Dedupe collection item IDs prior to fetching item data (#2116)

## Description

Under some conditions, items can be returned multiple times when enumerating the items in a folder in Exchange. Begin deduping those items by doing the following:
* use a map in ExchangeDataCollection to dedupe on item IDs
* have enumeration function return a single slice of items containing both additions and deletion so a "last-change-wins" policy can be implemented

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

## Issue(s)

* #1954 

## Test Plan

<!-- How will this be tested prior to merging.-->
- [ ] 💪 Manual
- [x] ⚡ Unit test
- [ ] 💚 E2E

src/internal/connector/exchange/api/api.go

@@ -24,6 +24,15 @@ type DeltaUpdate struct {
 	Reset bool
 }
 
+// DeltaResult contains the ID and whether the item referenced by the ID was
+// deleted. This allows functions that fetch items for a folder to return a
+// single consolidated stream which is easier to dedupe as the order between
+// add/update and delete operations is known.
+type DeltaResult struct {
+	ID      string
+	Deleted bool
+}
+
 // GraphQuery represents functions which perform exchange-specific queries
 // into M365 backstore. Responses -> returned items will only contain the information
 // that is included in the options

src/internal/connector/exchange/api/contacts.go

@@ -179,10 +179,10 @@ func (p *contactPager) valuesIn(pl pageLinker) ([]getIDAndAddtler, error) {
 func (c Contacts) GetAddedAndRemovedItemIDs(
 	ctx context.Context,
 	user, directoryID, oldDelta string,
-) ([]string, []string, DeltaUpdate, error) {
+) ([]DeltaResult, DeltaUpdate, error) {
 	service, err := c.service()
 	if err != nil {
-		return nil, nil, DeltaUpdate{}, err
+		return nil, DeltaUpdate{}, err
 	}
 
 	var (
@@ -192,22 +192,22 @@ func (c Contacts) GetAddedAndRemovedItemIDs(
 
 	options, err := optionsForContactFoldersItemDelta([]string{"parentFolderId"})
 	if err != nil {
-		return nil, nil, DeltaUpdate{}, errors.Wrap(err, "getting query options")
+		return nil, DeltaUpdate{}, errors.Wrap(err, "getting query options")
 	}
 
 	if len(oldDelta) > 0 {
 		builder := users.NewItemContactFoldersItemContactsDeltaRequestBuilder(oldDelta, service.Adapter())
 		pgr := &contactPager{service, builder, options}
 
-		added, removed, deltaURL, err := getItemsAddedAndRemovedFromContainer(ctx, pgr)
+		items, deltaURL, err := getItemsAddedAndRemovedFromContainer(ctx, pgr)
 		// note: happy path, not the error condition
 		if err == nil {
-			return added, removed, DeltaUpdate{deltaURL, false}, errs.ErrorOrNil()
+			return items, DeltaUpdate{deltaURL, false}, errs.ErrorOrNil()
 		}
 		// only return on error if it is NOT a delta issue.
 		// on bad deltas we retry the call with the regular builder
 		if graph.IsErrInvalidDelta(err) == nil {
-			return nil, nil, DeltaUpdate{}, err
+			return nil, DeltaUpdate{}, err
 		}
 
 		resetDelta = true
@@ -217,10 +217,10 @@ func (c Contacts) GetAddedAndRemovedItemIDs(
 	builder := service.Client().UsersById(user).ContactFoldersById(directoryID).Contacts().Delta()
 	pgr := &contactPager{service, builder, options}
 
-	added, removed, deltaURL, err := getItemsAddedAndRemovedFromContainer(ctx, pgr)
+	items, deltaURL, err := getItemsAddedAndRemovedFromContainer(ctx, pgr)
 	if err != nil {
-		return nil, nil, DeltaUpdate{}, err
+		return nil, DeltaUpdate{}, err
 	}
 
-	return added, removed, DeltaUpdate{deltaURL, resetDelta}, errs.ErrorOrNil()
+	return items, DeltaUpdate{deltaURL, resetDelta}, errs.ErrorOrNil()
 }

src/internal/connector/exchange/api/events.go

@@ -165,29 +165,29 @@ func (p *eventPager) valuesIn(pl pageLinker) ([]getIDAndAddtler, error) {
 func (c Events) GetAddedAndRemovedItemIDs(
 	ctx context.Context,
 	user, calendarID, oldDelta string,
-) ([]string, []string, DeltaUpdate, error) {
+) ([]DeltaResult, DeltaUpdate, error) {
 	service, err := c.service()
 	if err != nil {
-		return nil, nil, DeltaUpdate{}, err
+		return nil, DeltaUpdate{}, err
 	}
 
 	var errs *multierror.Error
 
 	options, err := optionsForEventsByCalendar([]string{"id"})
 	if err != nil {
-		return nil, nil, DeltaUpdate{}, err
+		return nil, DeltaUpdate{}, err
 	}
 
 	builder := service.Client().UsersById(user).CalendarsById(calendarID).Events()
 	pgr := &eventPager{service, builder, options}
 
-	added, _, _, err := getItemsAddedAndRemovedFromContainer(ctx, pgr)
+	items, _, err := getItemsAddedAndRemovedFromContainer(ctx, pgr)
 	if err != nil {
-		return nil, nil, DeltaUpdate{}, err
+		return nil, DeltaUpdate{}, err
 	}
 
 	// Events don't have a delta endpoint so just return an empty string.
-	return added, nil, DeltaUpdate{}, errs.ErrorOrNil()
+	return items, DeltaUpdate{}, errs.ErrorOrNil()
 }
 
 // ---------------------------------------------------------------------------

src/internal/connector/exchange/api/mail.go

@@ -177,10 +177,10 @@ func (p *mailPager) valuesIn(pl pageLinker) ([]getIDAndAddtler, error) {
 func (c Mail) GetAddedAndRemovedItemIDs(
 	ctx context.Context,
 	user, directoryID, oldDelta string,
-) ([]string, []string, DeltaUpdate, error) {
+) ([]DeltaResult, DeltaUpdate, error) {
 	service, err := c.service()
 	if err != nil {
-		return nil, nil, DeltaUpdate{}, err
+		return nil, DeltaUpdate{}, err
 	}
 
 	var (
@@ -191,22 +191,22 @@ func (c Mail) GetAddedAndRemovedItemIDs(
 
 	options, err := optionsForFolderMessagesDelta([]string{"isRead"})
 	if err != nil {
-		return nil, nil, DeltaUpdate{}, errors.Wrap(err, "getting query options")
+		return nil, DeltaUpdate{}, errors.Wrap(err, "getting query options")
 	}
 
 	if len(oldDelta) > 0 {
 		builder := users.NewItemMailFoldersItemMessagesDeltaRequestBuilder(oldDelta, service.Adapter())
 		pgr := &mailPager{service, builder, options}
 
-		added, removed, deltaURL, err := getItemsAddedAndRemovedFromContainer(ctx, pgr)
+		items, deltaURL, err := getItemsAddedAndRemovedFromContainer(ctx, pgr)
 		// note: happy path, not the error condition
 		if err == nil {
-			return added, removed, DeltaUpdate{deltaURL, false}, errs.ErrorOrNil()
+			return items, DeltaUpdate{deltaURL, false}, errs.ErrorOrNil()
 		}
 		// only return on error if it is NOT a delta issue.
 		// on bad deltas we retry the call with the regular builder
 		if graph.IsErrInvalidDelta(err) == nil {
-			return nil, nil, DeltaUpdate{}, err
+			return nil, DeltaUpdate{}, err
 		}
 
 		resetDelta = true
@@ -216,10 +216,10 @@ func (c Mail) GetAddedAndRemovedItemIDs(
 	builder := service.Client().UsersById(user).MailFoldersById(directoryID).Messages().Delta()
 	pgr := &mailPager{service, builder, options}
 
-	added, removed, deltaURL, err := getItemsAddedAndRemovedFromContainer(ctx, pgr)
+	items, deltaURL, err := getItemsAddedAndRemovedFromContainer(ctx, pgr)
 	if err != nil {
-		return nil, nil, DeltaUpdate{}, err
+		return nil, DeltaUpdate{}, err
 	}
 
-	return added, removed, DeltaUpdate{deltaURL, resetDelta}, errs.ErrorOrNil()
+	return items, DeltaUpdate{deltaURL, resetDelta}, errs.ErrorOrNil()
 }

src/internal/connector/exchange/api/shared.go

@@ -61,10 +61,9 @@ func toValues[T any](a any) ([]getIDAndAddtler, error) {
 func getItemsAddedAndRemovedFromContainer(
 	ctx context.Context,
 	pager itemPager,
-) ([]string, []string, string, error) {
+) ([]DeltaResult, string, error) {
 	var (
-		addedIDs   = []string{}
-		removedIDs = []string{}
+		foundItems = []DeltaResult{}
 		deltaURL   string
 	)
 
@@ -73,33 +72,37 @@ func getItemsAddedAndRemovedFromContainer(
 		resp, err := pager.getPage(ctx)
 		if err != nil {
 			if err := graph.IsErrDeletedInFlight(err); err != nil {
-				return nil, nil, deltaURL, err
+				return nil, deltaURL, err
 			}
 
 			if err := graph.IsErrInvalidDelta(err); err != nil {
-				return nil, nil, deltaURL, err
+				return nil, deltaURL, err
 			}
 
-			return nil, nil, deltaURL, errors.Wrap(err, support.ConnectorStackErrorTrace(err))
+			return nil, deltaURL, errors.Wrap(err, support.ConnectorStackErrorTrace(err))
 		}
 
 		// each category type responds with a different interface, but all
 		// of them comply with GetValue, which is where we'll get our item data.
 		items, err := pager.valuesIn(resp)
 		if err != nil {
-			return nil, nil, "", err
+			return nil, "", err
 		}
 
 		// iterate through the items in the page
 		for _, item := range items {
+			newItem := DeltaResult{
+				ID: *item.GetId(),
+			}
+
 			// if the additional data conains a `@removed` key, the value will either
 			// be 'changed' or 'deleted'.  We don't really care about the cause: both
 			// cases are handled the same way in storage.
-			if item.GetAdditionalData()[graph.AddtlDataRemoved] == nil {
-				addedIDs = append(addedIDs, *item.GetId())
-			} else {
-				removedIDs = append(removedIDs, *item.GetId())
+			if item.GetAdditionalData()[graph.AddtlDataRemoved] != nil {
+				newItem.Deleted = true
 			}
+
+			foundItems = append(foundItems, newItem)
 		}
 
 		// the deltaLink is kind of like a cursor for overall data state.
@@ -122,5 +125,5 @@ func getItemsAddedAndRemovedFromContainer(
 		pager.setNext(*nextLink)
 	}
 
-	return addedIDs, removedIDs, deltaURL, nil
+	return foundItems, deltaURL, nil
 }

src/internal/connector/exchange/exchange_data_collection.go

@@ -53,9 +53,9 @@ type Collection struct {
 	data chan data.Stream
 
 	// added is a list of existing item IDs that were added to a container
-	added []string
+	added map[string]struct{}
 	// removed is a list of item IDs that were deleted from, or moved out, of a container
-	removed []string
+	removed map[string]struct{}
 
 	// service - client/adapter pair used to access M365 back store
 	service graph.Servicer
@@ -102,8 +102,8 @@ func NewCollection(
 		data:            make(chan data.Stream, collectionChannelBufferSize),
 		doNotMergeItems: doNotMergeItems,
 		fullPath:        curr,
-		added:           make([]string, 0),
-		removed:         make([]string, 0),
+		added:           make(map[string]struct{}, 0),
+		removed:         make(map[string]struct{}, 0),
 		prevPath:        prev,
 		service:         service,
 		state:           stateOf(prev, curr),
@@ -222,7 +222,7 @@ func (col *Collection) streamItems(ctx context.Context) {
 	}
 
 	// delete all removed items
-	for _, id := range col.removed {
+	for id := range col.removed {
 		semaphoreCh <- struct{}{}
 
 		wg.Add(1)
@@ -247,7 +247,7 @@ func (col *Collection) streamItems(ctx context.Context) {
 	}
 
 	// add any new items
-	for _, id := range col.added {
+	for id := range col.added {
 		if col.ctrl.FailFast && errs != nil {
 			break
 		}

src/internal/connector/exchange/service_iterators.go

@@ -19,7 +19,7 @@ type addedAndRemovedItemIDsGetter interface {
 	GetAddedAndRemovedItemIDs(
 		ctx context.Context,
 		user, containerID, oldDeltaToken string,
-	) ([]string, []string, api.DeltaUpdate, error)
+	) ([]api.DeltaResult, api.DeltaUpdate, error)
 }
 
 // filterContainersAndFillCollections is a utility function
@@ -93,7 +93,7 @@ func filterContainersAndFillCollections(
 			}
 		}
 
-		added, removed, newDelta, err := getter.GetAddedAndRemovedItemIDs(ctx, qp.ResourceOwner, cID, prevDelta)
+		items, newDelta, err := getter.GetAddedAndRemovedItemIDs(ctx, qp.ResourceOwner, cID, prevDelta)
 		if err != nil {
 			// note == nil check; only catches non-inFlight error cases.
 			if graph.IsErrDeletedInFlight(err) == nil {
@@ -125,8 +125,22 @@ func filterContainersAndFillCollections(
 			newDelta.Reset)
 
 		collections[cID] = &edc
-		edc.added = append(edc.added, added...)
-		edc.removed = append(edc.removed, removed...)
+
+		// This results in "last one wins" if there's duplicate entries for an ID
+		// and some are deleted while some are added.
+		for _, i := range items {
+			m := edc.added
+			del := edc.removed
+
+			if i.Deleted {
+				m = edc.removed
+				del = edc.added
+			}
+
+			m[i.ID] = struct{}{}
+
+			delete(del, i.ID)
+		}
 
 		// add the current path for the container ID to be used in the next backup
 		// as the "previous path", for reference in case of a rename or relocation.

src/internal/connector/exchange/service_iterators_test.go

@@ -30,8 +30,7 @@ var _ addedAndRemovedItemIDsGetter = &mockGetter{}
 type (
 	mockGetter        map[string]mockGetterResults
 	mockGetterResults struct {
-		added    []string
-		removed  []string
+		items    []api.DeltaResult
 		newDelta api.DeltaUpdate
 		err      error
 	}
@@ -41,17 +40,16 @@ func (mg mockGetter) GetAddedAndRemovedItemIDs(
 	ctx context.Context,
 	userID, cID, prevDelta string,
 ) (
-	[]string,
-	[]string,
+	[]api.DeltaResult,
 	api.DeltaUpdate,
 	error,
 ) {
 	results, ok := mg[cID]
 	if !ok {
-		return nil, nil, api.DeltaUpdate{}, errors.New("mock not found for " + cID)
+		return nil, api.DeltaUpdate{}, errors.New("mock not found for " + cID)
 	}
 
-	return results.added, results.removed, results.newDelta, results.err
+	return results.items, results.newDelta, results.err
 }
 
 var _ graph.ContainerResolver = &mockResolver{}
@@ -112,20 +110,25 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections() {
 		statusUpdater = func(*support.ConnectorOperationStatus) {}
 		allScope      = selectors.NewExchangeBackup(nil).MailFolders(selectors.Any())[0]
 		dps           = DeltaPaths{} // incrementals are tested separately
-		commonResult  = mockGetterResults{
-			added:    []string{"a1", "a2", "a3"},
-			removed:  []string{"r1", "r2", "r3"},
+		getterItems   = []api.DeltaResult{
+			{ID: "a1"},
+			{ID: "a2"},
+			{ID: "a3"},
+			{ID: "r1", Deleted: true},
+			{ID: "r2", Deleted: true},
+			{ID: "r3", Deleted: true},
+		}
+		commonResult = mockGetterResults{
+			items:    getterItems,
 			newDelta: api.DeltaUpdate{URL: "delta_url"},
 		}
 		errorResult = mockGetterResults{
-			added:    []string{"a1", "a2", "a3"},
-			removed:  []string{"r1", "r2", "r3"},
+			items:    getterItems,
 			newDelta: api.DeltaUpdate{URL: "delta_url"},
 			err:      assert.AnError,
 		}
 		deletedInFlightResult = mockGetterResults{
-			added:    []string{"a1", "a2", "a3"},
-			removed:  []string{"r1", "r2", "r3"},
+			items:    getterItems,
 			newDelta: api.DeltaUpdate{URL: "delta_url"},
 			err:      graph.ErrDeletedInFlight{Err: *common.EncapsulateError(assert.AnError)},
 		}
@@ -333,13 +336,193 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections() {
 				exColl, ok := coll.(*Collection)
 				require.True(t, ok, "collection is an *exchange.Collection")
 
-				assert.ElementsMatch(t, expect.added, exColl.added, "added items")
-				assert.ElementsMatch(t, expect.removed, exColl.removed, "removed items")
+				expectAdded := map[string]struct{}{}
+				expectRemoved := map[string]struct{}{}
+
+				for _, i := range expect.items {
+					if i.Deleted {
+						expectRemoved[i.ID] = struct{}{}
+					} else {
+						expectAdded[i.ID] = struct{}{}
+					}
+				}
+
+				assert.Equal(t, expectAdded, exColl.added, "added items")
+				assert.Equal(t, expectRemoved, exColl.removed, "removed items")
 			}
 		})
 	}
 }
 
+func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_repeatedItems() {
+	var (
+		userID = "user_id"
+		qp     = graph.QueryParams{
+			Category:      path.EmailCategory, // doesn't matter which one we use.
+			ResourceOwner: userID,
+			Credentials:   suite.creds,
+		}
+		statusUpdater = func(*support.ConnectorOperationStatus) {}
+		allScope      = selectors.NewExchangeBackup(nil).MailFolders(selectors.Any())[0]
+		dps           = DeltaPaths{} // incrementals are tested separately
+		delta         = api.DeltaUpdate{URL: "delta_url"}
+		container1    = mockContainer{
+			id:          strPtr("1"),
+			displayName: strPtr("display_name_1"),
+			p:           path.Builder{}.Append("display_name_1"),
+		}
+	)
+
+	table := []struct {
+		name                string
+		getter              mockGetter
+		resolver            graph.ContainerResolver
+		scope               selectors.ExchangeScope
+		failFast            bool
+		expectErr           assert.ErrorAssertionFunc
+		expectNewColls      int
+		expectMetadataColls int
+		expectAdded         map[string]struct{}
+		expectRemoved       map[string]struct{}
+	}{
+		{
+			name: "repeated add",
+			getter: map[string]mockGetterResults{
+				"1": {
+					items: []api.DeltaResult{
+						{ID: "a1"},
+						{ID: "a1"},
+					},
+					newDelta: delta,
+				},
+			},
+			resolver:            newMockResolver(container1),
+			scope:               allScope,
+			expectErr:           assert.NoError,
+			expectNewColls:      1,
+			expectMetadataColls: 1,
+			expectAdded:         map[string]struct{}{"a1": {}},
+			// Avoid failures for nil map.
+			expectRemoved: map[string]struct{}{},
+		},
+		{
+			name: "repeated remove",
+			getter: map[string]mockGetterResults{
+				"1": {
+					items: []api.DeltaResult{
+						{ID: "a1", Deleted: true},
+						{ID: "a1", Deleted: true},
+					},
+					newDelta: delta,
+				},
+			},
+			resolver:            newMockResolver(container1),
+			scope:               allScope,
+			expectErr:           assert.NoError,
+			expectNewColls:      1,
+			expectMetadataColls: 1,
+			expectAdded:         map[string]struct{}{},
+			expectRemoved:       map[string]struct{}{"a1": {}},
+		},
+		{
+			name: "interleaved, final remove",
+			getter: map[string]mockGetterResults{
+				"1": {
+					items: []api.DeltaResult{
+						{ID: "a1"},
+						{ID: "a1", Deleted: true},
+						{ID: "a1"},
+						{ID: "a1", Deleted: true},
+					},
+					newDelta: delta,
+				},
+			},
+			resolver:            newMockResolver(container1),
+			scope:               allScope,
+			expectErr:           assert.NoError,
+			expectNewColls:      1,
+			expectMetadataColls: 1,
+			expectAdded:         map[string]struct{}{},
+			expectRemoved:       map[string]struct{}{"a1": {}},
+		},
+		{
+			name: "interleaved, final add",
+			getter: map[string]mockGetterResults{
+				"1": {
+					items: []api.DeltaResult{
+						{ID: "a1"},
+						{ID: "a1", Deleted: true},
+						{ID: "a1"},
+						{ID: "a1", Deleted: true},
+						{ID: "a1"},
+					},
+					newDelta: delta,
+				},
+			},
+			resolver:            newMockResolver(container1),
+			scope:               allScope,
+			expectErr:           assert.NoError,
+			expectNewColls:      1,
+			expectMetadataColls: 1,
+			expectAdded:         map[string]struct{}{"a1": {}},
+			expectRemoved:       map[string]struct{}{},
+		},
+	}
+	for _, test := range table {
+		suite.T().Run(test.name, func(t *testing.T) {
+			ctx, flush := tester.NewContext()
+			defer flush()
+
+			collections := map[string]data.Collection{}
+
+			err := filterContainersAndFillCollections(
+				ctx,
+				qp,
+				test.getter,
+				collections,
+				statusUpdater,
+				test.resolver,
+				test.scope,
+				dps,
+				control.Options{FailFast: test.failFast},
+			)
+			test.expectErr(t, err)
+
+			// collection assertions
+
+			deleteds, news, metadatas, doNotMerges := 0, 0, 0, 0
+			for _, c := range collections {
+				if c.FullPath().Service() == path.ExchangeMetadataService {
+					metadatas++
+					continue
+				}
+
+				if c.State() == data.DeletedState {
+					deleteds++
+				}
+
+				if c.State() == data.NewState {
+					news++
+				}
+
+				if c.DoNotMergeItems() {
+					doNotMerges++
+				}
+
+				exColl, ok := c.(*Collection)
+				require.True(t, ok, "collection is an *exchange.Collection")
+
+				assert.Equal(t, test.expectAdded, exColl.added)
+				assert.Equal(t, test.expectRemoved, exColl.removed)
+			}
+
+			assert.Zero(t, deleteds, "deleted collections")
+			assert.Equal(t, test.expectMetadataColls, metadatas, "metadata collections")
+			assert.Equal(t, test.expectNewColls, news, "new collections")
+		})
+	}
+}
+
 func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_incrementals() {
 	var (
 		userID   = "user_id"
@@ -353,11 +536,11 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_incre
 		statusUpdater = func(*support.ConnectorOperationStatus) {}
 		allScope      = selectors.NewExchangeBackup(nil).MailFolders(selectors.Any())[0]
 		commonResults = mockGetterResults{
-			added:    []string{"added"},
+			items:    []api.DeltaResult{{ID: "added"}},
 			newDelta: api.DeltaUpdate{URL: "new_delta_url"},
 		}
 		expiredResults = mockGetterResults{
-			added: []string{"added"},
+			items: []api.DeltaResult{{ID: "added"}},
 			newDelta: api.DeltaUpdate{
 				URL:   "new_delta_url",
 				Reset: true,

src/internal/operations/backup_integration_test.go

@@ -941,19 +941,35 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_exchangeIncrementals() {
 
 					switch category {
 					case path.EmailCategory:
-						ids, _, _, err := ac.Mail().GetAddedAndRemovedItemIDs(ctx, suite.user, containerID, "")
+						ids, _, err := ac.Mail().GetAddedAndRemovedItemIDs(ctx, suite.user, containerID, "")
 						require.NoError(t, err, "getting message ids")
 						require.NotEmpty(t, ids, "message ids in folder")
 
-						err = cli.MessagesById(ids[0]).Delete(ctx, nil)
+						var idx int
+
+						for _, item := range ids {
+							if item.Deleted {
+								idx++
+							}
+						}
+
+						err = cli.MessagesById(ids[idx].ID).Delete(ctx, nil)
 						require.NoError(t, err, "deleting email item: %s", support.ConnectorStackErrorTrace(err))
 
 					case path.ContactsCategory:
-						ids, _, _, err := ac.Contacts().GetAddedAndRemovedItemIDs(ctx, suite.user, containerID, "")
+						ids, _, err := ac.Contacts().GetAddedAndRemovedItemIDs(ctx, suite.user, containerID, "")
 						require.NoError(t, err, "getting contact ids")
 						require.NotEmpty(t, ids, "contact ids in folder")
 
-						err = cli.ContactsById(ids[0]).Delete(ctx, nil)
+						var idx int
+
+						for _, item := range ids {
+							if item.Deleted {
+								idx++
+							}
+						}
+
+						err = cli.ContactsById(ids[idx].ID).Delete(ctx, nil)
 						require.NoError(t, err, "deleting contact item: %s", support.ConnectorStackErrorTrace(err))
 					}
 				}