Improve robustness with custom exception that does not deinit() the TaskHandler

ThomasFarstrike · ThomasFarstrike · commit 304fa1a53768 · 2026-01-09T12:03:33.000+01:00
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -5,6 +5,8 @@
 - WiFi app: check "hidden" in EditNetwork
 - Wifi app: add support for scanning wifi QR codes to "Add Network"
 - Improve robustness by catching unhandled app exceptions
+- Improve robustness with custom exception that does not deinit() the TaskHandler
+- Improve robustness by removing TaskHandler callback that throws an uncaught exception
 
 0.5.2
 =====
diff --git a/internal_filesystem/lib/mpos/main.py b/internal_filesystem/lib/mpos/main.py
@@ -51,20 +51,27 @@
 if focusgroup: # on esp32 this may not be set
     focusgroup.remove_all_objs() #  might be better to save and restore the group for "back" actions
 
-# Can be passed to TaskHandler, currently unused:
+# Custom exception handler that does not deinit() the TaskHandler because then the UI hangs:
 def custom_exception_handler(e):
-    print(f"custom_exception_handler called: {e}")
-    mpos.ui.task_handler.deinit()
+    print(f"TaskHandler's custom_exception_handler called: {e}")
+    import sys
+    sys.print_exception(e)  # NOQA
+    # No need to deinit() and re-init LVGL:
+    #mpos.ui.task_handler.deinit() # default task handler does this, but then things hang
     # otherwise it does focus_next and then crashes while doing lv.deinit()
-    focusgroup.remove_all_objs()
-    focusgroup.delete()
-    lv.deinit()
+    #focusgroup.remove_all_objs()
+    #focusgroup.delete()
+    #lv.deinit()
 
 import sys
 if sys.platform == "esp32":
-    mpos.ui.task_handler = task_handler.TaskHandler(duration=5) # 1ms gives highest framerate on esp32-s3's but might have side effects?
+    mpos.ui.task_handler = task_handler.TaskHandler(duration=5, exception_hook=custom_exception_handler) # 1ms gives highest framerate on esp32-s3's but might have side effects?
 else:
-    mpos.ui.task_handler = task_handler.TaskHandler(duration=5) # 5ms is recommended for MicroPython+LVGL on desktop (less results in lower framerate)
+    mpos.ui.task_handler = task_handler.TaskHandler(duration=5, exception_hook=custom_exception_handler) # 5ms is recommended for MicroPython+LVGL on desktop (less results in lower framerate)
+
+# Convenient for apps to be able to access these:
+mpos.ui.task_handler.TASK_HANDLER_STARTED = task_handler.TASK_HANDLER_STARTED
+mpos.ui.task_handler.TASK_HANDLER_FINISHED = task_handler.TASK_HANDLER_FINISHED
 
 try:
     import freezefs_mount_builtin
diff --git a/lvgl_micropython b/lvgl_micropython
@@ -1 +1 @@
-Subproject commit 6a1409298593c557b724f3de6c2d0c7504c881d0
+Subproject commit 900c89296d7a6077f7532c6523e405ff06b7c3cd
diff --git a/scripts/build_mpos.sh b/scripts/build_mpos.sh
@@ -143,8 +143,8 @@ elif [ "$target" == "unix" -o "$target" == "macOS" ]; then
 	# Restore RLOTTIE:
 	if [ "$target" == "unix" ]; then
 		sed -i.backup 's/#define MICROPY_RLOTTIE 1/#define MICROPY_RLOTTIE 0/' "$codebasedir"/lvgl_micropython/lib/lv_conf.h
-		echo "After disabling MICROPY_RLOTTIE:"
-		cat "$codebasedir"/lvgl_micropython/lib/lv_conf.h
+		#echo "After disabling MICROPY_RLOTTIE:"
+		#cat "$codebasedir"/lvgl_micropython/lib/lv_conf.h
 	fi
 
 	# Restore @micropython.viper decorator after build
