avoid uninitialized value

This can happen when a new field,
such as the new lasttry, is added.

diff --git a/IkiWiki/Plugin/aggregate.pm b/IkiWiki/Plugin/aggregate.pm
index 9b531b6128c1de09d81e9c1b60da25ab736e2732..97dd036f6f4ca2816b6a2beee0f8aeefbbc0d405 100644 (file)
--- a/IkiWiki/Plugin/aggregate.pm
+++ b/IkiWiki/Plugin/aggregate.pm
@@ -343,7 +343,8 @@ sub savestate () {
                                push @line, "tag=$_" foreach @{$data->{tags}};
                        }
                        else {
-                               push @line, "$field=".$data->{$field};
+                               push @line, "$field=".$data->{$field}
+                                       if defined $data->{$field};
                        }
                }
                print OUT join(" ", @line)."\n" || error("write $newfile: $!", $cleanup);