clear of empty locked hash SEGVs

Message-ID: <3FBB8087.20206@sun.com>

p4raw-id: //depot/perl@21748

2 files changed, 16 insertions, 2 deletions

diff --git a/hv.c b/hv.c
index 53a0b3c992..29f25a3659 100644
--- a/hv.c
+++ b/hv.c
@@ -1803,7 +1803,7 @@ Perl_hv_clear(pTHX_ HV *hv)
 
     xhv = (XPVHV*)SvANY(hv);
 
-    if (SvREADONLY(hv)) {
+    if (SvREADONLY(hv) && xhv->xhv_array != NULL) {
 	/* restricted hash: convert all keys to placeholders */
 	I32 i;
 	HE* entry;
diff --git a/lib/Hash/Util.t b/lib/Hash/Util.t
index 48cbc7c007..1c77728c27 100644
--- a/lib/Hash/Util.t
+++ b/lib/Hash/Util.t
@@ -6,7 +6,7 @@ BEGIN {
         chdir 't';
     }
 }
-use Test::More tests => 157;
+use Test::More tests => 159;
 use strict;
 
 my @Exported_Funcs;
@@ -274,5 +274,19 @@ like( $@, qr/^Attempt to access disallowed key 'I_DONT_EXIST' in a restricted ha
   }
 }
 
+# Check clear works on locked empty hashes - SEGVs on 5.8.2.
+{
+    my %hash;
+    lock_hash(%hash);
+    %hash = ();
+    ok(keys(%hash) == 0, 'clear empty lock_hash() hash');
+}
+{
+    my %hash;
+    lock_keys(%hash);
+    %hash = ();
+    ok(keys(%hash) == 0, 'clear empty lock_keys() hash');
+}
+
 my $hash_seed = hash_seed();
 ok($hash_seed >= 0, "hash_seed $hash_seed");