When DEBUG_HEAP is defined, add free heap bytes to every log line in RedirectablePrint::log_to_serial

platformio.ini

@@ -55,6 +55,7 @@ build_flags = -Wno-missing-field-initializers
 	-D MAX_THREADS=40 ; As we've split modules, we have more threads to manage
 	#-DBUILD_EPOCH=$UNIX_TIME ; set in platformio-custom.py now
 	#-D OLED_PL=1
+	#-D DEBUG_HEAP=1 ; uncomment to add free heap space / memory leak debugging logs
 
 monitor_speed = 115200
 monitor_filters = direct

src/RedirectablePrint.cpp

@@ -4,6 +4,7 @@
 #include "concurrency/OSThread.h"
 #include "configuration.h"
 #include "main.h"
+#include "memGet.h"
 #include "mesh/generated/meshtastic/mesh.pb.h"
 #include <assert.h>
 #include <cstring>
@@ -166,6 +167,16 @@ void RedirectablePrint::log_to_serial(const char *logLevel, const char *format,
         print(thread->ThreadName);
         print("] ");
     }
+
+#ifdef DEBUG_HEAP
+    // Add heap free space bytes prefix before every log message
+#ifdef ARCH_PORTDUINO
+    ::printf("[heap %u] ", memGet.getFreeHeap());
+#else
+    printf("[heap %u] ", memGet.getFreeHeap());
+#endif
+#endif // DEBUG_HEAP
+
     r += vprintf(logLevel, format, arg);
 }