ecc_fast: require libsecp256k1 on lightning, channel graph breaks electrum without

electrum/ecc_fast.py

@@ -186,10 +186,8 @@ def _prepare_monkey_patching_of_python_ecdsa_internals_with_libsecp256k1():
 
 def do_monkey_patching_of_python_ecdsa_internals_with_libsecp256k1():
     if not _libsecp256k1:
-        # FIXME logging 'verbosity' is not yet initialised
-        _logger.info('libsecp256k1 library not available, falling back to python-ecdsa. '
-                     'This means signing operations will be slower.')
-        return
+        raise Exception('libsecp256k1 library not available. '
+                        'Verifying Lightning channels is too computationally expensive without libsecp256k1, aborting.')
     if not _patched_functions.prepared_to_patch:
         raise Exception("can't patch python-ecdsa without preparations")
     ecdsa.ecdsa.Private_key.sign      = _patched_functions.fast_sign