From 1ae0357171e3abd3597e5e5800052fb7a2938b49 Mon Sep 17 00:00:00 2001
From: Emery Hemingway <emery@vfemail.net>
Date: Thu, 21 Jul 2016 17:27:07 +0200
Subject: [PATCH] base/sesson_label.h: do not prefix empty strings

Session_label prefix(a, b) shall not return ' -> b' or 'a -> '.

Issue #1787
---
 repos/base/include/base/session_label.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/repos/base/include/base/session_label.h b/repos/base/include/base/session_label.h
index 5389661cd3..9256da78eb 100644
--- a/repos/base/include/base/session_label.h
+++ b/repos/base/include/base/session_label.h
@@ -91,10 +91,10 @@ namespace Genode {
 	inline Session_label prefixed_label(String<N1> const &prefix,
 	                                    String<N2> const &label)
 	{
-		if (!prefix.valid())
+		if (!prefix.valid() || prefix == "")
 			return Session_label(label.string());
 
-		if (!label.valid())
+		if (!label.valid() || label == "")
 			return Session_label(prefix.string());
 
 		char buf[Session_label::capacity()];