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 = '2.03';
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)],
98 ':2.01' => [qw(:default)],
99 ':2.02' => [qw(:default)],
100 ':2.03' => [qw(:default)],
104 $TAGS{':all'} = [ keys %TAGS ];
106 # This hash contains subroutines for which we should
107 # subroutine() // die() rather than subroutine() || die()
111 # CORE::open returns undef on failure. It can legitimately return
112 # 0 on success, eg: open(my $fh, '-|') || exec(...);
128 # Cached_fatalised_sub caches the various versions of our
129 # fatalised subs as they're produced. This means we don't
130 # have to build our own replacement of CORE::open and friends
131 # for every single package that wants to use them.
133 my %Cached_fatalised_sub = ();
135 # Every time we're called with package scope, we record the subroutine
136 # (including package or CORE::) in %Package_Fatal. This allows us
137 # to detect illegal combinations of autodie and Fatal, and makes sure
138 # we don't accidently make a Fatal function autodying (which isn't
141 my %Package_Fatal = ();
143 # The first time we're called with a user-sub, we cache it here.
144 # In the case of a "no autodie ..." we put back the cached copy.
146 my %Original_user_sub = ();
148 # Is_fatalised_sub simply records a big map of fatalised subroutine
149 # refs. It means we can avoid repeating work, or fatalising something
150 # we've already processed.
152 my %Is_fatalised_sub = ();
153 tie %Is_fatalised_sub, 'Tie::RefHash';
155 # We use our package in a few hash-keys. Having it in a scalar is
156 # convenient. The "guard $PACKAGE" string is used as a key when
157 # setting up lexical guards.
159 my $PACKAGE = __PACKAGE__;
160 my $PACKAGE_GUARD = "guard $PACKAGE";
161 my $NO_PACKAGE = "no $PACKAGE"; # Used to detect 'no autodie'
163 # Here's where all the magic happens when someone write 'use Fatal'
167 my $class = shift(@_);
170 my $insist_hints = 0;
172 my ($pkg, $filename) = caller();
174 @_ or return; # 'use Fatal' is a no-op.
176 # If we see the :lexical flag, then _all_ arguments are
179 if ($_[0] eq LEXICAL_TAG) {
183 # If we see no arguments and :lexical, we assume they
187 push(@_, ':default');
190 # Don't allow :lexical with :void, it's needlessly confusing.
191 if ( grep { $_ eq VOID_TAG } @_ ) {
192 croak(ERROR_VOID_LEX);
196 if ( grep { $_ eq LEXICAL_TAG } @_ ) {
197 # If we see the lexical tag as the non-first argument, complain.
198 croak(ERROR_LEX_FIRST);
201 my @fatalise_these = @_;
203 # Thiese subs will get unloaded at the end of lexical scope.
206 # This hash helps us track if we've alredy done work.
209 # NB: we're using while/shift rather than foreach, since
210 # we'll be modifying the array as we walk through it.
212 while (my $func = shift @fatalise_these) {
214 if ($func eq VOID_TAG) {
216 # When we see :void, set the void flag.
219 } elsif ($func eq INSIST_TAG) {
223 } elsif (exists $TAGS{$func}) {
225 # When it's a tag, expand it.
226 push(@fatalise_these, @{ $TAGS{$func} });
230 # Otherwise, fatalise it.
232 # Check to see if there's an insist flag at the front.
233 # If so, remove it, and insist we have hints for this sub.
236 if ($func =~ s/^!//) {
240 # TODO: Even if we've already fatalised, we should
241 # check we've done it with hints (if $insist_hints).
243 # If we've already made something fatal this call,
244 # then don't do it twice.
246 next if $done_this{$func};
248 # We're going to make a subroutine fatalistic.
249 # However if we're being invoked with 'use Fatal qw(x)'
250 # and we've already been called with 'no autodie qw(x)'
251 # in the same scope, we consider this to be an error.
252 # Mixing Fatal and autodie effects was considered to be
253 # needlessly confusing on p5p.
256 $sub = "${pkg}::$sub" unless $sub =~ /::/;
258 # If we're being called as Fatal, and we've previously
259 # had a 'no X' in scope for the subroutine, then complain
262 if (! $lexical and $^H{$NO_PACKAGE}{$sub}) {
263 croak(sprintf(ERROR_FATAL_CONFLICT, $func, $func));
266 # We're not being used in a confusing way, so make
267 # the sub fatal. Note that _make_fatal returns the
268 # old (original) version of the sub, or undef for
271 my $sub_ref = $class->_make_fatal(
272 $func, $pkg, $void, $lexical, $filename,
273 ( $insist_this || $insist_hints )
278 $Original_user_sub{$sub} ||= $sub_ref;
280 # If we're making lexical changes, we need to arrange
281 # for them to be cleaned at the end of our scope, so
284 $unload_later{$func} = $sub_ref if $lexical;
290 # Dark magic to have autodie work under 5.8
291 # Copied from namespace::clean, that copied it from
292 # autobox, that found it on an ancient scroll written
295 # This magic bit causes %^H to be lexically scoped.
299 # Our package guard gets invoked when we leave our lexical
302 push(@ { $^H{$PACKAGE_GUARD} }, autodie::Scope::Guard->new(sub {
303 $class->_install_subs($pkg, \%unload_later);
312 # The code here is originally lifted from namespace::clean,
313 # by Robert "phaylon" Sedlacek.
315 # It's been redesigned after feedback from ikegami on perlmonks.
316 # See http://perlmonks.org/?node_id=693338 . Ikegami rocks.
318 # Given a package, and hash of (subname => subref) pairs,
319 # we install the given subroutines into the package. If
320 # a subref is undef, the subroutine is removed. Otherwise
321 # it replaces any existing subs which were already there.
324 my ($class, $pkg, $subs_to_reinstate) = @_;
326 my $pkg_sym = "${pkg}::";
328 while(my ($sub_name, $sub_ref) = each %$subs_to_reinstate) {
330 my $full_path = $pkg_sym.$sub_name;
332 # Copy symbols across to temp area.
334 no strict 'refs'; ## no critic
336 local *__tmp = *{ $full_path };
339 { no strict; delete $pkg_sym->{$sub_name}; } ## no critic
341 # Copy innocent bystanders back. Note that we lose
342 # formats; it seems that Perl versions up to 5.10.0
343 # have a bug which causes copying formats to end up in
344 # the scalar slot. Thanks to Ben Morrow for spotting this.
346 foreach my $slot (qw( SCALAR ARRAY HASH IO ) ) {
347 next unless defined *__tmp{ $slot };
348 *{ $full_path } = *__tmp{ $slot };
351 # Put back the old sub (if there was one).
355 no strict; ## no critic
356 *{ $pkg_sym . $sub_name } = $sub_ref;
366 # Calling "no Fatal" must start with ":lexical"
367 if ($_[0] ne LEXICAL_TAG) {
368 croak(sprintf(ERROR_NO_LEX,$class));
371 shift @_; # Remove :lexical
373 my $pkg = (caller)[0];
375 # If we've been called with arguments, then the developer
376 # has explicitly stated 'no autodie qw(blah)',
377 # in which case, we disable Fatalistic behaviour for 'blah'.
379 my @unimport_these = @_ ? @_ : ':all';
381 while (my $symbol = shift @unimport_these) {
383 if ($symbol =~ /^:/) {
385 # Looks like a tag! Expand it!
386 push(@unimport_these, @{ $TAGS{$symbol} });
392 $sub = "${pkg}::$sub" unless $sub =~ /::/;
394 # If 'blah' was already enabled with Fatal (which has package
395 # scope) then, this is considered an error.
397 if (exists $Package_Fatal{$sub}) {
398 croak(sprintf(ERROR_AUTODIE_CONFLICT,$symbol,$symbol));
401 # Record 'no autodie qw($sub)' as being in effect.
402 # This is to catch conflicting semantics elsewhere
403 # (eg, mixing Fatal with no autodie)
405 $^H{$NO_PACKAGE}{$sub} = 1;
407 if (my $original_sub = $Original_user_sub{$sub}) {
408 # Hey, we've got an original one of these, put it back.
409 $class->_install_subs($pkg, { $symbol => $original_sub });
413 # We don't have an original copy of the sub, on the assumption
414 # it's core (or doesn't exist), we'll just nuke it.
416 $class->_install_subs($pkg,{ $symbol => undef });
424 # TODO - This is rather terribly inefficient right now.
426 # NB: Perl::Critic's dump-autodie-tag-contents depends upon this
427 # continuing to work.
433 my ($class, $tag) = @_;
435 if (my $cached = $tag_cache{$tag}) {
439 if (not exists $TAGS{$tag}) {
440 croak "Invalid exception class $tag";
443 my @to_process = @{$TAGS{$tag}};
447 while (my $item = shift @to_process) {
449 push(@to_process, @{$TAGS{$item}} );
451 push(@taglist, "CORE::$item");
455 $tag_cache{$tag} = \@taglist;
463 # This code is from the original Fatal. It scares me.
464 # It is 100% compatible with the 5.10.0 Fatal module, right down
465 # to the scary 'XXXX' comment. ;)
469 my ($n, $isref, @out, @out1, $seen_semi) = -1;
470 while ($proto =~ /\S/) {
472 push(@out1,[$n,@out]) if $seen_semi;
473 push(@out, $1 . "{\$_[$n]}"), next if $proto =~ s/^\s*\\([\@%\$\&])//;
474 push(@out, "\$_[$n]"), next if $proto =~ s/^\s*([_*\$&])//;
475 push(@out, "\@_[$n..\$#_]"), last if $proto =~ s/^\s*(;\s*)?\@//;
476 $seen_semi = 1, $n--, next if $proto =~ s/^\s*;//; # XXXX ????
477 die "Internal error: Unknown prototype letters: \"$proto\"";
479 push(@out1,[$n+1,@out]);
483 # This is a backwards compatible version of _write_invocation. It's
484 # recommended you don't use it.
486 sub write_invocation {
487 my ($core, $call, $name, $void, @args) = @_;
489 return Fatal->_write_invocation(
490 $core, $call, $name, $void,
492 undef, # Sub, unused in legacy mode
493 undef, # Subref, unused in legacy mode.
498 # This version of _write_invocation is used internally. It's not
499 # recommended you call it from external code, as the interface WILL
500 # change in the future.
502 sub _write_invocation {
504 my ($class, $core, $call, $name, $void, $lexical, $sub, $sref, @argvs) = @_;
506 if (@argvs == 1) { # No optional arguments
508 my @argv = @{$argvs[0]};
511 return $class->_one_invocation($core,$call,$name,$void,$sub,! $lexical, $sref, @argv);
515 my (@out, @argv, $n);
517 @argv = @{shift @argvs};
520 push @out, "${else}if (\@_ == $n) {\n";
523 push @out, $class->_one_invocation($core,$call,$name,$void,$sub,! $lexical, $sref, @argv);
527 die "Internal error: $name(\@_): Do not expect to get ", scalar(\@_), " arguments";
530 return join '', @out;
535 # This is a slim interface to ensure backward compatibility with
536 # anyone doing very foolish things with old versions of Fatal.
539 my ($core, $call, $name, $void, @argv) = @_;
541 return Fatal->_one_invocation(
542 $core, $call, $name, $void,
543 undef, # Sub. Unused in back-compat mode.
544 1, # Back-compat flag
545 undef, # Subref, unused in back-compat mode.
551 # This is the internal interface that generates code.
552 # NOTE: This interface WILL change in the future. Please do not
553 # call this subroutine directly.
555 # TODO: Whatever's calling this code has already looked up hints. Pass
556 # them in, rather than look them up a second time.
558 sub _one_invocation {
559 my ($class, $core, $call, $name, $void, $sub, $back_compat, $sref, @argv) = @_;
562 # If someone is calling us directly (a child class perhaps?) then
563 # they could try to mix void without enabling backwards
564 # compatibility. We just don't support this at all, so we gripe
565 # about it rather than doing something unwise.
567 if ($void and not $back_compat) {
568 Carp::confess("Internal error: :void mode not supported with $class");
571 # @argv only contains the results of the in-built prototype
572 # function, and is therefore safe to interpolate in the
573 # code generators below.
575 # TODO - The following clobbers context, but that's what the
576 # old Fatal did. Do we care?
580 # Use Fatal qw(system) will never be supported. It generated
581 # a compile-time error with legacy Fatal, and there's no reason
582 # to support it when autodie does a better job.
584 if ($call eq 'CORE::system') {
586 croak("UNIMPLEMENTED: use Fatal qw(system) not supported.");
593 return qq/return (defined wantarray)?$call(@argv):
594 $call(@argv) || croak "Can't $name(\@_)/ .
595 ($core ? ': $!' : ', \$! is \"$!\"') . '"'
597 return qq{return $call(@argv) || croak "Can't $name(\@_)} .
598 ($core ? ': $!' : ', \$! is \"$!\"') . '"';
602 # The name of our original function is:
603 # $call if the function is CORE
604 # $sub if our function is non-CORE
606 # The reason for this is that $call is what we're actualling
607 # calling. For our core functions, this is always
608 # CORE::something. However for user-defined subs, we're about to
609 # replace whatever it is that we're calling; as such, we actually
610 # calling a subroutine ref.
612 my $human_sub_name = $core ? $call : $sub;
614 # Should we be testing to see if our result is defined, or
619 my $hints; # All user-sub hints, including list hints.
623 # Core hints are built into autodie.
625 $use_defined_or = exists ( $Use_defined_or{$call} );
630 # User sub hints are looked up using autodie::hints,
631 # since users may wish to add their own hints.
633 require autodie::hints;
635 $hints = autodie::hints->get_hints_for( $sref );
637 # We'll look up the sub's fullname. This means we
638 # get better reports of where it came from in our
639 # error messages, rather than what imported it.
641 $human_sub_name = autodie::hints->sub_fullname( $sref );
645 # Checks for special core subs.
647 if ($call eq 'CORE::system') {
649 # Leverage IPC::System::Simple if we're making an autodying
654 # We need to stash $@ into $E, rather than using
655 # local $@ for the whole sub. If we don't then
656 # any exceptions from internal errors in autodie/Fatal
657 # will mysteriously disappear before propogating
669 \$retval = IPC::System::Simple::system(@argv);
677 # TODO - This can't be overridden in child
680 die autodie::exception::system->new(
681 function => q{CORE::system}, args => [ @argv ],
682 message => "\$E", errno => \$!,
693 # If we're going to throw an exception, here's the code to use.
696 function => q{$human_sub_name}, args => [ @argv ],
697 pragma => q{$class}, errno => \$!,
698 context => \$context, return => \$retval,
702 if ($call eq 'CORE::flock') {
704 # flock needs special treatment. When it fails with
705 # LOCK_UN and EWOULDBLOCK, then it's not really fatal, it just
706 # means we couldn't get the lock right now.
708 require POSIX; # For POSIX::EWOULDBLOCK
710 local $@; # Don't blat anyone else's $@.
712 # Ensure that our vendor supports EWOULDBLOCK. If they
713 # don't (eg, Windows), then we use known values for its
714 # equivalent on other systems.
716 my $EWOULDBLOCK = eval { POSIX::EWOULDBLOCK(); }
717 || $_EWOULDBLOCK{$^O}
718 || _autocroak("Internal error - can't overload flock - EWOULDBLOCK not defined on this system.");
720 require Fcntl; # For Fcntl::LOCK_NB
724 my \$context = wantarray() ? "list" : "scalar";
726 # Try to flock. If successful, return it immediately.
728 my \$retval = $call(@argv);
729 return \$retval if \$retval;
731 # If we failed, but we're using LOCK_NB and
732 # returned EWOULDBLOCK, it's not a real error.
734 if (\$_[1] & Fcntl::LOCK_NB() and \$! == $EWOULDBLOCK ) {
738 # Otherwise, we failed. Die noisily.
745 # AFAIK everything that can be given an unopned filehandle
746 # will fail if it tries to use it, so we don't really need
747 # the 'unopened' warning class here. Especially since they
748 # then report the wrong line number.
750 # Other warnings are disabled because they produce excessive
751 # complaints from smart-match hints under 5.10.1.
754 no warnings qw(unopened uninitialized numeric);
757 my \@results = $call(@argv);
758 my \$retval = \\\@results;
759 my \$context = "list";
763 if ( $hints and ( ref($hints->{list} ) || "" ) eq 'CODE' ) {
765 # NB: Subroutine hints are passed as a full list.
766 # This differs from the 5.10.0 smart-match behaviour,
767 # but means that context unaware subroutines can use
768 # the same hints in both list and scalar context.
771 if ( \$hints->{list}->(\@results) ) { $die };
774 elsif ( PERL510 and $hints ) {
776 if ( \@results ~~ \$hints->{list} ) { $die };
780 croak sprintf(ERROR_58_HINTS, 'list', $sub);
784 # An empty list, or a single undef is failure
785 if (! \@results or (\@results == 1 and ! defined \$results[0])) {
791 # Tidy up the end of our wantarray call.
799 # Otherwise, we're in scalar context.
800 # We're never in a void context, since we have to look
804 my \$retval = $call(@argv);
805 my \$context = "scalar";
808 if ( $hints and ( ref($hints->{scalar} ) || "" ) eq 'CODE' ) {
810 # We always call code refs directly, since that always
811 # works in 5.8.x, and always works in 5.10.1
814 if ( \$hints->{scalar}->(\$retval) ) { $die };
819 elsif (PERL510 and $hints) {
822 if ( \$retval ~~ \$hints->{scalar} ) { $die };
828 croak sprintf(ERROR_58_HINTS, 'scalar', $sub);
832 ( $use_defined_or ? qq{
834 $die if not defined \$retval;
840 return \$retval || $die;
846 # This returns the old copy of the sub, so we can
847 # put it back at end of scope.
849 # TODO : Check to make sure prototypes are restored correctly.
851 # TODO: Taking a huge list of arguments is awful. Rewriting to
852 # take a hash would be lovely.
854 # TODO - BACKCOMPAT - This is not yet compatible with 5.10.0
857 my($class, $sub, $pkg, $void, $lexical, $filename, $insist) = @_;
858 my($name, $code, $sref, $real_proto, $proto, $core, $call, $hints);
861 $sub = "${pkg}::$sub" unless $sub =~ /::/;
863 # Figure if we're using lexical or package semantics and
864 # twiddle the appropriate bits.
867 $Package_Fatal{$sub} = 1;
870 # TODO - We *should* be able to do skipping, since we know when
871 # we've lexicalised / unlexicalised a subroutine.
874 $name =~ s/.*::// or $name =~ s/^&//;
876 warn "# _make_fatal: sub=$sub pkg=$pkg name=$name void=$void\n" if $Debug;
877 croak(sprintf(ERROR_BADNAME, $class, $name)) unless $name =~ /^\w+$/;
879 if (defined(&$sub)) { # user subroutine
881 # NOTE: Previously we would localise $@ at this point, so
882 # the following calls to eval {} wouldn't interfere with anything
883 # that's already in $@. Unfortunately, it would also stop
884 # any of our croaks from triggering(!), which is even worse.
886 # This could be something that we've fatalised that
889 if ( $Package_Fatal{$sub} and do { local $@; eval { prototype "CORE::$name" } } ) {
891 # Something we previously made Fatal that was core.
892 # This is safe to replace with an autodying to core
896 $call = "CORE::$name";
897 $proto = prototype $call;
899 # We return our $sref from this subroutine later
900 # on, indicating this subroutine should be placed
901 # back when we're finished.
907 # If this is something we've already fatalised or played with,
908 # then look-up the name of the original sub for the rest of
911 $sub = $Is_fatalised_sub{\&$sub} || $sub;
913 # A regular user sub, or a user sub wrapping a
917 $proto = prototype $sref;
919 require autodie::hints;
921 $hints = autodie::hints->get_hints_for( $sref );
923 # If we've insisted on hints, but don't have them, then
926 if ($insist and not $hints) {
927 croak(sprintf(ERROR_NOHINTS, $name));
930 # Otherwise, use the default hints if we don't have
933 $hints ||= autodie::hints::DEFAULT_HINTS();
937 } elsif ($sub eq $ini && $sub !~ /^CORE::GLOBAL::/) {
938 # Stray user subroutine
939 croak(sprintf(ERROR_NOTSUB,$sub));
941 } elsif ($name eq 'system') {
943 # If we're fatalising system, then we need to load
946 # The business with $E is to avoid clobbering our caller's
947 # $@, and to avoid $@ being localised when we croak.
955 require IPC::System::Simple; # Only load it if we need it.
956 require autodie::exception::system;
961 if ($E) { croak ERROR_NO_IPC_SYS_SIMPLE; }
963 # Make sure we're using a recent version of ISS that actually
964 # support fatalised system.
965 if ($IPC::System::Simple::VERSION < MIN_IPC_SYS_SIMPLE_VER) {
967 ERROR_IPC_SYS_SIMPLE_OLD, MIN_IPC_SYS_SIMPLE_VER,
968 $IPC::System::Simple::VERSION
972 $call = 'CORE::system';
976 } elsif ($name eq 'exec') {
977 # Exec doesn't have a prototype. We don't care. This
978 # breaks the exotic form with lexical scope, and gives
979 # the regular form a "do or die" beaviour as expected.
981 $call = 'CORE::exec';
985 } else { # CORE subroutine
989 $proto = eval { prototype "CORE::$name" };
992 croak(sprintf(ERROR_NOT_BUILT,$name)) if $E;
993 croak(sprintf(ERROR_CANT_OVERRIDE,$name)) if not defined $proto;
995 $call = "CORE::$name";
998 if (defined $proto) {
999 $real_proto = " ($proto)";
1005 my $true_name = $core ? $call : $sub;
1007 # TODO: This caching works, but I don't like using $void and
1008 # $lexical as keys. In particular, I suspect our code may end up
1009 # wrapping already wrapped code when autodie and Fatal are used
1012 # NB: We must use '$sub' (the name plus package) and not
1013 # just '$name' (the short name) here. Failing to do so
1014 # results code that's in the wrong package, and hence has
1015 # access to the wrong package filehandles.
1017 if (my $subref = $Cached_fatalised_sub{$class}{$sub}{$void}{$lexical}) {
1018 $class->_install_subs($pkg, { $name => $subref });
1024 local(\$", \$!) = (', ', 0); # TODO - Why do we do this?
1027 # Don't have perl whine if exec fails, since we'll be handling
1028 # the exception now.
1029 $code .= "no warnings qw(exec);\n" if $call eq "CORE::exec";
1031 my @protos = fill_protos($proto);
1032 $code .= $class->_write_invocation($core, $call, $name, $void, $lexical, $sub, $sref, @protos);
1034 warn $code if $Debug;
1036 # I thought that changing package was a monumental waste of
1037 # time for CORE subs, since they'll always be the same. However
1038 # that's not the case, since they may refer to package-based
1039 # filehandles (eg, with open).
1041 # There is potential to more aggressively cache core subs
1042 # that we know will never want to interact with package variables
1046 no strict 'refs'; ## no critic # to avoid: Can't use string (...) as a symbol ref ...
1052 $code = eval("package $pkg; use Carp; $code"); ## no critic
1057 croak("Internal error in autodie/Fatal processing $true_name: $E");
1062 # Now we need to wrap our fatalised sub inside an itty bitty
1063 # closure, which can detect if we've leaked into another file.
1064 # Luckily, we only need to do this for lexical (autodie)
1065 # subs. Fatal subs can leak all they want, it's considered
1066 # a "feature" (or at least backwards compatible).
1068 # TODO: Cache our leak guards!
1070 # TODO: This is pretty hairy code. A lot more tests would
1071 # be really nice for this.
1082 # If we're inside a string eval, we can end up with a
1083 # whacky filename. The following code allows autodie
1084 # to propagate correctly into string evals.
1086 my \$caller_level = 0;
1088 while ( (caller \$caller_level)[1] =~ m{^\\(eval \\d+\\)\$} ) {
1092 # If we're called from the correct file, then use the
1094 goto &\$code if ((caller \$caller_level)[1] eq \$filename);
1096 # Oh bother, we've leaked into another file. Call the
1097 # original code. Note that \$sref may actually be a
1098 # reference to a Fatalised version of a core built-in.
1099 # That's okay, because Fatal *always* leaks between files.
1101 goto &\$sref if \$sref;
1105 # If we're here, it must have been a core subroutine called.
1106 # Warning: The following code may disturb some viewers.
1108 # TODO: It should be possible to combine this with
1109 # write_invocation().
1111 foreach my $proto (@protos) {
1112 local $" = ", "; # So @args is formatted correctly.
1113 my ($count, @args) = @$proto;
1115 if (\@_ == $count) {
1116 return $call(@args);
1121 $leak_guard .= qq< croak "Internal error in Fatal/autodie. Leak-guard failure"; } >;
1123 # warn "$leak_guard\n";
1129 $leak_guard = eval $leak_guard; ## no critic
1134 die "Internal error in $class: Leak-guard installation failure: $E" if $E;
1137 my $installed_sub = $leak_guard || $code;
1139 $class->_install_subs($pkg, { $name => $installed_sub });
1141 $Cached_fatalised_sub{$class}{$sub}{$void}{$lexical} = $installed_sub;
1143 # Cache that we've now overriddent this sub. If we get called
1144 # again, we may need to find that find subroutine again (eg, for hints).
1146 $Is_fatalised_sub{$installed_sub} = $sref;
1152 # This subroutine exists primarily so that child classes can override
1153 # it to point to their own exception class. Doing this is significantly
1154 # less complex than overriding throw()
1156 sub exception_class { return "autodie::exception" };
1159 my %exception_class_for;
1163 my ($class, @args) = @_;
1165 # Find our exception class if we need it.
1166 my $exception_class =
1167 $exception_class_for{$class} ||= $class->exception_class;
1169 if (not $class_loaded{$exception_class}) {
1170 if ($exception_class =~ /[^\w:']/) {
1171 confess "Bad exception class '$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.";
1174 # Alas, Perl does turn barewords into modules unless they're
1175 # actually barewords. As such, we're left doing a string eval
1176 # to make sure we load our file correctly.
1181 local $@; # We can't clobber $@, it's wrong!
1182 eval "require $exception_class"; ## no critic
1183 $E = $@; # Save $E despite ending our local.
1186 # We need quotes around $@ to make sure it's stringified
1187 # while still in scope. Without them, we run the risk of
1188 # $@ having been cleared by us exiting the local() block.
1190 confess "Failed to load '$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;
1192 $class_loaded{$exception_class}++;
1196 return $exception_class->new(@args);
1200 # For some reason, dying while replacing our subs doesn't
1201 # kill our calling program. It simply stops the loading of
1202 # autodie and keeps going with everything else. The _autocroak
1203 # sub allows us to die with a vegence. It should *only* ever be
1204 # used for serious internal errors, since the results of it can't
1208 warn Carp::longmess(@_);
1212 package autodie::Scope::Guard;
1214 # This code schedules the cleanup of subroutines at the end of
1215 # scope. It's directly inspired by chocolateboy's excellent
1216 # Scope::Guard module.
1219 my ($class, $handler) = @_;
1221 return bless $handler, $class;
1236 Fatal - Replace functions with equivalents which succeed or die
1240 use Fatal qw(open close);
1242 open(my $fh, "<", $filename); # No need to check errors!
1244 use File::Copy qw(move);
1247 move($file1, $file2); # No need to check errors!
1249 sub juggle { . . . }
1250 Fatal->import('juggle');
1252 =head1 BEST PRACTICE
1254 B<Fatal has been obsoleted by the new L<autodie> pragma.> Please use
1255 L<autodie> in preference to C<Fatal>. L<autodie> supports lexical scoping,
1256 throws real exception objects, and provides much nicer error messages.
1258 The use of C<:void> with Fatal is discouraged.
1262 C<Fatal> provides a way to conveniently replace
1263 functions which normally return a false value when they fail with
1264 equivalents which raise exceptions if they are not successful. This
1265 lets you use these functions without having to test their return
1266 values explicitly on each call. Exceptions can be caught using
1267 C<eval{}>. See L<perlfunc> and L<perlvar> for details.
1269 The do-or-die equivalents are set up simply by calling Fatal's
1270 C<import> routine, passing it the names of the functions to be
1271 replaced. You may wrap both user-defined functions and overridable
1272 CORE operators (except C<exec>, C<system>, C<print>, or any other
1273 built-in that cannot be expressed via prototypes) in this way.
1275 If the symbol C<:void> appears in the import list, then functions
1276 named later in that import list raise an exception only when
1277 these are called in void context--that is, when their return
1278 values are ignored. For example
1280 use Fatal qw/:void open close/;
1282 # properly checked, so no exception raised on error
1283 if (not open(my $fh, '<', '/bogotic') {
1284 warn "Can't open /bogotic: $!";
1287 # not checked, so error raises an exception
1290 The use of C<:void> is discouraged, as it can result in exceptions
1291 not being thrown if you I<accidentally> call a method without
1292 void context. Use L<autodie> instead if you need to be able to
1293 disable autodying/Fatal behaviour for a small block of code.
1299 =item Bad subroutine name for Fatal: %s
1301 You've called C<Fatal> with an argument that doesn't look like
1302 a subroutine name, nor a switch that this version of Fatal
1305 =item %s is not a Perl subroutine
1307 You've asked C<Fatal> to try and replace a subroutine which does not
1308 exist, or has not yet been defined.
1310 =item %s is neither a builtin, nor a Perl subroutine
1312 You've asked C<Fatal> to replace a subroutine, but it's not a Perl
1313 built-in, and C<Fatal> couldn't find it as a regular subroutine.
1314 It either doesn't exist or has not yet been defined.
1316 =item Cannot make the non-overridable %s fatal
1318 You've tried to use C<Fatal> on a Perl built-in that can't be
1319 overridden, such as C<print> or C<system>, which means that
1320 C<Fatal> can't help you, although some other modules might.
1321 See the L</"SEE ALSO"> section of this documentation.
1323 =item Internal error: %s
1325 You've found a bug in C<Fatal>. Please report it using
1326 the C<perlbug> command.
1332 C<Fatal> clobbers the context in which a function is called and always
1333 makes it a scalar context, except when the C<:void> tag is used.
1334 This problem does not exist in L<autodie>.
1336 "Used only once" warnings can be generated when C<autodie> or C<Fatal>
1337 is used with package filehandles (eg, C<FILE>). It's strongly recommended
1338 you use scalar filehandles instead.
1342 Original module by Lionel Cons (CERN).
1344 Prototype updates by Ilya Zakharevich <ilya@math.ohio-state.edu>.
1346 L<autodie> support, bugfixes, extended diagnostics, C<system>
1347 support, and major overhauling by Paul Fenwick <pjf@perltraining.com.au>
1351 This module is free software, you may distribute it under the
1352 same terms as Perl itself.
1356 L<autodie> for a nicer way to use lexical Fatal.
1358 L<IPC::System::Simple> for a similar idea for calls to C<system()>