config: remove a footgun

electrum/simple_config.py

@@ -186,6 +186,8 @@ class SimpleConfig(Logger):
                  read_user_dir_function=None):
         if options is None:
             options = {}
+        for config_key in options:
+            assert isinstance(config_key, str), f"{config_key=!r} has type={type(config_key)}, expected str"
 
         Logger.__init__(self)
 

run_electrum

@@ -326,7 +326,7 @@ def main():
             'cmd': 'gui',
             SimpleConfig.GUI_NAME.key(): 'qml',
             SimpleConfig.WALLET_USE_SINGLE_PASSWORD.key(): True,
-            SimpleConfig.SWAPSERVER_URL: 'https://swaps.electrum.org/api',
+            SimpleConfig.SWAPSERVER_URL.key(): 'https://swaps.electrum.org/api',
         }
         if util.get_android_package_name() == "org.electrum.testnet.electrum":
             # ~hack for easier testnet builds. pkgname subject to change.