Fix possible corner case in revalidation (#5172)

* remove all from members

* add test

substrate/client/transaction-pool/src/revalidation.rs

@@ -151,7 +151,6 @@ impl<Api: ChainApi> RevalidationWorker<Api> {
 				} else {
 					for xt in &to_queue {
 						extrinsics.remove(xt);
-						self.members.remove(xt);
 					}
 				}
 				left -= to_queue.len();
@@ -163,6 +162,10 @@ impl<Api: ChainApi> RevalidationWorker<Api> {
 			}
 		}
 
+		for hash in queued_exts.iter() {
+			self.members.remove(hash);
+		}
+
 		queued_exts
 	}
 

substrate/client/transaction-pool/src/testing/pool.rs

@@ -295,6 +295,36 @@ fn should_revalidate_transaction_multiple_times() {
 	assert_eq!(pool.status().ready, 0);
 }
 
+#[test]
+fn should_revalidate_across_many_blocks() {
+	let xt1 = uxt(Alice, 209);
+	let xt2 = uxt(Alice, 210);
+	let xt3 = uxt(Alice, 211);
+
+	let (pool, _guard) = maintained_pool();
+
+	block_on(pool.submit_one(&BlockId::number(1), xt1.clone())).expect("1. Imported");
+	block_on(pool.submit_one(&BlockId::number(1), xt2.clone())).expect("1. Imported");
+	assert_eq!(pool.status().ready, 2);
+
+	pool.api.push_block(1, vec![]);
+	block_on(pool.maintain(block_event(1)));
+	block_on(futures_timer::Delay::new(BACKGROUND_REVALIDATION_INTERVAL*2));
+
+
+	block_on(pool.submit_one(&BlockId::number(2), xt3.clone())).expect("1. Imported");
+	assert_eq!(pool.status().ready, 3);
+
+	pool.api.push_block(2, vec![xt1.clone()]);
+	block_on(pool.maintain(block_event(2)));
+	block_on(futures_timer::Delay::new(BACKGROUND_REVALIDATION_INTERVAL*2));
+
+	assert_eq!(pool.status().ready, 2);
+	// xt1 and xt2 validated twice, then xt3 once, then xt2 and xt3 again
+	assert_eq!(pool.api.validation_requests().len(), 7);
+}
+
+
 #[test]
 fn should_push_watchers_during_maintaince() {
 	fn alice_uxt(nonce: u64) -> Extrinsic {