Split collection interface (#2415)

## Description

Split the collection interface into stuff used during backup and stuff used during restore. Does not change other code beyond fixing types

## Does this PR need a docs update or release note?

- [ ] ✅ Yes, it's included
- [ ] 🕐 Yes, but in a later PR
- [x] ⛔ No 

## Type of change

- [ ] 🌻 Feature
- [ ] 🐛 Bugfix
- [ ] 🗺️ Documentation
- [ ] 🤖 Test
- [ ] 💻 CI/Deployment
- [x] 🧹 Tech Debt/Cleanup

## Issue(s)

* closes #1944

## Test Plan

- [ ] 💪 Manual
- [x] ⚡ Unit test
- [x] 💚 E2E

src/cmd/factory/impl/common.go

@@ -152,8 +152,8 @@ func buildCollections(
 	tenant, user string,
 	dest control.RestoreDestination,
 	colls []collection,
-) ([]data.Collection, error) {
+) ([]data.RestoreCollection, error) {
-	collections := make([]data.Collection, 0, len(colls))
+	collections := make([]data.RestoreCollection, 0, len(colls))
 
 	for _, c := range colls {
 		pth, err := toDataLayerPath(

src/internal/connector/data_collections.go

@@ -34,9 +34,9 @@ import (
 func (gc *GraphConnector) DataCollections(
 	ctx context.Context,
 	sels selectors.Selector,
-	metadata []data.Collection,
+	metadata []data.RestoreCollection,
 	ctrlOpts control.Options,
-) ([]data.Collection, map[string]struct{}, error) {
+) ([]data.BackupCollection, map[string]struct{}, error) {
 	ctx, end := D.Span(ctx, "gc:dataCollections", D.Index("service", sels.Service.String()))
 	defer end()
 
@@ -51,7 +51,7 @@ func (gc *GraphConnector) DataCollections(
 	}
 
 	if !serviceEnabled {
-		return []data.Collection{}, nil, nil
+		return []data.BackupCollection{}, nil, nil
 	}
 
 	switch sels.Service {
@@ -182,9 +182,9 @@ func (fm odFolderMatcher) Matches(dir string) bool {
 func (gc *GraphConnector) OneDriveDataCollections(
 	ctx context.Context,
 	selector selectors.Selector,
-	metadata []data.Collection,
+	metadata []data.RestoreCollection,
 	ctrlOpts control.Options,
-) ([]data.Collection, map[string]struct{}, error) {
+) ([]data.BackupCollection, map[string]struct{}, error) {
 	odb, err := selector.ToOneDriveBackup()
 	if err != nil {
 		return nil, nil, errors.Wrap(err, "oneDriveDataCollection: parsing selector")
@@ -192,7 +192,7 @@ func (gc *GraphConnector) OneDriveDataCollections(
 
 	var (
 		user        = selector.DiscreteOwner
-		collections = []data.Collection{}
+		collections = []data.BackupCollection{}
 		allExcludes = map[string]struct{}{}
 		errs        error
 	)

src/internal/connector/exchange/data_collections.go

@@ -63,7 +63,7 @@ type DeltaPath struct {
 // and path lookup maps.
 func parseMetadataCollections(
 	ctx context.Context,
-	colls []data.Collection,
+	colls []data.RestoreCollection,
 ) (CatDeltaPaths, error) {
 	// cdp stores metadata
 	cdp := CatDeltaPaths{
@@ -163,11 +163,11 @@ func parseMetadataCollections(
 func DataCollections(
 	ctx context.Context,
 	selector selectors.Selector,
-	metadata []data.Collection,
+	metadata []data.RestoreCollection,
 	acct account.M365Config,
 	su support.StatusUpdater,
 	ctrlOpts control.Options,
-) ([]data.Collection, map[string]struct{}, error) {
+) ([]data.BackupCollection, map[string]struct{}, error) {
 	eb, err := selector.ToExchangeBackup()
 	if err != nil {
 		return nil, nil, errors.Wrap(err, "exchangeDataCollection: parsing selector")
@@ -175,7 +175,7 @@ func DataCollections(
 
 	var (
 		user        = selector.DiscreteOwner
-		collections = []data.Collection{}
+		collections = []data.BackupCollection{}
 		errs        error
 	)
 
@@ -231,10 +231,10 @@ func createCollections(
 	dps DeltaPaths,
 	ctrlOpts control.Options,
 	su support.StatusUpdater,
-) ([]data.Collection, error) {
+) ([]data.BackupCollection, error) {
 	var (
 		errs           *multierror.Error
-		allCollections = make([]data.Collection, 0)
+		allCollections = make([]data.BackupCollection, 0)
 		ac             = api.Client{Credentials: creds}
 		category       = scope.Category().PathType()
 	)
@@ -245,7 +245,7 @@ func createCollections(
 	}
 
 	// Create collection of ExchangeDataCollection
-	collections := make(map[string]data.Collection)
+	collections := make(map[string]data.BackupCollection)
 
 	qp := graph.QueryParams{
 		Category:      category,

src/internal/connector/exchange/data_collections_test.go

@@ -174,7 +174,7 @@ func (suite *DataCollectionsUnitSuite) TestParseMetadataCollections() {
 			)
 			require.NoError(t, err)
 
-			cdps, err := parseMetadataCollections(ctx, []data.Collection{coll})
+			cdps, err := parseMetadataCollections(ctx, []data.RestoreCollection{coll})
 			test.expectError(t, err)
 
 			emails := cdps[path.EmailCategory]
@@ -335,7 +335,7 @@ func (suite *DataCollectionsIntegrationSuite) TestDelta() {
 			require.NoError(t, err)
 			assert.Less(t, 1, len(collections), "retrieved metadata and data collections")
 
-			var metadata data.Collection
+			var metadata data.BackupCollection
 
 			for _, coll := range collections {
 				if coll.FullPath().Service() == path.ExchangeMetadataService {
@@ -345,7 +345,7 @@ func (suite *DataCollectionsIntegrationSuite) TestDelta() {
 
 			require.NotNil(t, metadata, "collections contains a metadata collection")
 
-			cdps, err := parseMetadataCollections(ctx, []data.Collection{metadata})
+			cdps, err := parseMetadataCollections(ctx, []data.RestoreCollection{metadata})
 			require.NoError(t, err)
 
 			dps := cdps[test.scope.Category().PathType()]

src/internal/connector/exchange/exchange_data_collection.go

@@ -24,7 +24,7 @@ import (
 )
 
 var (
-	_ data.Collection    = &Collection{}
+	_ data.BackupCollection = &Collection{}
 	_ data.Stream           = &Stream{}
 	_ data.StreamInfo       = &Stream{}
 	_ data.StreamModTime    = &Stream{}

src/internal/connector/exchange/service_iterators.go

@@ -25,14 +25,14 @@ type addedAndRemovedItemIDsGetter interface {
 
 // filterContainersAndFillCollections is a utility function
 // that places the M365 object ids belonging to specific directories
-// into a Collection. Messages outside of those directories are omitted.
+// into a BackupCollection. Messages outside of those directories are omitted.
 // @param collection is filled with during this function.
 // Supports all exchange applications: Contacts, Events, and Mail
 func filterContainersAndFillCollections(
 	ctx context.Context,
 	qp graph.QueryParams,
 	getter addedAndRemovedItemIDsGetter,
-	collections map[string]data.Collection,
+	collections map[string]data.BackupCollection,
 	statusUpdater support.StatusUpdater,
 	resolver graph.ContainerResolver,
 	scope selectors.ExchangeScope,

src/internal/connector/exchange/service_iterators_test.go

@@ -280,7 +280,7 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections() {
 			ctx, flush := tester.NewContext()
 			defer flush()
 
-			collections := map[string]data.Collection{}
+			collections := map[string]data.BackupCollection{}
 
 			err := filterContainersAndFillCollections(
 				ctx,
@@ -433,7 +433,7 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_repea
 				resolver = newMockResolver(container1)
 			)
 
-			collections := map[string]data.Collection{}
+			collections := map[string]data.BackupCollection{}
 
 			err := filterContainersAndFillCollections(
 				ctx,
@@ -785,7 +785,7 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_incre
 			ctx, flush := tester.NewContext()
 			defer flush()
 
-			collections := map[string]data.Collection{}
+			collections := map[string]data.BackupCollection{}
 
 			err := filterContainersAndFillCollections(
 				ctx,

src/internal/connector/exchange/service_restore.go

@@ -297,7 +297,7 @@ func SendMailToBackStore(
 	return errs
 }
 
-// RestoreExchangeDataCollections restores M365 objects in data.Collection to MSFT
+// RestoreExchangeDataCollections restores M365 objects in data.RestoreCollection to MSFT
 // store through GraphAPI.
 // @param dest:  container destination to M365
 func RestoreExchangeDataCollections(
@@ -305,7 +305,7 @@ func RestoreExchangeDataCollections(
 	creds account.M365Config,
 	gs graph.Servicer,
 	dest control.RestoreDestination,
-	dcs []data.Collection,
+	dcs []data.RestoreCollection,
 	deets *details.Builder,
 ) (*support.ConnectorOperationStatus, error) {
 	var (
@@ -364,7 +364,7 @@ func RestoreExchangeDataCollections(
 func restoreCollection(
 	ctx context.Context,
 	gs graph.Servicer,
-	dc data.Collection,
+	dc data.RestoreCollection,
 	folderID string,
 	policy control.CollisionPolicy,
 	deets *details.Builder,

src/internal/connector/graph/metadata_collection.go

@@ -14,7 +14,7 @@ import (
 )
 
 var (
-	_ data.Collection = &MetadataCollection{}
+	_ data.BackupCollection = &MetadataCollection{}
 	_ data.Stream           = &MetadataItem{}
 )
 
@@ -67,7 +67,7 @@ func MakeMetadataCollection(
 	cat path.CategoryType,
 	metadata []MetadataCollectionEntry,
 	statusUpdater support.StatusUpdater,
-) (data.Collection, error) {
+) (data.BackupCollection, error) {
 	if len(metadata) == 0 {
 		return nil, nil
 	}

src/internal/connector/graph_connector.go

@@ -271,7 +271,7 @@ func (gc *GraphConnector) RestoreDataCollections(
 	selector selectors.Selector,
 	dest control.RestoreDestination,
 	opts control.Options,
-	dcs []data.Collection,
+	dcs []data.RestoreCollection,
 ) (*details.Details, error) {
 	ctx, end := D.Span(ctx, "connector:restore")
 	defer end()

src/internal/connector/graph_connector_helper_test.go

@@ -740,7 +740,7 @@ func compareItem(
 func checkHasCollections(
 	t *testing.T,
 	expected map[string]map[string][]byte,
-	got []data.Collection,
+	got []data.BackupCollection,
 ) {
 	t.Helper()
 
@@ -762,10 +762,10 @@ func checkCollections(
 	t *testing.T,
 	expectedItems int,
 	expected map[string]map[string][]byte,
-	got []data.Collection,
+	got []data.BackupCollection,
 	restorePermissions bool,
 ) int {
-	collectionsWithItems := []data.Collection{}
+	collectionsWithItems := []data.BackupCollection{}
 
 	skipped := 0
 	gotItems := 0
@@ -950,8 +950,8 @@ func collectionsForInfo(
 	tenant, user string,
 	dest control.RestoreDestination,
 	allInfo []colInfo,
-) (int, int, []data.Collection, map[string]map[string][]byte) {
+) (int, int, []data.RestoreCollection, map[string]map[string][]byte) {
-	collections := make([]data.Collection, 0, len(allInfo))
+	collections := make([]data.RestoreCollection, 0, len(allInfo))
 	expectedData := make(map[string]map[string][]byte, len(allInfo))
 	totalItems := 0
 	kopiaEntries := 0
@@ -1002,8 +1002,8 @@ func collectionsForInfoVersion0(
 	tenant, user string,
 	dest control.RestoreDestination,
 	allInfo []colInfo,
-) (int, int, []data.Collection, map[string]map[string][]byte) {
+) (int, int, []data.RestoreCollection, map[string]map[string][]byte) {
-	collections := make([]data.Collection, 0, len(allInfo))
+	collections := make([]data.RestoreCollection, 0, len(allInfo))
 	expectedData := make(map[string]map[string][]byte, len(allInfo))
 	totalItems := 0
 	kopiaEntries := 0

src/internal/connector/graph_connector_test.go

@@ -257,7 +257,7 @@ func (suite *GraphConnectorIntegrationSuite) TestEmptyCollections() {
 	dest := tester.DefaultTestRestoreDestination()
 	table := []struct {
 		name string
-		col  []data.Collection
+		col  []data.RestoreCollection
 		sel  selectors.Selector
 	}{
 		{
@@ -269,7 +269,7 @@ func (suite *GraphConnectorIntegrationSuite) TestEmptyCollections() {
 		},
 		{
 			name: "ExchangeEmpty",
-			col:  []data.Collection{},
+			col:  []data.RestoreCollection{},
 			sel: selectors.Selector{
 				Service: selectors.ServiceExchange,
 			},
@@ -283,7 +283,7 @@ func (suite *GraphConnectorIntegrationSuite) TestEmptyCollections() {
 		},
 		{
 			name: "OneDriveEmpty",
-			col:  []data.Collection{},
+			col:  []data.RestoreCollection{},
 			sel: selectors.Selector{
 				Service: selectors.ServiceOneDrive,
 			},
@@ -297,7 +297,7 @@ func (suite *GraphConnectorIntegrationSuite) TestEmptyCollections() {
 		},
 		{
 			name: "SharePointEmpty",
-			col:  []data.Collection{},
+			col:  []data.RestoreCollection{},
 			sel: selectors.Selector{
 				Service: selectors.ServiceSharePoint,
 			},
@@ -370,7 +370,7 @@ func runRestoreBackupTest(
 	opts control.Options,
 ) {
 	var (
-		collections     []data.Collection
+		collections     []data.RestoreCollection
 		expectedData    = map[string]map[string][]byte{}
 		totalItems      = 0
 		totalKopiaItems = 0
@@ -495,7 +495,7 @@ func runRestoreBackupTestVersion0(
 	opts control.Options,
 ) {
 	var (
-		collections     []data.Collection
+		collections     []data.RestoreCollection
 		expectedData    = map[string]map[string][]byte{}
 		totalItems      = 0
 		totalKopiaItems = 0

src/internal/connector/mockconnector/mock_data_collection.go

@@ -27,7 +27,10 @@ type MockExchangeDataCollection struct {
 }
 
 var (
-	_ data.Collection = &MockExchangeDataCollection{}
+	// Needs to implement both backup and restore interfaces so we can use it in
+	// integration tests.
+	_ data.BackupCollection  = &MockExchangeDataCollection{}
+	_ data.RestoreCollection = &MockExchangeDataCollection{}
 	_ data.Stream            = &MockExchangeData{}
 	_ data.StreamInfo        = &MockExchangeData{}
 	_ data.StreamSize        = &MockExchangeData{}

src/internal/connector/mockconnector/mock_data_list.go

@@ -15,7 +15,7 @@ import (
 
 var (
 	_ data.Stream           = &MockListData{}
-	_ data.Collection = &MockListCollection{}
+	_ data.BackupCollection = &MockListCollection{}
 )
 
 type MockListCollection struct {

src/internal/connector/onedrive/collection.go

@@ -42,7 +42,7 @@ const (
 )
 
 var (
-	_ data.Collection    = &Collection{}
+	_ data.BackupCollection = &Collection{}
 	_ data.Stream           = &Item{}
 	_ data.StreamInfo       = &Item{}
 	_ data.StreamModTime    = &Item{}

src/internal/connector/onedrive/collections.go

@@ -61,9 +61,9 @@ type Collections struct {
 
 	ctrl control.Options
 
-	// collectionMap allows lookup of the data.Collection
+	// collectionMap allows lookup of the data.BackupCollection
 	// for a OneDrive folder
-	CollectionMap map[string]data.Collection
+	CollectionMap map[string]data.BackupCollection
 
 	// Not the most ideal, but allows us to change the pager function for testing
 	// as needed. This will allow us to mock out some scenarios during testing.
@@ -100,7 +100,7 @@ func NewCollections(
 		resourceOwner:  resourceOwner,
 		source:         source,
 		matcher:        matcher,
-		CollectionMap:  map[string]data.Collection{},
+		CollectionMap:  map[string]data.BackupCollection{},
 		drivePagerFunc: PagerForSource,
 		itemPagerFunc:  defaultItemPager,
 		service:        service,
@@ -111,7 +111,7 @@ func NewCollections(
 
 func deserializeMetadata(
 	ctx context.Context,
-	cols []data.Collection,
+	cols []data.RestoreCollection,
 ) (map[string]string, map[string]map[string]string, error) {
 	logger.Ctx(ctx).Infow(
 		"deserialzing previous backup metadata",
@@ -249,8 +249,8 @@ func deserializeMap[T any](reader io.ReadCloser, alreadyFound map[string]T) erro
 // be excluded from the upcoming backup.
 func (c *Collections) Get(
 	ctx context.Context,
-	prevMetadata []data.Collection,
+	prevMetadata []data.RestoreCollection,
-) ([]data.Collection, map[string]struct{}, error) {
+) ([]data.BackupCollection, map[string]struct{}, error) {
 	prevDeltas, _, err := deserializeMetadata(ctx, prevMetadata)
 	if err != nil {
 		return nil, nil, err
@@ -327,7 +327,7 @@ func (c *Collections) Get(
 	observe.Message(ctx, observe.Safe(fmt.Sprintf("Discovered %d items to backup", c.NumItems)))
 
 	// Add an extra for the metadata collection.
-	collections := make([]data.Collection, 0, len(c.CollectionMap)+1)
+	collections := make([]data.BackupCollection, 0, len(c.CollectionMap)+1)
 	for _, coll := range c.CollectionMap {
 		collections = append(collections, coll)
 	}

src/internal/connector/onedrive/collections_test.go

@@ -983,7 +983,7 @@ func (suite *OneDriveCollectionsSuite) TestDeserializeMetadata() {
 			ctx, flush := tester.NewContext()
 			defer flush()
 
-			cols := []data.Collection{}
+			cols := []data.RestoreCollection{}
 
 			for _, c := range test.cols {
 				mc, err := graph.MakeMetadataCollection(
@@ -1529,7 +1529,7 @@ func (suite *OneDriveCollectionsSuite) TestGet() {
 			for _, baseCol := range cols {
 				folderPath := baseCol.FullPath().String()
 				if folderPath == metadataPath.String() {
-					deltas, paths, err := deserializeMetadata(ctx, []data.Collection{baseCol})
+					deltas, paths, err := deserializeMetadata(ctx, []data.RestoreCollection{baseCol})
 					if !assert.NoError(t, err, "deserializing metadata") {
 						continue
 					}

src/internal/connector/onedrive/restore.go

@@ -64,7 +64,7 @@ func RestoreCollections(
 	service graph.Servicer,
 	dest control.RestoreDestination,
 	opts control.Options,
-	dcs []data.Collection,
+	dcs []data.RestoreCollection,
 	deets *details.Builder,
 ) (*support.ConnectorOperationStatus, error) {
 	var (
@@ -148,7 +148,7 @@ func RestoreCollection(
 	ctx context.Context,
 	backupVersion int,
 	service graph.Servicer,
-	dc data.Collection,
+	dc data.RestoreCollection,
 	parentPerms []UserPermission,
 	source driveSource,
 	restoreContainerName string,

src/internal/connector/sharepoint/collection.go

@@ -30,7 +30,7 @@ const (
 )
 
 var (
-	_ data.Collection    = &Collection{}
+	_ data.BackupCollection = &Collection{}
 	_ data.Stream           = &Item{}
 	_ data.StreamInfo       = &Item{}
 	_ data.StreamModTime    = &Item{}

src/internal/connector/sharepoint/data_collections.go

@@ -34,7 +34,7 @@ func DataCollections(
 	serv graph.Servicer,
 	su statusUpdater,
 	ctrlOpts control.Options,
-) ([]data.Collection, map[string]struct{}, error) {
+) ([]data.BackupCollection, map[string]struct{}, error) {
 	b, err := selector.ToSharePointBackup()
 	if err != nil {
 		return nil, nil, errors.Wrap(err, "sharePointDataCollection: parsing selector")
@@ -42,7 +42,7 @@ func DataCollections(
 
 	var (
 		site        = b.DiscreteOwner
-		collections = []data.Collection{}
+		collections = []data.BackupCollection{}
 		errs        error
 	)
 
@@ -54,7 +54,7 @@ func DataCollections(
 		defer closer()
 		defer close(foldersComplete)
 
-		var spcs []data.Collection
+		var spcs []data.BackupCollection
 
 		switch scope.Category().PathType() {
 		case path.ListsCategory:
@@ -97,10 +97,10 @@ func collectLists(
 	tenantID, siteID string,
 	updater statusUpdater,
 	ctrlOpts control.Options,
-) ([]data.Collection, error) {
+) ([]data.BackupCollection, error) {
 	logger.Ctx(ctx).With("site", siteID).Debug("Creating SharePoint List Collections")
 
-	spcs := make([]data.Collection, 0)
+	spcs := make([]data.BackupCollection, 0)
 
 	tuples, err := preFetchLists(ctx, serv, siteID)
 	if err != nil {
@@ -137,9 +137,9 @@ func collectLibraries(
 	scope selectors.SharePointScope,
 	updater statusUpdater,
 	ctrlOpts control.Options,
-) ([]data.Collection, map[string]struct{}, error) {
+) ([]data.BackupCollection, map[string]struct{}, error) {
 	var (
-		collections = []data.Collection{}
+		collections = []data.BackupCollection{}
 		errs        error
 	)
 
@@ -175,10 +175,10 @@ func collectPages(
 	scope selectors.SharePointScope,
 	updater statusUpdater,
 	ctrlOpts control.Options,
-) ([]data.Collection, error) {
+) ([]data.BackupCollection, error) {
 	logger.Ctx(ctx).With("site", siteID).Debug("Creating SharePoint Pages collections")
 
-	spcs := make([]data.Collection, 0)
+	spcs := make([]data.BackupCollection, 0)
 
 	// make the betaClient
 	adpt, err := graph.CreateAdapter(creds.AzureTenantID, creds.AzureClientID, creds.AzureClientSecret)

src/internal/connector/sharepoint/restore.go

@@ -30,7 +30,7 @@ import (
 // -- Switch:
 // ---- Libraries restored via the same workflow as oneDrive
 // ---- Lists call RestoreCollection()
-// ----> for each data.Stream within  Collection.Items()
+// ----> for each data.Stream within  RestoreCollection.Items()
 // ----> restoreListItems() is called
 // Restored List can be found in the Site's `Site content` page
 // Restored Libraries can be found within the Site's `Pages` page
@@ -43,7 +43,7 @@ func RestoreCollections(
 	creds account.M365Config,
 	service graph.Servicer,
 	dest control.RestoreDestination,
-	dcs []data.Collection,
+	dcs []data.RestoreCollection,
 	deets *details.Builder,
 ) (*support.ConnectorOperationStatus, error) {
 	var (
@@ -219,7 +219,7 @@ func restoreListItem(
 func RestoreListCollection(
 	ctx context.Context,
 	service graph.Servicer,
-	dc data.Collection,
+	dc data.RestoreCollection,
 	restoreContainerName string,
 	deets *details.Builder,
 	errUpdater func(string, error),
@@ -291,7 +291,7 @@ func RestoreListCollection(
 func RestorePageCollection(
 	ctx context.Context,
 	creds account.M365Config,
-	dc data.Collection,
+	dc data.RestoreCollection,
 	restoreContainerName string,
 	deets *details.Builder,
 	errUpdater func(string, error),

src/internal/data/data_collection.go

@@ -21,8 +21,8 @@ const (
 	DeletedState
 )
 
-// A Collection represents a compilation of data from the
+// A Collection represents the set of data within a single logical location
-// same type application (e.g. mail)
+// denoted by FullPath.
 type Collection interface {
 	// Items returns a channel from which items in the collection can be read.
 	// Each returned struct contains the next item in the collection
@@ -30,10 +30,13 @@ type Collection interface {
 	// an unrecoverable error caused an early termination in the sender.
 	Items() <-chan Stream
 	// FullPath returns a path struct that acts as a metadata tag for this
-	// DataCollection. Returned items should be ordered from most generic to least
+	// Collection.
-	// generic. For example, a DataCollection for emails from a specific user
-	// would be {"<tenant id>", "exchange", "<user ID>", "emails"}.
 	FullPath() path.Path
+}
+
+// BackupCollection is an extension of Collection that is used during backups.
+type BackupCollection interface {
+	Collection
 	// PreviousPath returns the path.Path this collection used to reside at
 	// (according to the M365 ID for the container) if the collection was moved or
 	// renamed. Returns nil if the collection is new.
@@ -58,6 +61,11 @@ type Collection interface {
 	DoNotMergeItems() bool
 }
 
+// RestoreCollection is an extension of Collection that is used during restores.
+type RestoreCollection interface {
+	Collection
+}
+
 // Stream represents a single item within a Collection
 // that can be consumed as a stream (it embeds io.Reader)
 type Stream interface {

src/internal/kopia/data_collection.go

@@ -8,7 +8,7 @@ import (
 )
 
 var (
-	_ data.Collection = &kopiaDataCollection{}
+	_ data.RestoreCollection = &kopiaDataCollection{}
 	_ data.Stream            = &kopiaDataStream{}
 )
 
@@ -35,18 +35,6 @@ func (kdc kopiaDataCollection) FullPath() path.Path {
 	return kdc.path
 }
 
-func (kdc kopiaDataCollection) PreviousPath() path.Path {
-	return nil
-}
-
-func (kdc kopiaDataCollection) State() data.CollectionState {
-	return data.NewState
-}
-
-func (kdc kopiaDataCollection) DoNotMergeItems() bool {
-	return false
-}
-
 type kopiaDataStream struct {
 	reader io.ReadCloser
 	uuid   string

src/internal/kopia/upload.go

@@ -254,7 +254,7 @@ func (cp *corsoProgress) get(k string) *itemDetails {
 func collectionEntries(
 	ctx context.Context,
 	cb func(context.Context, fs.Entry) error,
-	streamedEnts data.Collection,
+	streamedEnts data.BackupCollection,
 	progress *corsoProgress,
 ) (map[string]struct{}, *multierror.Error) {
 	if streamedEnts == nil {
@@ -442,7 +442,7 @@ func getStreamItemFunc(
 	curPath path.Path,
 	prevPath path.Path,
 	staticEnts []fs.Entry,
-	streamedEnts data.Collection,
+	streamedEnts data.BackupCollection,
 	baseDir fs.Directory,
 	globalExcludeSet map[string]struct{},
 	progress *corsoProgress,
@@ -540,7 +540,7 @@ type treeMap struct {
 	childDirs map[string]*treeMap
 	// Reference to data pulled from the external service. Contains only items in
 	// this directory. Does not contain references to subdirectories.
-	collection data.Collection
+	collection data.BackupCollection
 	// Reference to directory in base snapshot. The referenced directory itself
 	// may contain files and subdirectories, but the subdirectories should
 	// eventually be added when walking the base snapshot to build the hierarchy,
@@ -617,7 +617,7 @@ func getTreeNode(roots map[string]*treeMap, pathElements []string) *treeMap {
 
 func inflateCollectionTree(
 	ctx context.Context,
-	collections []data.Collection,
+	collections []data.BackupCollection,
 ) (map[string]*treeMap, map[string]path.Path, error) {
 	roots := make(map[string]*treeMap)
 	// Contains the old path for collections that have been moved or renamed.
@@ -911,13 +911,13 @@ func inflateBaseTree(
 // exclude from base directories when uploading the snapshot. As items in *all*
 // base directories will be checked for in every base directory, this assumes
 // that items in the bases are unique. Deletions of directories or subtrees
-// should be represented as changes in the status of a Collection, not an entry
+// should be represented as changes in the status of a BackupCollection, not an
-// in the globalExcludeSet.
+// entry in the globalExcludeSet.
 func inflateDirTree(
 	ctx context.Context,
 	loader snapshotLoader,
 	baseSnaps []IncrementalBase,
-	collections []data.Collection,
+	collections []data.BackupCollection,
 	globalExcludeSet map[string]struct{},
 	progress *corsoProgress,
 ) (fs.Directory, error) {

src/internal/kopia/upload_test.go

@@ -683,7 +683,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTree() {
 
 	progress := &corsoProgress{pending: map[string]*itemDetails{}}
 
-	collections := []data.Collection{
+	collections := []data.BackupCollection{
 		mockconnector.NewMockExchangeCollection(
 			suite.testPath,
 			expectedFileCount[user1Encoded],
@@ -759,11 +759,11 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTree_MixedDirectory()
 	//           - 42 separate files
 	table := []struct {
 		name   string
-		layout []data.Collection
+		layout []data.BackupCollection
 	}{
 		{
 			name: "SubdirFirst",
-			layout: []data.Collection{
+			layout: []data.BackupCollection{
 				mockconnector.NewMockExchangeCollection(
 					p2,
 					5,
@@ -776,7 +776,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTree_MixedDirectory()
 		},
 		{
 			name: "SubdirLast",
-			layout: []data.Collection{
+			layout: []data.BackupCollection{
 				mockconnector.NewMockExchangeCollection(
 					suite.testPath,
 					42,
@@ -845,7 +845,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTree_Fails() {
 
 	table := []struct {
 		name   string
-		layout []data.Collection
+		layout []data.BackupCollection
 	}{
 		{
 			"MultipleRoots",
@@ -862,7 +862,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTree_Fails() {
 			//       - emails
 			//         - Inbox
 			//           - 42 separate files
-			[]data.Collection{
+			[]data.BackupCollection{
 				mockconnector.NewMockExchangeCollection(
 					suite.testPath,
 					5,
@@ -875,7 +875,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTree_Fails() {
 		},
 		{
 			"NoCollectionPath",
-			[]data.Collection{
+			[]data.BackupCollection{
 				mockconnector.NewMockExchangeCollection(
 					nil,
 					5,
@@ -973,7 +973,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeErrors() {
 
 			progress := &corsoProgress{pending: map[string]*itemDetails{}}
 
-			cols := []data.Collection{}
+			cols := []data.BackupCollection{}
 			for _, s := range test.states {
 				prevPath := dirPath
 				nowPath := dirPath
@@ -1037,17 +1037,17 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeSingleSubtree() {
 
 	table := []struct {
 		name             string
-		inputCollections func() []data.Collection
+		inputCollections func() []data.BackupCollection
 		expected         *expectedNode
 	}{
 		{
 			name: "SkipsDeletedItems",
-			inputCollections: func() []data.Collection {
+			inputCollections: func() []data.BackupCollection {
 				mc := mockconnector.NewMockExchangeCollection(dirPath, 1)
 				mc.Names[0] = testFileName
 				mc.DeletedItems[0] = true
 
-				return []data.Collection{mc}
+				return []data.BackupCollection{mc}
 			},
 			expected: expectedTreeWithChildren(
 				[]string{
@@ -1066,13 +1066,13 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeSingleSubtree() {
 		},
 		{
 			name: "AddsNewItems",
-			inputCollections: func() []data.Collection {
+			inputCollections: func() []data.BackupCollection {
 				mc := mockconnector.NewMockExchangeCollection(dirPath, 1)
 				mc.Names[0] = testFileName2
 				mc.Data[0] = testFileData2
 				mc.ColState = data.NotMovedState
 
-				return []data.Collection{mc}
+				return []data.BackupCollection{mc}
 			},
 			expected: expectedTreeWithChildren(
 				[]string{
@@ -1101,13 +1101,13 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeSingleSubtree() {
 		},
 		{
 			name: "SkipsUpdatedItems",
-			inputCollections: func() []data.Collection {
+			inputCollections: func() []data.BackupCollection {
 				mc := mockconnector.NewMockExchangeCollection(dirPath, 1)
 				mc.Names[0] = testFileName
 				mc.Data[0] = testFileData2
 				mc.ColState = data.NotMovedState
 
-				return []data.Collection{mc}
+				return []data.BackupCollection{mc}
 			},
 			expected: expectedTreeWithChildren(
 				[]string{
@@ -1132,7 +1132,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeSingleSubtree() {
 		},
 		{
 			name: "DeleteAndNew",
-			inputCollections: func() []data.Collection {
+			inputCollections: func() []data.BackupCollection {
 				mc1 := mockconnector.NewMockExchangeCollection(dirPath, 0)
 				mc1.ColState = data.DeletedState
 				mc1.PrevPath = dirPath
@@ -1142,7 +1142,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeSingleSubtree() {
 				mc2.Names[0] = testFileName2
 				mc2.Data[0] = testFileData2
 
-				return []data.Collection{mc1, mc2}
+				return []data.BackupCollection{mc1, mc2}
 			},
 			expected: expectedTreeWithChildren(
 				[]string{
@@ -1167,7 +1167,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeSingleSubtree() {
 		},
 		{
 			name: "MovedAndNew",
-			inputCollections: func() []data.Collection {
+			inputCollections: func() []data.BackupCollection {
 				mc1 := mockconnector.NewMockExchangeCollection(dirPath2, 0)
 				mc1.ColState = data.MovedState
 				mc1.PrevPath = dirPath
@@ -1177,7 +1177,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeSingleSubtree() {
 				mc2.Names[0] = testFileName2
 				mc2.Data[0] = testFileData2
 
-				return []data.Collection{mc1, mc2}
+				return []data.BackupCollection{mc1, mc2}
 			},
 			expected: expectedTreeWithChildren(
 				[]string{
@@ -1211,13 +1211,13 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeSingleSubtree() {
 		},
 		{
 			name: "NewDoesntMerge",
-			inputCollections: func() []data.Collection {
+			inputCollections: func() []data.BackupCollection {
 				mc1 := mockconnector.NewMockExchangeCollection(dirPath, 1)
 				mc1.ColState = data.NewState
 				mc1.Names[0] = testFileName2
 				mc1.Data[0] = testFileData2
 
-				return []data.Collection{mc1}
+				return []data.BackupCollection{mc1}
 			},
 			expected: expectedTreeWithChildren(
 				[]string{
@@ -1369,13 +1369,13 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeMultipleSubdirecto
 
 	table := []struct {
 		name             string
-		inputCollections func(t *testing.T) []data.Collection
+		inputCollections func(t *testing.T) []data.BackupCollection
 		inputExcludes    map[string]struct{}
 		expected         *expectedNode
 	}{
 		{
 			name: "GlobalExcludeSet",
-			inputCollections: func(t *testing.T) []data.Collection {
+			inputCollections: func(t *testing.T) []data.BackupCollection {
 				return nil
 			},
 			inputExcludes: map[string]struct{}{
@@ -1417,7 +1417,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeMultipleSubdirecto
 		},
 		{
 			name: "MovesSubtree",
-			inputCollections: func(t *testing.T) []data.Collection {
+			inputCollections: func(t *testing.T) []data.BackupCollection {
 				newPath := makePath(
 					t,
 					[]string{testTenant, service, testUser, category, testInboxDir + "2"},
@@ -1428,7 +1428,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeMultipleSubdirecto
 				mc.PrevPath = inboxPath
 				mc.ColState = data.MovedState
 
-				return []data.Collection{mc}
+				return []data.BackupCollection{mc}
 			},
 			expected: expectedTreeWithChildren(
 				[]string{
@@ -1474,7 +1474,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeMultipleSubdirecto
 		},
 		{
 			name: "MovesChildAfterAncestorMove",
-			inputCollections: func(t *testing.T) []data.Collection {
+			inputCollections: func(t *testing.T) []data.BackupCollection {
 				newInboxPath := makePath(
 					t,
 					[]string{testTenant, service, testUser, category, testInboxDir + "2"},
@@ -1494,7 +1494,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeMultipleSubdirecto
 				work.PrevPath = workPath
 				work.ColState = data.MovedState
 
-				return []data.Collection{inbox, work}
+				return []data.BackupCollection{inbox, work}
 			},
 			expected: expectedTreeWithChildren(
 				[]string{
@@ -1540,7 +1540,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeMultipleSubdirecto
 		},
 		{
 			name: "MovesChildAfterAncestorDelete",
-			inputCollections: func(t *testing.T) []data.Collection {
+			inputCollections: func(t *testing.T) []data.BackupCollection {
 				newWorkPath := makePath(
 					t,
 					[]string{testTenant, service, testUser, category, workDir},
@@ -1555,7 +1555,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeMultipleSubdirecto
 				work.PrevPath = workPath
 				work.ColState = data.MovedState
 
-				return []data.Collection{inbox, work}
+				return []data.BackupCollection{inbox, work}
 			},
 			expected: expectedTreeWithChildren(
 				[]string{
@@ -1579,7 +1579,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeMultipleSubdirecto
 		},
 		{
 			name: "ReplaceDeletedDirectory",
-			inputCollections: func(t *testing.T) []data.Collection {
+			inputCollections: func(t *testing.T) []data.BackupCollection {
 				personal := mockconnector.NewMockExchangeCollection(personalPath, 0)
 				personal.PrevPath = personalPath
 				personal.ColState = data.DeletedState
@@ -1588,7 +1588,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeMultipleSubdirecto
 				work.PrevPath = workPath
 				work.ColState = data.MovedState
 
-				return []data.Collection{personal, work}
+				return []data.BackupCollection{personal, work}
 			},
 			expected: expectedTreeWithChildren(
 				[]string{
@@ -1620,7 +1620,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeMultipleSubdirecto
 		},
 		{
 			name: "ReplaceDeletedDirectoryWithNew",
-			inputCollections: func(t *testing.T) []data.Collection {
+			inputCollections: func(t *testing.T) []data.BackupCollection {
 				personal := mockconnector.NewMockExchangeCollection(personalPath, 0)
 				personal.PrevPath = personalPath
 				personal.ColState = data.DeletedState
@@ -1630,7 +1630,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeMultipleSubdirecto
 				newCol.Names[0] = workFileName2
 				newCol.Data[0] = workFileData2
 
-				return []data.Collection{personal, newCol}
+				return []data.BackupCollection{personal, newCol}
 			},
 			expected: expectedTreeWithChildren(
 				[]string{
@@ -1671,7 +1671,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeMultipleSubdirecto
 		},
 		{
 			name: "ReplaceMovedDirectory",
-			inputCollections: func(t *testing.T) []data.Collection {
+			inputCollections: func(t *testing.T) []data.BackupCollection {
 				newPersonalPath := makePath(
 					t,
 					[]string{testTenant, service, testUser, category, personalDir},
@@ -1686,7 +1686,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeMultipleSubdirecto
 				work.PrevPath = workPath
 				work.ColState = data.MovedState
 
-				return []data.Collection{personal, work}
+				return []data.BackupCollection{personal, work}
 			},
 			expected: expectedTreeWithChildren(
 				[]string{
@@ -1729,7 +1729,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeMultipleSubdirecto
 		},
 		{
 			name: "MoveDirectoryAndMergeItems",
-			inputCollections: func(t *testing.T) []data.Collection {
+			inputCollections: func(t *testing.T) []data.BackupCollection {
 				newPersonalPath := makePath(
 					t,
 					[]string{testTenant, service, testUser, category, workDir},
@@ -1744,7 +1744,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeMultipleSubdirecto
 				personal.Names[1] = testFileName4
 				personal.Data[1] = testFileData4
 
-				return []data.Collection{personal}
+				return []data.BackupCollection{personal}
 			},
 			expected: expectedTreeWithChildren(
 				[]string{
@@ -1793,7 +1793,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeMultipleSubdirecto
 		},
 		{
 			name: "MoveParentDeleteFileNoMergeSubtreeMerge",
-			inputCollections: func(t *testing.T) []data.Collection {
+			inputCollections: func(t *testing.T) []data.BackupCollection {
 				newInboxPath := makePath(
 					t,
 					[]string{testTenant, service, testUser, category, personalDir},
@@ -1824,7 +1824,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeMultipleSubdirecto
 				work.Names[0] = testFileName6
 				work.Data[0] = testFileData6
 
-				return []data.Collection{inbox, work}
+				return []data.BackupCollection{inbox, work}
 			},
 			expected: expectedTreeWithChildren(
 				[]string{
@@ -1876,7 +1876,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeMultipleSubdirecto
 		},
 		{
 			name: "NoMoveParentDeleteFileNoMergeSubtreeMerge",
-			inputCollections: func(t *testing.T) []data.Collection {
+			inputCollections: func(t *testing.T) []data.BackupCollection {
 				inbox := mockconnector.NewMockExchangeCollection(inboxPath, 1)
 				inbox.PrevPath = inboxPath
 				inbox.ColState = data.NotMovedState
@@ -1892,7 +1892,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeMultipleSubdirecto
 				work.Names[0] = testFileName6
 				work.Data[0] = testFileData6
 
-				return []data.Collection{inbox, work}
+				return []data.BackupCollection{inbox, work}
 			},
 			expected: expectedTreeWithChildren(
 				[]string{
@@ -2105,7 +2105,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeSkipsDeletedSubtre
 		snapshotRoot: getBaseSnapshot(),
 	}
 
-	collections := []data.Collection{mc}
+	collections := []data.BackupCollection{mc}
 
 	// Returned directory structure should look like:
 	// - a-tenant
@@ -2361,7 +2361,7 @@ func (suite *HierarchyBuilderUnitSuite) TestBuildDirectoryTreeSelectsCorrectSubt
 		},
 	}
 
-	collections := []data.Collection{mc}
+	collections := []data.BackupCollection{mc}
 
 	dirTree, err := inflateDirTree(
 		ctx,

src/internal/kopia/wrapper.go

@@ -118,7 +118,7 @@ type IncrementalBase struct {
 func (w Wrapper) BackupCollections(
 	ctx context.Context,
 	previousSnapshots []IncrementalBase,
-	collections []data.Collection,
+	collections []data.BackupCollection,
 	globalExcludeSet map[string]struct{},
 	tags map[string]string,
 	buildTreeWithBase bool,
@@ -368,7 +368,7 @@ func (w Wrapper) RestoreMultipleItems(
 	snapshotID string,
 	paths []path.Path,
 	bcounter ByteCounter,
-) ([]data.Collection, error) {
+) ([]data.RestoreCollection, error) {
 	ctx, end := D.Span(ctx, "kopia:restoreMultipleItems")
 	defer end()
 
@@ -409,7 +409,7 @@ func (w Wrapper) RestoreMultipleItems(
 		c.streams = append(c.streams, ds)
 	}
 
-	res := make([]data.Collection, 0, len(cols))
+	res := make([]data.RestoreCollection, 0, len(cols))
 	for _, c := range cols {
 		res = append(res, c)
 	}

src/internal/kopia/wrapper_test.go

@@ -52,7 +52,7 @@ var (
 func testForFiles(
 	t *testing.T,
 	expected map[string][]byte,
-	collections []data.Collection,
+	collections []data.RestoreCollection,
 ) {
 	t.Helper()
 
@@ -196,7 +196,7 @@ func (suite *KopiaIntegrationSuite) TearDownTest() {
 }
 
 func (suite *KopiaIntegrationSuite) TestBackupCollections() {
-	collections := []data.Collection{
+	collections := []data.BackupCollection{
 		mockconnector.NewMockExchangeCollection(
 			suite.testPath1,
 			5,
@@ -353,7 +353,7 @@ func (suite *KopiaIntegrationSuite) TestRestoreAfterCompressionChange() {
 	stats, _, _, err := w.BackupCollections(
 		ctx,
 		nil,
-		[]data.Collection{dc1, dc2},
+		[]data.BackupCollection{dc1, dc2},
 		nil,
 		tags,
 		true,
@@ -382,6 +382,41 @@ func (suite *KopiaIntegrationSuite) TestRestoreAfterCompressionChange() {
 	testForFiles(t, expected, result)
 }
 
+type mockBackupCollection struct {
+	path    path.Path
+	streams []data.Stream
+}
+
+func (c *mockBackupCollection) Items() <-chan data.Stream {
+	res := make(chan data.Stream)
+
+	go func() {
+		defer close(res)
+
+		for _, s := range c.streams {
+			res <- s
+		}
+	}()
+
+	return res
+}
+
+func (c mockBackupCollection) FullPath() path.Path {
+	return c.path
+}
+
+func (c mockBackupCollection) PreviousPath() path.Path {
+	return nil
+}
+
+func (c mockBackupCollection) State() data.CollectionState {
+	return data.NewState
+}
+
+func (c mockBackupCollection) DoNotMergeItems() bool {
+	return false
+}
+
 func (suite *KopiaIntegrationSuite) TestBackupCollections_ReaderError() {
 	t := suite.T()
 
@@ -396,8 +431,8 @@ func (suite *KopiaIntegrationSuite) TestBackupCollections_ReaderError() {
 		tags[k] = ""
 	}
 
-	collections := []data.Collection{
+	collections := []data.BackupCollection{
-		&kopiaDataCollection{
+		&mockBackupCollection{
 			path: suite.testPath1,
 			streams: []data.Stream{
 				&mockconnector.MockExchangeData{
@@ -410,7 +445,7 @@ func (suite *KopiaIntegrationSuite) TestBackupCollections_ReaderError() {
 				},
 			},
 		},
-		&kopiaDataCollection{
+		&mockBackupCollection{
 			path: suite.testPath2,
 			streams: []data.Stream{
 				&mockconnector.MockExchangeData{
@@ -477,7 +512,7 @@ type backedupFile struct {
 func (suite *KopiaIntegrationSuite) TestBackupCollectionsHandlesNoCollections() {
 	table := []struct {
 		name        string
-		collections []data.Collection
+		collections []data.BackupCollection
 	}{
 		{
 			name:        "NilCollections",
@@ -485,7 +520,7 @@ func (suite *KopiaIntegrationSuite) TestBackupCollectionsHandlesNoCollections()
 		},
 		{
 			name:        "EmptyCollections",
-			collections: []data.Collection{},
+			collections: []data.BackupCollection{},
 		},
 	}
 
@@ -624,10 +659,10 @@ func (suite *KopiaSimpleRepoIntegrationSuite) SetupTest() {
 
 	suite.w = &Wrapper{c}
 
-	collections := []data.Collection{}
+	collections := []data.BackupCollection{}
 
 	for _, parent := range []path.Path{suite.testPath1, suite.testPath2} {
-		collection := &kopiaDataCollection{path: parent}
+		collection := &mockBackupCollection{path: parent}
 
 		for _, item := range suite.files[parent.String()] {
 			collection.streams = append(
@@ -723,7 +758,7 @@ func (suite *KopiaSimpleRepoIntegrationSuite) TestBackupExcludeItem() {
 		excludeItem           bool
 		expectedCachedItems   int
 		expectedUncachedItems int
-		cols                  func() []data.Collection
+		cols                  func() []data.BackupCollection
 		backupIDCheck         require.ValueAssertionFunc
 		restoreCheck          assert.ErrorAssertionFunc
 	}{
@@ -732,7 +767,7 @@ func (suite *KopiaSimpleRepoIntegrationSuite) TestBackupExcludeItem() {
 			excludeItem:           true,
 			expectedCachedItems:   len(suite.filesByPath) - 1,
 			expectedUncachedItems: 0,
-			cols: func() []data.Collection {
+			cols: func() []data.BackupCollection {
 				return nil
 			},
 			backupIDCheck: require.NotEmpty,
@@ -743,7 +778,7 @@ func (suite *KopiaSimpleRepoIntegrationSuite) TestBackupExcludeItem() {
 			// No snapshot should be made since there were no changes.
 			expectedCachedItems:   0,
 			expectedUncachedItems: 0,
-			cols: func() []data.Collection {
+			cols: func() []data.BackupCollection {
 				return nil
 			},
 			// Backup doesn't run.
@@ -753,14 +788,14 @@ func (suite *KopiaSimpleRepoIntegrationSuite) TestBackupExcludeItem() {
 			name:                  "NoExcludeItemWithChanges",
 			expectedCachedItems:   len(suite.filesByPath),
 			expectedUncachedItems: 1,
-			cols: func() []data.Collection {
+			cols: func() []data.BackupCollection {
 				c := mockconnector.NewMockExchangeCollection(
 					suite.testPath1,
 					1,
 				)
 				c.ColState = data.NotMovedState
 
-				return []data.Collection{c}
+				return []data.BackupCollection{c}
 			},
 			backupIDCheck: require.NotEmpty,
 			restoreCheck:  assert.NoError,

src/internal/operations/backup.go

@@ -308,9 +308,9 @@ func produceBackupDataCollections(
 	ctx context.Context,
 	gc *connector.GraphConnector,
 	sel selectors.Selector,
-	metadata []data.Collection,
+	metadata []data.RestoreCollection,
 	ctrlOpts control.Options,
-) ([]data.Collection, map[string]struct{}, error) {
+) ([]data.BackupCollection, map[string]struct{}, error) {
 	complete, closer := observe.MessageWithCompletion(ctx, observe.Safe("Discovering items to backup"))
 	defer func() {
 		complete <- struct{}{}
@@ -331,7 +331,7 @@ type backuper interface {
 	BackupCollections(
 		ctx context.Context,
 		bases []kopia.IncrementalBase,
-		cs []data.Collection,
+		cs []data.BackupCollection,
 		excluded map[string]struct{},
 		tags map[string]string,
 		buildTreeWithBase bool,
@@ -389,7 +389,7 @@ func consumeBackupDataCollections(
 	tenantID string,
 	reasons []kopia.Reason,
 	mans []*kopia.ManifestEntry,
-	cs []data.Collection,
+	cs []data.BackupCollection,
 	excludes map[string]struct{},
 	backupID model.StableID,
 	isIncremental bool,

src/internal/operations/backup_integration_test.go

@@ -387,10 +387,10 @@ func buildCollections(
 	tenant, user string,
 	dest control.RestoreDestination,
 	colls []incrementalCollection,
-) []data.Collection {
+) []data.RestoreCollection {
 	t.Helper()
 
-	collections := make([]data.Collection, 0, len(colls))
+	collections := make([]data.RestoreCollection, 0, len(colls))
 
 	for _, c := range colls {
 		pth := toDataLayerPath(

src/internal/operations/backup_test.go

@@ -36,20 +36,20 @@ import (
 
 type mockRestorer struct {
 	gotPaths  []path.Path
-	colls     []data.Collection
+	colls     []data.RestoreCollection
-	collsByID map[string][]data.Collection // snapshotID: []Collection
+	collsByID map[string][]data.RestoreCollection // snapshotID: []RestoreCollection
 	err       error
 	onRestore restoreFunc
 }
 
-type restoreFunc func(id string, ps []path.Path) ([]data.Collection, error)
+type restoreFunc func(id string, ps []path.Path) ([]data.RestoreCollection, error)
 
 func (mr *mockRestorer) buildRestoreFunc(
 	t *testing.T,
 	oid string,
 	ops []path.Path,
 ) {
-	mr.onRestore = func(id string, ps []path.Path) ([]data.Collection, error) {
+	mr.onRestore = func(id string, ps []path.Path) ([]data.RestoreCollection, error) {
 		assert.Equal(t, oid, id, "manifest id")
 		checkPaths(t, ops, ps)
 
@@ -62,7 +62,7 @@ func (mr *mockRestorer) RestoreMultipleItems(
 	snapshotID string,
 	paths []path.Path,
 	bc kopia.ByteCounter,
-) ([]data.Collection, error) {
+) ([]data.RestoreCollection, error) {
 	mr.gotPaths = append(mr.gotPaths, paths...)
 
 	if mr.onRestore != nil {
@@ -85,7 +85,7 @@ func checkPaths(t *testing.T, expected, got []path.Path) {
 type mockBackuper struct {
 	checkFunc func(
 		bases []kopia.IncrementalBase,
-		cs []data.Collection,
+		cs []data.BackupCollection,
 		tags map[string]string,
 		buildTreeWithBase bool,
 	)
@@ -94,7 +94,7 @@ type mockBackuper struct {
 func (mbu mockBackuper) BackupCollections(
 	ctx context.Context,
 	bases []kopia.IncrementalBase,
-	cs []data.Collection,
+	cs []data.BackupCollection,
 	excluded map[string]struct{},
 	tags map[string]string,
 	buildTreeWithBase bool,
@@ -559,7 +559,7 @@ func (suite *BackupOpSuite) TestBackupOperation_ConsumeBackupDataCollections_Pat
 			mbu := &mockBackuper{
 				checkFunc: func(
 					bases []kopia.IncrementalBase,
-					cs []data.Collection,
+					cs []data.BackupCollection,
 					tags map[string]string,
 					buildTreeWithBase bool,
 				) {

src/internal/operations/manifests.go

@@ -46,10 +46,10 @@ func produceManifestsAndMetadata(
 	tenantID string,
 	getMetadata bool,
 	errs fault.Adder,
-) ([]*kopia.ManifestEntry, []data.Collection, bool, error) {
+) ([]*kopia.ManifestEntry, []data.RestoreCollection, bool, error) {
 	var (
 		metadataFiles = graph.AllMetadataFileNames()
-		collections   []data.Collection
+		collections   []data.RestoreCollection
 	)
 
 	ms, err := mr.FetchPrevSnapshotManifests(
@@ -183,7 +183,7 @@ func collectMetadata(
 	man *kopia.ManifestEntry,
 	fileNames []string,
 	tenantID string,
-) ([]data.Collection, error) {
+) ([]data.RestoreCollection, error) {
 	paths := []path.Path{}
 
 	for _, fn := range fileNames {

src/internal/operations/manifests_test.go

@@ -51,7 +51,6 @@ func (mg mockGetDetailsIDer) GetDetailsIDFromBackupID(
 type mockColl struct {
 	id string // for comparisons
 	p  path.Path
-	prevP path.Path
 }
 
 func (mc mockColl) Items() <-chan data.Stream {
@@ -62,18 +61,6 @@ func (mc mockColl) FullPath() path.Path {
 	return mc.p
 }
 
-func (mc mockColl) PreviousPath() path.Path {
-	return mc.prevP
-}
-
-func (mc mockColl) State() data.CollectionState {
-	return data.NewState
-}
-
-func (mc mockColl) DoNotMergeItems() bool {
-	return false
-}
-
 // ---------------------------------------------------------------------------
 // tests
 // ---------------------------------------------------------------------------
@@ -447,7 +434,7 @@ func (suite *OperationsManifestsUnitSuite) TestProduceManifestsAndMetadata() {
 		getMeta       bool
 		assertErr     assert.ErrorAssertionFunc
 		assertB       assert.BoolAssertionFunc
-		expectDCS     []data.Collection
+		expectDCS     []data.RestoreCollection
 		expectNilMans bool
 	}{
 		{
@@ -550,7 +537,7 @@ func (suite *OperationsManifestsUnitSuite) TestProduceManifestsAndMetadata() {
 		{
 			name: "man missing backup id",
 			mr: mockManifestRestorer{
-				mockRestorer: mockRestorer{collsByID: map[string][]data.Collection{
+				mockRestorer: mockRestorer{collsByID: map[string][]data.RestoreCollection{
 					"id": {mockColl{id: "id_coll"}},
 				}},
 				mans: []*kopia.ManifestEntry{makeMan(path.EmailCategory, "id", "", "")},
@@ -577,7 +564,7 @@ func (suite *OperationsManifestsUnitSuite) TestProduceManifestsAndMetadata() {
 		{
 			name: "one complete, one incomplete",
 			mr: mockManifestRestorer{
-				mockRestorer: mockRestorer{collsByID: map[string][]data.Collection{
+				mockRestorer: mockRestorer{collsByID: map[string][]data.RestoreCollection{
 					"id":        {mockColl{id: "id_coll"}},
 					"incmpl_id": {mockColl{id: "incmpl_id_coll"}},
 				}},
@@ -591,12 +578,12 @@ func (suite *OperationsManifestsUnitSuite) TestProduceManifestsAndMetadata() {
 			getMeta:   true,
 			assertErr: assert.NoError,
 			assertB:   assert.True,
-			expectDCS: []data.Collection{mockColl{id: "id_coll"}},
+			expectDCS: []data.RestoreCollection{mockColl{id: "id_coll"}},
 		},
 		{
 			name: "single valid man",
 			mr: mockManifestRestorer{
-				mockRestorer: mockRestorer{collsByID: map[string][]data.Collection{
+				mockRestorer: mockRestorer{collsByID: map[string][]data.RestoreCollection{
 					"id": {mockColl{id: "id_coll"}},
 				}},
 				mans: []*kopia.ManifestEntry{makeMan(path.EmailCategory, "id", "", "bid")},
@@ -606,12 +593,12 @@ func (suite *OperationsManifestsUnitSuite) TestProduceManifestsAndMetadata() {
 			getMeta:   true,
 			assertErr: assert.NoError,
 			assertB:   assert.True,
-			expectDCS: []data.Collection{mockColl{id: "id_coll"}},
+			expectDCS: []data.RestoreCollection{mockColl{id: "id_coll"}},
 		},
 		{
 			name: "multiple valid mans",
 			mr: mockManifestRestorer{
-				mockRestorer: mockRestorer{collsByID: map[string][]data.Collection{
+				mockRestorer: mockRestorer{collsByID: map[string][]data.RestoreCollection{
 					"mail":    {mockColl{id: "mail_coll"}},
 					"contact": {mockColl{id: "contact_coll"}},
 				}},
@@ -625,7 +612,7 @@ func (suite *OperationsManifestsUnitSuite) TestProduceManifestsAndMetadata() {
 			getMeta:   true,
 			assertErr: assert.NoError,
 			assertB:   assert.True,
-			expectDCS: []data.Collection{
+			expectDCS: []data.RestoreCollection{
 				mockColl{id: "mail_coll"},
 				mockColl{id: "contact_coll"},
 			},

src/internal/operations/restore.go

@@ -88,7 +88,7 @@ func (op RestoreOperation) validate() error {
 // pointer wrapping the values, while those values
 // get populated asynchronously.
 type restoreStats struct {
-	cs                []data.Collection
+	cs                []data.RestoreCollection
 	gc                *support.ConnectorOperationStatus
 	bytesRead         *stats.ByteCounter
 	resourceCount     int
@@ -104,7 +104,7 @@ type restorer interface {
 		snapshotID string,
 		paths []path.Path,
 		bc kopia.ByteCounter,
-	) ([]data.Collection, error)
+	) ([]data.RestoreCollection, error)
 }
 
 // Run begins a synchronous restore operation.

src/internal/operations/restore_test.go

@@ -10,6 +10,7 @@ import (
 	"github.com/stretchr/testify/suite"
 
 	"github.com/alcionai/corso/src/internal/connector/exchange"
+	"github.com/alcionai/corso/src/internal/connector/mockconnector"
 	"github.com/alcionai/corso/src/internal/connector/support"
 	"github.com/alcionai/corso/src/internal/data"
 	"github.com/alcionai/corso/src/internal/events"
@@ -61,7 +62,7 @@ func (suite *RestoreOpSuite) TestRestoreOperation_PersistResults() {
 				bytesRead: &stats.ByteCounter{
 					NumBytes: 42,
 				},
-				cs: []data.Collection{&exchange.Collection{}},
+				cs: []data.RestoreCollection{&mockconnector.MockExchangeDataCollection{}},
 				gc: &support.ConnectorOperationStatus{
 					ObjectCount: 1,
 					Successful:  1,
@@ -82,7 +83,7 @@ func (suite *RestoreOpSuite) TestRestoreOperation_PersistResults() {
 			expectErr:    assert.NoError,
 			stats: restoreStats{
 				bytesRead: &stats.ByteCounter{},
-				cs:        []data.Collection{},
+				cs:        []data.RestoreCollection{},
 				gc:        &support.ConnectorOperationStatus{},
 			},
 		},

src/internal/streamstore/streamstore.go

@@ -76,7 +76,7 @@ func (ss *streamStore) WriteBackupDetails(
 	backupStats, _, _, err := ss.kw.BackupCollections(
 		ctx,
 		nil,
-		[]data.Collection{dc},
+		[]data.BackupCollection{dc},
 		nil,
 		nil,
 		false)
@@ -164,7 +164,7 @@ func (ss *streamStore) DeleteBackupDetails(
 	return nil
 }
 
-// streamCollection is a data.Collection used to persist
+// streamCollection is a data.BackupCollection used to persist
 // a single data stream
 type streamCollection struct {
 	// folderPath indicates what level in the hierarchy this collection