in Carp, avoid vivifying utf8 stash on Perl 5.6

Carp was breaking swash loading on Perl 5.6.  Makes no difference to
blead, where the utf8 stash is previvified, but it matters for the
CPAN release.

5 files changed, 26 insertions, 15 deletions

diff --git a/MANIFEST b/MANIFEST
index 5c06411f5a..0295b7c5ab 100644
--- a/MANIFEST
+++ b/MANIFEST
@@ -3050,7 +3050,9 @@ dist/Carp/lib/Carp.pm		Error message extension
 dist/Carp/Makefile.PL		makefile writer for Carp
 dist/Carp/t/Carp.t		See if Carp works
 dist/Carp/t/heavy.t		See if Carp::Heavy works
+dist/Carp/t/swash.t		See if Carp avoids breaking swash loading
 dist/Carp/t/vivify_gv.t		See if Carp leaves utf8:: stuff alone
+dist/Carp/t/vivify_stash.t		See if Carp leaves utf8:: stash alone
 dist/constant/lib/constant.pm	For "use constant"
 dist/constant/t/constant.t	See if compile-time constants work
 dist/constant/t/utf8.t		Test Unicode constants under utf8 pragma
diff --git a/dist/Carp/lib/Carp.pm b/dist/Carp/lib/Carp.pm
index b4dce03e2b..658f24045b 100644
--- a/dist/Carp/lib/Carp.pm
+++ b/dist/Carp/lib/Carp.pm
@@ -6,8 +6,8 @@ use warnings;
 
 BEGIN {
     no strict "refs";
-    if(exists($::{"utf8::"}) && exists($utf8::{"is_utf8"}) &&
-	    defined(*{"utf8::is_utf8"}{CODE})) {
+    if(exists($::{"utf8::"}) && exists(*{$::{"utf8::"}}{HASH}->{"is_utf8"}) &&
+	    defined(*{*{$::{"utf8::"}}{HASH}->{"is_utf8"}}{CODE})) {
 	*is_utf8 = \&{"utf8::is_utf8"};
     } else {
 	*is_utf8 = sub { 0 };
@@ -16,8 +16,8 @@ BEGIN {
 
 BEGIN {
     no strict "refs";
-    if(exists($::{"utf8::"}) && exists($utf8::{"downgrade"}) &&
-	    defined(*{"utf8::downgrade"}{CODE})) {
+    if(exists($::{"utf8::"}) && exists(*{$::{"utf8::"}}{HASH}->{"downgrade"}) &&
+	    defined(*{*{$::{"utf8::"}}{HASH}->{"downgrade"}}{CODE})) {
 	*downgrade = \&{"utf8::downgrade"};
     } else {
 	*downgrade = sub {};
diff --git a/dist/Carp/t/swash.t b/dist/Carp/t/swash.t
new file mode 100644
index 0000000000..7ef0bc81cf
--- /dev/null
+++ b/dist/Carp/t/swash.t
@@ -0,0 +1,5 @@
+BEGIN { print "1..1\n"; }
+use Carp;
+my $x = "foo\x{666}"; $x =~ /foo\p{Alnum}/;
+print "ok 1\n";
+1;
diff --git a/dist/Carp/t/vivify_gv.t b/dist/Carp/t/vivify_gv.t
index fdc018324b..3ed9912093 100644
--- a/dist/Carp/t/vivify_gv.t
+++ b/dist/Carp/t/vivify_gv.t
@@ -1,16 +1,11 @@
-use warnings;
-use strict;
+BEGIN { print "1..2\n"; }
 
-our $has_is_utf8;
-BEGIN { $has_is_utf8 = exists($utf8::{"is_utf8"}); }
+our $has_is_utf8; BEGIN { $has_is_utf8 = exists($utf8::{"is_utf8"}); }
+our $has_dgrade; BEGIN { $has_dgrade = exists($utf8::{"downgrade"}); }
 
-our $has_downgrade;
-BEGIN { $has_downgrade = exists($utf8::{"downgrade"}); }
+use Carp;
 
-use Test::More tests => 3;
-
-BEGIN { use_ok "Carp"; }
-ok(!(exists($utf8::{"is_utf8"}) xor $has_is_utf8));
-ok(!(exists($utf8::{"downgrade"}) xor $has_downgrade));
+print !(exists($utf8::{"is_utf8"}) xor $has_is_utf8) ? "" : "not ", "ok 1\n";
+print !(exists($utf8::{"downgrade"}) xor $has_dgrade) ? "" : "not ", "ok 2\n";
 
 1;
diff --git a/dist/Carp/t/vivify_stash.t b/dist/Carp/t/vivify_stash.t
new file mode 100644
index 0000000000..7906748a4f
--- /dev/null
+++ b/dist/Carp/t/vivify_stash.t
@@ -0,0 +1,9 @@
+BEGIN { print "1..1\n"; }
+
+our $has_utf8; BEGIN { $has_utf8 = exists($::{"utf8::"}); }
+
+use Carp;
+
+print !(exists($::{"utf8::"}) xor $has_utf8) ? "" : "not ", "ok 1\n";
+
+1;