moves fetch_sprout_final_treestates out of rayon thread

zebra-state/src/service/check/anchors.rs

@@ -451,26 +451,35 @@ pub(crate) fn tx_anchors_refer_to_final_treestates(
     parent_chain: Option<&Arc<Chain>>,
     unmined_tx: &UnminedTx,
 ) -> Result<(), ValidateContextError> {
+    sapling_orchard_anchors_refer_to_final_treestates(
+        finalized_state,
+        parent_chain,
+        &unmined_tx.transaction,
+        unmined_tx.id.mined_id(),
+        None,
+        None,
+    )?;
+
+    // If there are no sprout transactions in the block, avoid running a rayon scope
     if unmined_tx.transaction.has_sprout_joinsplit_data() {
+        let mut sprout_final_treestates = HashMap::new();
+
+        fetch_sprout_final_treestates(
+            &mut sprout_final_treestates,
+            finalized_state,
+            parent_chain,
+            &unmined_tx.transaction,
+            None,
+            None,
+        );
+
         let mut sprout_anchors_result = None;
-        let mut sapling_orchard_anchors_result = None;
         rayon::in_place_scope_fifo(|s| {
             // This check is expensive, because it updates a note commitment tree for each sprout JoinSplit.
             // Since we could be processing attacker-controlled mempool transactions, we need to run each one
             // in its own thread, separately from tokio's blocking I/O threads. And if we are under heavy load,
             // we want verification to finish in order, so that later transactions can't delay earlier ones.
             s.spawn_fifo(|_s| {
-                let mut sprout_final_treestates = HashMap::new();
-
-                fetch_sprout_final_treestates(
-                    &mut sprout_final_treestates,
-                    finalized_state,
-                    parent_chain,
-                    &unmined_tx.transaction,
-                    None,
-                    None,
-                );
-
                 tracing::trace!(
                     sprout_final_treestate_count = ?sprout_final_treestates.len(),
                     ?sprout_final_treestates,
@@ -485,32 +494,9 @@ pub(crate) fn tx_anchors_refer_to_final_treestates(
                     None,
                 ));
             });
-
-            s.spawn_fifo(|_s| {
-                sapling_orchard_anchors_result =
-                    Some(sapling_orchard_anchors_refer_to_final_treestates(
-                        finalized_state,
-                        parent_chain,
-                        &unmined_tx.transaction,
-                        unmined_tx.id.mined_id(),
-                        None,
-                        None,
-                    ));
-            });
         });
 
         sprout_anchors_result.expect("scope has finished")?;
-        sapling_orchard_anchors_result.expect("scope has finished")?;
-    } else {
-        // If there are no sprout transactions in the block, avoid running a rayon scope
-        sapling_orchard_anchors_refer_to_final_treestates(
-            finalized_state,
-            parent_chain,
-            &unmined_tx.transaction,
-            unmined_tx.id.mined_id(),
-            None,
-            None,
-        )?;
     }
 
     Ok(())