=item Did not produce a valid header
-See Server error.
+See L</500 Server error>.
=item %s did not return a true value
=item Document contains no data
-See Server error.
+See L</500 Server error>.
=item %s does not define %s::VERSION--version check failed
C3-consistent, and you have enabled the C3 MRO for this class. See the C3
documentation in L<mro> for more information.
+=item Indentation on line %d of here-doc doesn't match delimiter
+
+(F) You have an indented here-document where one or more of its lines
+have whitespace at the beginning that does not match the closing
+delimiter.
+
+For example, line 2 below is wrong because it does not have at least
+2 spaces, but lines 1 and 3 are fine because they have at least 2:
+
+ if ($something) {
+ print <<~EOF;
+ Line 1
+ Line 2 not
+ Line 3
+ EOF
+ }
+
+Note that tabs and spaces are compared strictly, meaning 1 tab will
+not match 8 spaces.
+
=item Infinite recursion in regex
(F) You used a pattern that references itself without consuming any input
=item Initialization of state variables in list context currently forbidden
-(F) Currently the implementation of "state" only permits the
-initialization of scalar variables in scalar context. Re-write
-C<state ($a) = 42> as C<state $a = 42> to change from list to scalar
-context. Constructions such as C<state (@a) = foo()> will be
-supported in a future perl release.
+(F) C<state> only permits initializing a single scalar variable, in scalar
+context. So C<state $a = 42> is allowed, but not C<state ($a) = 42>. To apply
+state semantics to a hash or array, store a hash or array reference in a
+scalar variable.
=item %%s[%s] in scalar context better written as $%s[%s]
=item %s() is deprecated on :utf8 handles
-(W deprecated) The sysread(), recv(), syswrite() and send() operators are
+(D deprecated) 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.
but didn't enable that feature first (C<use feature 'signatures'>),
so the signature was instead interpreted as a bad prototype.
-=item Malformed UTF-8 character (%s)
+=item Malformed UTF-8 character%s
-(S utf8)(F) Perl detected a string that didn't comply with UTF-8
-encoding rules, even though it had the UTF8 flag on.
+(S utf8)(F) Perl detected a string that should be UTF-8, but didn't
+comply with UTF-8 encoding rules, or represents a code point whose
+ordinal integer value doesn't fit into the word size of the current
+platform (overflows). Details as to the exact malformation are given in
+the variable, C<%s>, part of the message.
One possible cause is that you set the UTF8 flag yourself for data that
you thought to be in UTF-8 but it wasn't (it was for example legacy
=item Method %s not permitted
-See Server error.
+See L</500 Server error>.
=item Might be a runaway multi-line %s string starting on line %d
(S syntax) This is an educated guess made in conjunction with the message
"%s found where operator expected". Often the missing operator is a comma.
-=item Missing or undefined argument to require
+=item Missing or undefined argument to %s
-(F) You tried to call require with no argument or with an undefined
+(F) You tried to call require or do with no argument or with an undefined
value as an argument. Require expects either a package name or a
-file-specification as an argument. See L<perlfunc/require>.
+file-specification as an argument; do expects a filename. See
+L<perlfunc/require EXPR> and L<perlfunc/do EXPR>.
=item Missing right brace on \%c{} in regex; marked by S<<-- HERE> in m/%s/
for I/O (in anticipation of future reads and to imitate the behavior
with real files).
-=item Only one /x regex modifier is allowed
-
-=item Only one /x regex modifier is allowed in regex; marked by <-- HERE in m/%s/
-
-(F) You used the C</x> regular expression pattern modifier at least twice in a
-string of modifiers. This has been made illegal, in order to allow future
-extensions to the Perl language.
-
=item %s() on unopened %s
(W unopened) An I/O operation was attempted on a filehandle that was
(P) Failed an internal consistency check trying to compile a grep.
-=item panic: ck_split, type=%u
-
-(P) Failed an internal consistency check trying to compile a split.
-
=item panic: corrupt saved stack index %ld
(P) The savestack was requested to restore more localized values than
(P) The internal pp_match() routine was called with invalid operational
data.
-=item panic: pp_split, pm=%p, s=%p
-
-(P) Something terrible went wrong in setting up for the split.
-
=item panic: realloc, %s
(P) Something requested a negative number of bytes of realloc.
(F) Parsing code supplied by an extension violated the parser's API in
a detectable way.
-=item Passing malformed UTF-8 to "%s" is deprecated
-
-(D deprecated, utf8) 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. If C<utf8> warnings are enabled, a further message is raised,
-giving details of the malformation.
-
=item Pattern subroutine nesting without pos change exceeded limit in regex
(F) You used a pattern that uses too many nested subpattern calls without
=item Premature end of script headers
-See Server error.
+See L</500 Server error>.
=item printf() on closed filehandle %s
(F) An C<(?R)> or C<(?0)> sequence in a regular expression was missing the
final parenthesis.
-=item Server error (a.k.a. "500 Server error")
+=item Z<>500 Server error
(A) This is the error message generally seen in a browser window
when trying to run a CGI program (including SSI) over the web. The
=back
+=item Unescaped literal '%c' in regex; marked by <-- HERE in m/%s/
+
+(W regexp) (only under C<S<use re 'strict'>>)
+
+Within the scope of C<S<use re 'strict'>> in a regular expression
+pattern, you included an unescaped C<}> or C<]> which was interpreted
+literally. These two characters are sometimes metacharacters, and
+sometimes literals, depending on what precedes them in the
+pattern. This is unlike the similar C<)> which is always a
+metacharacter unless escaped.
+
+This action at a distance, perhaps a large distance, can lead to Perl
+silently misinterpreting what you meant, so when you specify that you
+want extra checking by C<S<use re 'strict'>>, this warning is generated.
+If you meant the character as a literal, simply confirm that to Perl by
+preceding the character with a backslash, or make it into a bracketed
+character class (like C<[}]>). If you meant it as closing a
+corresponding C<[> or C<{>, you'll need to look back through the pattern
+to find out why that isn't happening.
+
=item unexec of %s into %s failed!
(F) The unexec() routine failed for some reason. See your local FSF
it may skip items, or visit items more than once. Consider using
C<keys()> instead of C<each()>.
+=item Infinite recursion via empty pattern
+
+(F) You tried to use the empty pattern inside of a regex code block,
+for instance C</(?{ s!!! })/>, which resulted in re-executing
+the same pattern, which is an infinite loop which is broken by
+throwing an exception.
+
=item Use of := for an empty attribute list is not allowed
(F) The construction C<my $x := 42> used to parse as equivalent to
but will become a fatal error in a future version of perl. Untaint your
arguments. See L<perlsec>.
+=item Use of unassigned code point or non-standalone grapheme for a
+delimiter will be a fatal error starting in Perl v5.30
+
+(D deprecated)
+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 when displayed to be a single character with
+the circumflex hovering over the "R". Perl currently allows things like
+that circumflex to be delimiters of strings, patterns, I<etc>. When
+displayed, the circumflex would look like it belongs to the character
+just to the left of it. In order to move the language to be able to
+accept graphemes as delimiters, we have to deprecate the use of
+delimiters which aren't graphemes by themselves. Also, a delimiter must
+already be assigned (or known to be never going to be assigned) to try
+to future-proof code, for 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, and
+their use won't raise this warning.
+
=item Use of uninitialized value%s
(W uninitialized) An undefined value was used as if it were already
(F) Lookbehind is allowed only for subexpressions whose length is fixed and
known at compile time. For positive lookbehind, you can use the C<\K>
regex construct as a way to get the equivalent functionality. See
-L<perlre/(?<=pattern) \K>.
+L<(?<=pattern) and \K in perlre|perlre/\K>.
There are non-obvious Unicode rules under C</i> that can match variably,
but which you might not think could. For example, the substring C<"ss">
https://perl5.git.perl.org / perl5.git / blobdiff