spend: reword warning messages

src/commands/mod.rs

@@ -1571,7 +1571,14 @@ mod tests {
         );
         assert_eq!(tx.output[0].value.to_sat(), 95_000);
         // change = 100_000 - 95_000 - /* fee without change */ 127 - /* extra fee for change output */ 43 = 4830
-        assert_eq!(warnings, vec!["Change amount of 4830 sats added to fee as it was too small to create a transaction output."]);
+        assert_eq!(
+            warnings,
+            vec![
+                "Dust UTXO. The minimal change output allowed by Liana is 5000 sats. \
+                Instead of creating a change of 4830 sats, it was added to the \
+                transaction fee. Select a larger input to avoid this from happening."
+            ]
+        );
 
         // Increase the target value by the change amount and the warning will disappear.
         *destinations.get_mut(&dummy_addr).unwrap() = 95_000 + 4_830;
@@ -1622,7 +1629,14 @@ mod tests {
             panic!("expect successful spend creation")
         };
         // Message uses "sat" instead of "sats" when value is 1.
-        assert_eq!(warnings, vec!["Change amount of 1 sat added to fee as it was too small to create a transaction output."]);
+        assert_eq!(
+            warnings,
+            vec![
+                "Dust UTXO. The minimal change output allowed by Liana is 5000 sats. \
+                Instead of creating a change of 1 sat, it was added to the \
+                transaction fee. Select a larger input to avoid this from happening."
+            ]
+        );
 
         // Now decrease the target value so that we have enough for a change output.
         *destinations.get_mut(&dummy_addr).unwrap() =
@@ -1651,7 +1665,14 @@ mod tests {
         } else {
             panic!("expect successful spend creation")
         };
-        assert_eq!(warnings, vec!["Change amount of 4999 sats added to fee as it was too small to create a transaction output."]);
+        assert_eq!(
+            warnings,
+            vec![
+                "Dust UTXO. The minimal change output allowed by Liana is 5000 sats. \
+                Instead of creating a change of 4999 sats, it was added to the \
+                transaction fee. Select a larger input to avoid this from happening."
+            ]
+        );
 
         // Now if we mark the coin as spent, we won't create another Spend transaction containing
         // it.

src/spend.rs

@@ -551,15 +551,20 @@ impl fmt::Display for CreateSpendWarning {
         match self {
             CreateSpendWarning::ChangeAddedToFee(amt) => write!(
                 f,
-                "Change amount of {} sat{} added to fee as it was too small to create a transaction output.",
+                "Dust UTXO. The minimal change output allowed by Liana is {} sats. \
+                Instead of creating a change of {} sat{}, it was added to the \
+                transaction fee. Select a larger input to avoid this from happening.",
+                DUST_OUTPUT_SATS,
                 amt,
-                if *amt > 1 {"s"} else {""},
+                if *amt > 1 { "s" } else { "" },
             ),
             CreateSpendWarning::AdditionalFeeForAncestors(amt) => write!(
                 f,
-                "An additional fee of {} sat{} has been added to pay for ancestors at the target feerate.",
+                "CPFP: an unconfirmed input was selected. The current transaction fee \
+                was increased by {} sat{} to make the average feerate of both the input \
+                and current transaction equal to the selected feerate.",
                 amt,
-                if *amt > 1 {"s"} else {""},
+                if *amt > 1 { "s" } else { "" },
             ),
         }
     }

tests/test_spend.py

@@ -141,7 +141,9 @@ def test_coin_marked_spent(lianad, bitcoind):
     assert len(res["warnings"]) == 1
     assert (
         res["warnings"][0]
-        == f"Change amount of {change_amount} sats added to fee as it was too small to create a transaction output."
+        == "Dust UTXO. The minimal change output allowed by Liana is 5000 sats. "
+        f"Instead of creating a change of {change_amount} sats, it was added to the "
+        "transaction fee. Select a larger input to avoid this from happening."
     )
 
     # Spend the third coin to an address of ours, no change
@@ -158,7 +160,9 @@ def test_coin_marked_spent(lianad, bitcoind):
     assert len(res["warnings"]) == 1
     assert (
         res["warnings"][0]
-        == f"Change amount of {change_amount} sats added to fee as it was too small to create a transaction output."
+        == "Dust UTXO. The minimal change output allowed by Liana is 5000 sats. "
+        f"Instead of creating a change of {change_amount} sats, it was added to the "
+        "transaction fee. Select a larger input to avoid this from happening."
     )
 
     # Spend the fourth coin to an address of ours, with change
@@ -194,7 +198,9 @@ def test_coin_marked_spent(lianad, bitcoind):
     assert len(res["warnings"]) == 1
     assert (
         res["warnings"][0]
-        == f"An additional fee of {additional_fee} sats has been added to pay for ancestors at the target feerate."
+        == "CPFP: an unconfirmed input was selected. The current transaction fee "
+        f"was increased by {additional_fee} sats to make the average feerate of "
+        "both the input and current transaction equal to the selected feerate."
     )
 
     # All the spent coins must have been detected as such
@@ -346,7 +352,9 @@ def test_coin_selection(lianad, bitcoind):
     assert len(spend_res_2["warnings"]) == 1
     assert (
         spend_res_2["warnings"][0]
-        == f"An additional fee of {additional_fee} sats has been added to pay for ancestors at the target feerate."
+        == "CPFP: an unconfirmed input was selected. The current transaction fee "
+        f"was increased by {additional_fee} sats to make the average feerate of "
+        "both the input and current transaction equal to the selected feerate."
     )
 
     # Try 3 sat/vb:
@@ -366,7 +374,9 @@ def test_coin_selection(lianad, bitcoind):
     assert len(spend_res_2["warnings"]) == 1
     assert (
         spend_res_2["warnings"][0]
-        == f"An additional fee of {additional_fee} sats has been added to pay for ancestors at the target feerate."
+        == "CPFP: an unconfirmed input was selected. The current transaction fee "
+        f"was increased by {additional_fee} sats to make the average feerate of "
+        "both the input and current transaction equal to the selected feerate."
     )
 
     # 2 sat/vb is same feerate as ancestor and we have no warnings:
@@ -416,7 +426,9 @@ def test_coin_selection(lianad, bitcoind):
     assert len(spend_res_3["warnings"]) == 1
     assert (
         spend_res_3["warnings"][0]
-        == f"An additional fee of {additional_fee} sats has been added to pay for ancestors at the target feerate."
+        == "CPFP: an unconfirmed input was selected. The current transaction fee "
+        f"was increased by {additional_fee} sats to make the average feerate of "
+        "both the input and current transaction equal to the selected feerate."
     )
     spend_psbt_3 = PSBT.from_base64(spend_res_3["psbt"])
     spend_txid_3 = sign_and_broadcast_psbt(lianad, spend_psbt_3)