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 = '2.06';
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)],
101 ':2.04' => [qw(:default)],
102 ':2.05' => [qw(:default)],
103 ':2.06' => [qw(:default)],
106 $TAGS{':all'} = [ keys %TAGS ];
108 # This hash contains subroutines for which we should
109 # subroutine() // die() rather than subroutine() || die()
113 # CORE::open returns undef on failure. It can legitimately return
114 # 0 on success, eg: open(my $fh, '-|') || exec(...);
130 # Cached_fatalised_sub caches the various versions of our
131 # fatalised subs as they're produced. This means we don't
132 # have to build our own replacement of CORE::open and friends
133 # for every single package that wants to use them.
135 my %Cached_fatalised_sub = ();
137 # Every time we're called with package scope, we record the subroutine
138 # (including package or CORE::) in %Package_Fatal. This allows us
139 # to detect illegal combinations of autodie and Fatal, and makes sure
140 # we don't accidently make a Fatal function autodying (which isn't
143 my %Package_Fatal = ();
145 # The first time we're called with a user-sub, we cache it here.
146 # In the case of a "no autodie ..." we put back the cached copy.
148 my %Original_user_sub = ();
150 # Is_fatalised_sub simply records a big map of fatalised subroutine
151 # refs. It means we can avoid repeating work, or fatalising something
152 # we've already processed.
154 my %Is_fatalised_sub = ();
155 tie %Is_fatalised_sub, 'Tie::RefHash';
157 # We use our package in a few hash-keys. Having it in a scalar is
158 # convenient. The "guard $PACKAGE" string is used as a key when
159 # setting up lexical guards.
161 my $PACKAGE = __PACKAGE__;
162 my $PACKAGE_GUARD = "guard $PACKAGE";
163 my $NO_PACKAGE = "no $PACKAGE"; # Used to detect 'no autodie'
165 # Here's where all the magic happens when someone write 'use Fatal'
169 my $class = shift(@_);
172 my $insist_hints = 0;
174 my ($pkg, $filename) = caller();
176 @_ or return; # 'use Fatal' is a no-op.
178 # If we see the :lexical flag, then _all_ arguments are
181 if ($_[0] eq LEXICAL_TAG) {
185 # If we see no arguments and :lexical, we assume they
189 push(@_, ':default');
192 # Don't allow :lexical with :void, it's needlessly confusing.
193 if ( grep { $_ eq VOID_TAG } @_ ) {
194 croak(ERROR_VOID_LEX);
198 if ( grep { $_ eq LEXICAL_TAG } @_ ) {
199 # If we see the lexical tag as the non-first argument, complain.
200 croak(ERROR_LEX_FIRST);
203 my @fatalise_these = @_;
205 # Thiese subs will get unloaded at the end of lexical scope.
208 # This hash helps us track if we've alredy done work.
211 # NB: we're using while/shift rather than foreach, since
212 # we'll be modifying the array as we walk through it.
214 while (my $func = shift @fatalise_these) {
216 if ($func eq VOID_TAG) {
218 # When we see :void, set the void flag.
221 } elsif ($func eq INSIST_TAG) {
225 } elsif (exists $TAGS{$func}) {
227 # When it's a tag, expand it.
228 push(@fatalise_these, @{ $TAGS{$func} });
232 # Otherwise, fatalise it.
234 # Check to see if there's an insist flag at the front.
235 # If so, remove it, and insist we have hints for this sub.
238 if ($func =~ s/^!//) {
242 # TODO: Even if we've already fatalised, we should
243 # check we've done it with hints (if $insist_hints).
245 # If we've already made something fatal this call,
246 # then don't do it twice.
248 next if $done_this{$func};
250 # We're going to make a subroutine fatalistic.
251 # However if we're being invoked with 'use Fatal qw(x)'
252 # and we've already been called with 'no autodie qw(x)'
253 # in the same scope, we consider this to be an error.
254 # Mixing Fatal and autodie effects was considered to be
255 # needlessly confusing on p5p.
258 $sub = "${pkg}::$sub" unless $sub =~ /::/;
260 # If we're being called as Fatal, and we've previously
261 # had a 'no X' in scope for the subroutine, then complain
264 if (! $lexical and $^H{$NO_PACKAGE}{$sub}) {
265 croak(sprintf(ERROR_FATAL_CONFLICT, $func, $func));
268 # We're not being used in a confusing way, so make
269 # the sub fatal. Note that _make_fatal returns the
270 # old (original) version of the sub, or undef for
273 my $sub_ref = $class->_make_fatal(
274 $func, $pkg, $void, $lexical, $filename,
275 ( $insist_this || $insist_hints )
280 $Original_user_sub{$sub} ||= $sub_ref;
282 # If we're making lexical changes, we need to arrange
283 # for them to be cleaned at the end of our scope, so
286 $unload_later{$func} = $sub_ref if $lexical;
292 # Dark magic to have autodie work under 5.8
293 # Copied from namespace::clean, that copied it from
294 # autobox, that found it on an ancient scroll written
297 # This magic bit causes %^H to be lexically scoped.
301 # Our package guard gets invoked when we leave our lexical
304 push(@ { $^H{$PACKAGE_GUARD} }, autodie::Scope::Guard->new(sub {
305 $class->_install_subs($pkg, \%unload_later);
314 # The code here is originally lifted from namespace::clean,
315 # by Robert "phaylon" Sedlacek.
317 # It's been redesigned after feedback from ikegami on perlmonks.
318 # See http://perlmonks.org/?node_id=693338 . Ikegami rocks.
320 # Given a package, and hash of (subname => subref) pairs,
321 # we install the given subroutines into the package. If
322 # a subref is undef, the subroutine is removed. Otherwise
323 # it replaces any existing subs which were already there.
326 my ($class, $pkg, $subs_to_reinstate) = @_;
328 my $pkg_sym = "${pkg}::";
330 while(my ($sub_name, $sub_ref) = each %$subs_to_reinstate) {
332 my $full_path = $pkg_sym.$sub_name;
334 # Copy symbols across to temp area.
336 no strict 'refs'; ## no critic
338 local *__tmp = *{ $full_path };
341 { no strict; delete $pkg_sym->{$sub_name}; } ## no critic
343 # Copy innocent bystanders back. Note that we lose
344 # formats; it seems that Perl versions up to 5.10.0
345 # have a bug which causes copying formats to end up in
346 # the scalar slot. Thanks to Ben Morrow for spotting this.
348 foreach my $slot (qw( SCALAR ARRAY HASH IO ) ) {
349 next unless defined *__tmp{ $slot };
350 *{ $full_path } = *__tmp{ $slot };
353 # Put back the old sub (if there was one).
357 no strict; ## no critic
358 *{ $pkg_sym . $sub_name } = $sub_ref;
368 # Calling "no Fatal" must start with ":lexical"
369 if ($_[0] ne LEXICAL_TAG) {
370 croak(sprintf(ERROR_NO_LEX,$class));
373 shift @_; # Remove :lexical
375 my $pkg = (caller)[0];
377 # If we've been called with arguments, then the developer
378 # has explicitly stated 'no autodie qw(blah)',
379 # in which case, we disable Fatalistic behaviour for 'blah'.
381 my @unimport_these = @_ ? @_ : ':all';
383 while (my $symbol = shift @unimport_these) {
385 if ($symbol =~ /^:/) {
387 # Looks like a tag! Expand it!
388 push(@unimport_these, @{ $TAGS{$symbol} });
394 $sub = "${pkg}::$sub" unless $sub =~ /::/;
396 # If 'blah' was already enabled with Fatal (which has package
397 # scope) then, this is considered an error.
399 if (exists $Package_Fatal{$sub}) {
400 croak(sprintf(ERROR_AUTODIE_CONFLICT,$symbol,$symbol));
403 # Record 'no autodie qw($sub)' as being in effect.
404 # This is to catch conflicting semantics elsewhere
405 # (eg, mixing Fatal with no autodie)
407 $^H{$NO_PACKAGE}{$sub} = 1;
409 if (my $original_sub = $Original_user_sub{$sub}) {
410 # Hey, we've got an original one of these, put it back.
411 $class->_install_subs($pkg, { $symbol => $original_sub });
415 # We don't have an original copy of the sub, on the assumption
416 # it's core (or doesn't exist), we'll just nuke it.
418 $class->_install_subs($pkg,{ $symbol => undef });
426 # TODO - This is rather terribly inefficient right now.
428 # NB: Perl::Critic's dump-autodie-tag-contents depends upon this
429 # continuing to work.
435 my ($class, $tag) = @_;
437 if (my $cached = $tag_cache{$tag}) {
441 if (not exists $TAGS{$tag}) {
442 croak "Invalid exception class $tag";
445 my @to_process = @{$TAGS{$tag}};
449 while (my $item = shift @to_process) {
451 push(@to_process, @{$TAGS{$item}} );
453 push(@taglist, "CORE::$item");
457 $tag_cache{$tag} = \@taglist;
465 # This code is from the original Fatal. It scares me.
466 # It is 100% compatible with the 5.10.0 Fatal module, right down
467 # to the scary 'XXXX' comment. ;)
471 my ($n, $isref, @out, @out1, $seen_semi) = -1;
472 while ($proto =~ /\S/) {
474 push(@out1,[$n,@out]) if $seen_semi;
475 push(@out, $1 . "{\$_[$n]}"), next if $proto =~ s/^\s*\\([\@%\$\&])//;
476 push(@out, "\$_[$n]"), next if $proto =~ s/^\s*([_*\$&])//;
477 push(@out, "\@_[$n..\$#_]"), last if $proto =~ s/^\s*(;\s*)?\@//;
478 $seen_semi = 1, $n--, next if $proto =~ s/^\s*;//; # XXXX ????
479 die "Internal error: Unknown prototype letters: \"$proto\"";
481 push(@out1,[$n+1,@out]);
485 # This is a backwards compatible version of _write_invocation. It's
486 # recommended you don't use it.
488 sub write_invocation {
489 my ($core, $call, $name, $void, @args) = @_;
491 return Fatal->_write_invocation(
492 $core, $call, $name, $void,
494 undef, # Sub, unused in legacy mode
495 undef, # Subref, unused in legacy mode.
500 # This version of _write_invocation is used internally. It's not
501 # recommended you call it from external code, as the interface WILL
502 # change in the future.
504 sub _write_invocation {
506 my ($class, $core, $call, $name, $void, $lexical, $sub, $sref, @argvs) = @_;
508 if (@argvs == 1) { # No optional arguments
510 my @argv = @{$argvs[0]};
513 return $class->_one_invocation($core,$call,$name,$void,$sub,! $lexical, $sref, @argv);
517 my (@out, @argv, $n);
519 @argv = @{shift @argvs};
522 push @out, "${else}if (\@_ == $n) {\n";
525 push @out, $class->_one_invocation($core,$call,$name,$void,$sub,! $lexical, $sref, @argv);
529 die "Internal error: $name(\@_): Do not expect to get ", scalar(\@_), " arguments";
532 return join '', @out;
537 # This is a slim interface to ensure backward compatibility with
538 # anyone doing very foolish things with old versions of Fatal.
541 my ($core, $call, $name, $void, @argv) = @_;
543 return Fatal->_one_invocation(
544 $core, $call, $name, $void,
545 undef, # Sub. Unused in back-compat mode.
546 1, # Back-compat flag
547 undef, # Subref, unused in back-compat mode.
553 # This is the internal interface that generates code.
554 # NOTE: This interface WILL change in the future. Please do not
555 # call this subroutine directly.
557 # TODO: Whatever's calling this code has already looked up hints. Pass
558 # them in, rather than look them up a second time.
560 sub _one_invocation {
561 my ($class, $core, $call, $name, $void, $sub, $back_compat, $sref, @argv) = @_;
564 # If someone is calling us directly (a child class perhaps?) then
565 # they could try to mix void without enabling backwards
566 # compatibility. We just don't support this at all, so we gripe
567 # about it rather than doing something unwise.
569 if ($void and not $back_compat) {
570 Carp::confess("Internal error: :void mode not supported with $class");
573 # @argv only contains the results of the in-built prototype
574 # function, and is therefore safe to interpolate in the
575 # code generators below.
577 # TODO - The following clobbers context, but that's what the
578 # old Fatal did. Do we care?
582 # Use Fatal qw(system) will never be supported. It generated
583 # a compile-time error with legacy Fatal, and there's no reason
584 # to support it when autodie does a better job.
586 if ($call eq 'CORE::system') {
588 croak("UNIMPLEMENTED: use Fatal qw(system) not supported.");
595 return qq/return (defined wantarray)?$call(@argv):
596 $call(@argv) || croak "Can't $name(\@_)/ .
597 ($core ? ': $!' : ', \$! is \"$!\"') . '"'
599 return qq{return $call(@argv) || croak "Can't $name(\@_)} .
600 ($core ? ': $!' : ', \$! is \"$!\"') . '"';
604 # The name of our original function is:
605 # $call if the function is CORE
606 # $sub if our function is non-CORE
608 # The reason for this is that $call is what we're actualling
609 # calling. For our core functions, this is always
610 # CORE::something. However for user-defined subs, we're about to
611 # replace whatever it is that we're calling; as such, we actually
612 # calling a subroutine ref.
614 my $human_sub_name = $core ? $call : $sub;
616 # Should we be testing to see if our result is defined, or
621 my $hints; # All user-sub hints, including list hints.
625 # Core hints are built into autodie.
627 $use_defined_or = exists ( $Use_defined_or{$call} );
632 # User sub hints are looked up using autodie::hints,
633 # since users may wish to add their own hints.
635 require autodie::hints;
637 $hints = autodie::hints->get_hints_for( $sref );
639 # We'll look up the sub's fullname. This means we
640 # get better reports of where it came from in our
641 # error messages, rather than what imported it.
643 $human_sub_name = autodie::hints->sub_fullname( $sref );
647 # Checks for special core subs.
649 if ($call eq 'CORE::system') {
651 # Leverage IPC::System::Simple if we're making an autodying
656 # We need to stash $@ into $E, rather than using
657 # local $@ for the whole sub. If we don't then
658 # any exceptions from internal errors in autodie/Fatal
659 # will mysteriously disappear before propogating
671 \$retval = IPC::System::Simple::system(@argv);
679 # TODO - This can't be overridden in child
682 die autodie::exception::system->new(
683 function => q{CORE::system}, args => [ @argv ],
684 message => "\$E", errno => \$!,
695 # If we're going to throw an exception, here's the code to use.
698 function => q{$human_sub_name}, args => [ @argv ],
699 pragma => q{$class}, errno => \$!,
700 context => \$context, return => \$retval,
704 if ($call eq 'CORE::flock') {
706 # flock needs special treatment. When it fails with
707 # LOCK_UN and EWOULDBLOCK, then it's not really fatal, it just
708 # means we couldn't get the lock right now.
710 require POSIX; # For POSIX::EWOULDBLOCK
712 local $@; # Don't blat anyone else's $@.
714 # Ensure that our vendor supports EWOULDBLOCK. If they
715 # don't (eg, Windows), then we use known values for its
716 # equivalent on other systems.
718 my $EWOULDBLOCK = eval { POSIX::EWOULDBLOCK(); }
719 || $_EWOULDBLOCK{$^O}
720 || _autocroak("Internal error - can't overload flock - EWOULDBLOCK not defined on this system.");
722 require Fcntl; # For Fcntl::LOCK_NB
726 my \$context = wantarray() ? "list" : "scalar";
728 # Try to flock. If successful, return it immediately.
730 my \$retval = $call(@argv);
731 return \$retval if \$retval;
733 # If we failed, but we're using LOCK_NB and
734 # returned EWOULDBLOCK, it's not a real error.
736 if (\$_[1] & Fcntl::LOCK_NB() and \$! == $EWOULDBLOCK ) {
740 # Otherwise, we failed. Die noisily.
747 # AFAIK everything that can be given an unopned filehandle
748 # will fail if it tries to use it, so we don't really need
749 # the 'unopened' warning class here. Especially since they
750 # then report the wrong line number.
752 # Other warnings are disabled because they produce excessive
753 # complaints from smart-match hints under 5.10.1.
756 no warnings qw(unopened uninitialized numeric);
759 my \@results = $call(@argv);
760 my \$retval = \\\@results;
761 my \$context = "list";
765 if ( $hints and ( ref($hints->{list} ) || "" ) eq 'CODE' ) {
767 # NB: Subroutine hints are passed as a full list.
768 # This differs from the 5.10.0 smart-match behaviour,
769 # but means that context unaware subroutines can use
770 # the same hints in both list and scalar context.
773 if ( \$hints->{list}->(\@results) ) { $die };
776 elsif ( PERL510 and $hints ) {
778 if ( \@results ~~ \$hints->{list} ) { $die };
782 croak sprintf(ERROR_58_HINTS, 'list', $sub);
786 # An empty list, or a single undef is failure
787 if (! \@results or (\@results == 1 and ! defined \$results[0])) {
793 # Tidy up the end of our wantarray call.
801 # Otherwise, we're in scalar context.
802 # We're never in a void context, since we have to look
806 my \$retval = $call(@argv);
807 my \$context = "scalar";
810 if ( $hints and ( ref($hints->{scalar} ) || "" ) eq 'CODE' ) {
812 # We always call code refs directly, since that always
813 # works in 5.8.x, and always works in 5.10.1
816 if ( \$hints->{scalar}->(\$retval) ) { $die };
821 elsif (PERL510 and $hints) {
824 if ( \$retval ~~ \$hints->{scalar} ) { $die };
830 croak sprintf(ERROR_58_HINTS, 'scalar', $sub);
834 ( $use_defined_or ? qq{
836 $die if not defined \$retval;
842 return \$retval || $die;
848 # This returns the old copy of the sub, so we can
849 # put it back at end of scope.
851 # TODO : Check to make sure prototypes are restored correctly.
853 # TODO: Taking a huge list of arguments is awful. Rewriting to
854 # take a hash would be lovely.
856 # TODO - BACKCOMPAT - This is not yet compatible with 5.10.0
859 my($class, $sub, $pkg, $void, $lexical, $filename, $insist) = @_;
860 my($name, $code, $sref, $real_proto, $proto, $core, $call, $hints);
863 $sub = "${pkg}::$sub" unless $sub =~ /::/;
865 # Figure if we're using lexical or package semantics and
866 # twiddle the appropriate bits.
869 $Package_Fatal{$sub} = 1;
872 # TODO - We *should* be able to do skipping, since we know when
873 # we've lexicalised / unlexicalised a subroutine.
876 $name =~ s/.*::// or $name =~ s/^&//;
878 warn "# _make_fatal: sub=$sub pkg=$pkg name=$name void=$void\n" if $Debug;
879 croak(sprintf(ERROR_BADNAME, $class, $name)) unless $name =~ /^\w+$/;
881 if (defined(&$sub)) { # user subroutine
883 # NOTE: Previously we would localise $@ at this point, so
884 # the following calls to eval {} wouldn't interfere with anything
885 # that's already in $@. Unfortunately, it would also stop
886 # any of our croaks from triggering(!), which is even worse.
888 # This could be something that we've fatalised that
891 if ( $Package_Fatal{$sub} and do { local $@; eval { prototype "CORE::$name" } } ) {
893 # Something we previously made Fatal that was core.
894 # This is safe to replace with an autodying to core
898 $call = "CORE::$name";
899 $proto = prototype $call;
901 # We return our $sref from this subroutine later
902 # on, indicating this subroutine should be placed
903 # back when we're finished.
909 # If this is something we've already fatalised or played with,
910 # then look-up the name of the original sub for the rest of
913 $sub = $Is_fatalised_sub{\&$sub} || $sub;
915 # A regular user sub, or a user sub wrapping a
919 $proto = prototype $sref;
921 require autodie::hints;
923 $hints = autodie::hints->get_hints_for( $sref );
925 # If we've insisted on hints, but don't have them, then
928 if ($insist and not $hints) {
929 croak(sprintf(ERROR_NOHINTS, $name));
932 # Otherwise, use the default hints if we don't have
935 $hints ||= autodie::hints::DEFAULT_HINTS();
939 } elsif ($sub eq $ini && $sub !~ /^CORE::GLOBAL::/) {
940 # Stray user subroutine
941 croak(sprintf(ERROR_NOTSUB,$sub));
943 } elsif ($name eq 'system') {
945 # If we're fatalising system, then we need to load
948 # The business with $E is to avoid clobbering our caller's
949 # $@, and to avoid $@ being localised when we croak.
957 require IPC::System::Simple; # Only load it if we need it.
958 require autodie::exception::system;
963 if ($E) { croak ERROR_NO_IPC_SYS_SIMPLE; }
965 # Make sure we're using a recent version of ISS that actually
966 # support fatalised system.
967 if ($IPC::System::Simple::VERSION < MIN_IPC_SYS_SIMPLE_VER) {
969 ERROR_IPC_SYS_SIMPLE_OLD, MIN_IPC_SYS_SIMPLE_VER,
970 $IPC::System::Simple::VERSION
974 $call = 'CORE::system';
978 } elsif ($name eq 'exec') {
979 # Exec doesn't have a prototype. We don't care. This
980 # breaks the exotic form with lexical scope, and gives
981 # the regular form a "do or die" beaviour as expected.
983 $call = 'CORE::exec';
987 } else { # CORE subroutine
991 $proto = eval { prototype "CORE::$name" };
994 croak(sprintf(ERROR_NOT_BUILT,$name)) if $E;
995 croak(sprintf(ERROR_CANT_OVERRIDE,$name)) if not defined $proto;
997 $call = "CORE::$name";
1000 if (defined $proto) {
1001 $real_proto = " ($proto)";
1007 my $true_name = $core ? $call : $sub;
1009 # TODO: This caching works, but I don't like using $void and
1010 # $lexical as keys. In particular, I suspect our code may end up
1011 # wrapping already wrapped code when autodie and Fatal are used
1014 # NB: We must use '$sub' (the name plus package) and not
1015 # just '$name' (the short name) here. Failing to do so
1016 # results code that's in the wrong package, and hence has
1017 # access to the wrong package filehandles.
1019 if (my $subref = $Cached_fatalised_sub{$class}{$sub}{$void}{$lexical}) {
1020 $class->_install_subs($pkg, { $name => $subref });
1026 local(\$", \$!) = (', ', 0); # TODO - Why do we do this?
1029 # Don't have perl whine if exec fails, since we'll be handling
1030 # the exception now.
1031 $code .= "no warnings qw(exec);\n" if $call eq "CORE::exec";
1033 my @protos = fill_protos($proto);
1034 $code .= $class->_write_invocation($core, $call, $name, $void, $lexical, $sub, $sref, @protos);
1036 warn $code if $Debug;
1038 # I thought that changing package was a monumental waste of
1039 # time for CORE subs, since they'll always be the same. However
1040 # that's not the case, since they may refer to package-based
1041 # filehandles (eg, with open).
1043 # There is potential to more aggressively cache core subs
1044 # that we know will never want to interact with package variables
1048 no strict 'refs'; ## no critic # to avoid: Can't use string (...) as a symbol ref ...
1054 $code = eval("package $pkg; use Carp; $code"); ## no critic
1059 croak("Internal error in autodie/Fatal processing $true_name: $E");
1064 # Now we need to wrap our fatalised sub inside an itty bitty
1065 # closure, which can detect if we've leaked into another file.
1066 # Luckily, we only need to do this for lexical (autodie)
1067 # subs. Fatal subs can leak all they want, it's considered
1068 # a "feature" (or at least backwards compatible).
1070 # TODO: Cache our leak guards!
1072 # TODO: This is pretty hairy code. A lot more tests would
1073 # be really nice for this.
1084 # If we're inside a string eval, we can end up with a
1085 # whacky filename. The following code allows autodie
1086 # to propagate correctly into string evals.
1088 my \$caller_level = 0;
1092 while ( (\$caller = (caller \$caller_level)[1]) =~ m{^\\(eval \\d+\\)\$} ) {
1094 # If our filename is actually an eval, and we
1095 # reach it, then go to our autodying code immediatately.
1097 goto &\$code if (\$caller eq \$filename);
1101 # We're now out of the eval stack.
1103 # If we're called from the correct file, then use the
1105 goto &\$code if ((caller \$caller_level)[1] eq \$filename);
1107 # Oh bother, we've leaked into another file. Call the
1108 # original code. Note that \$sref may actually be a
1109 # reference to a Fatalised version of a core built-in.
1110 # That's okay, because Fatal *always* leaks between files.
1112 goto &\$sref if \$sref;
1116 # If we're here, it must have been a core subroutine called.
1117 # Warning: The following code may disturb some viewers.
1119 # TODO: It should be possible to combine this with
1120 # write_invocation().
1122 foreach my $proto (@protos) {
1123 local $" = ", "; # So @args is formatted correctly.
1124 my ($count, @args) = @$proto;
1126 if (\@_ == $count) {
1127 return $call(@args);
1132 $leak_guard .= qq< croak "Internal error in Fatal/autodie. Leak-guard failure"; } >;
1134 # warn "$leak_guard\n";
1140 $leak_guard = eval $leak_guard; ## no critic
1145 die "Internal error in $class: Leak-guard installation failure: $E" if $E;
1148 my $installed_sub = $leak_guard || $code;
1150 $class->_install_subs($pkg, { $name => $installed_sub });
1152 $Cached_fatalised_sub{$class}{$sub}{$void}{$lexical} = $installed_sub;
1154 # Cache that we've now overriddent this sub. If we get called
1155 # again, we may need to find that find subroutine again (eg, for hints).
1157 $Is_fatalised_sub{$installed_sub} = $sref;
1163 # This subroutine exists primarily so that child classes can override
1164 # it to point to their own exception class. Doing this is significantly
1165 # less complex than overriding throw()
1167 sub exception_class { return "autodie::exception" };
1170 my %exception_class_for;
1174 my ($class, @args) = @_;
1176 # Find our exception class if we need it.
1177 my $exception_class =
1178 $exception_class_for{$class} ||= $class->exception_class;
1180 if (not $class_loaded{$exception_class}) {
1181 if ($exception_class =~ /[^\w:']/) {
1182 confess "Bad exception class '$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.";
1185 # Alas, Perl does turn barewords into modules unless they're
1186 # actually barewords. As such, we're left doing a string eval
1187 # to make sure we load our file correctly.
1192 local $@; # We can't clobber $@, it's wrong!
1193 eval "require $exception_class"; ## no critic
1194 $E = $@; # Save $E despite ending our local.
1197 # We need quotes around $@ to make sure it's stringified
1198 # while still in scope. Without them, we run the risk of
1199 # $@ having been cleared by us exiting the local() block.
1201 confess "Failed to load '$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;
1203 $class_loaded{$exception_class}++;
1207 return $exception_class->new(@args);
1211 # For some reason, dying while replacing our subs doesn't
1212 # kill our calling program. It simply stops the loading of
1213 # autodie and keeps going with everything else. The _autocroak
1214 # sub allows us to die with a vegence. It should *only* ever be
1215 # used for serious internal errors, since the results of it can't
1219 warn Carp::longmess(@_);
1223 package autodie::Scope::Guard;
1225 # This code schedules the cleanup of subroutines at the end of
1226 # scope. It's directly inspired by chocolateboy's excellent
1227 # Scope::Guard module.
1230 my ($class, $handler) = @_;
1232 return bless $handler, $class;
1247 Fatal - Replace functions with equivalents which succeed or die
1251 use Fatal qw(open close);
1253 open(my $fh, "<", $filename); # No need to check errors!
1255 use File::Copy qw(move);
1258 move($file1, $file2); # No need to check errors!
1260 sub juggle { . . . }
1261 Fatal->import('juggle');
1263 =head1 BEST PRACTICE
1265 B<Fatal has been obsoleted by the new L<autodie> pragma.> Please use
1266 L<autodie> in preference to C<Fatal>. L<autodie> supports lexical scoping,
1267 throws real exception objects, and provides much nicer error messages.
1269 The use of C<:void> with Fatal is discouraged.
1273 C<Fatal> provides a way to conveniently replace
1274 functions which normally return a false value when they fail with
1275 equivalents which raise exceptions if they are not successful. This
1276 lets you use these functions without having to test their return
1277 values explicitly on each call. Exceptions can be caught using
1278 C<eval{}>. See L<perlfunc> and L<perlvar> for details.
1280 The do-or-die equivalents are set up simply by calling Fatal's
1281 C<import> routine, passing it the names of the functions to be
1282 replaced. You may wrap both user-defined functions and overridable
1283 CORE operators (except C<exec>, C<system>, C<print>, or any other
1284 built-in that cannot be expressed via prototypes) in this way.
1286 If the symbol C<:void> appears in the import list, then functions
1287 named later in that import list raise an exception only when
1288 these are called in void context--that is, when their return
1289 values are ignored. For example
1291 use Fatal qw/:void open close/;
1293 # properly checked, so no exception raised on error
1294 if (not open(my $fh, '<', '/bogotic') {
1295 warn "Can't open /bogotic: $!";
1298 # not checked, so error raises an exception
1301 The use of C<:void> is discouraged, as it can result in exceptions
1302 not being thrown if you I<accidentally> call a method without
1303 void context. Use L<autodie> instead if you need to be able to
1304 disable autodying/Fatal behaviour for a small block of code.
1310 =item Bad subroutine name for Fatal: %s
1312 You've called C<Fatal> with an argument that doesn't look like
1313 a subroutine name, nor a switch that this version of Fatal
1316 =item %s is not a Perl subroutine
1318 You've asked C<Fatal> to try and replace a subroutine which does not
1319 exist, or has not yet been defined.
1321 =item %s is neither a builtin, nor a Perl subroutine
1323 You've asked C<Fatal> to replace a subroutine, but it's not a Perl
1324 built-in, and C<Fatal> couldn't find it as a regular subroutine.
1325 It either doesn't exist or has not yet been defined.
1327 =item Cannot make the non-overridable %s fatal
1329 You've tried to use C<Fatal> on a Perl built-in that can't be
1330 overridden, such as C<print> or C<system>, which means that
1331 C<Fatal> can't help you, although some other modules might.
1332 See the L</"SEE ALSO"> section of this documentation.
1334 =item Internal error: %s
1336 You've found a bug in C<Fatal>. Please report it using
1337 the C<perlbug> command.
1343 C<Fatal> clobbers the context in which a function is called and always
1344 makes it a scalar context, except when the C<:void> tag is used.
1345 This problem does not exist in L<autodie>.
1347 "Used only once" warnings can be generated when C<autodie> or C<Fatal>
1348 is used with package filehandles (eg, C<FILE>). It's strongly recommended
1349 you use scalar filehandles instead.
1353 Original module by Lionel Cons (CERN).
1355 Prototype updates by Ilya Zakharevich <ilya@math.ohio-state.edu>.
1357 L<autodie> support, bugfixes, extended diagnostics, C<system>
1358 support, and major overhauling by Paul Fenwick <pjf@perltraining.com.au>
1362 This module is free software, you may distribute it under the
1363 same terms as Perl itself.
1367 L<autodie> for a nicer way to use lexical Fatal.
1369 L<IPC::System::Simple> for a similar idea for calls to C<system()>