Fix subst for non-matching patterns

src/setting/Regex.pm

@@ -13,17 +13,17 @@ given, then return an array of all non-overlapping matches.
 
 our sub match ($text, $regex, :$global?) {
     my $match := $text ~~ $regex;
+    my @matches;
     if $global {
-        my @matches;
         while $match {
             @matches.push($match);
             $match := $match.CURSOR.parse($text, :rule($regex), :c($match.to));
         }
-        @matches;
     }
-    else {
-        $match;
+    elsif $match {
+        @matches.push($match);
     }
+    @matches;
 }
 
 
@@ -34,8 +34,8 @@ perform the replacement on all matches of C<$text>.
 =end item
 
 our sub subst ($text, $regex, $repl, :$global?) {
-    my @matches := $global ?? match($text, $regex, :global)
-                           !! [ $text ~~ $regex ];
+    my @matches := match($text, $regex, $global);
+
     my $is_code := pir::isa($repl, 'Sub');
     my $offset  := 0;
     my $result  := pir::new__Ps('StringBuilder');

t/setting/05-subst.t

@@ -2,7 +2,7 @@
 
 pir::load_bytecode('nqp-setting.pbc' );
 
-plan(5);
+plan(7);
 
 my $str := 'hello';
 
@@ -15,3 +15,8 @@ my $i := 0;
 ok(subst($str, /l/, {$i++}) eq 'he0lo', 'We can have a closure as replacement');
 ok($i == 1, '.. and $i updated');
 
+ok(subst($str, /FOO/, 'BAR') eq 'hello', "Non-existing string doesn't clobber string");
+ok(subst($str, /FOO/, 'BAR', :global) eq 'hello', "Non-existing string doesn't clobber string globally");
+
+# vim: ft=perl6
+