3 use 5.008; # 5.8.x needed for autodie
8 use constant LEXICAL_TAG => q{:lexical};
9 use constant VOID_TAG => q{:void};
11 use constant ERROR_NOARGS => 'Cannot use lexical %s with no arguments';
12 use constant ERROR_VOID_LEX => VOID_TAG.' cannot be used with lexical scope';
13 use constant ERROR_LEX_FIRST => LEXICAL_TAG.' must be used as first argument';
14 use constant ERROR_NO_LEX => "no %s can only start with ".LEXICAL_TAG;
15 use constant ERROR_BADNAME => "Bad subroutine name for %s: %s";
16 use constant ERROR_NOTSUB => "%s is not a Perl subroutine";
17 use constant ERROR_NOT_BUILT => "%s is neither a builtin, nor a Perl subroutine";
18 use constant ERROR_CANT_OVERRIDE => "Cannot make the non-overridable builtin %s fatal";
20 use constant ERROR_NO_IPC_SYS_SIMPLE => "IPC::System::Simple required for Fatalised/autodying system()";
22 use constant ERROR_IPC_SYS_SIMPLE_OLD => "IPC::System::Simple version %f required for Fatalised/autodying system(). We only have version %f";
24 use constant ERROR_AUTODIE_CONFLICT => q{"no autodie '%s'" is not allowed while "use Fatal '%s'" is in effect};
26 use constant ERROR_FATAL_CONFLICT => q{"use Fatal '%s'" is not allowed while "no autodie '%s'" is in effect};
28 # Older versions of IPC::System::Simple don't support all the
31 use constant MIN_IPC_SYS_SIMPLE_VER => 0.12;
33 # All the Fatal/autodie modules share the same version number.
34 our $VERSION = '1.998';
38 # EWOULDBLOCK values for systems that don't supply their own.
39 # Even though this is defined with our, that's to help our
40 # test code. Please don't rely upon this variable existing in
47 # We have some tags that can be passed in for use with import.
48 # These are all assumed to be CORE::
51 ':io' => [qw(:dbm :file :filesys :ipc :socket
52 read seek sysread syswrite sysseek )],
53 ':dbm' => [qw(dbmopen dbmclose)],
54 ':file' => [qw(open close flock sysopen fcntl fileno binmode
56 ':filesys' => [qw(opendir closedir chdir link unlink rename mkdir
57 symlink rmdir readlink umask)],
58 ':ipc' => [qw(:msg :semaphore :shm pipe)],
59 ':msg' => [qw(msgctl msgget msgrcv msgsnd)],
60 ':threads' => [qw(fork)],
61 ':semaphore'=>[qw(semctl semget semop)],
62 ':shm' => [qw(shmctl shmget shmread)],
63 ':system' => [qw(system exec)],
65 # Can we use qw(getpeername getsockname)? What do they do on failure?
66 # XXX - Can socket return false?
67 ':socket' => [qw(accept bind connect getsockopt listen recv send
68 setsockopt shutdown socketpair)],
70 # Our defaults don't include system(), because it depends upon
71 # an optional module, and it breaks the exotic form.
73 # This *may* change in the future. I'd love IPC::System::Simple
74 # to be a dependency rather than a recommendation, and hence for
75 # system() to be autodying by default.
77 ':default' => [qw(:io :threads)],
79 # Version specific tags. These allow someone to specify
80 # use autodie qw(:1.994) and know exactly what they'll get.
82 ':1.994' => [qw(:default)],
83 ':1.995' => [qw(:default)],
84 ':1.996' => [qw(:default)],
85 ':1.997' => [qw(:default)],
86 ':1.998' => [qw(:default)],
90 $TAGS{':all'} = [ keys %TAGS ];
92 # This hash contains subroutines for which we should
93 # subroutine() // die() rather than subroutine() || die()
97 # CORE::open returns undef on failure. It can legitimately return
98 # 0 on success, eg: open(my $fh, '-|') || exec(...);
114 # Cached_fatalised_sub caches the various versions of our
115 # fatalised subs as they're produced. This means we don't
116 # have to build our own replacement of CORE::open and friends
117 # for every single package that wants to use them.
119 my %Cached_fatalised_sub = ();
121 # Every time we're called with package scope, we record the subroutine
122 # (including package or CORE::) in %Package_Fatal. This allows us
123 # to detect illegal combinations of autodie and Fatal, and makes sure
124 # we don't accidently make a Fatal function autodying (which isn't
127 my %Package_Fatal = ();
129 # The first time we're called with a user-sub, we cache it here.
130 # In the case of a "no autodie ..." we put back the cached copy.
132 my %Original_user_sub = ();
134 # We use our package in a few hash-keys. Having it in a scalar is
135 # convenient. The "guard $PACKAGE" string is used as a key when
136 # setting up lexical guards.
138 my $PACKAGE = __PACKAGE__;
139 my $PACKAGE_GUARD = "guard $PACKAGE";
140 my $NO_PACKAGE = "no $PACKAGE"; # Used to detect 'no autodie'
142 # Here's where all the magic happens when someone write 'use Fatal'
146 my $class = shift(@_);
150 my ($pkg, $filename) = caller();
152 @_ or return; # 'use Fatal' is a no-op.
154 # If we see the :lexical flag, then _all_ arguments are
157 if ($_[0] eq LEXICAL_TAG) {
161 # If we see no arguments and :lexical, we assume they
165 push(@_, ':default');
168 # Don't allow :lexical with :void, it's needlessly confusing.
169 if ( grep { $_ eq VOID_TAG } @_ ) {
170 croak(ERROR_VOID_LEX);
174 if ( grep { $_ eq LEXICAL_TAG } @_ ) {
175 # If we see the lexical tag as the non-first argument, complain.
176 croak(ERROR_LEX_FIRST);
179 my @fatalise_these = @_;
181 # Thiese subs will get unloaded at the end of lexical scope.
184 # This hash helps us track if we've alredy done work.
187 # NB: we're using while/shift rather than foreach, since
188 # we'll be modifying the array as we walk through it.
190 while (my $func = shift @fatalise_these) {
192 if ($func eq VOID_TAG) {
194 # When we see :void, set the void flag.
197 } elsif (exists $TAGS{$func}) {
199 # When it's a tag, expand it.
200 push(@fatalise_these, @{ $TAGS{$func} });
204 # Otherwise, fatalise it.
206 # If we've already made something fatal this call,
207 # then don't do it twice.
209 next if $done_this{$func};
211 # We're going to make a subroutine fatalistic.
212 # However if we're being invoked with 'use Fatal qw(x)'
213 # and we've already been called with 'no autodie qw(x)'
214 # in the same scope, we consider this to be an error.
215 # Mixing Fatal and autodie effects was considered to be
216 # needlessly confusing on p5p.
219 $sub = "${pkg}::$sub" unless $sub =~ /::/;
221 # If we're being called as Fatal, and we've previously
222 # had a 'no X' in scope for the subroutine, then complain
225 if (! $lexical and $^H{$NO_PACKAGE}{$sub}) {
226 croak(sprintf(ERROR_FATAL_CONFLICT, $func, $func));
229 # We're not being used in a confusing way, so make
230 # the sub fatal. Note that _make_fatal returns the
231 # old (original) version of the sub, or undef for
234 my $sub_ref = $class->_make_fatal(
235 $func, $pkg, $void, $lexical, $filename
240 $Original_user_sub{$sub} ||= $sub_ref;
242 # If we're making lexical changes, we need to arrange
243 # for them to be cleaned at the end of our scope, so
246 $unload_later{$func} = $sub_ref if $lexical;
252 # Dark magic to have autodie work under 5.8
253 # Copied from namespace::clean, that copied it from
254 # autobox, that found it on an ancient scroll written
257 # This magic bit causes %^H to be lexically scoped.
261 # Our package guard gets invoked when we leave our lexical
264 push(@ { $^H{$PACKAGE_GUARD} }, autodie::Scope::Guard->new(sub {
265 $class->_install_subs($pkg, \%unload_later);
274 # The code here is originally lifted from namespace::clean,
275 # by Robert "phaylon" Sedlacek.
277 # It's been redesigned after feedback from ikegami on perlmonks.
278 # See http://perlmonks.org/?node_id=693338 . Ikegami rocks.
280 # Given a package, and hash of (subname => subref) pairs,
281 # we install the given subroutines into the package. If
282 # a subref is undef, the subroutine is removed. Otherwise
283 # it replaces any existing subs which were already there.
286 my ($class, $pkg, $subs_to_reinstate) = @_;
288 my $pkg_sym = "${pkg}::";
290 while(my ($sub_name, $sub_ref) = each %$subs_to_reinstate) {
292 my $full_path = $pkg_sym.$sub_name;
294 # Copy symbols across to temp area.
296 no strict 'refs'; ## no critic
298 local *__tmp = *{ $full_path };
301 { no strict; delete $pkg_sym->{$sub_name}; } ## no critic
303 # Copy innocent bystanders back.
305 foreach my $slot (qw( SCALAR ARRAY HASH IO FORMAT ) ) {
306 next unless defined *__tmp{ $slot };
307 *{ $full_path } = *__tmp{ $slot };
310 # Put back the old sub (if there was one).
314 no strict; ## no critic
315 *{ $pkg_sym . $sub_name } = $sub_ref;
325 # Calling "no Fatal" must start with ":lexical"
326 if ($_[0] ne LEXICAL_TAG) {
327 croak(sprintf(ERROR_NO_LEX,$class));
330 shift @_; # Remove :lexical
332 my $pkg = (caller)[0];
334 # If we've been called with arguments, then the developer
335 # has explicitly stated 'no autodie qw(blah)',
336 # in which case, we disable Fatalistic behaviour for 'blah'.
338 my @unimport_these = @_ ? @_ : ':all';
340 while (my $symbol = shift @unimport_these) {
342 if ($symbol =~ /^:/) {
344 # Looks like a tag! Expand it!
345 push(@unimport_these, @{ $TAGS{$symbol} });
351 $sub = "${pkg}::$sub" unless $sub =~ /::/;
353 # If 'blah' was already enabled with Fatal (which has package
354 # scope) then, this is considered an error.
356 if (exists $Package_Fatal{$sub}) {
357 croak(sprintf(ERROR_AUTODIE_CONFLICT,$symbol,$symbol));
360 # Record 'no autodie qw($sub)' as being in effect.
361 # This is to catch conflicting semantics elsewhere
362 # (eg, mixing Fatal with no autodie)
364 $^H{$NO_PACKAGE}{$sub} = 1;
366 if (my $original_sub = $Original_user_sub{$sub}) {
367 # Hey, we've got an original one of these, put it back.
368 $class->_install_subs($pkg, { $symbol => $original_sub });
372 # We don't have an original copy of the sub, on the assumption
373 # it's core (or doesn't exist), we'll just nuke it.
375 $class->_install_subs($pkg,{ $symbol => undef });
383 # TODO - This is rather terribly inefficient right now.
385 # NB: Perl::Critic's dump-autodie-tag-contents depends upon this
386 # continuing to work.
392 my ($class, $tag) = @_;
394 if (my $cached = $tag_cache{$tag}) {
398 if (not exists $TAGS{$tag}) {
399 croak "Invalid exception class $tag";
402 my @to_process = @{$TAGS{$tag}};
406 while (my $item = shift @to_process) {
408 push(@to_process, @{$TAGS{$item}} );
410 push(@taglist, "CORE::$item");
414 $tag_cache{$tag} = \@taglist;
422 # This code is from the original Fatal. It scares me.
426 my ($n, $isref, @out, @out1, $seen_semi) = -1;
427 while ($proto =~ /\S/) {
429 push(@out1,[$n,@out]) if $seen_semi;
430 push(@out, $1 . "{\$_[$n]}"), next if $proto =~ s/^\s*\\([\@%\$\&])//;
431 push(@out, "\$_[$n]"), next if $proto =~ s/^\s*([_*\$&])//;
432 push(@out, "\@_[$n..\$#_]"), last if $proto =~ s/^\s*(;\s*)?\@//;
433 $seen_semi = 1, $n--, next if $proto =~ s/^\s*;//; # XXXX ????
434 die "Internal error: Unknown prototype letters: \"$proto\"";
436 push(@out1,[$n+1,@out]);
440 # This generates the code that will become our fatalised subroutine.
442 sub write_invocation {
443 my ($class, $core, $call, $name, $void, $lexical, $sub, @argvs) = @_;
445 if (@argvs == 1) { # No optional arguments
447 my @argv = @{$argvs[0]};
450 return $class->one_invocation($core,$call,$name,$void,$sub,! $lexical,@argv);
454 my (@out, @argv, $n);
456 @argv = @{shift @argvs};
459 push @out, "${else}if (\@_ == $n) {\n";
462 push @out, $class->one_invocation($core,$call,$name,$void,$sub,! $lexical,@argv);
466 die "Internal error: $name(\@_): Do not expect to get ", scalar \@_, " arguments";
469 return join '', @out;
474 my ($class, $core, $call, $name, $void, $sub, $back_compat, @argv) = @_;
476 # If someone is calling us directly (a child class perhaps?) then
477 # they could try to mix void without enabling backwards
478 # compatibility. We just don't support this at all, so we gripe
479 # about it rather than doing something unwise.
481 if ($void and not $back_compat) {
482 Carp::confess("Internal error: :void mode not supported with $class");
485 # @argv only contains the results of the in-built prototype
486 # function, and is therefore safe to interpolate in the
487 # code generators below.
489 # TODO - The following clobbers context, but that's what the
490 # old Fatal did. Do we care?
494 # TODO - Use Fatal qw(system) is not yet supported. It should be!
496 if ($call eq 'CORE::system') {
498 croak("UNIMPLEMENTED: use Fatal qw(system) not yet supported.");
505 return qq/return (defined wantarray)?$call(@argv):
506 $call(@argv) || croak "Can't $name(\@_)/ .
507 ($core ? ': $!' : ', \$! is \"$!\"') . '"'
509 return qq{return $call(@argv) || croak "Can't $name(\@_)} .
510 ($core ? ': $!' : ', \$! is \"$!\"') . '"';
514 # The name of our original function is:
515 # $call if the function is CORE
516 # $sub if our function is non-CORE
518 # The reason for this is that $call is what we're actualling
519 # calling. For our core functions, this is always
520 # CORE::something. However for user-defined subs, we're about to
521 # replace whatever it is that we're calling; as such, we actually
522 # calling a subroutine ref.
524 # Unfortunately, none of this tells us the *ultimate* name.
525 # For example, if I export 'copy' from File::Copy, I'd like my
526 # ultimate name to be File::Copy::copy.
528 # TODO - Is there any way to find the ultimate name of a sub, as
531 my $true_sub_name = $core ? $call : $sub;
533 if ($call eq 'CORE::system') {
535 # Leverage IPC::System::Simple if we're making an autodying
540 # We need to stash $@ into $E, rather than using
541 # local $@ for the whole sub. If we don't then
542 # any exceptions from internal errors in autodie/Fatal
543 # will mysteriously disappear before propogating
555 \$retval = IPC::System::Simple::system(@argv);
563 # XXX - TODO - This can't be overridden in child
566 die autodie::exception::system->new(
567 function => q{CORE::system}, args => [ @argv ],
568 message => "\$E", errno => \$!,
577 # Should we be testing to see if our result is defined, or
579 my $use_defined_or = exists ( $Use_defined_or{$call} );
583 # If we're going to throw an exception, here's the code to use.
586 function => q{$true_sub_name}, args => [ @argv ],
587 pragma => q{$class}, errno => \$!,
591 if ($call eq 'CORE::flock') {
593 # flock needs special treatment. When it fails with
594 # LOCK_UN and EWOULDBLOCK, then it's not really fatal, it just
595 # means we couldn't get the lock right now.
597 require POSIX; # For POSIX::EWOULDBLOCK
599 local $@; # Don't blat anyone else's $@.
601 # Ensure that our vendor supports EWOULDBLOCK. If they
602 # don't (eg, Windows), then we use known values for its
603 # equivalent on other systems.
605 my $EWOULDBLOCK = eval { POSIX::EWOULDBLOCK(); }
606 || $_EWOULDBLOCK{$^O}
607 || _autocroak("Internal error - can't overload flock - EWOULDBLOCK not defined on this system.");
609 require Fcntl; # For Fcntl::LOCK_NB
613 # Try to flock. If successful, return it immediately.
615 my \$retval = $call(@argv);
616 return \$retval if \$retval;
618 # If we failed, but we're using LOCK_NB and
619 # returned EWOULDBLOCK, it's not a real error.
621 if (\$_[1] & Fcntl::LOCK_NB() and \$! == $EWOULDBLOCK ) {
625 # Otherwise, we failed. Die noisily.
632 # AFAIK everything that can be given an unopned filehandle
633 # will fail if it tries to use it, so we don't really need
634 # the 'unopened' warning class here. Especially since they
635 # then report the wrong line number.
638 no warnings qw(unopened);
641 my \@results = $call(@argv);
642 # If we got back nothing, or we got back a single
644 if (! \@results or (\@results == 1 and ! defined \$results[0])) {
650 # Otherwise, we're in scalar context.
651 # We're never in a void context, since we have to look
654 my \$result = $call(@argv);
656 } . ( $use_defined_or ? qq{
658 $die if not defined \$result;
664 return \$result || $die;
670 # This returns the old copy of the sub, so we can
671 # put it back at end of scope.
673 # TODO : Check to make sure prototypes are restored correctly.
675 # TODO: Taking a huge list of arguments is awful. Rewriting to
676 # take a hash would be lovely.
679 my($class, $sub, $pkg, $void, $lexical, $filename) = @_;
680 my($name, $code, $sref, $real_proto, $proto, $core, $call);
683 $sub = "${pkg}::$sub" unless $sub =~ /::/;
685 # Figure if we're using lexical or package semantics and
686 # twiddle the appropriate bits.
689 $Package_Fatal{$sub} = 1;
692 # TODO - We *should* be able to do skipping, since we know when
693 # we've lexicalised / unlexicalised a subroutine.
696 $name =~ s/.*::// or $name =~ s/^&//;
698 warn "# _make_fatal: sub=$sub pkg=$pkg name=$name void=$void\n" if $Debug;
699 croak(sprintf(ERROR_BADNAME, $class, $name)) unless $name =~ /^\w+$/;
701 if (defined(&$sub)) { # user subroutine
703 # This could be something that we've fatalised that
706 local $@; # Don't clobber anyone else's $@
708 if ( $Package_Fatal{$sub} and eval { prototype "CORE::$name" } ) {
710 # Something we previously made Fatal that was core.
711 # This is safe to replace with an autodying to core
715 $call = "CORE::$name";
716 $proto = prototype $call;
718 # We return our $sref from this subroutine later
719 # on, indicating this subroutine should be placed
720 # back when we're finished.
726 # A regular user sub, or a user sub wrapping a
730 $proto = prototype $sref;
735 } elsif ($sub eq $ini && $sub !~ /^CORE::GLOBAL::/) {
736 # Stray user subroutine
737 croak(sprintf(ERROR_NOTSUB,$sub));
739 } elsif ($name eq 'system') {
741 # If we're fatalising system, then we need to load
745 require IPC::System::Simple; # Only load it if we need it.
746 require autodie::exception::system;
749 if ($@) { croak ERROR_NO_IPC_SYS_SIMPLE; }
751 # Make sure we're using a recent version of ISS that actually
752 # support fatalised system.
753 if ($IPC::System::Simple::VERSION < MIN_IPC_SYS_SIMPLE_VER) {
755 ERROR_IPC_SYS_SIMPLE_OLD, MIN_IPC_SYS_SIMPLE_VER,
756 $IPC::System::Simple::VERSION
760 $call = 'CORE::system';
763 } elsif ($name eq 'exec') {
764 # Exec doesn't have a prototype. We don't care. This
765 # breaks the exotic form with lexical scope, and gives
766 # the regular form a "do or die" beaviour as expected.
768 $call = 'CORE::exec';
772 } else { # CORE subroutine
773 $proto = eval { prototype "CORE::$name" };
774 croak(sprintf(ERROR_NOT_BUILT,$name)) if $@;
775 croak(sprintf(ERROR_CANT_OVERRIDE,$name)) if not defined $proto;
777 $call = "CORE::$name";
780 if (defined $proto) {
781 $real_proto = " ($proto)";
787 my $true_name = $core ? $call : $sub;
789 # TODO: This caching works, but I don't like using $void and
790 # $lexical as keys. In particular, I suspect our code may end up
791 # wrapping already wrapped code when autodie and Fatal are used
794 # NB: We must use '$sub' (the name plus package) and not
795 # just '$name' (the short name) here. Failing to do so
796 # results code that's in the wrong package, and hence has
797 # access to the wrong package filehandles.
799 if (my $subref = $Cached_fatalised_sub{$class}{$sub}{$void}{$lexical}) {
800 $class->_install_subs($pkg, { $name => $subref });
806 local(\$", \$!) = (', ', 0); # TODO - Why do we do this?
809 # Don't have perl whine if exec fails, since we'll be handling
811 $code .= "no warnings qw(exec);\n" if $call eq "CORE::exec";
813 my @protos = fill_protos($proto);
814 $code .= $class->write_invocation($core, $call, $name, $void, $lexical, $sub, @protos);
816 warn $code if $Debug;
818 # I thought that changing package was a monumental waste of
819 # time for CORE subs, since they'll always be the same. However
820 # that's not the case, since they may refer to package-based
821 # filehandles (eg, with open).
823 # There is potential to more aggressively cache core subs
824 # that we know will never want to interact with package variables
829 no strict 'refs'; ## no critic # to avoid: Can't use string (...) as a symbol ref ...
830 $code = eval("package $pkg; use Carp; $code"); ## no critic
833 # For some reason, using a die, croak, or confess in here
834 # results in the error being completely surpressed. As such,
835 # we need to do our own reporting.
837 # TODO: Fix the above.
839 _autocroak("Internal error in autodie/Fatal processing $true_name: $@");
844 # Now we need to wrap our fatalised sub inside an itty bitty
845 # closure, which can detect if we've leaked into another file.
846 # Luckily, we only need to do this for lexical (autodie)
847 # subs. Fatal subs can leak all they want, it's considered
848 # a "feature" (or at least backwards compatible).
850 # TODO: Cache our leak guards!
852 # TODO: This is pretty hairy code. A lot more tests would
853 # be really nice for this.
864 # If we're called from the correct file, then use the
866 goto &\$code if ((caller)[1] eq \$filename);
868 # Oh bother, we've leaked into another file. Call the
869 # original code. Note that \$sref may actually be a
870 # reference to a Fatalised version of a core built-in.
871 # That's okay, because Fatal *always* leaks between files.
873 goto &\$sref if \$sref;
877 # If we're here, it must have been a core subroutine called.
878 # Warning: The following code may disturb some viewers.
880 # TODO: It should be possible to combine this with
881 # write_invocation().
883 foreach my $proto (@protos) {
884 local $" = ", "; # So @args is formatted correctly.
885 my ($count, @args) = @$proto;
893 $leak_guard .= qq< croak "Internal error in Fatal/autodie. Leak-guard failure"; } >;
895 # warn "$leak_guard\n";
899 $leak_guard = eval $leak_guard; ## no critic
901 die "Internal error in $class: Leak-guard installation failure: $@" if $@;
904 $class->_install_subs($pkg, { $name => $leak_guard || $code });
906 $Cached_fatalised_sub{$class}{$sub}{$void}{$lexical} = $leak_guard || $code;
912 # This subroutine exists primarily so that child classes can override
913 # it to point to their own exception class. Doing this is significantly
914 # less complex than overriding throw()
916 sub exception_class { return "autodie::exception" };
919 my %exception_class_for;
923 my ($class, @args) = @_;
925 # Find our exception class if we need it.
926 my $exception_class =
927 $exception_class_for{$class} ||= $class->exception_class;
929 if (not $class_loaded{$exception_class}) {
930 if ($exception_class =~ /[^\w:']/) {
931 confess "Bad exception class '$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.";
934 # Alas, Perl does turn barewords into modules unless they're
935 # actually barewords. As such, we're left doing a string eval
936 # to make sure we load our file correctly.
941 local $@; # We can't clobber $@, it's wrong!
942 eval "require $exception_class"; ## no critic
943 $E = $@; # Save $E despite ending our local.
946 # We need quotes around $@ to make sure it's stringified
947 # while still in scope. Without them, we run the risk of
948 # $@ having been cleared by us exiting the local() block.
950 confess "Failed to load '$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;
952 $class_loaded{$exception_class}++;
956 return $exception_class->new(@args);
960 # For some reason, dying while replacing our subs doesn't
961 # kill our calling program. It simply stops the loading of
962 # autodie and keeps going with everything else. The _autocroak
963 # sub allows us to die with a vegence. It should *only* ever be
964 # used for serious internal errors, since the results of it can't
968 warn Carp::longmess(@_);
972 package autodie::Scope::Guard;
974 # This code schedules the cleanup of subroutines at the end of
975 # scope. It's directly inspired by chocolateboy's excellent
976 # Scope::Guard module.
979 my ($class, $handler) = @_;
981 return bless $handler, $class;
996 Fatal - Replace functions with equivalents which succeed or die
1000 use Fatal qw(open close);
1002 open(my $fh, "<", $filename); # No need to check errors!
1004 use File::Copy qw(move);
1007 move($file1, $file2); # No need to check errors!
1009 sub juggle { . . . }
1010 Fatal->import('juggle');
1012 =head1 BEST PRACTICE
1014 B<Fatal has been obsoleted by the new L<autodie> pragma.> Please use
1015 L<autodie> in preference to C<Fatal>. L<autodie> supports lexical scoping,
1016 throws real exception objects, and provides much nicer error messages.
1018 The use of C<:void> with Fatal is discouraged.
1022 C<Fatal> provides a way to conveniently replace
1023 functions which normally return a false value when they fail with
1024 equivalents which raise exceptions if they are not successful. This
1025 lets you use these functions without having to test their return
1026 values explicitly on each call. Exceptions can be caught using
1027 C<eval{}>. See L<perlfunc> and L<perlvar> for details.
1029 The do-or-die equivalents are set up simply by calling Fatal's
1030 C<import> routine, passing it the names of the functions to be
1031 replaced. You may wrap both user-defined functions and overridable
1032 CORE operators (except C<exec>, C<system>, C<print>, or any other
1033 built-in that cannot be expressed via prototypes) in this way.
1035 If the symbol C<:void> appears in the import list, then functions
1036 named later in that import list raise an exception only when
1037 these are called in void context--that is, when their return
1038 values are ignored. For example
1040 use Fatal qw/:void open close/;
1042 # properly checked, so no exception raised on error
1043 if (not open(my $fh, '<' '/bogotic') {
1044 warn "Can't open /bogotic: $!";
1047 # not checked, so error raises an exception
1050 The use of C<:void> is discouraged, as it can result in exceptions
1051 not being thrown if you I<accidentally> call a method without
1052 void context. Use L<autodie> instead if you need to be able to
1053 disable autodying/Fatal behaviour for a small block of code.
1059 =item Bad subroutine name for Fatal: %s
1061 You've called C<Fatal> with an argument that doesn't look like
1062 a subroutine name, nor a switch that this version of Fatal
1065 =item %s is not a Perl subroutine
1067 You've asked C<Fatal> to try and replace a subroutine which does not
1068 exist, or has not yet been defined.
1070 =item %s is neither a builtin, nor a Perl subroutine
1072 You've asked C<Fatal> to replace a subroutine, but it's not a Perl
1073 built-in, and C<Fatal> couldn't find it as a regular subroutine.
1074 It either doesn't exist or has not yet been defined.
1076 =item Cannot make the non-overridable %s fatal
1078 You've tried to use C<Fatal> on a Perl built-in that can't be
1079 overridden, such as C<print> or C<system>, which means that
1080 C<Fatal> can't help you, although some other modules might.
1081 See the L</"SEE ALSO"> section of this documentation.
1083 =item Internal error: %s
1085 You've found a bug in C<Fatal>. Please report it using
1086 the C<perlbug> command.
1092 C<Fatal> clobbers the context in which a function is called and always
1093 makes it a scalar context, except when the C<:void> tag is used.
1094 This problem does not exist in L<autodie>.
1096 "Used only once" warnings can be generated when C<autodie> or C<Fatal>
1097 is used with package filehandles (eg, C<FILE>). It's strongly recommended
1098 you use scalar filehandles instead.
1102 Original module by Lionel Cons (CERN).
1104 Prototype updates by Ilya Zakharevich <ilya@math.ohio-state.edu>.
1106 L<autodie> support, bugfixes, extended diagnostics, C<system>
1107 support, and major overhauling by Paul Fenwick <pjf@perltraining.com.au>
1111 This module is free software, you may distribute it under the
1112 same terms as Perl itself.
1116 L<autodie> for a nicer way to use lexical Fatal.
1118 L<IPC::System::Simple> for a similar idea for calls to C<system()>