fix: Custom stick and switch names were being mangled internally (#1770)

* followup to PR1754

* Cleanup

* Formatting

* Long comment

radio/src/lua/api_general.cpp

@@ -91,6 +91,10 @@
   { "EVT_"#xxx"_LONG", EVT_KEY_LONG(yyy) }, \
   { "EVT_"#xxx"_REPT", EVT_KEY_REPT(yyy) }
 
+// see strhelpers.cpp for pre-instantiation of function-template
+// getSourceString() for this parametrization
+static constexpr uint8_t maxSourceNameLength{16};
+
 // Note:
 // - luaRxFifo & luaReceiveData are used only for USB serial
 // - otherwise, the AUX serial buffer is used directly
@@ -2301,22 +2305,23 @@ This function is rather time consuming, and should not be used repeatedly in a s
 @status current Introduced in 2.6
 */
 
-static int luaGetSourceIndex(lua_State * L)
+static int luaGetSourceIndex(lua_State* const L)
 {
-  const char * name = luaL_checkstring(L, 1);
+  const char* const name = luaL_checkstring(L, 1);
   bool found = false;
   mixsrc_t idx;
-  
+
   for (idx = MIXSRC_NONE; idx <= MIXSRC_LAST_TELEM; idx++) {
     if (isSourceAvailable(idx)) {
-      char* s = getSourceString(idx);
-      if (!strncasecmp(s, name, 31)) {
+      char srcName[maxSourceNameLength];
+      getSourceString(srcName, idx);
+      if (!strncasecmp(srcName, name)) {
         found = true;
         break;
       }
     }
   }
-  
+
   if (found)
     lua_pushinteger(L, idx);
   else
@@ -2341,11 +2346,12 @@ static int luaGetSourceName(lua_State * L)
 {
   mixsrc_t idx = luaL_checkinteger(L, 1);
   if (idx <= MIXSRC_LAST_TELEM && isSourceAvailable(idx)) {
-    char* name = getSourceString(idx);
-    lua_pushstring(L, name);
-  }
-  else
+    char srcName[maxSourceNameLength];
+    getSourceString(srcName, idx);
+    lua_pushstring(L, srcName);
+  } else {
     lua_pushnil(L);
+  }
   return 1;
 }
 
@@ -2368,9 +2374,10 @@ static int luaNextSource(lua_State * L)
   
   while (++idx <= last) {
     if (isSourceAvailable(idx)) {
-      char* name = getSourceString(idx);
+      char srcName[maxSourceNameLength];
+      getSourceString(srcName, idx);
       lua_pushinteger(L, idx);
-      lua_pushstring(L, name);
+      lua_pushstring(L, srcName);
       return 2;
     }
   }