3 use 5.008; # 5.8.x needed for autodie
7 use Tie::RefHash; # To cache subroutine refs
9 use constant PERL510 => ( $] >= 5.010 );
11 use constant LEXICAL_TAG => q{:lexical};
12 use constant VOID_TAG => q{:void};
13 use constant INSIST_TAG => q{!};
15 use constant ERROR_NOARGS => 'Cannot use lexical %s with no arguments';
16 use constant ERROR_VOID_LEX => VOID_TAG.' cannot be used with lexical scope';
17 use constant ERROR_LEX_FIRST => LEXICAL_TAG.' must be used as first argument';
18 use constant ERROR_NO_LEX => "no %s can only start with ".LEXICAL_TAG;
19 use constant ERROR_BADNAME => "Bad subroutine name for %s: %s";
20 use constant ERROR_NOTSUB => "%s is not a Perl subroutine";
21 use constant ERROR_NOT_BUILT => "%s is neither a builtin, nor a Perl subroutine";
22 use constant ERROR_NOHINTS => "No user hints defined for %s";
24 use constant ERROR_CANT_OVERRIDE => "Cannot make the non-overridable builtin %s fatal";
26 use constant ERROR_NO_IPC_SYS_SIMPLE => "IPC::System::Simple required for Fatalised/autodying system()";
28 use constant ERROR_IPC_SYS_SIMPLE_OLD => "IPC::System::Simple version %f required for Fatalised/autodying system(). We only have version %f";
30 use constant ERROR_AUTODIE_CONFLICT => q{"no autodie '%s'" is not allowed while "use Fatal '%s'" is in effect};
32 use constant ERROR_FATAL_CONFLICT => q{"use Fatal '%s'" is not allowed while "no autodie '%s'" is in effect};
34 use constant ERROR_58_HINTS => q{Non-subroutine %s hints for %s are not supported under Perl 5.8.x};
36 # Older versions of IPC::System::Simple don't support all the
39 use constant MIN_IPC_SYS_SIMPLE_VER => 0.12;
41 # All the Fatal/autodie modules share the same version number.
42 our $VERSION = '2.00';
46 # EWOULDBLOCK values for systems that don't supply their own.
47 # Even though this is defined with our, that's to help our
48 # test code. Please don't rely upon this variable existing in
55 # We have some tags that can be passed in for use with import.
56 # These are all assumed to be CORE::
59 ':io' => [qw(:dbm :file :filesys :ipc :socket
60 read seek sysread syswrite sysseek )],
61 ':dbm' => [qw(dbmopen dbmclose)],
62 ':file' => [qw(open close flock sysopen fcntl fileno binmode
64 ':filesys' => [qw(opendir closedir chdir link unlink rename mkdir
65 symlink rmdir readlink umask)],
66 ':ipc' => [qw(:msg :semaphore :shm pipe)],
67 ':msg' => [qw(msgctl msgget msgrcv msgsnd)],
68 ':threads' => [qw(fork)],
69 ':semaphore'=>[qw(semctl semget semop)],
70 ':shm' => [qw(shmctl shmget shmread)],
71 ':system' => [qw(system exec)],
73 # Can we use qw(getpeername getsockname)? What do they do on failure?
74 # TODO - Can socket return false?
75 ':socket' => [qw(accept bind connect getsockopt listen recv send
76 setsockopt shutdown socketpair)],
78 # Our defaults don't include system(), because it depends upon
79 # an optional module, and it breaks the exotic form.
81 # This *may* change in the future. I'd love IPC::System::Simple
82 # to be a dependency rather than a recommendation, and hence for
83 # system() to be autodying by default.
85 ':default' => [qw(:io :threads)],
87 # Version specific tags. These allow someone to specify
88 # use autodie qw(:1.994) and know exactly what they'll get.
90 ':1.994' => [qw(:default)],
91 ':1.995' => [qw(:default)],
92 ':1.996' => [qw(:default)],
93 ':1.997' => [qw(:default)],
94 ':1.998' => [qw(:default)],
95 ':1.999' => [qw(:default)],
96 ':1.999_01' => [qw(:default)],
97 ':2.00' => [qw(:default)],
101 $TAGS{':all'} = [ keys %TAGS ];
103 # This hash contains subroutines for which we should
104 # subroutine() // die() rather than subroutine() || die()
108 # CORE::open returns undef on failure. It can legitimately return
109 # 0 on success, eg: open(my $fh, '-|') || exec(...);
125 # Cached_fatalised_sub caches the various versions of our
126 # fatalised subs as they're produced. This means we don't
127 # have to build our own replacement of CORE::open and friends
128 # for every single package that wants to use them.
130 my %Cached_fatalised_sub = ();
132 # Every time we're called with package scope, we record the subroutine
133 # (including package or CORE::) in %Package_Fatal. This allows us
134 # to detect illegal combinations of autodie and Fatal, and makes sure
135 # we don't accidently make a Fatal function autodying (which isn't
138 my %Package_Fatal = ();
140 # The first time we're called with a user-sub, we cache it here.
141 # In the case of a "no autodie ..." we put back the cached copy.
143 my %Original_user_sub = ();
145 # Is_fatalised_sub simply records a big map of fatalised subroutine
146 # refs. It means we can avoid repeating work, or fatalising something
147 # we've already processed.
149 my %Is_fatalised_sub = ();
150 tie %Is_fatalised_sub, 'Tie::RefHash';
152 # We use our package in a few hash-keys. Having it in a scalar is
153 # convenient. The "guard $PACKAGE" string is used as a key when
154 # setting up lexical guards.
156 my $PACKAGE = __PACKAGE__;
157 my $PACKAGE_GUARD = "guard $PACKAGE";
158 my $NO_PACKAGE = "no $PACKAGE"; # Used to detect 'no autodie'
160 # Here's where all the magic happens when someone write 'use Fatal'
164 my $class = shift(@_);
167 my $insist_hints = 0;
169 my ($pkg, $filename) = caller();
171 @_ or return; # 'use Fatal' is a no-op.
173 # If we see the :lexical flag, then _all_ arguments are
176 if ($_[0] eq LEXICAL_TAG) {
180 # If we see no arguments and :lexical, we assume they
184 push(@_, ':default');
187 # Don't allow :lexical with :void, it's needlessly confusing.
188 if ( grep { $_ eq VOID_TAG } @_ ) {
189 croak(ERROR_VOID_LEX);
193 if ( grep { $_ eq LEXICAL_TAG } @_ ) {
194 # If we see the lexical tag as the non-first argument, complain.
195 croak(ERROR_LEX_FIRST);
198 my @fatalise_these = @_;
200 # Thiese subs will get unloaded at the end of lexical scope.
203 # This hash helps us track if we've alredy done work.
206 # NB: we're using while/shift rather than foreach, since
207 # we'll be modifying the array as we walk through it.
209 while (my $func = shift @fatalise_these) {
211 if ($func eq VOID_TAG) {
213 # When we see :void, set the void flag.
216 } elsif ($func eq INSIST_TAG) {
220 } elsif (exists $TAGS{$func}) {
222 # When it's a tag, expand it.
223 push(@fatalise_these, @{ $TAGS{$func} });
227 # Otherwise, fatalise it.
229 # Check to see if there's an insist flag at the front.
230 # If so, remove it, and insist we have hints for this sub.
233 if ($func =~ s/^!//) {
237 # TODO: Even if we've already fatalised, we should
238 # check we've done it with hints (if $insist_hints).
240 # If we've already made something fatal this call,
241 # then don't do it twice.
243 next if $done_this{$func};
245 # We're going to make a subroutine fatalistic.
246 # However if we're being invoked with 'use Fatal qw(x)'
247 # and we've already been called with 'no autodie qw(x)'
248 # in the same scope, we consider this to be an error.
249 # Mixing Fatal and autodie effects was considered to be
250 # needlessly confusing on p5p.
253 $sub = "${pkg}::$sub" unless $sub =~ /::/;
255 # If we're being called as Fatal, and we've previously
256 # had a 'no X' in scope for the subroutine, then complain
259 if (! $lexical and $^H{$NO_PACKAGE}{$sub}) {
260 croak(sprintf(ERROR_FATAL_CONFLICT, $func, $func));
263 # We're not being used in a confusing way, so make
264 # the sub fatal. Note that _make_fatal returns the
265 # old (original) version of the sub, or undef for
268 my $sub_ref = $class->_make_fatal(
269 $func, $pkg, $void, $lexical, $filename,
270 ( $insist_this || $insist_hints )
275 $Original_user_sub{$sub} ||= $sub_ref;
277 # If we're making lexical changes, we need to arrange
278 # for them to be cleaned at the end of our scope, so
281 $unload_later{$func} = $sub_ref if $lexical;
287 # Dark magic to have autodie work under 5.8
288 # Copied from namespace::clean, that copied it from
289 # autobox, that found it on an ancient scroll written
292 # This magic bit causes %^H to be lexically scoped.
296 # Our package guard gets invoked when we leave our lexical
299 push(@ { $^H{$PACKAGE_GUARD} }, autodie::Scope::Guard->new(sub {
300 $class->_install_subs($pkg, \%unload_later);
309 # The code here is originally lifted from namespace::clean,
310 # by Robert "phaylon" Sedlacek.
312 # It's been redesigned after feedback from ikegami on perlmonks.
313 # See http://perlmonks.org/?node_id=693338 . Ikegami rocks.
315 # Given a package, and hash of (subname => subref) pairs,
316 # we install the given subroutines into the package. If
317 # a subref is undef, the subroutine is removed. Otherwise
318 # it replaces any existing subs which were already there.
321 my ($class, $pkg, $subs_to_reinstate) = @_;
323 my $pkg_sym = "${pkg}::";
325 while(my ($sub_name, $sub_ref) = each %$subs_to_reinstate) {
327 my $full_path = $pkg_sym.$sub_name;
329 # Copy symbols across to temp area.
331 no strict 'refs'; ## no critic
333 local *__tmp = *{ $full_path };
336 { no strict; delete $pkg_sym->{$sub_name}; } ## no critic
338 # Copy innocent bystanders back. Note that we lose
339 # formats; it seems that Perl versions up to 5.10.0
340 # have a bug which causes copying formats to end up in
341 # the scalar slot. Thanks to Ben Morrow for spotting this.
343 foreach my $slot (qw( SCALAR ARRAY HASH IO ) ) {
344 next unless defined *__tmp{ $slot };
345 *{ $full_path } = *__tmp{ $slot };
348 # Put back the old sub (if there was one).
352 no strict; ## no critic
353 *{ $pkg_sym . $sub_name } = $sub_ref;
363 # Calling "no Fatal" must start with ":lexical"
364 if ($_[0] ne LEXICAL_TAG) {
365 croak(sprintf(ERROR_NO_LEX,$class));
368 shift @_; # Remove :lexical
370 my $pkg = (caller)[0];
372 # If we've been called with arguments, then the developer
373 # has explicitly stated 'no autodie qw(blah)',
374 # in which case, we disable Fatalistic behaviour for 'blah'.
376 my @unimport_these = @_ ? @_ : ':all';
378 while (my $symbol = shift @unimport_these) {
380 if ($symbol =~ /^:/) {
382 # Looks like a tag! Expand it!
383 push(@unimport_these, @{ $TAGS{$symbol} });
389 $sub = "${pkg}::$sub" unless $sub =~ /::/;
391 # If 'blah' was already enabled with Fatal (which has package
392 # scope) then, this is considered an error.
394 if (exists $Package_Fatal{$sub}) {
395 croak(sprintf(ERROR_AUTODIE_CONFLICT,$symbol,$symbol));
398 # Record 'no autodie qw($sub)' as being in effect.
399 # This is to catch conflicting semantics elsewhere
400 # (eg, mixing Fatal with no autodie)
402 $^H{$NO_PACKAGE}{$sub} = 1;
404 if (my $original_sub = $Original_user_sub{$sub}) {
405 # Hey, we've got an original one of these, put it back.
406 $class->_install_subs($pkg, { $symbol => $original_sub });
410 # We don't have an original copy of the sub, on the assumption
411 # it's core (or doesn't exist), we'll just nuke it.
413 $class->_install_subs($pkg,{ $symbol => undef });
421 # TODO - This is rather terribly inefficient right now.
423 # NB: Perl::Critic's dump-autodie-tag-contents depends upon this
424 # continuing to work.
430 my ($class, $tag) = @_;
432 if (my $cached = $tag_cache{$tag}) {
436 if (not exists $TAGS{$tag}) {
437 croak "Invalid exception class $tag";
440 my @to_process = @{$TAGS{$tag}};
444 while (my $item = shift @to_process) {
446 push(@to_process, @{$TAGS{$item}} );
448 push(@taglist, "CORE::$item");
452 $tag_cache{$tag} = \@taglist;
460 # This code is from the original Fatal. It scares me.
461 # It is 100% compatible with the 5.10.0 Fatal module, right down
462 # to the scary 'XXXX' comment. ;)
466 my ($n, $isref, @out, @out1, $seen_semi) = -1;
467 while ($proto =~ /\S/) {
469 push(@out1,[$n,@out]) if $seen_semi;
470 push(@out, $1 . "{\$_[$n]}"), next if $proto =~ s/^\s*\\([\@%\$\&])//;
471 push(@out, "\$_[$n]"), next if $proto =~ s/^\s*([_*\$&])//;
472 push(@out, "\@_[$n..\$#_]"), last if $proto =~ s/^\s*(;\s*)?\@//;
473 $seen_semi = 1, $n--, next if $proto =~ s/^\s*;//; # XXXX ????
474 die "Internal error: Unknown prototype letters: \"$proto\"";
476 push(@out1,[$n+1,@out]);
480 # This is a backwards compatible version of _write_invocation. It's
481 # recommended you don't use it.
483 sub write_invocation {
484 my ($core, $call, $name, $void, @args) = @_;
486 return Fatal->_write_invocation(
487 $core, $call, $name, $void,
489 undef, # Sub, unused in legacy mode
490 undef, # Subref, unused in legacy mode.
495 # This version of _write_invocation is used internally. It's not
496 # recommended you call it from external code, as the interface WILL
497 # change in the future.
499 sub _write_invocation {
501 my ($class, $core, $call, $name, $void, $lexical, $sub, $sref, @argvs) = @_;
503 if (@argvs == 1) { # No optional arguments
505 my @argv = @{$argvs[0]};
508 return $class->_one_invocation($core,$call,$name,$void,$sub,! $lexical, $sref, @argv);
512 my (@out, @argv, $n);
514 @argv = @{shift @argvs};
517 push @out, "${else}if (\@_ == $n) {\n";
520 push @out, $class->_one_invocation($core,$call,$name,$void,$sub,! $lexical, $sref, @argv);
524 die "Internal error: $name(\@_): Do not expect to get ", scalar(\@_), " arguments";
527 return join '', @out;
532 # This is a slim interface to ensure backward compatibility with
533 # anyone doing very foolish things with old versions of Fatal.
536 my ($core, $call, $name, $void, @argv) = @_;
538 return Fatal->_one_invocation(
539 $core, $call, $name, $void,
540 undef, # Sub. Unused in back-compat mode.
541 1, # Back-compat flag
542 undef, # Subref, unused in back-compat mode.
548 # This is the internal interface that generates code.
549 # NOTE: This interface WILL change in the future. Please do not
550 # call this subroutine directly.
552 # TODO: Whatever's calling this code has already looked up hints. Pass
553 # them in, rather than look them up a second time.
555 sub _one_invocation {
556 my ($class, $core, $call, $name, $void, $sub, $back_compat, $sref, @argv) = @_;
559 # If someone is calling us directly (a child class perhaps?) then
560 # they could try to mix void without enabling backwards
561 # compatibility. We just don't support this at all, so we gripe
562 # about it rather than doing something unwise.
564 if ($void and not $back_compat) {
565 Carp::confess("Internal error: :void mode not supported with $class");
568 # @argv only contains the results of the in-built prototype
569 # function, and is therefore safe to interpolate in the
570 # code generators below.
572 # TODO - The following clobbers context, but that's what the
573 # old Fatal did. Do we care?
577 # Use Fatal qw(system) will never be supported. It generated
578 # a compile-time error with legacy Fatal, and there's no reason
579 # to support it when autodie does a better job.
581 if ($call eq 'CORE::system') {
583 croak("UNIMPLEMENTED: use Fatal qw(system) not supported.");
590 return qq/return (defined wantarray)?$call(@argv):
591 $call(@argv) || croak "Can't $name(\@_)/ .
592 ($core ? ': $!' : ', \$! is \"$!\"') . '"'
594 return qq{return $call(@argv) || croak "Can't $name(\@_)} .
595 ($core ? ': $!' : ', \$! is \"$!\"') . '"';
599 # The name of our original function is:
600 # $call if the function is CORE
601 # $sub if our function is non-CORE
603 # The reason for this is that $call is what we're actualling
604 # calling. For our core functions, this is always
605 # CORE::something. However for user-defined subs, we're about to
606 # replace whatever it is that we're calling; as such, we actually
607 # calling a subroutine ref.
609 my $human_sub_name = $core ? $call : $sub;
611 # Should we be testing to see if our result is defined, or
616 my $hints; # All user-sub hints, including list hints.
620 # Core hints are built into autodie.
622 $use_defined_or = exists ( $Use_defined_or{$call} );
627 # User sub hints are looked up using autodie::hints,
628 # since users may wish to add their own hints.
630 require autodie::hints;
632 $hints = autodie::hints->get_hints_for( $sref );
635 # Checks for special core subs.
637 if ($call eq 'CORE::system') {
639 # Leverage IPC::System::Simple if we're making an autodying
644 # We need to stash $@ into $E, rather than using
645 # local $@ for the whole sub. If we don't then
646 # any exceptions from internal errors in autodie/Fatal
647 # will mysteriously disappear before propogating
659 \$retval = IPC::System::Simple::system(@argv);
667 # TODO - This can't be overridden in child
670 die autodie::exception::system->new(
671 function => q{CORE::system}, args => [ @argv ],
672 message => "\$E", errno => \$!,
683 # If we're going to throw an exception, here's the code to use.
686 function => q{$human_sub_name}, args => [ @argv ],
687 pragma => q{$class}, errno => \$!,
691 if ($call eq 'CORE::flock') {
693 # flock needs special treatment. When it fails with
694 # LOCK_UN and EWOULDBLOCK, then it's not really fatal, it just
695 # means we couldn't get the lock right now.
697 require POSIX; # For POSIX::EWOULDBLOCK
699 local $@; # Don't blat anyone else's $@.
701 # Ensure that our vendor supports EWOULDBLOCK. If they
702 # don't (eg, Windows), then we use known values for its
703 # equivalent on other systems.
705 my $EWOULDBLOCK = eval { POSIX::EWOULDBLOCK(); }
706 || $_EWOULDBLOCK{$^O}
707 || _autocroak("Internal error - can't overload flock - EWOULDBLOCK not defined on this system.");
709 require Fcntl; # For Fcntl::LOCK_NB
713 # Try to flock. If successful, return it immediately.
715 my \$retval = $call(@argv);
716 return \$retval if \$retval;
718 # If we failed, but we're using LOCK_NB and
719 # returned EWOULDBLOCK, it's not a real error.
721 if (\$_[1] & Fcntl::LOCK_NB() and \$! == $EWOULDBLOCK ) {
725 # Otherwise, we failed. Die noisily.
732 # AFAIK everything that can be given an unopned filehandle
733 # will fail if it tries to use it, so we don't really need
734 # the 'unopened' warning class here. Especially since they
735 # then report the wrong line number.
738 no warnings qw(unopened);
741 my \@results = $call(@argv);
745 if ( $hints and ( ref($hints->{list} ) || "" ) eq 'CODE' ) {
747 # NB: Subroutine hints are passed as a full list.
748 # This differs from the 5.10.0 smart-match behaviour,
749 # but means that context unaware subroutines can use
750 # the same hints in both list and scalar context.
753 if ( \$hints->{list}->(\@results) ) { $die };
756 elsif ( PERL510 and $hints ) {
758 if ( \@results ~~ \$hints->{list} ) { $die };
762 croak sprintf(ERROR_58_HINTS, 'list', $sub);
766 # An empty list, or a single undef is failure
767 if (! \@results or (\@results == 1 and ! defined \$results[0])) {
773 # Tidy up the end of our wantarray call.
781 # Otherwise, we're in scalar context.
782 # We're never in a void context, since we have to look
786 my \$result = $call(@argv);
789 if ( $hints and ( ref($hints->{scalar} ) || "" ) eq 'CODE' ) {
791 # We always call code refs directly, since that always
792 # works in 5.8.x, and always works in 5.10.1
795 if ( \$hints->{scalar}->(\$result) ) { $die };
800 elsif (PERL510 and $hints) {
803 if ( \$result ~~ \$hints->{scalar} ) { $die };
809 croak sprintf(ERROR_58_HINTS, 'scalar', $sub);
813 ( $use_defined_or ? qq{
815 $die if not defined \$result;
821 return \$result || $die;
827 # This returns the old copy of the sub, so we can
828 # put it back at end of scope.
830 # TODO : Check to make sure prototypes are restored correctly.
832 # TODO: Taking a huge list of arguments is awful. Rewriting to
833 # take a hash would be lovely.
835 # TODO - BACKCOMPAT - This is not yet compatible with 5.10.0
838 my($class, $sub, $pkg, $void, $lexical, $filename, $insist) = @_;
839 my($name, $code, $sref, $real_proto, $proto, $core, $call, $hints);
842 $sub = "${pkg}::$sub" unless $sub =~ /::/;
844 # Figure if we're using lexical or package semantics and
845 # twiddle the appropriate bits.
848 $Package_Fatal{$sub} = 1;
851 # TODO - We *should* be able to do skipping, since we know when
852 # we've lexicalised / unlexicalised a subroutine.
855 $name =~ s/.*::// or $name =~ s/^&//;
857 warn "# _make_fatal: sub=$sub pkg=$pkg name=$name void=$void\n" if $Debug;
858 croak(sprintf(ERROR_BADNAME, $class, $name)) unless $name =~ /^\w+$/;
860 if (defined(&$sub)) { # user subroutine
862 # NOTE: Previously we would localise $@ at this point, so
863 # the following calls to eval {} wouldn't interfere with anything
864 # that's already in $@. Unfortunately, it would also stop
865 # any of our croaks from triggering(!), which is even worse.
867 # This could be something that we've fatalised that
870 if ( $Package_Fatal{$sub} and do { local $@; eval { prototype "CORE::$name" } } ) {
872 # Something we previously made Fatal that was core.
873 # This is safe to replace with an autodying to core
877 $call = "CORE::$name";
878 $proto = prototype $call;
880 # We return our $sref from this subroutine later
881 # on, indicating this subroutine should be placed
882 # back when we're finished.
888 # If this is something we've already fatalised or played with,
889 # then look-up the name of the original sub for the rest of
892 $sub = $Is_fatalised_sub{\&$sub} || $sub;
894 # A regular user sub, or a user sub wrapping a
898 $proto = prototype $sref;
900 require autodie::hints;
902 $hints = autodie::hints->get_hints_for( $sref );
904 # If we've insisted on hints, but don't have them, then
907 if ($insist and not $hints) {
908 croak(sprintf(ERROR_NOHINTS, $name));
911 # Otherwise, use the default hints if we don't have
914 $hints ||= autodie::hints::DEFAULT_HINTS();
918 } elsif ($sub eq $ini && $sub !~ /^CORE::GLOBAL::/) {
919 # Stray user subroutine
920 croak(sprintf(ERROR_NOTSUB,$sub));
922 } elsif ($name eq 'system') {
924 # If we're fatalising system, then we need to load
927 # The business with $E is to avoid clobbering our caller's
928 # $@, and to avoid $@ being localised when we croak.
936 require IPC::System::Simple; # Only load it if we need it.
937 require autodie::exception::system;
942 if ($E) { croak ERROR_NO_IPC_SYS_SIMPLE; }
944 # Make sure we're using a recent version of ISS that actually
945 # support fatalised system.
946 if ($IPC::System::Simple::VERSION < MIN_IPC_SYS_SIMPLE_VER) {
948 ERROR_IPC_SYS_SIMPLE_OLD, MIN_IPC_SYS_SIMPLE_VER,
949 $IPC::System::Simple::VERSION
953 $call = 'CORE::system';
957 } elsif ($name eq 'exec') {
958 # Exec doesn't have a prototype. We don't care. This
959 # breaks the exotic form with lexical scope, and gives
960 # the regular form a "do or die" beaviour as expected.
962 $call = 'CORE::exec';
966 } else { # CORE subroutine
970 $proto = eval { prototype "CORE::$name" };
973 croak(sprintf(ERROR_NOT_BUILT,$name)) if $E;
974 croak(sprintf(ERROR_CANT_OVERRIDE,$name)) if not defined $proto;
976 $call = "CORE::$name";
979 if (defined $proto) {
980 $real_proto = " ($proto)";
986 my $true_name = $core ? $call : $sub;
988 # TODO: This caching works, but I don't like using $void and
989 # $lexical as keys. In particular, I suspect our code may end up
990 # wrapping already wrapped code when autodie and Fatal are used
993 # NB: We must use '$sub' (the name plus package) and not
994 # just '$name' (the short name) here. Failing to do so
995 # results code that's in the wrong package, and hence has
996 # access to the wrong package filehandles.
998 if (my $subref = $Cached_fatalised_sub{$class}{$sub}{$void}{$lexical}) {
999 $class->_install_subs($pkg, { $name => $subref });
1005 local(\$", \$!) = (', ', 0); # TODO - Why do we do this?
1008 # Don't have perl whine if exec fails, since we'll be handling
1009 # the exception now.
1010 $code .= "no warnings qw(exec);\n" if $call eq "CORE::exec";
1012 my @protos = fill_protos($proto);
1013 $code .= $class->_write_invocation($core, $call, $name, $void, $lexical, $sub, $sref, @protos);
1015 warn $code if $Debug;
1017 # I thought that changing package was a monumental waste of
1018 # time for CORE subs, since they'll always be the same. However
1019 # that's not the case, since they may refer to package-based
1020 # filehandles (eg, with open).
1022 # There is potential to more aggressively cache core subs
1023 # that we know will never want to interact with package variables
1027 no strict 'refs'; ## no critic # to avoid: Can't use string (...) as a symbol ref ...
1033 $code = eval("package $pkg; use Carp; $code"); ## no critic
1038 croak("Internal error in autodie/Fatal processing $true_name: $E");
1043 # Now we need to wrap our fatalised sub inside an itty bitty
1044 # closure, which can detect if we've leaked into another file.
1045 # Luckily, we only need to do this for lexical (autodie)
1046 # subs. Fatal subs can leak all they want, it's considered
1047 # a "feature" (or at least backwards compatible).
1049 # TODO: Cache our leak guards!
1051 # TODO: This is pretty hairy code. A lot more tests would
1052 # be really nice for this.
1063 # If we're inside a string eval, we can end up with a
1064 # whacky filename. The following code allows autodie
1065 # to propagate correctly into string evals.
1067 my \$caller_level = 0;
1069 while ( (caller \$caller_level)[1] =~ m{^\\(eval \\d+\\)\$} ) {
1073 # If we're called from the correct file, then use the
1075 goto &\$code if ((caller \$caller_level)[1] eq \$filename);
1077 # Oh bother, we've leaked into another file. Call the
1078 # original code. Note that \$sref may actually be a
1079 # reference to a Fatalised version of a core built-in.
1080 # That's okay, because Fatal *always* leaks between files.
1082 goto &\$sref if \$sref;
1086 # If we're here, it must have been a core subroutine called.
1087 # Warning: The following code may disturb some viewers.
1089 # TODO: It should be possible to combine this with
1090 # write_invocation().
1092 foreach my $proto (@protos) {
1093 local $" = ", "; # So @args is formatted correctly.
1094 my ($count, @args) = @$proto;
1096 if (\@_ == $count) {
1097 return $call(@args);
1102 $leak_guard .= qq< croak "Internal error in Fatal/autodie. Leak-guard failure"; } >;
1104 # warn "$leak_guard\n";
1110 $leak_guard = eval $leak_guard; ## no critic
1115 die "Internal error in $class: Leak-guard installation failure: $E" if $E;
1118 my $installed_sub = $leak_guard || $code;
1120 $class->_install_subs($pkg, { $name => $installed_sub });
1122 $Cached_fatalised_sub{$class}{$sub}{$void}{$lexical} = $installed_sub;
1124 # Cache that we've now overriddent this sub. If we get called
1125 # again, we may need to find that find subroutine again (eg, for hints).
1127 $Is_fatalised_sub{$installed_sub} = $sref;
1133 # This subroutine exists primarily so that child classes can override
1134 # it to point to their own exception class. Doing this is significantly
1135 # less complex than overriding throw()
1137 sub exception_class { return "autodie::exception" };
1140 my %exception_class_for;
1144 my ($class, @args) = @_;
1146 # Find our exception class if we need it.
1147 my $exception_class =
1148 $exception_class_for{$class} ||= $class->exception_class;
1150 if (not $class_loaded{$exception_class}) {
1151 if ($exception_class =~ /[^\w:']/) {
1152 confess "Bad exception class '$exception_class'.\nThe '$class->exception_class' method wants to use $exception_class\nfor exceptions, but it contains characters which are not word-characters or colons.";
1155 # Alas, Perl does turn barewords into modules unless they're
1156 # actually barewords. As such, we're left doing a string eval
1157 # to make sure we load our file correctly.
1162 local $@; # We can't clobber $@, it's wrong!
1163 eval "require $exception_class"; ## no critic
1164 $E = $@; # Save $E despite ending our local.
1167 # We need quotes around $@ to make sure it's stringified
1168 # while still in scope. Without them, we run the risk of
1169 # $@ having been cleared by us exiting the local() block.
1171 confess "Failed to load '$exception_class'.\nThis may be a typo in the '$class->exception_class' method,\nor the '$exception_class' module may not exist.\n\n $E" if $E;
1173 $class_loaded{$exception_class}++;
1177 return $exception_class->new(@args);
1181 # For some reason, dying while replacing our subs doesn't
1182 # kill our calling program. It simply stops the loading of
1183 # autodie and keeps going with everything else. The _autocroak
1184 # sub allows us to die with a vegence. It should *only* ever be
1185 # used for serious internal errors, since the results of it can't
1189 warn Carp::longmess(@_);
1193 package autodie::Scope::Guard;
1195 # This code schedules the cleanup of subroutines at the end of
1196 # scope. It's directly inspired by chocolateboy's excellent
1197 # Scope::Guard module.
1200 my ($class, $handler) = @_;
1202 return bless $handler, $class;
1217 Fatal - Replace functions with equivalents which succeed or die
1221 use Fatal qw(open close);
1223 open(my $fh, "<", $filename); # No need to check errors!
1225 use File::Copy qw(move);
1228 move($file1, $file2); # No need to check errors!
1230 sub juggle { . . . }
1231 Fatal->import('juggle');
1233 =head1 BEST PRACTICE
1235 B<Fatal has been obsoleted by the new L<autodie> pragma.> Please use
1236 L<autodie> in preference to C<Fatal>. L<autodie> supports lexical scoping,
1237 throws real exception objects, and provides much nicer error messages.
1239 The use of C<:void> with Fatal is discouraged.
1243 C<Fatal> provides a way to conveniently replace
1244 functions which normally return a false value when they fail with
1245 equivalents which raise exceptions if they are not successful. This
1246 lets you use these functions without having to test their return
1247 values explicitly on each call. Exceptions can be caught using
1248 C<eval{}>. See L<perlfunc> and L<perlvar> for details.
1250 The do-or-die equivalents are set up simply by calling Fatal's
1251 C<import> routine, passing it the names of the functions to be
1252 replaced. You may wrap both user-defined functions and overridable
1253 CORE operators (except C<exec>, C<system>, C<print>, or any other
1254 built-in that cannot be expressed via prototypes) in this way.
1256 If the symbol C<:void> appears in the import list, then functions
1257 named later in that import list raise an exception only when
1258 these are called in void context--that is, when their return
1259 values are ignored. For example
1261 use Fatal qw/:void open close/;
1263 # properly checked, so no exception raised on error
1264 if (not open(my $fh, '<', '/bogotic') {
1265 warn "Can't open /bogotic: $!";
1268 # not checked, so error raises an exception
1271 The use of C<:void> is discouraged, as it can result in exceptions
1272 not being thrown if you I<accidentally> call a method without
1273 void context. Use L<autodie> instead if you need to be able to
1274 disable autodying/Fatal behaviour for a small block of code.
1280 =item Bad subroutine name for Fatal: %s
1282 You've called C<Fatal> with an argument that doesn't look like
1283 a subroutine name, nor a switch that this version of Fatal
1286 =item %s is not a Perl subroutine
1288 You've asked C<Fatal> to try and replace a subroutine which does not
1289 exist, or has not yet been defined.
1291 =item %s is neither a builtin, nor a Perl subroutine
1293 You've asked C<Fatal> to replace a subroutine, but it's not a Perl
1294 built-in, and C<Fatal> couldn't find it as a regular subroutine.
1295 It either doesn't exist or has not yet been defined.
1297 =item Cannot make the non-overridable %s fatal
1299 You've tried to use C<Fatal> on a Perl built-in that can't be
1300 overridden, such as C<print> or C<system>, which means that
1301 C<Fatal> can't help you, although some other modules might.
1302 See the L</"SEE ALSO"> section of this documentation.
1304 =item Internal error: %s
1306 You've found a bug in C<Fatal>. Please report it using
1307 the C<perlbug> command.
1313 C<Fatal> clobbers the context in which a function is called and always
1314 makes it a scalar context, except when the C<:void> tag is used.
1315 This problem does not exist in L<autodie>.
1317 "Used only once" warnings can be generated when C<autodie> or C<Fatal>
1318 is used with package filehandles (eg, C<FILE>). It's strongly recommended
1319 you use scalar filehandles instead.
1323 Original module by Lionel Cons (CERN).
1325 Prototype updates by Ilya Zakharevich <ilya@math.ohio-state.edu>.
1327 L<autodie> support, bugfixes, extended diagnostics, C<system>
1328 support, and major overhauling by Paul Fenwick <pjf@perltraining.com.au>
1332 This module is free software, you may distribute it under the
1333 same terms as Perl itself.
1337 L<autodie> for a nicer way to use lexical Fatal.
1339 L<IPC::System::Simple> for a similar idea for calls to C<system()>