Ensure fetchUsedContracts can deal with renewed contracts properly

stores/metadata.go

@@ -1469,13 +1469,16 @@ func (s *SQLStore) isKnownContract(fcid types.FileContractID) bool {
 	return found
 }
 
-func fetchUsedContracts(tx *gorm.DB, usedContracts map[types.PublicKey]map[types.FileContractID]struct{}) (map[types.FileContractID]dbContract, error) {
-	fcids := make([]fileContractID, 0, len(usedContracts))
-	for _, hostFCIDs := range usedContracts {
+func fetchUsedContracts(tx *gorm.DB, usedContractsByHost map[types.PublicKey]map[types.FileContractID]struct{}) (map[types.FileContractID]dbContract, error) {
+	// flatten map to get all used contract ids
+	fcids := make([]fileContractID, 0, len(usedContractsByHost))
+	for _, hostFCIDs := range usedContractsByHost {
 		for fcid := range hostFCIDs {
 			fcids = append(fcids, fileContractID(fcid))
 		}
 	}
+
+	// fetch all contracts, take into account renewals
 	var contracts []dbContract
 	err := tx.Model(&dbContract{}).
 		Joins("Host").
@@ -1484,17 +1487,19 @@ func fetchUsedContracts(tx *gorm.DB, usedContracts map[types.PublicKey]map[types
 	if err != nil {
 		return nil, err
 	}
-	fetchedContracts := make(map[types.FileContractID]dbContract, len(contracts))
+
+	// build map of used contracts
+	usedContracts := make(map[types.FileContractID]dbContract, len(contracts))
 	for _, c := range contracts {
-		// If a contract has been renewed, we add the renewed contract to the
-		// map using the old contract's id.
-		if _, renewed := usedContracts[types.PublicKey(c.Host.PublicKey)][types.FileContractID(c.RenewedFrom)]; renewed {
-			fetchedContracts[types.FileContractID(c.RenewedFrom)] = c
-		} else {
-			fetchedContracts[types.FileContractID(c.FCID)] = c
+		if _, used := usedContractsByHost[types.PublicKey(c.Host.PublicKey)][types.FileContractID(c.FCID)]; used {
+			usedContracts[types.FileContractID(c.FCID)] = c
+		}
+		if _, used := usedContractsByHost[types.PublicKey(c.Host.PublicKey)][types.FileContractID(c.RenewedFrom)]; used {
+			usedContracts[types.FileContractID(c.RenewedFrom)] = c
 		}
 	}
-	return fetchedContracts, nil
+
+	return usedContracts, nil
 }
 
 func (s *SQLStore) RenameObject(ctx context.Context, bucket, keyOld, keyNew string, force bool) error {

stores/metadata_test.go

@@ -4664,3 +4664,83 @@ func TestUpdateObjectParallel(t *testing.T) {
 	close(c)
 	wg.Wait()
 }
+
+// TestFetchUsedContracts is a unit test that verifies the functionality of
+// fetchUsedContracts
+func TestFetchUsedContracts(t *testing.T) {
+	// create store
+	ss := newTestSQLStore(t, defaultTestSQLStoreConfig)
+	defer ss.Close()
+
+	// add test host
+	hk1 := types.PublicKey{1}
+	err := ss.addTestHost(hk1)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// add test contract
+	fcid1 := types.FileContractID{1}
+	_, err = ss.addTestContract(fcid1, hk1)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// assert empty map returns no contracts
+	usedContracts := make(map[types.PublicKey]map[types.FileContractID]struct{})
+	contracts, err := fetchUsedContracts(ss.db, usedContracts)
+	if err != nil {
+		t.Fatal(err)
+	} else if len(contracts) != 0 {
+		t.Fatal("expected 0 contracts", len(contracts))
+	}
+
+	// add an entry for fcid1
+	usedContracts[hk1] = make(map[types.FileContractID]struct{})
+	usedContracts[hk1][types.FileContractID{1}] = struct{}{}
+
+	// assert we get the used contract
+	contracts, err = fetchUsedContracts(ss.db, usedContracts)
+	if err != nil {
+		t.Fatal(err)
+	} else if len(contracts) != 1 {
+		t.Fatal("expected 1 contract", len(contracts))
+	} else if _, ok := contracts[fcid1]; !ok {
+		t.Fatal("contract not found")
+	}
+
+	// renew the contract
+	fcid2 := types.FileContractID{2}
+	_, err = ss.addTestRenewedContract(fcid2, fcid1, hk1, 1)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// assert used contracts contains one entry and it points to the renewal
+	contracts, err = fetchUsedContracts(ss.db, usedContracts)
+	if err != nil {
+		t.Fatal(err)
+	} else if len(contracts) != 1 {
+		t.Fatal("expected 1 contract", len(contracts))
+	} else if contract, ok := contracts[fcid1]; !ok {
+		t.Fatal("contract not found")
+	} else if contract.convert().ID != fcid2 {
+		t.Fatal("contract should point to the renewed contract")
+	}
+
+	// add an entry for fcid2
+	usedContracts[hk1][types.FileContractID{2}] = struct{}{}
+
+	// assert used contracts now contains an entry for both contracts and both
+	// point to the renewed contract
+	contracts, err = fetchUsedContracts(ss.db, usedContracts)
+	if err != nil {
+		t.Fatal(err)
+	} else if len(contracts) != 2 {
+		t.Fatal("expected 2 contracts", len(contracts))
+	} else if !reflect.DeepEqual(contracts[types.FileContractID{1}], contracts[types.FileContractID{2}]) {
+		t.Fatal("contracts should match")
+	} else if contracts[types.FileContractID{1}].convert().ID != fcid2 {
+		t.Fatal("contracts should point to the renewed contract")
+	}
+}