make sure balance is set correctly

fix: deduct mint NUT-02 input fee when crediting trusted-mint topups

routstr/wallet.py

@@ -35,6 +35,24 @@ async def get_balance(unit: str) -> int:
     return wallet.available_balance.amount
 
 
+async def _redeem_same_mint(
+    wallet: Wallet, token_obj: Token
+) -> tuple[int, str, str]:  # amount, unit, mint_url
+    """Redeem proofs at their own issuing mint (no cross-mint swap).
+
+    split() re-mints the incoming proofs into fresh ones we own so the sender
+    can't double-spend them. With include_fees=True the mint deducts its NUT-02
+    per-proof input fee, so we end up holding only `amount - input_fees`. Credit
+    that, not the face value, or routstr over-credits the user and its wallet
+    drifts insolvent.
+    """
+    await wallet.load_mint(keyset_id=token_obj.keysets[0])
+    wallet.verify_proofs_dleq(token_obj.proofs)
+    input_fees = wallet.get_fees_for_proofs(token_obj.proofs)
+    await wallet.split(proofs=token_obj.proofs, amount=0, include_fees=True)
+    return int(token_obj.amount) - input_fees, token_obj.unit, token_obj.mint
+
+
 async def recieve_token(
     token: str,
 ) -> tuple[int, str, str]:  # amount, unit, mint_url
@@ -48,12 +66,7 @@ async def recieve_token(
     if token_obj.mint not in settings.cashu_mints:
         return await swap_to_primary_mint(token_obj, wallet)
 
-    await wallet.load_mint(keyset_id=token_obj.keysets[0])
-
-    wallet.verify_proofs_dleq(token_obj.proofs)
-    await wallet.split(proofs=token_obj.proofs, amount=0, include_fees=True)
-
-    return token_obj.amount, token_obj.unit, token_obj.mint
+    return await _redeem_same_mint(wallet, token_obj)
 
 
 async def send(amount: int, unit: str, mint_url: str | None = None) -> tuple[int, str]:
@@ -213,10 +226,9 @@ async def swap_to_primary_mint(
         amount_msat = token_amount
     else:
         raise ValueError("Invalid unit")
-    primary_wallet = await get_wallet(settings.primary_mint, settings.primary_mint_unit)
-
-    # If the token is already from the primary mint, we don't need to swap
-    # and we definitely don't want to calculate or pay fees.
+    # If the token is already from the primary mint, we don't need a cross-mint
+    # swap — redeem it same-mint. There's no melt/Lightning fee, but the mint's
+    # NUT-02 input fee still applies; _redeem_same_mint accounts for it.
     if token_obj.mint == settings.primary_mint:
         logger.info(
             "swap_to_primary_mint: token already on primary mint, skipping swap",
@@ -226,8 +238,9 @@ async def swap_to_primary_mint(
                 "unit": token_obj.unit,
             },
         )
-        await token_wallet.split(proofs=token_obj.proofs, amount=0, include_fees=True)
-        return token_amount, token_obj.unit, token_obj.mint
+        return await _redeem_same_mint(token_wallet, token_obj)
+
+    primary_wallet = await get_wallet(settings.primary_mint, settings.primary_mint_unit)
 
     minted_amount = await _calculate_swap_amount(
         amount_msat,
@@ -567,11 +580,19 @@ async def fetch_all_balances(
             }
             return error_result
 
+    # Build the set of mints to inspect. Received tokens are stored against
+    # ``primary_mint`` (which defaults to a real mint even when ``cashu_mints``
+    # is empty), so include it as a fallback — otherwise a node that accepts
+    # payments would still report empty balances when ``cashu_mints`` is unset.
+    mint_urls: list[str] = list(settings.cashu_mints)
+    if settings.primary_mint and settings.primary_mint not in mint_urls:
+        mint_urls.append(settings.primary_mint)
+
     # Create tasks for all mint/unit combinations
     async with db.create_session() as session:
         tasks = [
             fetch_balance(session, mint_url, unit)
-            for mint_url in settings.cashu_mints
+            for mint_url in mint_urls
             for unit in units
         ]
 

tests/unit/test_fetch_all_balances.py

@@ -0,0 +1,73 @@
+from contextlib import asynccontextmanager
+from unittest.mock import AsyncMock, MagicMock, patch
+
+import pytest
+
+from routstr.wallet import fetch_all_balances
+
+
+@asynccontextmanager
+async def _fake_session():  # type: ignore[no-untyped-def]
+    yield MagicMock()
+
+
+def _patches(proof_amount: int = 1000):  # type: ignore[no-untyped-def]
+    proof = MagicMock(amount=proof_amount)
+    return [
+        patch("routstr.wallet.get_wallet", AsyncMock(return_value=MagicMock())),
+        patch(
+            "routstr.wallet.get_proofs_per_mint_and_unit",
+            MagicMock(return_value=[proof]),
+        ),
+        patch(
+            "routstr.wallet.slow_filter_spend_proofs",
+            AsyncMock(side_effect=lambda proofs, wallet: proofs),
+        ),
+        patch(
+            "routstr.wallet.db.balances_for_mint_and_unit",
+            AsyncMock(return_value=0),
+        ),
+        patch("routstr.wallet.db.create_session", _fake_session),
+    ]
+
+
+@pytest.mark.asyncio
+async def test_fetch_all_balances_falls_back_to_primary_mint() -> None:
+    """With empty cashu_mints, balances are still fetched for primary_mint."""
+    from routstr.core.settings import settings
+
+    with patch.object(settings, "cashu_mints", []), patch.object(
+        settings, "primary_mint", "http://primary:3338"
+    ):
+        for p in _patches(proof_amount=1000):
+            p.start()
+        try:
+            details, total_wallet, total_user, owner = await fetch_all_balances(
+                units=["sat"]
+            )
+        finally:
+            patch.stopall()
+
+    assert [d["mint_url"] for d in details] == ["http://primary:3338"]
+    assert total_wallet == 1000
+
+
+@pytest.mark.asyncio
+async def test_fetch_all_balances_no_duplicate_primary_mint() -> None:
+    """primary_mint already in cashu_mints is not inspected twice."""
+    from routstr.core.settings import settings
+
+    with patch.object(
+        settings, "cashu_mints", ["http://primary:3338"]
+    ), patch.object(settings, "primary_mint", "http://primary:3338"):
+        for p in _patches(proof_amount=1000):
+            p.start()
+        try:
+            details, total_wallet, _total_user, _owner = await fetch_all_balances(
+                units=["sat"]
+            )
+        finally:
+            patch.stopall()
+
+    assert [d["mint_url"] for d in details] == ["http://primary:3338"]
+    assert total_wallet == 1000

tests/unit/test_wallet.py

@@ -39,6 +39,8 @@ async def test_recieve_token_valid() -> None:
 
     mock_wallet = Mock()
     mock_wallet.split = AsyncMock()
+    # Fee-free trusted mint (e.g. Minibits): nothing deducted.
+    mock_wallet.get_fees_for_proofs = Mock(return_value=0)
 
     from routstr.core.settings import settings
 
@@ -61,6 +63,69 @@ async def test_recieve_token_valid() -> None:
                 assert mint == "http://mint:3338"
 
 
+@pytest.mark.asyncio
+async def test_recieve_token_trusted_mint_deducts_input_fee() -> None:
+    """A trusted mint that charges NUT-02 input fees.
+
+    The same-mint receive (`wallet.split(..., include_fees=True)`, a NUT-03 swap
+    at the same mint — not swap_to_primary_mint) pays the mint's per-proof fee,
+    so routstr only ends up with `face - input_fee` in fresh proofs. The credited
+    amount must reflect that, otherwise routstr over-credits the user and its own
+    wallet drifts toward insolvency.
+    """
+    token_data = {
+        "token": [
+            {
+                "mint": "http://mint:3338",
+                "proofs": [
+                    {"amount": 1000, "id": "test", "secret": "secret", "C": "curve"}
+                ],
+            }
+        ],
+        "unit": "sat",
+    }
+    token_json = json.dumps(token_data)
+    token_b64 = base64.urlsafe_b64encode(token_json.encode()).decode()
+    token_str = f"cashuA{token_b64}"
+
+    mock_wallet = Mock()
+    mock_wallet.split = AsyncMock()
+    # Mock a 3-sat input fee from the Cashu wallet API.
+    mock_wallet.get_fees_for_proofs = Mock(return_value=3)
+
+    from routstr.core.settings import settings
+
+    with patch.object(settings, "cashu_mints", ["http://mint:3338"]):
+        with patch("routstr.wallet.deserialize_token_from_string") as mock_deserialize:
+            mock_token = Mock()
+            mock_token.keysets = ["keyset1"]
+            mock_token.mint = "http://mint:3338"
+            mock_token.unit = "sat"
+            mock_token.amount = 1000
+            mock_token.proofs = [{"amount": 1000}]
+            mock_deserialize.return_value = mock_token
+
+            mock_wallet.load_mint = AsyncMock()
+            mock_wallet.load_proofs = AsyncMock()
+            # Patch get_wallet directly so the module-level `_wallets` cache
+            # (keyed by mint URL) can't hand back a wallet from another test.
+            with patch(
+                "routstr.wallet.get_wallet",
+                AsyncMock(return_value=mock_wallet),
+            ):
+                amount, unit, mint = await recieve_token(token_str)
+                assert amount == 997  # 1000 face - 3 sat input fee paid on swap
+                assert unit == "sat"
+                assert mint == "http://mint:3338"
+                mock_wallet.get_fees_for_proofs.assert_called_once_with(
+                    mock_token.proofs
+                )
+                # DLEQ is verified before re-minting the incoming proofs.
+                mock_wallet.verify_proofs_dleq.assert_called_once_with(
+                    mock_token.proofs
+                )
+
+
 @pytest.mark.asyncio
 async def test_send_token() -> None:
     mock_wallet = Mock()
@@ -254,19 +319,31 @@ async def test_recieve_token_untrusted_mint() -> None:
                 assert mint == "http://mint:3338"
 
 
-@pytest.mark.asyncio
 @pytest.mark.asyncio
 async def test_swap_to_primary_mint_already_on_primary() -> None:
+    """Same-mint shortcut: the token is already on the primary mint.
+
+    No cross-mint swap (no melt/mint), but the same-mint split(include_fees=True)
+    still burns the mint's NUT-02 input fee, so the credited amount must be face
+    minus the input fee — not full face value (the over-credit bug). DLEQ is
+    verified too, matching the trusted same-mint receive path.
+    """
     from routstr.core.settings import settings
     from routstr.wallet import swap_to_primary_mint
 
     mock_token = Mock()
     mock_token.mint = settings.primary_mint
+    mock_token.keysets = ["keyset1"]
     mock_token.amount = 1000
     mock_token.unit = "sat"
-    mock_token.proofs = []
+    mock_token.proofs = [{"amount": 1000}]
 
     mock_token_wallet = Mock()
+    mock_token_wallet.load_mint = AsyncMock()
+    mock_token_wallet.load_proofs = AsyncMock()
+    mock_token_wallet.verify_proofs_dleq = Mock()
+    # Mock a 3-sat input fee from the Cashu wallet API.
+    mock_token_wallet.get_fees_for_proofs = Mock(return_value=3)
     mock_token_wallet.split = AsyncMock(return_value=None)
     mock_token_wallet.request_mint = AsyncMock()
     mock_token_wallet.melt_quote = AsyncMock()
@@ -274,9 +351,11 @@ async def test_swap_to_primary_mint_already_on_primary() -> None:
     with patch("routstr.wallet.get_wallet", AsyncMock(return_value=mock_token_wallet)):
         amount, unit, mint = await swap_to_primary_mint(mock_token, mock_token_wallet)
 
-    assert amount == 1000
+    assert amount == 997  # 1000 face - 3 sat input fee
     assert unit == "sat"
     assert mint == settings.primary_mint
+    mock_token_wallet.verify_proofs_dleq.assert_called_once_with(mock_token.proofs)
+    mock_token_wallet.get_fees_for_proofs.assert_called_once_with(mock_token.proofs)
     mock_token_wallet.split.assert_called_once()
     mock_token_wallet.request_mint.assert_not_called()
     mock_token_wallet.melt_quote.assert_not_called()