feat(chain): impl Append for Option<T>

fix fmt crates/chain

Author: notmandatory

crates/chain/src/tx_data_traits.rs

@@ -128,6 +128,17 @@ impl<T> Append for Vec<T> {
     }
 }
 
+impl<T> Append for Option<T> {
+    // If other is Some then replace self's value with other's value, if other is None do nothing.
+    fn append(&mut self, other: Self) {
+        other.and_then(|v| self.replace(v));
+    }
+
+    fn is_empty(&self) -> bool {
+        self.is_none()
+    }
+}
+
 macro_rules! impl_append_for_tuple {
     ($($a:ident $b:tt)*) => {
         impl<$($a),*> Append for ($($a,)*) where $($a: Append),* {

crates/chain/src/tx_graph.rs

@@ -559,10 +559,7 @@ impl<A: Clone + Ord> TxGraph<A> {
         }
 
         for (outpoint, txout) in changeset.txouts {
-            let tx_entry = self
-                .txs
-                .entry(outpoint.txid)
-                .or_insert_with(Default::default);
+            let tx_entry = self.txs.entry(outpoint.txid).or_default();
 
             match tx_entry {
                 (TxNodeInternal::Whole(_), _, _) => { /* do nothing since we already have full tx */
@@ -575,13 +572,13 @@ impl<A: Clone + Ord> TxGraph<A> {
 
         for (anchor, txid) in changeset.anchors {
             if self.anchors.insert((anchor.clone(), txid)) {
-                let (_, anchors, _) = self.txs.entry(txid).or_insert_with(Default::default);
+                let (_, anchors, _) = self.txs.entry(txid).or_default();
                 anchors.insert(anchor);
             }
         }
 
         for (txid, new_last_seen) in changeset.last_seen {
-            let (_, _, last_seen) = self.txs.entry(txid).or_insert_with(Default::default);
+            let (_, _, last_seen) = self.txs.entry(txid).or_default();
             if new_last_seen > *last_seen {
                 *last_seen = new_last_seen;
             }