Fix a import+prune+replace case for multi-provides transactions. (#3939)

* Fix a import+prune+replace case for multi-provides transactions.

* Fix tests.

substrate/core/transaction-pool/graph/src/pool.rs

@@ -240,6 +240,7 @@ impl<B: ChainApi> Pool<B> {
 		tags: impl IntoIterator<Item=Tag>,
 		known_imported_hashes: impl IntoIterator<Item=ExHash<B>> + Clone,
 	) -> impl Future<Output=Result<(), B::Error>> {
+		log::trace!(target: "txpool", "Pruning at {:?}", at);
 		// Prune all transactions that provide given tags
 		let prune_status = match self.validated_pool.prune_tags(tags) {
 			Ok(prune_status) => prune_status,
@@ -257,6 +258,7 @@ impl<B: ChainApi> Pool<B> {
 		let pruned_transactions = prune_status.pruned.into_iter().map(|tx| tx.data.clone());
 		let reverify_future = self.verify(at, pruned_transactions, false);
 
+		log::trace!(target: "txpool", "Prunning at {:?}. Resubmitting transactions.", at);
 		// And finally - submit reverified transactions back to the pool
 		let at = at.clone();
 		let validated_pool = self.validated_pool.clone();
@@ -908,3 +910,4 @@ mod tests {
 		}
 	}
 }
+

substrate/core/transaction-pool/graph/src/ready.rs

@@ -338,7 +338,20 @@ impl<Hash: hash::Hash + Member + Serialize, Ex> ReadyTransactions<Hash, Ex> {
 					}
 				}
 
-				debug!(target: "txpool", "[{:?}] Pruned.", tx.hash);
+				// we also need to remove all other tags that this transaction provides,
+				// but since all the hard work is done, we only clear the provided_tag -> hash
+				// mapping.
+				let current_tag = &tag;
+				for tag in &tx.provides {
+					let removed = self.provided_tags.remove(tag);
+					assert_eq!(
+						removed.as_ref(),
+						if current_tag == tag { None } else { Some(&tx.hash) },
+						"The pool contains exactly one transaction providing given tag; the removed transaction
+						claims to provide that tag, so it has to be mapped to it's hash; qed"
+					);
+				}
+
 				removed.push(tx);
 			}
 		}