fix: exceptions in callback should not terminate caller

Signed-off-by: Matthias Blankertz <matthias@blankertz.org>

software/src/nfc/nfc.py

@@ -6,6 +6,7 @@ Copyright (c) 2025 Matthias Blankertz <matthias@blankertz.org>
 
 import asyncio
 import time
+from utils import safe_callback
 
 from mfrc522 import MFRC522
 try:
@@ -74,7 +75,7 @@ class Nfc:
                 self.last_uid = uid
                 self.last_uid_timestamp = time.ticks_us()
             if self.cb is not None and last_callback_uid != uid:
-                self.cb.onTagChange(uid)
+                safe_callback(lambda: self.cb.onTagChange(uid), "nfc tag change")
                 last_callback_uid = uid
 
             await asyncio.sleep_ms(poll_interval_ms)

software/src/utils/__init__.py

@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: MIT
 # Copyright (c) 2025 Matthias Blankertz <matthias@blankertz.org>
 
+from utils.helpers import safe_callback
 from utils.buttons import Buttons
 from utils.config import Configuration
 from utils.leds import LedManager
@@ -11,4 +12,4 @@ from utils.sdcontext import SDContext
 from utils.timer import TimerManager
 
 __all__ = ["BTreeDB", "BTreeFileManager", "Buttons", "Configuration", "get_pin_index", "LedManager", "MBRPartition",
-           "SDContext", "TimerManager"]
+           "safe_callback", "SDContext", "TimerManager"]

software/src/utils/buttons.py

@@ -5,6 +5,7 @@ import asyncio
 import machine
 import micropython
 import time
+from utils import safe_callback
 try:
     from typing import TYPE_CHECKING  # type: ignore
 except ImportError:
@@ -74,4 +75,4 @@ class Buttons:
             await self.int_flag.wait()
             while len(self.pressed) > 0:
                 what = self.pressed.pop()
-                self.cb.onButtonPressed(what)
+                safe_callback(lambda: self.cb.onButtonPressed(what), "button callback")

software/src/utils/helpers.py

@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: MIT
+# Copyright (c) 2025 Matthias Blankertz <matthias@blankertz.org>
+
+import sys
+
+
+def safe_callback(func, name="callback"):
+    try:
+        func()
+    except Exception as ex:
+        print(f"Uncaught exception in {name}")
+        sys.print_exception(ex)

software/src/utils/timer.py

@@ -4,6 +4,7 @@
 import asyncio
 import heapq
 import time
+from utils import safe_callback
 
 TIMER_DEBUG = True
 
@@ -72,5 +73,7 @@ class TimerManager(object):
                     continue
                 except asyncio.TimeoutError:
                     pass
+            if len(self.timers) == 0:
+                continue
             _, callback = heapq.heappop(self.timers)
-            callback()
+            safe_callback(callback, "timer callback")