diff --git a/lib/net/ldap/connection.rb b/lib/net/ldap/connection.rb
index 91fb7e90..c690a8c3 100644
--- a/lib/net/ldap/connection.rb
+++ b/lib/net/ldap/connection.rb
@@ -562,12 +562,13 @@ def search(args = nil)
       result_pdu || OpenStruct.new(:status => :failure, :result_code => Net::LDAP::ResultCodeOperationsError, :message => "Invalid search")
     end # instrument
   ensure
+
     # clean up message queue for this search
     messages = message_queue.delete(message_id)
 
     # in the exceptional case some messages were *not* consumed from the queue,
     # instrument the event but do not fail.
-    unless messages.empty?
+    unless messages.nil? or messages.empty?
       instrument "search_messages_unread.net_ldap_connection",
                  message_id: message_id, messages: messages
     end
diff --git a/lib/net/ldap/filter.rb b/lib/net/ldap/filter.rb
index 5d91f9f6..5a2528bd 100644
--- a/lib/net/ldap/filter.rb
+++ b/lib/net/ldap/filter.rb
@@ -644,10 +644,18 @@ def match(entry)
   end
 
   ##
-  # Converts escaped characters (e.g., "\\28") to unescaped characters
+  # If the argument is a string, converts escaped characters (e.g., "\\28") to unescaped characters.
+  # If the argument is a number, just return as-is.
+  # Otherwise, an exception is thrown and the rhs argument is rejected.
   # ("(").
   def unescape(right)
-    right.gsub(/\\([a-fA-F\d]{2})/) { [$1.hex].pack("U") }
+    if defined? right.gsub
+      right.gsub(/\\([a-fA-F\d]{2})/) { [$1.hex].pack("U") }
+    elsif right.is_a? Fixnum
+      right.to_s
+    else
+      raise ArgumentError, "Did not know how to convert argument \"#{right}\" into the rhs of an LDAP filter"
+    end
   end
   private :unescape