From 7e442eadadd239b3f364d1fd04941520a794706e Mon Sep 17 00:00:00 2001
From: The MMGen Project <mmgen@tuta.io>
Date: Tue, 27 Oct 2026 13:30:14 +0000
Subject: [PATCH] proto.eth.params: add `multiple_txhex` mmcap

---
 mmgen/main_txsend.py         |  9 +++++++++
 mmgen/proto/btc/tx/status.py |  1 -
 mmgen/proto/eth/params.py    |  2 +-
 mmgen/proto/eth/tx/online.py |  7 ++++++-
 mmgen/tx/online.py           | 12 ++----------
 5 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/mmgen/main_txsend.py b/mmgen/main_txsend.py
index 11823634..9aaa1a0f 100644
--- a/mmgen/main_txsend.py
+++ b/mmgen/main_txsend.py
@@ -159,6 +159,15 @@ async def process_tx(tx):
 	if tx.is_compat and not cfg.autosign:
 		die(1, 'Sending XMR transaction via compatibility layer requires --autosign')
 
+	if cfg.txhex_idx:
+		if not 'multiple_txhex' in tx.proto.mmcaps:
+			die(1, f'--txhex-idx not supported for {tx.proto.name} protocol')
+		if getattr(tx, 'coin_txid2', None):
+			if cfg.txhex_idx not in ('1', '2'):
+				die(1, f'{cfg.txhex_idx}: invalid parameter for --txhex-idx (must be 1 or 2)')
+		else:
+			die(1, '--txhex-idx not supported for transactions with only one part')
+
 	txcfg = Config({'_clone': cfg, 'proto': tx.proto, 'coin': tx.proto.coin})
 
 	if (not post_send_op) and cfg.tx_proxy:
diff --git a/mmgen/proto/btc/tx/status.py b/mmgen/proto/btc/tx/status.py
index 18ff5ed7..d503171f 100644
--- a/mmgen/proto/btc/tx/status.py
+++ b/mmgen/proto/btc/tx/status.py
@@ -25,7 +25,6 @@ class Status(TxBase.Status):
 				msg(message)
 			return exitval
 
-		assert idx == '', f'multiple txhex not supported for {self.tx.proto}'
 		tx = self.tx
 
 		class r:
diff --git a/mmgen/proto/eth/params.py b/mmgen/proto/eth/params.py
index 9fad696a..b656b3b4 100644
--- a/mmgen/proto/eth/params.py
+++ b/mmgen/proto/eth/params.py
@@ -29,7 +29,7 @@ class mainnet(CoinProtocol.DummyWIF, CoinProtocol.Secp256k1):
 	chain_names   = ['ethereum', 'foundation']
 	sign_mode     = 'standalone'
 	caps          = ('token',)
-	mmcaps        = ('rpc', 'rpc_init', 'tw', 'msg')
+	mmcaps        = ('rpc', 'rpc_init', 'tw', 'msg', 'multiple_txhex')
 	base_proto    = 'Ethereum'
 	base_proto_coin = 'ETH'
 	base_coin     = 'ETH'
diff --git a/mmgen/proto/eth/tx/online.py b/mmgen/proto/eth/tx/online.py
index d06b0fcc..74fd6275 100644
--- a/mmgen/proto/eth/tx/online.py
+++ b/mmgen/proto/eth/tx/online.py
@@ -10,7 +10,7 @@
 proto.eth.tx.online: Ethereum online signed transaction class
 """
 
-from ....util import msg, die
+from ....util import msg, ymsg, die
 from ....color import yellow, green, orange
 from ....tx import online as TxBase
 from .. import erigon_sleep
@@ -21,6 +21,11 @@ class OnlineSigned(Signed, TxBase.OnlineSigned):
 	async def test_sendable(self, txhex):
 		raise NotImplementedError('transaction testing not implemented for Ethereum')
 
+	def confirm_send(self, idxs):
+		super().confirm_send(idxs)
+		if len(idxs) > 1 and self.is_swap:
+			ymsg('Warning: two transactions (approval and router) will be broadcast to the network')
+
 	async def send_checks(self):
 		self.check_correct_chain()
 		if not self.disable_fee_check and (self.fee > self.proto.max_tx_fee):
diff --git a/mmgen/tx/online.py b/mmgen/tx/online.py
index cf3b501f..b3192b82 100644
--- a/mmgen/tx/online.py
+++ b/mmgen/tx/online.py
@@ -67,8 +67,6 @@ class OnlineSigned(Signed):
 				self.proto.network.upper()),
 			expect = 'YES')
 		msg('Sending transaction')
-		if len(idxs) > 1 and getattr(self, 'coin_txid2', None) and self.is_swap:
-			ymsg('Warning: two transactions (approval and router) will be broadcast to the network')
 
 	async def post_send(self, asi):
 		from . import SentTX
@@ -90,14 +88,8 @@ class OnlineSigned(Signed):
 		all_ok = True
 		idxs = ['', '2']
 
-		if cfg.txhex_idx:
-			if getattr(self, 'coin_txid2', None):
-				if cfg.txhex_idx in ('1', '2'):
-					idxs = ['' if cfg.txhex_idx == '1' else cfg.txhex_idx]
-				else:
-					die(1, f'{cfg.txhex_idx}: invalid parameter for --txhex-idx (must be 1 or 2)')
-			else:
-				die(1, 'Transaction has only one part, so --txhex-idx makes no sense')
+		if cfg.txhex_idx and getattr(self, 'coin_txid2', None):
+			idxs = ['' if cfg.txhex_idx == '1' else cfg.txhex_idx]
 
 		if not (cfg.status or cfg.receipt or cfg.dump_hex or cfg.test):
 			self.confirm_send(idxs)