2nd try: [perl #91834] utf8::decode does not respect copy-on-write

I reverted the first version of this patch because I put the if()
statement before a declaration. I did a revert, rather than a correc-
tion, to make back-porting easier.

1 files changed, 12 insertions, 0 deletions

diff --git a/lib/utf8.t b/lib/utf8.t
index ae81ccdc46..b13bb5377d 100644
--- a/lib/utf8.t
+++ b/lib/utf8.t
@@ -427,6 +427,18 @@ SKIP: {
 }
 
 {
+    # Make sure utf8::decode respects copy-on-write [perl #91834].
+    # Hash keys are the easiest way to test this.
+    my $name = "\x{c3}\x{b3}";
+    my ($k1) = keys %{ { $name=>undef } };
+    my $k2 = $name;
+    utf8::decode($k1);
+    utf8::decode($k2);
+    my $h = { $k1 => 1, $k2 => 2 };
+    is join('', keys $h), $k2, 'utf8::decode respects copy-on-write';
+}
+
+{
     my $a = "456\xb6";
     utf8::upgrade($a);