Silence Perl warning

Now that warnings are enabled across the board, this code that tries to
print an undef variable emits one.  Silently printing the empty string
achieves the previous behavior.

Author: Álvaro Herrera <alvherre@alvh.no-ip.org>
Reviewed-by: Andrew Dunstan <andrew.dunstan@2ndquadrant.com>
Discussion: https://postgr.es/m/E1jO1VT-0008Qk-TM@gemulon.postgresql.org

diff --git a/doc/src/sgml/mk_feature_tables.pl b/doc/src/sgml/mk_feature_tables.pl
index ee158cb1969fa7637b169eab6252fa4e76d1d943..a9dfebfbb311a686579961efb3643fe0dc4b2d35 100644 (file)
--- a/doc/src/sgml/mk_feature_tables.pl
+++ b/doc/src/sgml/mk_feature_tables.pl
@@ -54,7 +54,9 @@ while (<$feat>)
        {
                print "  <entry>$feature_id</entry>\n";
        }
-       print "  <entry>" . $feature_packages{$feature_id} . "</entry>\n";
+       print "  <entry>",
+                 defined($feature_packages{$feature_id}) ? $feature_packages{$feature_id} : "",
+                 "</entry>\n";
        if ($subfeature_id)
        {
                print "  <entry>$subfeature_name</entry>\n";