fix i2c decode issue

Adafruit_MQTT.cpp

@@ -563,9 +563,12 @@ Adafruit_MQTT_Subscribe *Adafruit_MQTT::handleSubscriptionPacket(uint16_t len) {
   }
 
   // Parse out length of packet.
-  uint16_t const topicoffset = packetAdditionalLen(len);
+  // NOTE: This includes data in the variable header and the payload.
+  uint16_t remainingLen = len - 4; // subtract the 4 header bytes
+  uint16_t const topicoffset = packetAdditionalLen(remainingLen);
   uint16_t const topicstart = topicoffset + 4;
-  topiclen = buffer[3 + topicoffset];
+
+  topiclen = int((buffer[2 + topicoffset]) << 8 | buffer[3 + topicoffset]);
   DEBUG_PRINT(F("Looking for subscription len "));
   DEBUG_PRINTLN(topiclen);
 

Adafruit_MQTT.h

@@ -107,7 +107,13 @@
 // Largest full packet we're able to send.
 // Need to be able to store at least ~90 chars for a connect packet with full
 // 23 char client ID.
+// Future TODO: This should be replaced by the ability to
+#if defined(ARDUINO_ARCH_ESP8266) || defined(ARDUINO_ARCH_ESP32) ||            \
+    defined(ARDUINO_ARCH_RP2040) || defined(ARDUINO_ARCH_SAMD)
+#define MAXBUFFERSIZE (512)
+#else
 #define MAXBUFFERSIZE (150)
+#endif
 
 #define MQTT_CONN_USERNAMEFLAG 0x80
 #define MQTT_CONN_PASSWORDFLAG 0x40

library.properties

@@ -1,5 +1,5 @@
 name=Adafruit MQTT Library
-version=2.5.7
+version=2.5.8
 author=Adafruit
 maintainer=Adafruit <info@adafruit.com>
 sentence=MQTT library that supports the FONA, ESP8266, ESP32, Yun, and generic Arduino Client hardware.