Do not change CMock_Guts_Buffer or CMock_Guts_BufferSize unless

realloc() was successful. Prior to this change, if realloc() failed, the
current test would fail for out-of-memory, but subsequent tests would
continue trying to run with CMock_Guts_Buffer at address 0x00000000 and
thinking that the buffer size was sufficient. Therefore depending on the
system and how it handles (or doesn't handle) null pointer
dereferencing, subsequent tests might pass, fail in strange ways, or
crash the test app.

src/cmock.c

@@ -48,12 +48,17 @@ CMOCK_MEM_INDEX_TYPE CMock_Guts_MemNew(CMOCK_MEM_INDEX_TYPE size)
     size = (size + CMOCK_MEM_ALIGN_MASK) & ~CMOCK_MEM_ALIGN_MASK;
   if ((CMock_Guts_BufferSize - CMock_Guts_FreePtr) < size)
   {
-#ifdef CMOCK_MEM_DYNAMIC
-    CMock_Guts_BufferSize += CMOCK_MEM_SIZE + size;
-    CMock_Guts_Buffer = realloc(CMock_Guts_Buffer, (size_t)CMock_Guts_BufferSize);
-    if (CMock_Guts_Buffer == NULL)
-#endif //yes that if will continue to the return below if TRUE
-      return CMOCK_GUTS_NONE;
+#ifndef CMOCK_MEM_DYNAMIC
+    return CMOCK_GUTS_NONE; // nothing we can do; our static buffer is out of memory
+#else
+    // our dynamic buffer does not have enough room; request more via realloc()
+    CMOCK_MEM_INDEX_TYPE new_buffersize = CMock_Guts_BufferSize + CMOCK_MEM_SIZE + size;
+    unsigned char* new_buffer = realloc(CMock_Guts_Buffer, (size_t)new_buffersize);
+    if (new_buffer == NULL)
+      return CMOCK_GUTS_NONE; // realloc() failed; out of memory
+    CMock_Guts_Buffer = new_buffer;
+    CMock_Guts_BufferSize = new_buffersize;
+#endif
   }
 
   //determine where we're putting this new block, and init its pointer to be the end of the line