Re: [perl #40216] SelfLoader::croak doesn't protect $@ from being clobbered by require

From: "Adriano Ferreira" <a.r.ferreira@gmail.com>
Message-ID: <73ddeb6c0608240620s207124d1mc202aea6a4598576@mail.gmail.com>

p4raw-id: //depot/perl@28758

diff --git a/MANIFEST b/MANIFEST
index d742541..247d50b 100644 (file)
--- a/MANIFEST
+++ b/MANIFEST
@@ -2384,6 +2384,7 @@ lib/SelectSaver.pm                Enforce proper select scoping
 lib/SelectSaver.t              See if SelectSaver works
 lib/SelfLoader.pm              Load functions only on demand
 lib/SelfLoader.t               See if SelfLoader works
+lib/SelfLoader-buggy.t         See if SelfLoader works
 lib/Shell.pm                   Make AUTOLOADed system() calls
 lib/Shell.t                    Tests for above
 lib/shellwords.pl              Perl library to split into words with shell quoting

diff --git a/lib/SelfLoader-buggy.t b/lib/SelfLoader-buggy.t
new file mode 100644 (file)
index 0000000..e8eb19a
--- /dev/null
+++ b/lib/SelfLoader-buggy.t
@@ -0,0 +1,50 @@
+#!./perl
+
+BEGIN {
+    if( $ENV{PERL_CORE} ) {
+        chdir 't' if -d 't';
+        @INC = '../lib';
+    }
+}
+
+use SelfLoader;
+
+# this script checks that errors on self-loaded
+# subroutines that affect $@ are reported
+
+eval { buggy(); };
+unless ($@ =~ /^syntax error/) {
+    print "not ";
+}
+print "ok 1 - syntax errors are reported\n";
+
+__END__
+
+sub buggy
+{
+    +>*;
+}
+
+
+=head1 RT 40216 
+
+  by Bo Lindbergh <blgl@hagernas.com>, at Aug 22, 2006 5:42 PM
+
+In the example below, there's a syntax error in the selfloaded
+code for main::buggy.  When the eval fails, SelfLoader::AUTOLOAD
+tries to report this with "croak $@;".  Unfortunately,
+SelfLoader::croak does "require Carp;" without protecting $@,
+which gets clobbered.  The program then dies with the
+uninformative message " at ./example line 3".
+
+#! /usr/local/bin/perl
+use SelfLoader;
+buggy();
+__END__
+sub buggy
+{
+    +>*;
+}
+
+=cut
+

diff --git a/lib/SelfLoader.pm b/lib/SelfLoader.pm
index 87587c3..294b6bc 100644 (file)
--- a/lib/SelfLoader.pm
+++ b/lib/SelfLoader.pm
@@ -16,8 +16,10 @@ $nested = qr{ \( (?: (?> [^()]+ ) | (??{ $nested }) )* \) }x;
 our $one_attr = qr{ (?> (?! \d) \w+ (?:$nested)? ) (?:\s*\:\s*|\s+(?!\:)) }x;
 our $attr_list = qr{ \s* : \s* (?: $one_attr )* }x;
 
-sub croak { require Carp; goto &Carp::croak }
-sub carp { require Carp; goto &Carp::carp }
+# in croak and carp, protect $@ from "require Carp;" RT #40216
+
+sub croak { { local $@; require Carp; } goto &Carp::croak }
+sub carp { { local $@; require Carp; } goto &Carp::carp }
 
 AUTOLOAD {
     print STDERR "SelfLoader::AUTOLOAD for $AUTOLOAD\n" if $DEBUG;