Merge pull request #10165 from spesmilo/swaps_prepayment

reverse swaps: in the CLI, replace 'server_mining_fee' with

electrum/commands.py

@@ -1995,7 +1995,7 @@ class Commands(Logger):
                 "max_forward_sat": offer.pairs.max_forward,
                 "max_reverse_sat": offer.pairs.max_reverse,
                 "min_amount_sat": offer.pairs.min_amount,
-                "provider_mining_fee": offer.pairs.mining_fee,
+                "prepayment": 2 * offer.pairs.mining_fee,
             }
         return result
 
@@ -2041,14 +2041,14 @@ class Commands(Logger):
 
     @command('wnpl')
     async def reverse_swap(
-        self, lightning_amount, onchain_amount, provider_mining_fee='dryrun', password=None, wallet: Abstract_Wallet = None,
+        self, lightning_amount, onchain_amount, prepayment='dryrun', password=None, wallet: Abstract_Wallet = None,
     ):
         """
         Reverse submarine swap: send on Lightning, receive on-chain
 
         arg:decimal_or_dryrun:lightning_amount:Amount to be sent, in BTC. Set it to 'dryrun' to receive a value
         arg:decimal_or_dryrun:onchain_amount:Amount to be received, in BTC. Set it to 'dryrun' to receive a value
-        arg:decimal_or_dryrun:provider_mining_fee:Mining fee required by the swap provider, in BTC. Set it to 'dryrun' to receive a value
+        arg:decimal_or_dryrun:prepayment:Lightning payment required by the swap provider in order to cover their mining fees. This is included in lightning_amount. However, this part of the operation is not trustless; the provider is trusted to fail this payment if the swap fails.
         """
         sm = wallet.lnworker.swap_manager
         assert self.config.SWAPSERVER_NPUB or self.config.SWAPSERVER_URL, \
@@ -2061,32 +2061,32 @@ class Commands(Logger):
             if onchain_amount == 'dryrun':
                 lightning_amount_sat = satoshis(lightning_amount)
                 onchain_amount_sat = sm.get_recv_amount(lightning_amount_sat, is_reverse=True)
-                assert provider_mining_fee == "dryrun", f"Cannot use {provider_mining_fee=} in dryrun. Set it to 'dryrun'."
+                assert prepayment == "dryrun", f"Cannot use {prepayment=} in dryrun. Set it to 'dryrun'."
-                provider_mining_fee = sm.mining_fee
+                prepayment_sat = 2 * sm.mining_fee
                 funding_txid = None
             elif lightning_amount == 'dryrun':
                 onchain_amount_sat = satoshis(onchain_amount)
                 lightning_amount_sat = sm.get_send_amount(onchain_amount_sat, is_reverse=True)
-                assert provider_mining_fee == "dryrun", f"Cannot use {provider_mining_fee=} in dryrun. Set it to 'dryrun'."
+                assert prepayment == "dryrun", f"Cannot use {prepayment=} in dryrun. Set it to 'dryrun'."
-                provider_mining_fee = sm.mining_fee
+                prepayment_sat = 2 * sm.mining_fee
                 funding_txid = None
             else:
                 lightning_amount_sat = satoshis(lightning_amount)
                 claim_fee = sm.get_fee_for_txbatcher()
                 onchain_amount_sat = satoshis(onchain_amount) + claim_fee
-                assert provider_mining_fee != "dryrun", "Provide the 'provider_mining_fee' obtained from the dryrun."
+                assert prepayment != "dryrun", "Provide the 'prepayment' obtained from the dryrun."
-                provider_mining_fee = satoshis(provider_mining_fee)
+                prepayment_sat = satoshis(prepayment)
                 funding_txid = await wallet.lnworker.swap_manager.reverse_swap(
                     transport=transport,
                     lightning_amount_sat=lightning_amount_sat,
                     expected_onchain_amount_sat=onchain_amount_sat,
-                    server_mining_fee_sat=provider_mining_fee,
+                    prepayment_sat=prepayment_sat,
                 )
         return {
             'funding_txid': funding_txid,
             'lightning_amount': format_satoshis(lightning_amount_sat),
             'onchain_amount': format_satoshis(onchain_amount_sat),
-            'provider_mining_fee': format_satoshis(provider_mining_fee)
+            'prepayment': format_satoshis(prepayment_sat)
         }
 
     @command('n')

electrum/gui/qml/qeswaphelper.py

@@ -719,7 +719,7 @@ class QESwapHelper(AuthMixin, QObject, QtEventListener):
                     transport=self.swap_transport,
                     lightning_amount_sat=lightning_amount,
                     expected_onchain_amount_sat=onchain_amount + swap_manager.get_fee_for_txbatcher(),
-                    server_mining_fee_sat=self.serverMiningfee.satsInt,
+                    prepayment_sat=2 * self.serverMiningfee.satsInt,
                 )
                 try:  # swaphelper might be destroyed at this point
                     if txid:

electrum/gui/qt/swap_dialog.py

@@ -338,7 +338,7 @@ class SwapDialog(WindowModalDialog, QtEventListener):
                 transport=transport,
                 lightning_amount_sat=lightning_amount,
                 expected_onchain_amount_sat=onchain_amount + self.swap_manager.get_fee_for_txbatcher(),
-                server_mining_fee_sat=self.last_server_mining_fee_sat,
+                prepayment_sat=2 * self.last_server_mining_fee_sat,
             )
             try:
                 # we must not leave the context, so we use run_couroutine_dialog

electrum/submarine_swaps.py

@@ -926,7 +926,7 @@ class SwapManager(Logger):
             transport: 'SwapServerTransport',
             lightning_amount_sat: int,
             expected_onchain_amount_sat: int,
-            server_mining_fee_sat: int,
+            prepayment_sat: int,
             channels: Optional[Sequence['Channel']] = None,
     ) -> Optional[str]:
         """send on Lightning, receive on-chain
@@ -943,9 +943,9 @@ class SwapManager(Logger):
         - Server fulfills HTLC using preimage.
 
         Note: expected_onchain_amount_sat is BEFORE deducting the on-chain claim tx fee.
-        Note: server_mining_fee_sat is passed as argument instead of accessing self.mining_fee to ensure
+        Note: prepayment_sat is passed as argument instead of accessing self.mining_fee to ensure
         the mining fees the user sees in the GUI are also the values used for the checks performed here.
-        We commit to server_mining_fee_sat as it limits the max fee pre-payment amt, which the server is trusted with.
+        We commit to prepayment_sat as it limits the max fee pre-payment amt, which the server is trusted with.
         """
         assert self.network
         assert self.lnwatcher
@@ -1007,7 +1007,7 @@ class SwapManager(Logger):
             raise Exception("rswap check failed: inconsistent RHASH and invoice")
         if fee_invoice:
             fee_lnaddr = self.lnworker._check_bolt11_invoice(fee_invoice)
-            if fee_lnaddr.get_amount_sat() > server_mining_fee_sat * 2:
+            if fee_lnaddr.get_amount_sat() > prepayment_sat:
                 raise SwapServerError(_("Mining fee requested by swap-server larger "
                                         "than what was announced in their offer."))
             invoice_amount += fee_lnaddr.get_amount_sat()

tests/regtest/regtest.sh

@@ -248,8 +248,8 @@ if [[ $1 == "swapserver_success" ]]; then
     echo "alice initiates swap"
     dryrun=$($alice reverse_swap 0.02 dryrun)
     onchain_amount=$(echo $dryrun| jq -r ".onchain_amount")
-    swapserver_mining_fee=$(echo $dryrun| jq -r ".provider_mining_fee")
+    prepayment=$(echo $dryrun| jq -r ".prepayment")
-    swap=$($alice reverse_swap 0.02 $onchain_amount --provider_mining_fee $swapserver_mining_fee)
+    swap=$($alice reverse_swap 0.02 $onchain_amount --prepayment $prepayment)
     echo $swap | jq
     funding_txid=$(echo $swap| jq -r ".funding_txid")
     new_blocks 1
@@ -273,8 +273,8 @@ if [[ $1 == "swapserver_forceclose" ]]; then
     echo "alice initiates swap"
     dryrun=$($alice reverse_swap 0.02 dryrun)
     onchain_amount=$(echo $dryrun| jq -r ".onchain_amount")
-    swapserver_mining_fee=$(echo $dryrun| jq -r ".provider_mining_fee")
+    prepayment=$(echo $dryrun| jq -r ".prepayment")
-    swap=$($alice reverse_swap 0.02 $onchain_amount --provider_mining_fee $swapserver_mining_fee)
+    swap=$($alice reverse_swap 0.02 $onchain_amount --prepayment $prepayment)
     echo $swap | jq
     funding_txid=$(echo $swap| jq -r ".funding_txid")
     ctx_id=$($bob close_channel --force $channel)
@@ -309,8 +309,8 @@ if [[ $1 == "swapserver_refund" ]]; then
     echo "alice initiates swap"
     dryrun=$($alice reverse_swap 0.02 dryrun)
     onchain_amount=$(echo $dryrun| jq -r ".onchain_amount")
-    swapserver_mining_fee=$(echo $dryrun| jq -r ".provider_mining_fee")
+    prepayment=$(echo $dryrun| jq -r ".prepayment")
-    swap=$($alice reverse_swap 0.02 $onchain_amount --provider_mining_fee $swapserver_mining_fee)
+    swap=$($alice reverse_swap 0.02 $onchain_amount --prepayment $prepayment)
     echo $swap | jq
     funding_txid=$(echo $swap| jq -r ".funding_txid")
     new_blocks 140

tests/test_commands.py

@@ -711,14 +711,14 @@ class TestCommandsTestnet(ElectrumTestCase):
                 "max_forward_sat": offer1.pairs.max_forward,
                 "max_reverse_sat": offer1.pairs.max_reverse,
                 "min_amount_sat": offer1.pairs.min_amount,
-                "provider_mining_fee": offer1.pairs.mining_fee,
+                "prepayment": 2 * offer1.pairs.mining_fee,
             },
             offer2.server_npub: {
                 "percentage_fee": offer2.pairs.percentage,
                 "max_forward_sat": offer2.pairs.max_forward,
                 "max_reverse_sat": offer2.pairs.max_reverse,
                 "min_amount_sat": offer2.pairs.min_amount,
-                "provider_mining_fee": offer2.pairs.mining_fee,
+                "prepayment": 2 * offer2.pairs.mining_fee,
             }
         }
         self.assertEqual(result, expected_result)