tx.unsigned: new sign() method

mmgen/proto/btc/tx/unsigned.py

@@ -21,13 +21,7 @@ class Unsigned(Completed, TxBase.Unsigned):
 	desc = 'unsigned transaction'
 
 	# Return signed object or False. Don’t exit or raise exception:
-	async def sign(self, keys, tx_num_str=''):
-
-		from ....exception import TransactionChainMismatch
-		try:
-			self.check_correct_chain()
-		except TransactionChainMismatch:
-			return False
+	async def proto_sign(self, keys, tx_num_str=''):
 
 		if (self.has_segwit_inputs() or self.has_segwit_outputs()) and not self.proto.cap('segwit'):
 			ymsg(f"TX has Segwit inputs or outputs, but {self.coin} doesn't support Segwit!")

mmgen/proto/vm/tx/unsigned.py

@@ -18,13 +18,7 @@ class Unsigned:
 	desc = 'unsigned transaction'
 
 	# Return signed object or False. Don’t exit or raise exception:
-	async def sign(self, keys, tx_num_str=''):
-
-		from ....exception import TransactionChainMismatch
-		try:
-			self.check_correct_chain()
-		except TransactionChainMismatch:
-			return False
+	async def proto_sign(self, keys, tx_num_str=''):
 
 		o = self.txobj
 

mmgen/tx/unsigned.py

@@ -20,6 +20,18 @@ class Unsigned(Completed):
 	ext  = 'rawtx'
 	automount = False
 
+	# Return signed object or False.  Don’t exit or raise exception, unless fatal:
+	async def sign(self, keys, tx_num_str=''):
+
+		try:
+			self.check_correct_chain()
+		except Exception as e:
+			if type(e).__name__ == 'TransactionChainMismatch':
+				return False
+			raise # fatal
+
+		return await self.proto_sign(keys, tx_num_str=tx_num_str)
+
 	def delete_attrs(self, desc, attr):
 		for e in getattr(self, desc):
 			if hasattr(e, attr):