Berry lv.start() raises an error instead of crashing when the display can't start (#25193)

CHANGELOG.md

@@ -27,6 +27,7 @@ All notable changes to this project will be documented in this file.
 - LVGL touch more responsive (#25172)
 - VEML7700 lux/white rounding, add new command (#25150)
 - WifiManager name the setup AP as it is turned on (#25169)
+- Berry `lv.start()` raises an error instead of crashing when the display can't start
 
 ### Removed
 

tasmota/tasmota_xdrv_driver/xdrv_52_3_berry_lvgl.ino

@@ -111,7 +111,7 @@ public:
 };
 LVBE_globals lvbe;
 
-extern void start_lvgl(const char * uconfig);
+extern bool start_lvgl(const char * uconfig);
 extern void lv_ex_get_started_1(void);
 
 extern "C" {
@@ -496,7 +496,10 @@ extern "C" {
       if (argc == 1) {
         uconfig = be_tostring(vm, 1);
       }
-      start_lvgl(uconfig);
+      if (!start_lvgl(uconfig)) {
+        // abort here, otherwise any following lv.* call crashes with LVGL not initialized
+        be_raise(vm, "internal_error", "LVGL could not start, check display configuration (display.ini, Option A3)");
+      }
 
       // call lv.splash_remove() to kill any current splash screen
       if (be_getglobal(vm, "lv")) {

tasmota/tasmota_xdrv_driver/xdrv_54_lvgl.ino

@@ -467,18 +467,21 @@ void lvgl_touchscreen_read(lv_indev_t *indev_drv, lv_indev_data_t *data) {
  ************************************************************/
 extern Renderer *Init_uDisplay(const char *desc);
 
-void start_lvgl(const char * uconfig);
-void start_lvgl(const char * uconfig) {
+// Returns true if LVGL is running (already or newly started), false on failure
+bool start_lvgl(const char * uconfig);
+bool start_lvgl(const char * uconfig) {
 
   if (lvgl_glue != nullptr) {
     AddLog(LOG_LEVEL_DEBUG_MORE, D_LOG_LVGL "LVGL was already initialized");
-    return;
+    return true;
   }
 
   if (!renderer || uconfig) {
     renderer  = Init_uDisplay((char*)uconfig);
-    AddLog(LOG_LEVEL_ERROR, "LVG: Could not start Universal Display");
-    if (!renderer) return;
+    if (!renderer) {
+      AddLog(LOG_LEVEL_ERROR, "LVG: Could not start Universal Display");
+      return false;
+    }
   }
 
   renderer->DisplayOnff(true);
@@ -539,7 +542,7 @@ void start_lvgl(const char * uconfig) {
     delete lvgl_glue;
     lvgl_glue = nullptr;
     AddLog(LOG_LEVEL_ERROR, "LVG: Could not allocate buffers");
-    return;
+    return false;
   }
 
   // Initialize LvGL display driver
@@ -610,6 +613,7 @@ void start_lvgl(const char * uconfig) {
   }
 
   AddLog(LOG_LEVEL_INFO, PSTR(D_LOG_LVGL "LVGL initialized"));
+  return true;
 }
 
 /*********************************************************************************************\