impr: detect invalid config changes (#4)

bot/bot.py

@@ -251,27 +251,27 @@ async def config_handle(update: Update, context: CallbackContext):
         await message.reply_text(text, parse_mode=ParseMode.HTML)
         return
 
+    property = parts[1]
+    value = config.get_value(property)
+    value = value if value is not None else "(empty)"
+
     if len(parts) == 2:
         # view config property (`/config {property}`)
-        property = parts[1]
-        value = config.get_value(property) or "(empty)"
         await message.reply_text(f"`{value}`", parse_mode=ParseMode.MARKDOWN)
         return
 
-    # change config property (`/config {property} {value}`)
-    property = parts[1]
-    old_value = config.get_value(property) or "(empty)"
-    value = " ".join(parts[2:])
-    has_changed, is_immediate = config.set_value(property, value)
+    # change config property (`/config {property} {new_value}`)
+    new_value = " ".join(parts[2:])
+    has_changed, is_immediate = config.set_value(property, new_value)
 
     if not has_changed:
-        text = f"✗ The `{property}` property already equals to `{value}`"
+        text = f"✗ The `{property}` property already equals to `{new_value}`"
         await message.reply_text(text, parse_mode=ParseMode.MARKDOWN)
         return
 
     config.save()
     Filters.reload()
-    text = f"✓ Changed the `{property}` property: `{old_value}` → `{value}`"
+    text = f"✓ Changed the `{property}` property: `{value}` → `{new_value}`"
     if not is_immediate:
         text += "\n❗️Restart the bot for changes to take effect."
     await message.reply_text(text, parse_mode=ParseMode.MARKDOWN)

bot/config.py

@@ -183,8 +183,11 @@ def set_value(self, property: str, value: str) -> tuple[bool, bool]:
           - `has_changed` = True if the value has actually changed, False otherwise.
           - `is_immediate` = True if the change takes effect immediately, False otherwise.
         """
+        try:
+            val = yaml.safe_load(value)
+        except Exception:
+            raise ValueError(f"Invalid value: {value}")
 
-        val = yaml.safe_load(value)
         old_val = self.get_value(property)
         if val == old_val:
             return False, False

tests/test_config.py

@@ -171,6 +171,10 @@ def test_dict_value_does_not_exist(self):
         value = self.config.get_value("shortcuts.bugfix")
         self.assertEqual(value, "Fix bugs in the code")
 
+    def test_invalid_value(self):
+        with self.assertRaises(ValueError):
+            self.config.set_value("imagine", '"on')
+
     def test_has_changed(self):
         has_changed, _ = self.config.set_value("imagine", "on")
         self.assertTrue(has_changed)