gui: set PSBT with no inputs as Deprecated

gui/src/daemon/model.rs

@@ -78,7 +78,13 @@ impl SpendTx {
         );
 
         let mut inputs_amount = Amount::from_sat(0);
-        let mut status = SpendStatus::Pending;
+        let mut status = if coins.is_empty() {
+            // Coins will be empty if transaction was spending outputs from an unconfirmed
+            // transaction that is no longer in the mempool, e.g. if it was replaced.
+            SpendStatus::Deprecated
+        } else {
+            SpendStatus::Pending
+        };
         for coin in &coins {
             inputs_amount += coin.amount;
             if let Some(info) = coin.spend_info {
@@ -88,10 +94,11 @@ impl SpendTx {
                     } else {
                         status = SpendStatus::Broadcast
                     }
-                // FIXME: This is a quick change so that replacement transactions can be
-                // signed and broadcast.
-                // A replacement transaction would use a coin with a different spend tx.
-                // It should remain as Pending so that it can be broadcast.
+                // The txid will be different if this PSBT is to replace another transaction
+                // that is currently spending the coin.
+                // The PSBT status should remain as Pending so that it can be signed and broadcast.
+                // Once the replacement transaction has been confirmed, the PSBT for the
+                // transaction currently spending this coin will be shown as Deprecated.
                 } else if info.height.is_some() {
                     status = SpendStatus::Deprecated
                 }