Re-add is_active_or_upcoming_validator

node/src/types/validator_matrix.rs

@@ -236,6 +236,20 @@ impl ValidatorMatrix {
         }
     }
 
+    /// Determine if the active validator is in a current or upcoming set of active validators.
+    ///
+    /// This function may produce false positives, as it works backwards from the highest known era.
+    /// Depending on the current network state, this may be an upcoming or active era, at least the
+    /// previous era validators may be positively identified by this function.
+    #[inline]
+    pub(crate) fn is_active_or_upcoming_validator(&self, public_key: &PublicKey) -> bool {
+        self.read_inner()
+            .values()
+            .rev()
+            .take(self.auction_delay as usize + 1)
+            .any(|validator_weights| validator_weights.is_validator(public_key))
+    }
+
     /// Returns the public keys of all validators in a given era.
     ///
     /// Will return `None` if the era is not known.