x++ } }
+
+The use of C<my()> in a false conditional has been deprecated in
+Perl 5.10, and it will become a fatal error in Perl 5.30.
+
+
+=head3 Reading/writing bytes from/to :utf8 handles.
+
+The sysread(), recv(), syswrite() and send() operators are
+deprecated on handles that have the C<:utf8> layer, either explicitly, or
+implicitly, eg., with the C<:encoding(UTF-16LE)> layer.
+
+Both sysread() and recv() currently use only the C<:utf8> flag for the stream,
+ignoring the actual layers. Since sysread() and recv() do no UTF-8
+validation they can end up creating invalidly encoded scalars.
+
+Similarly, syswrite() and send() use only the C<:utf8> flag, otherwise ignoring
+any layers. If the flag is set, both write the value UTF-8 encoded, even if
+the layer is some different encoding, such as the example above.
+
+Ideally, all of these operators would completely ignore the C<:utf8> state,
+working only with bytes, but this would result in silently breaking existing
+code. To avoid this a future version of perl will throw an exception when
+any of sysread(), recv(), syswrite() or send() are called on handle with the
+C<:utf8> layer.
+
+In Perl 5.30, it will no longer be possible to use sysread(), recv(),
+syswrite() or send() to read or send bytes from/to :utf8 handles.
+
+
+=head3 Use of unassigned code point or non-standalone grapheme for a delimiter.
+
+A grapheme is what appears to a native-speaker of a language to be a
+character. In Unicode (and hence Perl) a grapheme may actually be
+several adjacent characters that together form a complete grapheme. For
+example, there can be a base character, like "R" and an accent, like a
+circumflex "^", that appear to be a single character when displayed,
+with the circumflex hovering over the "R".
+
+As of Perl 5.30, use of delimiters which are non-standalone graphemes is
+fatal, in order to move the language to be able to accept
+multi-character graphemes as delimiters.
+
+Also, as of Perl 5.30, delimiters which are unassigned code points
+but that may someday become assigned are prohibited. Otherwise, code
+that works today would fail to compile if the currently unassigned
+delimiter ends up being something that isn't a stand-alone grapheme.
+Because Unicode is never going to assign L<non-character code
+points|perlunicode/Noncharacter code points>, nor L<code points that are
+above the legal Unicode maximum|perlunicode/Beyond Unicode code
+points>, those can be delimiters.
+
=head2 Perl 5.28
-=head3 Attribute "%s" is deprecated, and will disappear in 5.28
+=head3 Attributes C<< :locked >> and C<< :unique >>
The attributes C<< :locked >> (on code references) and C<< :unique >>
(on array, hash and scalar references) have had no effect since
Perl 5.005 and Perl 5.8.8 respectively. Their use has been deprecated
since.
-These attributes will no longer be recognized in Perl 5.28, and will
-then result in a syntax error. Since the attributes do not do anything,
-removing them from your code fixes the deprecation warning; and removing
-them will not influence the behaviour of your code.
+As of Perl 5.28, these attributes are syntax errors. Since the
+attributes do not do anything, removing them from your code fixes
+the syntax error; and removing them will not influence the behaviour
+of your code.
=head3 Bare here-document terminators
Perl has allowed you to use a bare here-document terminator to have the
here-document end at the first empty line. This practise was deprecated
-in Perl 5.000, and this will be a fatal error in Perl 5.28.
+in Perl 5.000; as of Perl 5.28, using a bare here-document terminator
+throws a fatal error.
-You are encouraged to use the explictly quoted form if you wish to
+You are encouraged to use the explicitly quoted form if you wish to
use an empty line as the terminator of the here-document:
print <<"";
setting C<$/> to undef, with the exception that this warning would be
thrown.
-In Perl 5.28, this will throw a fatal error.
+As of Perl 5.28, setting C<$/> to a reference of a non-positive
+integer throws a fatal error.
You are recommended to change your code to set C<$/> to C<undef> explicitly
if you wish to slurp the file.
=head3 Limit on the value of Unicode code points.
-Unicode only allows code points up to 0x10FFFF, but Perl allows much
-larger ones. However, using code points exceeding the maximum value
-of an integer (C<IV_MAX>) may break the perl interpreter in some constructs,
-including causing it to hang in a few cases. The known problem areas
-are in C<tr///>, regular expression pattern matching using quantifiers,
-as quote delimiters in C<qI<X>...I<X>> (where I<X> is the C<chr()> of a large
-code point), and as the upper limits in loops.
+Unicode only allows code points up to 0x10FFFF, but Perl allows
+much larger ones. Up till Perl 5.28, it was allowed to use code
+points exceeding the maximum value of an integer (C<IV_MAX>).
+However, that did break the perl interpreter in some constructs,
+including causing it to hang in a few cases. The known problem
+areas were in C<tr///>, regular expression pattern matching using
+quantifiers, as quote delimiters in C<qI<X>...I<X>> (where I<X> is
+the C<chr()> of a large code point), and as the upper limits in
+loops.
-The use of out of range code points was deprecated in Perl 5.24, and
-it will be a fatal error in Perl 5.28.
+The use of out of range code points was deprecated in Perl 5.24; as of
+Perl 5.28 using a code point exceeding C<IV_MAX> throws a fatal error.
If your code is to run on various platforms, keep in mind that the upper
-limit depends on the platform. It is much larger on 64-bit word sizes
-than 32-bit ones.
+limit depends on the platform. It is much larger on 64-bit word sizes
+than 32-bit ones. For 32-bit integers, C<IV_MAX> equals C<0x7FFFFFFF>,
+for 64-bit integers, C<IV_MAX> equals C<0x7FFFFFFFFFFFFFFF>.
=head3 Use of comma-less variable list in formats.
-It's allowed to use a list of variables in a format, without
+It was allowed to use a list of variables in a format, without
separating them with commas. This usage has been deprecated
-for a long time, and it will be a fatal error in Perl 5.28.
-
-
+for a long time, and as of Perl 5.28, this throws a fatal error.
=head3 Use of C<\N{}>
Use of C<\N{}> with nothing between the braces was deprecated in
-Perl 5.24, and will throw a fatal error in Perl 5.28.
+Perl 5.24, and throws a fatal error as of Perl 5.28.
Since such a construct is equivalent to using an empty string,
you are recommended to remove such C<\N{}> constructs.
-
=head3 Using the same symbol to open a filehandle and a dirhandle
It used to be legal to use C<open()> to associate both a
Perl 5.10.
Using the same symbol to C<open()> a filehandle and a dirhandle
-will be a fatal error in Perl 5.28.
+throws a fatal error as of Perl 5.28.
You should be using two different symbols instead.
-
-
-=head3 Use of "goto" to jump into a construct.
-
-Use of C<goto> to jump from an outer scope into an inner scope was
-deprecated in Perl 5.12, and it will be a fatal error in Perl 5.28.
-
-This means, you should not write constructs like:
-
- $x = 1;
- while ($x) {
- $foo = 1;
- LABEL:
- $bar = 1;
- }
- goto LABEL;
-
-This will jump into the block belonging to C<while>. Not only has
-been this a cause of subtle bugs in the past, it's generally
-considered to lead to hard to understand programs.
-
-This means, soon it's not possible anymore to write
-L<Duff's device|https://www.lysator.liu.se/c/duffs-device.html> in pure Perl.
-But you never wanted to do this anyway.
-
-
=head3 ${^ENCODING} is no longer supported.
The special variable C<${^ENCODING}> was used to implement
than C<undef> was deprecated in Perl 5.22. Full deprecation
of the variable happened in Perl 5.25.3.
-Setting this variable will become a fatal error in Perl 5.28.
+Setting this variable to anything other than an undefined value
+throws a fatal error as of Perl 5.28.
=head3 C<< B::OP::terse >>
This method, which just calls C<< B::Concise::b_terse >>, has been
-deprecated, and will disappear in Perl 5.28. Please use
+deprecated, and disappeared in Perl 5.28. Please use
C<< B::Concise >> instead.
-=head3 Use of inherited AUTOLOAD for non-method %s() is deprecated
+=head3 Use of inherited AUTOLOAD for non-method %s::%s() is no longer allowed
-As an (ahem) accidental feature, C<AUTOLOAD> subroutines are looked
+As an (ahem) accidental feature, C<AUTOLOAD> subroutines were looked
up as methods (using the C<@ISA> hierarchy) even when the subroutines
to be autoloaded were called as plain functions (e.g. C<Foo::bar()>),
not as methods (e.g. C<< Foo->bar() >> or C<< $obj->bar() >>).
-This bug will be rectified in future by using method lookup only for
-methods' C<AUTOLOAD>s.
+This bug was deprecated in Perl 5.004, has been rectified in Perl 5.28
+
by using method lookup only for methods' C<AUTOLOAD>s.
The simple rule is: Inheritance will not work when autoloading
non-methods. The simple fix for old code is: In any module that used
you should remove AutoLoader from @ISA and change C<use AutoLoader;> to
C<use AutoLoader 'AUTOLOAD';>.
-This feature was deprecated in Perl 5.004, and will be fatal in Perl 5.28.
-
-
-=head3 Use of C<< \cI<X> >> to specify a printable character.
-In a double quoted context, Perl has the C<< \c >> construct to write
-control characters in a readable way. For instance, the tab character
-can be written as C<< \cI >> (I<< control-I >>), and the escape
-character can be written as C<< \c[ >>.
+=head3 Use of code points over 0xFF in string bitwise operators
-Due to implementation details, the C<< \c >> construct can be used
-to create regular, printable, characters as well. For instance,
-C<< \c >> maps a C<< , >> to C<< l >>; that is C<< \c, >> is an
-obscure way of writing C<< l >>. And not only that, it's also not
-portable between ASCII and EBCDIC platforms.
-
-Using the C<< \c >> construct with an argument which maps to a
-printable character was deprecated in Perl 5.14, and will be a fatal
-error in Perl 5.28. You're recommended to just write the intended
-character instead.
+The string bitwise operators, C<&>, C<|>, C<^>, and C<~>, treat
+their operands as strings of bytes. As such, values above 0xFF
+are nonsensical. Using such code points with these operators
+was deprecated in Perl 5.24, and is fatal as of Perl 5.28.
+=head3 In XS code, use of C<to_utf8_case()>
+This function has been removed as of Perl 5.28; instead convert to call
+the appropriate one of:
+L<C<toFOLD_utf8_safe>|perlapi/toFOLD_utf8_safe>.
+L<C<toLOWER_utf8_safe>|perlapi/toLOWER_utf8_safe>,
+L<C<toTITLE_utf8_safe>|perlapi/toTITLE_utf8_safe>,
+or
+L<C<toUPPER_utf8_safe>|perlapi/toUPPER_utf8_safe>.
=head2 Perl 5.26
Since Perl 5.18, the option C<< --libpods >> has been deprecated, and
using this option did not do anything other than producing a warning.
-The C<< --libpods >> option is no longer recognized in Perl 5.26.
+The C<< --libpods >> option is no longer recognized as of Perl 5.26.
=head3 The utilities C<< c2ph >> and C<< pstruct >>
These old, perl3-era utilities have been deprecated in favour of
-C<< h2xs >> for a long time. In Perl 5.26, they have been removed.
+C<< h2xs >> for a long time. As of Perl 5.26, they have been removed.
=head3 Trapping C<< $SIG {__DIE__} >> other than during program exit.
Perl never issued a deprecation warning for this; the deprecation
was by documentation policy only. But this deprecation has been
-lifted in Perl 5.26.
+lifted as of Perl 5.26.
+
+
+=head3 Malformed UTF-8 string in "%s"
+
+This message indicates a bug either in the Perl core or in XS
+code. Such code was trying to find out if a character, allegedly
+stored internally encoded as UTF-8, was of a given type, such as
+being punctuation or a digit. But the character was not encoded
+in legal UTF-8. The C<%s> is replaced by a string that can be used
+by knowledgeable people to determine what the type being checked
+against was.
+
+Passing malformed strings was deprecated in Perl 5.18, and
+became fatal in Perl 5.26.
=head2 Perl 5.24
applies to C<tied *$scalar> and C<untie *$scalar>.
-=head2 Perl 5.10
-
-=head3 $* is no longer supported
-
-C<$*> was once a magic variable. C<$*> enabled or disabled
-multi-line matching within a string. Deprecated since Perl 5.000,
-its special meaning was removed in Perl 5.10. Aftwards, an
-deprecation message was issued when using this variable; this message
-was discontinued in Perl 5.26.
-
-Instead of using C<$*> you should use the C</m> (and maybe C</s>) regexp
-modifiers. You can enable C</m> for a lexical scope (even a whole file)
-with C<use re '/m'>. (In older versions: when C<$*> was set to a true value
-then all regular expressions behaved as if they were written using C</m>.)
-
-Although you can use C<$*> as a normal variable, you are discouraged
-from doing so.
-
-=head3 $# is no longer supported
-
-C<$#> was once a magic variable. C<$#> could be used to format
-printed numbers. Deprecated since Perl 5.000,
-its special meaning was removed in Perl 5.10. Aftwards, an
-deprecation message was issued when using this variable; this message
-was discontinued in Perl 5.26.
-
-Instead of using C<$#>, you should be using C<(s)printf> to format
-your numbers.
-
-Although you can use C<$#> as a normal variable, you are discouraged
-from doing so.
-
-
=head1 SEE ALSO
L<warnings>, L<diagnostics>.
https://perl5.git.perl.org / perl5.git / blobdiff