From b996b096b39fc9f14e65f0327b93173abb8f38ce Mon Sep 17 00:00:00 2001
From: Matthijs Kooijman <matthijs@stdin.nl>
Date: Thu, 2 Jul 2015 13:28:38 +0200
Subject: [PATCH] Fix Adafruit_MQTT:subscribe()

This method contained a loop that checked for an existing subscription,
but it only printed a debug message if so. Now, it immediately returns
true if the subscription is already registered.

When this method succesfully adds a subscription, it was documented to
return true, but the actual code did not return anything in this case,
resulting in a compiler warning. In practice, on AVR, the value of the
first argument would be returned, which likely evaluates as true, so
it is likely it actually seemed to work fine.
---
 Adafruit_MQTT.cpp | 11 +++++------
 Adafruit_MQTT.h   |  2 +-
 2 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/Adafruit_MQTT.cpp b/Adafruit_MQTT.cpp
index b0dbb16..557ee06 100644
--- a/Adafruit_MQTT.cpp
+++ b/Adafruit_MQTT.cpp
@@ -176,7 +176,7 @@ bool Adafruit_MQTT::subscribe(Adafruit_MQTT_Subscribe *sub) {
   for (i=0; i<MAXSUBSCRIPTIONS; i++) {
     if (subscriptions[i] == sub) {
       DEBUG_PRINTLN(F("Already subscribed"));
-      break;
+      return true;
     }
   }
   if (i==MAXSUBSCRIPTIONS) { // add to subscriptionlist
@@ -184,14 +184,13 @@ bool Adafruit_MQTT::subscribe(Adafruit_MQTT_Subscribe *sub) {
       if (subscriptions[i] == 0) {
         DEBUG_PRINT(F("Added sub ")); DEBUG_PRINTLN(i);
         subscriptions[i] = sub;
-        break;
+        return true;
       }
     }
   }
-  if (i==MAXSUBSCRIPTIONS) {
-    DEBUG_PRINTLN(F("no more subscription space :("));
-    return false;
-  }
+
+  DEBUG_PRINTLN(F("no more subscription space :("));
+  return false;
 }
 
 Adafruit_MQTT_Subscribe *Adafruit_MQTT::readSubscription(int16_t timeout) {
diff --git a/Adafruit_MQTT.h b/Adafruit_MQTT.h
index 909ee58..dc703bc 100644
--- a/Adafruit_MQTT.h
+++ b/Adafruit_MQTT.h
@@ -127,7 +127,7 @@ class Adafruit_MQTT {
   bool publish(const char *topic, const char *payload, uint8_t qos);
 
   // Add a subscription to receive messages for a topic.  Returns true if the
-  // subscription could be added, false otherwise.
+  // subscription could be added or was already present, false otherwise.
   bool subscribe(Adafruit_MQTT_Subscribe *sub);
 
   // Check if any subscriptions have new messages.  Will return a reference to