From de4914f412bf0aaf489fc511babd66c4d4140e45 Mon Sep 17 00:00:00 2001
From: Roger Light <roger@atchoo.org>
Date: Sun, 16 Mar 2014 23:21:00 +0000
Subject: [PATCH] Fix topic matching for $ topics.

Change-Id: I7a3f73037cc11333316cfd8503aad23ce70e8661
---
 src/paho/mqtt/client.py                      | 4 ++++
 test/lib/python/09-util-topic-matching.test  | 4 ++++
 test/lib/python3/09-util-topic-matching.test | 4 ++++
 3 files changed, 12 insertions(+)

diff --git a/src/paho/mqtt/client.py b/src/paho/mqtt/client.py
index f7a3a8f..c3650f4 100755
--- a/src/paho/mqtt/client.py
+++ b/src/paho/mqtt/client.py
@@ -197,6 +197,10 @@ def topic_matches_sub(sub, topic):
     slen = len(sub)
     tlen = len(topic)
 
+    if slen > 0 and tlen > 0:
+        if (sub[0] == '$' and topic[0] != '$') or (topic[0] == '$' and sub[0] != '$'):
+            return False
+
     spos = 0
     tpos = 0
 
diff --git a/test/lib/python/09-util-topic-matching.test b/test/lib/python/09-util-topic-matching.test
index 6ce4234..ef5c18c 100755
--- a/test/lib/python/09-util-topic-matching.test
+++ b/test/lib/python/09-util-topic-matching.test
@@ -23,4 +23,8 @@ do_check("#", "/foo/bar", False)
 do_check("/#", "/foo/bar", False)
 do_check("/#", "foo/bar", True)
 
+do_check("$SYS/bar", "$SYS/bar", False)
+do_check("#", "$SYS/bar", True)
+do_check("$BOB/bar", "$SYS/bar", True)
+
 sys.exit(0)
diff --git a/test/lib/python3/09-util-topic-matching.test b/test/lib/python3/09-util-topic-matching.test
index a3cc8d9..2f4424a 100755
--- a/test/lib/python3/09-util-topic-matching.test
+++ b/test/lib/python3/09-util-topic-matching.test
@@ -23,4 +23,8 @@ do_check("#", "/foo/bar", False)
 do_check("/#", "/foo/bar", False)
 do_check("/#", "foo/bar", True)
 
+do_check("$SYS/bar", "$SYS/bar", False)
+do_check("#", "$SYS/bar", True)
+do_check("$BOB/bar", "$SYS/bar", True)
+
 sys.exit(0)
-- 
2.39.5