9 if(exists($::{"utf8::"}) && exists(*{$::{"utf8::"}}{HASH}->{"is_utf8"}) &&
10 defined(*{*{$::{"utf8::"}}{HASH}->{"is_utf8"}}{CODE})) {
11 *is_utf8 = \&{"utf8::is_utf8"};
19 if(exists($::{"utf8::"}) && exists(*{$::{"utf8::"}}{HASH}->{"downgrade"}) &&
20 defined(*{*{$::{"utf8::"}}{HASH}->{"downgrade"}}{CODE})) {
21 *downgrade = \&{"utf8::downgrade"};
27 our $VERSION = '1.25';
32 our $MaxArgLen = 64; # How much of each argument to print. 0 = all.
33 our $MaxArgNums = 8; # How many arguments to print. 0 = all.
36 our @ISA = ('Exporter');
37 our @EXPORT = qw(confess croak carp);
38 our @EXPORT_OK = qw(cluck verbose longmess shortmess);
39 our @EXPORT_FAIL = qw(verbose); # hook to enable verbose mode
41 # The members of %Internal are packages that are internal to perl.
42 # Carp will not report errors from within these packages if it
43 # can. The members of %CarpInternal are internal to Perl's warning
44 # system. Carp will not report errors from within these packages
45 # either, and will not report calls *to* these packages for carp and
46 # croak. They replace $CarpLevel, which is deprecated. The
47 # $Max(EvalLen|(Arg(Len|Nums)) variables are used to specify how the eval
48 # text and function arguments should be formatted when printed.
53 # disable these by default, so they can live w/o require Carp
54 $CarpInternal{Carp}++;
55 $CarpInternal{warnings}++;
56 $Internal{Exporter}++;
57 $Internal{'Exporter::Heavy'}++;
59 # if the caller specifies verbose usage ("perl -MCarp=verbose script.pl")
60 # then the following method will be called by the Exporter which knows
61 # to do this thanks to @EXPORT_FAIL, above. $_[1] will contain the word
64 sub export_fail { shift; $Verbose = shift if $_[0] eq 'verbose'; @_ }
68 return \&{"CORE::GLOBAL::caller"} if defined &{"CORE::GLOBAL::caller"};
73 # Icky backwards compatibility wrapper. :-(
75 # The story is that the original implementation hard-coded the
76 # number of call levels to go back, so calls to longmess were off
77 # by one. Other code began calling longmess and expecting this
78 # behaviour, so the replacement has to emulate that behaviour.
80 my $call_pack = $cgc ? $cgc->() : caller();
81 if ( $Internal{$call_pack} or $CarpInternal{$call_pack} ) {
82 return longmess_heavy(@_);
85 local $CarpLevel = $CarpLevel + 1;
86 return longmess_heavy(@_);
95 # Icky backwards compatibility wrapper. :-(
96 local @CARP_NOT = $cgc ? $cgc->() : caller();
100 sub croak { die shortmess @_ }
101 sub confess { die longmess @_ }
102 sub carp { warn shortmess @_ }
103 sub cluck { warn longmess @_ }
106 if("$]" >= 5.015002 || ("$]" >= 5.014002 && "$]" < 5.015) ||
107 ("$]" >= 5.012005 && "$]" < 5.013)) {
108 *CALLER_OVERRIDE_CHECK_OK = sub () { 1 };
110 *CALLER_OVERRIDE_CHECK_OK = sub () { 0 };
115 my $i = shift(@_) + 1;
119 # Some things override caller() but forget to implement the
120 # @DB::args part of it, which we need. We check for this by
121 # pre-populating @DB::args with a sentinel which no-one else
122 # has the address of, so that we can detect whether @DB::args
123 # has been properly populated. However, on earlier versions
124 # of perl this check tickles a bug in CORE::caller() which
125 # leaks memory. So we only check on fixed perls.
126 @DB::args = \$i if CALLER_OVERRIDE_CHECK_OK;
129 qw(pack file line sub has_args wantarray evaltext is_require) }
130 = $cgc ? $cgc->($i) : caller($i);
133 unless ( defined $call_info{pack} ) {
137 my $sub_name = Carp::get_subname( \%call_info );
138 if ( $call_info{has_args} ) {
140 if (CALLER_OVERRIDE_CHECK_OK && @DB::args == 1
141 && ref $DB::args[0] eq ref \$i
142 && $DB::args[0] == \$i ) {
143 @DB::args = (); # Don't let anyone see the address of $i
146 my $func = $cgc or return '';
149 ( $::{"B::"} || return '') # B stash
150 ->{svref_2object} || return '' # entry in stash
151 }{CODE} # coderef in entry
153 my $package = $gv->STASH->NAME;
154 my $subname = $gv->NAME;
155 return unless defined $package && defined $subname;
157 # returning CORE::GLOBAL::caller isn't useful for tracing the cause:
158 return if $package eq 'CORE::GLOBAL' && $subname eq 'caller';
159 " in &${package}::$subname";
162 = "** Incomplete caller override detected$where; \@DB::args were not set **";
165 @args = map { Carp::format_arg($_) } @DB::args;
167 if ( $MaxArgNums and @args > $MaxArgNums )
168 { # More than we want to show?
169 $#args = $MaxArgNums;
173 # Push the args onto the subroutine
174 $sub_name .= '(' . join( ', ', @args ) . ')';
176 $call_info{sub_name} = $sub_name;
177 return wantarray() ? %call_info : \%call_info;
180 # Transform an argument to a function into a string.
184 $arg = defined($overload::VERSION) ? overload::StrVal($arg) : "$arg";
186 if ( defined($arg) ) {
188 $arg = str_len_trim( $arg, $MaxArgLen );
191 # Downgrade, and use [0-9] rather than \d, to avoid loading
192 # Unicode tables, which would be liable to fail if we're
193 # processing a syntax error.
195 $arg = "'$arg'" unless $arg =~ /^-?[0-9.]+\z/;
201 # The following handling of "control chars" is direct from
202 # the original code - it is broken on Unicode though.
205 or $arg =~ s/([[:cntrl:]]|[[:^ascii:]])/sprintf("\\x{%x}",ord($1))/eg;
209 # Takes an inheritance cache and a package and returns
210 # an anon hash of known inheritances and anon array of
211 # inheritances which consequences have not been figured
216 $cache->{$pkg} ||= [ { $pkg => $pkg }, [ trusts_directly($pkg) ] ];
217 return @{ $cache->{$pkg} };
220 # Takes the info from caller() and figures out the name of
221 # the sub/require/eval
224 if ( defined( $info->{evaltext} ) ) {
225 my $eval = $info->{evaltext};
226 if ( $info->{is_require} ) {
227 return "require $eval";
230 $eval =~ s/([\\\'])/\\$1/g;
231 return "eval '" . str_len_trim( $eval, $MaxEvalLen ) . "'";
235 return ( $info->{sub} eq '(eval)' ) ? 'eval {...}' : $info->{sub};
238 # Figures out what call (from the point of view of the caller)
239 # the long error backtrace should start at.
242 my $lvl = $CarpLevel;
246 my $pkg = $cgc ? $cgc->($i) : caller($i);
247 unless ( defined($pkg) ) {
249 # This *shouldn't* happen.
252 $i = long_error_loc();
257 # OK, now I am irritated.
261 redo if $CarpInternal{$pkg};
262 redo unless 0 > --$lvl;
263 redo if $Internal{$pkg};
269 return @_ if ref( $_[0] ); # don't break references as exceptions
270 my $i = long_error_loc();
271 return ret_backtrace( $i, @_ );
274 # Returns a full stack backtrace starting from where it is
277 my ( $i, @error ) = @_;
279 my $err = join '', @error;
283 if ( defined &threads::tid ) {
284 my $tid = threads->tid;
285 $tid_msg = " thread $tid" if $tid;
288 my %i = caller_info($i);
289 $mess = "$err at $i{file} line $i{line}$tid_msg";
296 if($@ =~ /^Died at .*(, <.*?> line \d+).$/ ) {
302 while ( my %i = caller_info( ++$i ) ) {
303 $mess .= "\t$i{sub_name} called at $i{file} line $i{line}$tid_msg\n";
310 my ( $i, @error ) = @_;
311 my $err = join '', @error;
315 if ( defined &threads::tid ) {
316 my $tid = threads->tid;
317 $tid_msg = " thread $tid" if $tid;
320 my %i = caller_info($i);
321 return "$err at $i{file} line $i{line}$tid_msg\.\n";
324 sub short_error_loc {
325 # You have to create your (hash)ref out here, rather than defaulting it
326 # inside trusts *on a lexical*, as you want it to persist across calls.
327 # (You can default it on $_[2], but that gets messy)
330 my $lvl = $CarpLevel;
333 my $called = $cgc ? $cgc->($i) : caller($i);
335 my $caller = $cgc ? $cgc->($i) : caller($i);
337 return 0 unless defined($caller); # What happened?
338 redo if $Internal{$caller};
339 redo if $CarpInternal{$caller};
340 redo if $CarpInternal{$called};
341 redo if trusts( $called, $caller, $cache );
342 redo if trusts( $caller, $called, $cache );
343 redo unless 0 > --$lvl;
348 sub shortmess_heavy {
349 return longmess_heavy(@_) if $Verbose;
350 return @_ if ref( $_[0] ); # don't break references as exceptions
351 my $i = short_error_loc();
353 ret_summary( $i, @_ );
360 # If a string is too long, trims it with ...
363 my $max = shift || 0;
364 if ( 2 < $max and $max < length($str) ) {
365 substr( $str, $max - 3 ) = '...';
370 # Takes two packages and an optional cache. Says whether the
371 # first inherits from the second.
373 # Recursive versions of this have to work to avoid certain
374 # possible endless loops, and when following long chains of
375 # inheritance are less efficient.
380 my ( $known, $partial ) = get_status( $cache, $child );
382 # Figure out consequences until we have an answer
383 while ( @$partial and not exists $known->{$parent} ) {
384 my $anc = shift @$partial;
385 next if exists $known->{$anc};
387 my ( $anc_knows, $anc_partial ) = get_status( $cache, $anc );
388 my @found = keys %$anc_knows;
389 @$known{@found} = ();
390 push @$partial, @$anc_partial;
392 return exists $known->{$parent};
395 # Takes a package and gives a list of those trusted directly
396 sub trusts_directly {
400 return @{"$class\::CARP_NOT"}
401 ? @{"$class\::CARP_NOT"}
405 if(!defined($warnings::VERSION) || $warnings::VERSION < 1.03) {
406 # Very old versions of warnings.pm import from Carp. This can go
407 # wrong due to the circular dependency. If Carp is invoked before
408 # warnings, then Carp starts by loading warnings, then warnings
409 # tries to import from Carp, and gets nothing because Carp is in
410 # the process of loading and hasn't defined its import method yet.
411 # So we work around that by manually exporting to warnings here.
413 *{"warnings::$_"} = \&$_ foreach @EXPORT;
422 Carp - alternative warn and die for modules
428 # warn user (from perspective of caller)
429 carp "string trimmed to 80 chars";
431 # die of errors (from perspective of caller)
432 croak "We're outta here!";
434 # die of errors with stack backtrace
435 confess "not implemented";
437 # cluck not exported by default
439 cluck "This is how we got here!";
443 The Carp routines are useful in your own modules because
444 they act like die() or warn(), but with a message which is more
445 likely to be useful to a user of your module. In the case of
446 cluck, confess, and longmess that context is a summary of every
447 call in the call-stack. For a shorter message you can use C<carp>
448 or C<croak> which report the error as being from where your module
449 was called. There is no guarantee that that is where the error
450 was, but it is a good educated guess.
452 You can also alter the way the output and logic of C<Carp> works, by
453 changing some global variables in the C<Carp> namespace. See the
454 section on C<GLOBAL VARIABLES> below.
456 Here is a more complete description of how C<carp> and C<croak> work.
457 What they do is search the call-stack for a function call stack where
458 they have not been told that there shouldn't be an error. If every
459 call is marked safe, they give up and give a full stack backtrace
460 instead. In other words they presume that the first likely looking
461 potential suspect is guilty. Their rules for telling whether
462 a call shouldn't generate errors work as follows:
468 Any call from a package to itself is safe.
472 Packages claim that there won't be errors on calls to or from
473 packages explicitly marked as safe by inclusion in C<@CARP_NOT>, or
474 (if that array is empty) C<@ISA>. The ability to override what
475 @ISA says is new in 5.8.
479 The trust in item 2 is transitive. If A trusts B, and B
480 trusts C, then A trusts C. So if you do not override C<@ISA>
481 with C<@CARP_NOT>, then this trust relationship is identical to,
486 Any call from an internal Perl module is safe. (Nothing keeps
487 user modules from marking themselves as internal to Perl, but
488 this practice is discouraged.)
492 Any call to Perl's warning system (eg Carp itself) is safe.
493 (This rule is what keeps it from reporting the error at the
494 point where you call C<carp> or C<croak>.)
498 C<$Carp::CarpLevel> can be set to skip a fixed number of additional
499 call levels. Using this is not recommended because it is very
500 difficult to get it to behave correctly.
504 =head2 Forcing a Stack Trace
506 As a debugging aid, you can force Carp to treat a croak as a confess
507 and a carp as a cluck across I<all> modules. In other words, force a
508 detailed stack trace to be given. This can be very helpful when trying
509 to understand why, or from where, a warning or error is being generated.
511 This feature is enabled by 'importing' the non-existent symbol
512 'verbose'. You would typically enable it by saying
514 perl -MCarp=verbose script.pl
516 or by including the string C<-MCarp=verbose> in the PERL5OPT
517 environment variable.
519 Alternately, you can set the global variable C<$Carp::Verbose> to true.
520 See the C<GLOBAL VARIABLES> section below.
522 =head1 GLOBAL VARIABLES
524 =head2 $Carp::MaxEvalLen
526 This variable determines how many characters of a string-eval are to
527 be shown in the output. Use a value of C<0> to show all text.
531 =head2 $Carp::MaxArgLen
533 This variable determines how many characters of each argument to a
534 function to print. Use a value of C<0> to show the full length of the
539 =head2 $Carp::MaxArgNums
541 This variable determines how many arguments to each function to show.
542 Use a value of C<0> to show all arguments to a function call.
546 =head2 $Carp::Verbose
548 This variable makes C<carp> and C<croak> generate stack backtraces
549 just like C<cluck> and C<confess>. This is how C<use Carp 'verbose'>
550 is implemented internally.
556 This variable, I<in your package>, says which packages are I<not> to be
557 considered as the location of an error. The C<carp()> and C<cluck()>
558 functions will skip over callers when reporting where an error occurred.
560 NB: This variable must be in the package's symbol table, thus:
563 our @CARP_NOT; # file scope
564 use vars qw(@CARP_NOT); # package scope
565 @My::Package::CARP_NOT = ... ; # explicit package variable
568 sub xyz { ... @CARP_NOT = ... } # w/o declarations above
569 my @CARP_NOT; # even at top-level
573 package My::Carping::Package;
576 sub bar { .... or _error('Wrong input') }
578 # temporary control of where'ness, __PACKAGE__ is implicit
579 local @CARP_NOT = qw(My::Friendly::Caller);
583 This would make C<Carp> report the error as coming from a caller not
584 in C<My::Carping::Package>, nor from C<My::Friendly::Caller>.
586 Also read the L</DESCRIPTION> section above, about how C<Carp> decides
587 where the error is reported from.
589 Use C<@CARP_NOT>, instead of C<$Carp::CarpLevel>.
591 Overrides C<Carp>'s use of C<@ISA>.
593 =head2 %Carp::Internal
595 This says what packages are internal to Perl. C<Carp> will never
596 report an error as being from a line in a package that is internal to
599 $Carp::Internal{ (__PACKAGE__) }++;
601 sub foo { ... or confess("whatever") };
603 would give a full stack backtrace starting from the first caller
604 outside of __PACKAGE__. (Unless that package was also internal to
607 =head2 %Carp::CarpInternal
609 This says which packages are internal to Perl's warning system. For
610 generating a full stack backtrace this is the same as being internal
611 to Perl, the stack backtrace will not start inside packages that are
612 listed in C<%Carp::CarpInternal>. But it is slightly different for
613 the summary message generated by C<carp> or C<croak>. There errors
614 will not be reported on any lines that are calling packages in
615 C<%Carp::CarpInternal>.
617 For example C<Carp> itself is listed in C<%Carp::CarpInternal>.
618 Therefore the full stack backtrace from C<confess> will not start
619 inside of C<Carp>, and the short message from calling C<croak> is
620 not placed on the line where C<croak> was called.
622 =head2 $Carp::CarpLevel
624 This variable determines how many additional call frames are to be
625 skipped that would not otherwise be when reporting where an error
626 occurred on a call to one of C<Carp>'s functions. It is fairly easy
627 to count these call frames on calls that generate a full stack
628 backtrace. However it is much harder to do this accounting for calls
629 that generate a short message. Usually people skip too many call
630 frames. If they are lucky they skip enough that C<Carp> goes all of
631 the way through the call stack, realizes that something is wrong, and
632 then generates a full stack backtrace. If they are unlucky then the
633 error is reported from somewhere misleading very high in the call
636 Therefore it is best to avoid C<$Carp::CarpLevel>. Instead use
637 C<@CARP_NOT>, C<%Carp::Internal> and C<%Carp::CarpInternal>.
643 The Carp routines don't handle exception objects currently.
644 If called with a first argument that is a reference, they simply
645 call die() or warn(), as appropriate.
654 The Carp module first appeared in Larry Wall's perl 5.000 distribution.
655 Since then it has been modified by several of the perl 5 porters.
656 Andrew Main (Zefram) <zefram@fysh.org> divested Carp into an independent
661 Copyright (C) 1994-2012 Larry Wall
663 Copyright (C) 2011, 2012 Andrew Main (Zefram) <zefram@fysh.org>
667 This module is free software; you can redistribute it and/or modify it
668 under the same terms as Perl itself.