Add non delta pagers to exchange (#3212)

When the user's mailbox is full, we cannot make use of delta apis. This adds initial changes needed to create separate delta and non delta pagers for all of exchange.

*I would suggest looking commit wise when reviewing the PR.*

---

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

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

#### Type of change

<!--- Please check the type of change your PR introduces: --->
- [ ] 🌻 Feature
- [x] 🐛 Bugfix
- [ ] 🗺️ Documentation
- [ ] 🤖 Supportability/Tests
- [ ] 💻 CI/Deployment
- [ ] 🧹 Tech Debt/Cleanup

#### Issue(s)

<!-- Can reference multiple issues. Use one of the following "magic words" - "closes, fixes" to auto-close the Github issue. -->
* #<issue>

#### Test Plan

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

.github/workflows/sanity-test.yaml

@@ -253,6 +253,99 @@ jobs:
           set -euo pipefail
           ./sanityTest
 
+      # non-delta backup
+      - name: Backup exchange incremental without delta
+        id: exchange-incremental-test-no-delta
+        run: |
+          set -euo pipefail
+          echo -e "\nBackup Exchange incremental test without delta\n" >> ${CORSO_LOG_FILE}
+          ./corso backup create exchange \
+          --no-stats \
+          --hide-progress \
+          --disable-delta \
+          --mailbox "${TEST_USER}" \
+          --json \
+          2>&1 | tee $TEST_RESULT/backup_exchange_incremental.txt 
+
+          resultjson=$(sed -e '1,/Completed Backups/d' $TEST_RESULT/backup_exchange_incremental.txt ) 
+
+          if  [[ $( echo $resultjson | jq -r '.[0] | .stats.errorCount') -ne 0 ]]; then
+            echo "backup was not successful"
+            exit 1
+          fi
+
+          echo result=$( echo $resultjson | jq -r '.[0] | .id' ) >> $GITHUB_OUTPUT
+
+      # restore from non delta
+      - name: Backup non delta exchange restore
+        id: exchange-non-delta-restore-test
+        run: |
+          set -euo pipefail
+          echo -e "\nBackup Exchange incremental without delta restore test\n" >> ${CORSO_LOG_FILE}
+          ./corso restore exchange \
+          --no-stats \
+          --hide-progress \
+          --backup "${{ steps.exchange-incremental-test-no-delta.outputs.result }}" \
+          --email-folder Corso_Restore_st_${{ steps.repo-init.outputs.result }} \
+          2>&1 | tee $TEST_RESULT/exchange-incremantal-restore-test.txt
+          echo result=$(grep -i -e 'Restoring to folder ' $TEST_RESULT/exchange-incremantal-restore-test.txt | sed "s/Restoring to folder//" )  >> $GITHUB_OUTPUT
+        
+      - name: Restoration check
+        env:
+          SANITY_RESTORE_FOLDER: ${{ steps.exchange-non-delta-restore-test.outputs.result }}
+          SANITY_RESTORE_SERVICE: "exchange"
+          TEST_DATA: Corso_Restore_st_${{ steps.repo-init.outputs.result }}
+          BASE_BACKUP: ${{ steps.exchange-restore-test.outputs.result }}
+        run: |
+          set -euo pipefail
+          ./sanityTest
+
+      # incremental backup after non-delta
+      - name: Backup exchange incremental after non-delta
+        id: exchange-incremental-test-after-non-delta
+        run: |
+          set -euo pipefail
+          echo -e "\nBackup Exchange incremental test after non-delta\n" >> ${CORSO_LOG_FILE}
+          ./corso backup create exchange \
+          --no-stats \
+          --hide-progress \
+          --mailbox "${TEST_USER}" \
+          --json \
+          2>&1 | tee $TEST_RESULT/backup_exchange_incremental_after_non_delta.txt
+
+          resultjson=$(sed -e '1,/Completed Backups/d' $TEST_RESULT/backup_exchange_incremental_after_non_delta.txt ) 
+
+          if  [[ $( echo $resultjson | jq -r '.[0] | .stats.errorCount') -ne 0 ]]; then
+            echo "backup was not successful"
+            exit 1
+          fi
+
+          echo result=$( echo $resultjson | jq -r '.[0] | .id' ) >> $GITHUB_OUTPUT
+
+      # restore from incremental
+      - name: Backup incremantal exchange restore after non-delta
+        id: exchange-incremantal-restore-test-after-non-delta
+        run: |
+          set -euo pipefail
+          echo -e "\nBackup Exchange incremental restore test after non-delta\n" >> ${CORSO_LOG_FILE}
+          ./corso restore exchange \
+          --no-stats \
+          --hide-progress \
+          --backup "${{ steps.exchange-incremental-test-after-non-delta.outputs.result }}" \
+          --email-folder Corso_Restore_st_${{ steps.repo-init.outputs.result }} \
+          2>&1 | tee $TEST_RESULT/exchange-incremantal-restore-test-after-non-delta.txt
+          echo result=$(grep -i -e 'Restoring to folder ' $TEST_RESULT/exchange-incremantal-restore-test-after-non-delta.txt | sed "s/Restoring to folder//" )  >> $GITHUB_OUTPUT
+
+      - name: Restoration check
+        env:
+          SANITY_RESTORE_FOLDER: ${{ steps.exchange-incremantal-restore-test-after-non-delta.outputs.result }}
+          SANITY_RESTORE_SERVICE: "exchange"
+          TEST_DATA: Corso_Restore_st_${{ steps.repo-init.outputs.result }}
+          BASE_BACKUP: ${{ steps.exchange-restore-test.outputs.result }}
+        run: |
+          set -euo pipefail
+          ./sanityTest
+
 ##########################################################################################################################################
 
 # Onedrive

CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 - Released the --mask-sensitive-data flag, which will automatically obscure private data in logs.
+- Added `--disable-delta` flag to disable delta based backups for Exchange
 
 ### Fixed
 - Graph requests now automatically retry in case of a Bad Gateway or Gateway Timeout.
@@ -21,6 +22,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - OneDrive and SharePoint file downloads will properly redirect from 3xx responses.
 - Refined oneDrive rate limiter controls to reduce throttling errors.
 - Fix handling of duplicate folders at the same hierarchy level in Exchange. Duplicate folders will be merged during restore operations.
+- Fix backup for mailboxes that has used up all their storage quota
 
 ### Known Issues
 - Restore operations will merge duplicate Exchange folders at the same hierarchy level into a single folder.
@@ -52,6 +54,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - The CORSO_LOG_FILE env is appropriately utilized if no --log-file flag is provided.
 - Fixed Exchange events progress output to show calendar names instead of IDs.
 - Fixed reporting no items match if restoring or listing details on an older Exchange backup and filtering by folder.
+- Fix backup for mailboxes that has used up all their storage quota
 
 ### Known Issues
 - Restoring a OneDrive or SharePoint file with the same name as a file with that name as its M365 ID may restore both items.

src/cli/backup/exchange.go

@@ -87,6 +87,7 @@ func addExchangeCommands(cmd *cobra.Command) *cobra.Command {
 		options.AddFetchParallelismFlag(c)
 		options.AddFailFastFlag(c)
 		options.AddDisableIncrementalsFlag(c)
+		options.AddDisableDeltaFlag(c)
 		options.AddEnableImmutableIDFlag(c)
 		options.AddDisableConcurrencyLimiterFlag(c)
 

src/cli/backup/exchange_test.go

@@ -43,6 +43,7 @@ func (suite *ExchangeUnitSuite) TestAddExchangeCommands() {
 				utils.UserFN,
 				utils.CategoryDataFN,
 				options.DisableIncrementalsFN,
+				options.DisableDeltaFN,
 				options.FailFastFN,
 				options.FetchParallelismFN,
 				options.SkipReduceFN,

src/cli/options/options.go

@@ -18,6 +18,7 @@ func Control() control.Options {
 	opt.RestorePermissions = restorePermissionsFV
 	opt.SkipReduce = skipReduceFV
 	opt.ToggleFeatures.DisableIncrementals = disableIncrementalsFV
+	opt.ToggleFeatures.DisableDelta = disableDeltaFV
 	opt.ToggleFeatures.ExchangeImmutableIDs = enableImmutableID
 	opt.ToggleFeatures.DisableConcurrencyLimiter = disableConcurrencyLimiterFV
 	opt.Parallelism.ItemFetch = fetchParallelismFV
@@ -35,6 +36,7 @@ const (
 	NoStatsFN                   = "no-stats"
 	RestorePermissionsFN        = "restore-permissions"
 	SkipReduceFN                = "skip-reduce"
+	DisableDeltaFN              = "disable-delta"
 	DisableIncrementalsFN       = "disable-incrementals"
 	EnableImmutableIDFN         = "enable-immutable-id"
 	DisableConcurrencyLimiterFN = "disable-concurrency-limiter"
@@ -92,7 +94,10 @@ func AddFetchParallelismFlag(cmd *cobra.Command) {
 // Feature Flags
 // ---------------------------------------------------------------------------
 
-var disableIncrementalsFV bool
+var (
+	disableIncrementalsFV bool
+	disableDeltaFV        bool
+)
 
 // Adds the hidden '--disable-incrementals' cli flag which, when set, disables
 // incremental backups.
@@ -106,6 +111,18 @@ func AddDisableIncrementalsFlag(cmd *cobra.Command) {
 	cobra.CheckErr(fs.MarkHidden(DisableIncrementalsFN))
 }
 
+// Adds the hidden '--disable-delta' cli flag which, when set, disables
+// delta based backups.
+func AddDisableDeltaFlag(cmd *cobra.Command) {
+	fs := cmd.Flags()
+	fs.BoolVar(
+		&disableDeltaFV,
+		DisableDeltaFN,
+		false,
+		"Disable delta based data retrieval in backups.")
+	cobra.CheckErr(fs.MarkHidden(DisableDeltaFN))
+}
+
 var enableImmutableID bool
 
 // Adds the hidden '--enable-immutable-id' cli flag which, when set, enables

src/cli/options/options_test.go

@@ -28,6 +28,7 @@ func (suite *OptionsUnitSuite) TestAddExchangeCommands() {
 		Run: func(cmd *cobra.Command, args []string) {
 			assert.True(t, failFastFV, FailFastFN)
 			assert.True(t, disableIncrementalsFV, DisableIncrementalsFN)
+			assert.True(t, disableDeltaFV, DisableDeltaFN)
 			assert.True(t, noStatsFV, NoStatsFN)
 			assert.True(t, restorePermissionsFV, RestorePermissionsFN)
 			assert.True(t, skipReduceFV, SkipReduceFN)
@@ -41,6 +42,7 @@ func (suite *OptionsUnitSuite) TestAddExchangeCommands() {
 
 	AddFailFastFlag(cmd)
 	AddDisableIncrementalsFlag(cmd)
+	AddDisableDeltaFlag(cmd)
 	AddRestorePermissionsFlag(cmd)
 	AddSkipReduceFlag(cmd)
 	AddFetchParallelismFlag(cmd)
@@ -51,6 +53,7 @@ func (suite *OptionsUnitSuite) TestAddExchangeCommands() {
 		"test",
 		"--" + FailFastFN,
 		"--" + DisableIncrementalsFN,
+		"--" + DisableDeltaFN,
 		"--" + NoStatsFN,
 		"--" + RestorePermissionsFN,
 		"--" + SkipReduceFN,

src/internal/connector/data_collections.go

@@ -21,6 +21,7 @@ import (
 	"github.com/alcionai/corso/src/pkg/control"
 	"github.com/alcionai/corso/src/pkg/fault"
 	"github.com/alcionai/corso/src/pkg/filters"
+	"github.com/alcionai/corso/src/pkg/logger"
 	"github.com/alcionai/corso/src/pkg/path"
 	"github.com/alcionai/corso/src/pkg/selectors"
 )
@@ -60,11 +61,12 @@ func (gc *GraphConnector) ProduceBackupCollections(
 		return nil, nil, clues.Stack(err).WithClues(ctx)
 	}
 
-	serviceEnabled, err := checkServiceEnabled(
+	serviceEnabled, canMakeDeltaQueries, err := checkServiceEnabled(
 		ctx,
 		gc.Discovery.Users(),
 		path.ServiceType(sels.Service),
-		sels.DiscreteOwner)
+		sels.DiscreteOwner,
+	)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -78,6 +80,12 @@ func (gc *GraphConnector) ProduceBackupCollections(
 		ssmb  *prefixmatcher.StringSetMatcher
 	)
 
+	if !canMakeDeltaQueries {
+		logger.Ctx(ctx).Info("delta requests not available")
+
+		ctrlOpts.ToggleFeatures.DisableDelta = true
+	}
+
 	switch sels.Service {
 	case selectors.ServiceExchange:
 		colls, ssmb, err = exchange.DataCollections(
@@ -171,22 +179,28 @@ func checkServiceEnabled(
 	gi discovery.GetInfoer,
 	service path.ServiceType,
 	resource string,
-) (bool, error) {
+) (bool, bool, error) {
 	if service == path.SharePointService {
 		// No "enabled" check required for sharepoint
-		return true, nil
+		return true, true, nil
 	}
 
 	info, err := gi.GetInfo(ctx, resource)
 	if err != nil {
-		return false, err
+		return false, false, err
 	}
 
 	if !info.ServiceEnabled(service) {
-		return false, clues.Wrap(graph.ErrServiceNotEnabled, "checking service access")
+		return false, false, clues.Wrap(graph.ErrServiceNotEnabled, "checking service access")
 	}
 
-	return true, nil
+	canMakeDeltaQueries := true
+	if service == path.ExchangeService {
+		// we currently can only check quota exceeded for exchange
+		canMakeDeltaQueries = info.CanMakeDeltaQueries()
+	}
+
+	return true, canMakeDeltaQueries, nil
 }
 
 // ConsumeRestoreCollections restores data from the specified collections

src/internal/connector/data_collections_test.go

@@ -95,11 +95,23 @@ func (suite *DataCollectionIntgSuite) TestExchangeDataCollection() {
 	}
 
 	for _, test := range tests {
-		suite.Run(test.name, func() {
+		for _, canMakeDeltaQueries := range []bool{true, false} {
+			name := test.name
+
+			if canMakeDeltaQueries {
+				name += "-delta"
+			} else {
+				name += "-non-delta"
+			}
+
+			suite.Run(name, func() {
 				t := suite.T()
 
 				sel := test.getSelector(t)
 
+				ctrlOpts := control.Defaults()
+				ctrlOpts.ToggleFeatures.DisableDelta = !canMakeDeltaQueries
+
 				collections, excludes, err := exchange.DataCollections(
 					ctx,
 					sel,
@@ -107,7 +119,7 @@ func (suite *DataCollectionIntgSuite) TestExchangeDataCollection() {
 					nil,
 					connector.credentials,
 					connector.UpdateStatus,
-				control.Defaults(),
+					ctrlOpts,
 					fault.New(true))
 				require.NoError(t, err, clues.ToCore(err))
 				assert.True(t, excludes.Empty())
@@ -135,6 +147,7 @@ func (suite *DataCollectionIntgSuite) TestExchangeDataCollection() {
 			})
 		}
 	}
+}
 
 // TestInvalidUserForDataCollections ensures verification process for users
 func (suite *DataCollectionIntgSuite) TestDataCollections_invalidResourceOwner() {

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

@@ -191,77 +191,35 @@ var _ itemPager = &contactPager{}
 
 type contactPager struct {
 	gs      graph.Servicer
-	builder *users.ItemContactFoldersItemContactsDeltaRequestBuilder
+	builder *users.ItemContactFoldersItemContactsRequestBuilder
-	options *users.ItemContactFoldersItemContactsDeltaRequestBuilderGetRequestConfiguration
+	options *users.ItemContactFoldersItemContactsRequestBuilderGetRequestConfiguration
 }
 
-func (p *contactPager) getPage(ctx context.Context) (api.DeltaPageLinker, error) {
+func NewContactPager(
-	resp, err := p.builder.Get(ctx, p.options)
-	if err != nil {
-		return nil, graph.Stack(ctx, err)
-	}
-
-	return resp, nil
-}
-
-func (p *contactPager) setNext(nextLink string) {
-	p.builder = users.NewItemContactFoldersItemContactsDeltaRequestBuilder(nextLink, p.gs.Adapter())
-}
-
-func (p *contactPager) valuesIn(pl api.DeltaPageLinker) ([]getIDAndAddtler, error) {
-	return toValues[models.Contactable](pl)
-}
-
-func (c Contacts) GetAddedAndRemovedItemIDs(
 	ctx context.Context,
-	user, directoryID, oldDelta string,
+	gs graph.Servicer,
+	user, directoryID string,
 	immutableIDs bool,
-) ([]string, []string, DeltaUpdate, error) {
+) (itemPager, error) {
-	service, err := c.service()
+	selecting, err := buildOptions([]string{"parentFolderId"}, fieldsForContacts)
 	if err != nil {
-		return nil, nil, DeltaUpdate{}, graph.Stack(ctx, err)
+		return nil, err
 	}
 
-	var resetDelta bool
+	requestParameters := &users.ItemContactFoldersItemContactsRequestBuilderGetQueryParameters{
+		Select: selecting,
+	}
 
-	ctx = clues.Add(
+	options := &users.ItemContactFoldersItemContactsRequestBuilderGetRequestConfiguration{
-		ctx,
+		QueryParameters: requestParameters,
-		"category", selectors.ExchangeContact,
+		Headers:         buildPreferHeaders(true, immutableIDs),
-		"container_id", directoryID)
+	}
 
-	options, err := optionsForContactFoldersItemDelta(
-		[]string{"parentFolderId"},
-		immutableIDs)
 	if err != nil {
-		return nil,
+		return &contactPager{}, err
-			nil,
-			DeltaUpdate{},
-			graph.Wrap(ctx, err, "setting contact folder options")
 	}
 
-	if len(oldDelta) > 0 {
+	builder := gs.Client().UsersById(user).ContactFoldersById(directoryID).Contacts()
-		var (
-			builder = users.NewItemContactFoldersItemContactsDeltaRequestBuilder(oldDelta, service.Adapter())
-			pgr     = &contactPager{service, builder, options}
-		)
-
-		added, removed, deltaURL, err := getItemsAddedAndRemovedFromContainer(ctx, pgr)
-		// note: happy path, not the error condition
-		if err == nil {
-			return added, removed, DeltaUpdate{deltaURL, false}, err
-		}
-
-		// 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) {
-			return nil, nil, DeltaUpdate{}, graph.Stack(ctx, err)
-		}
-
-		resetDelta = true
-	}
-
-	builder := service.Client().UsersById(user).ContactFoldersById(directoryID).Contacts().Delta()
-	pgr := &contactPager{service, builder, options}
 
 	if len(os.Getenv("CORSO_URL_LOGGING")) > 0 {
 		gri, err := builder.ToGetRequestInformation(ctx, options)
@@ -273,12 +231,146 @@ func (c Contacts) GetAddedAndRemovedItemIDs(
 		}
 	}
 
-	added, removed, deltaURL, err := getItemsAddedAndRemovedFromContainer(ctx, pgr)
+	return &contactPager{gs, builder, options}, nil
-	if err != nil {
-		return nil, nil, DeltaUpdate{}, err
 }
 
-	return added, removed, DeltaUpdate{deltaURL, resetDelta}, nil
+func (p *contactPager) getPage(ctx context.Context) (api.PageLinker, error) {
+	resp, err := p.builder.Get(ctx, p.options)
+	if err != nil {
+		return nil, graph.Stack(ctx, err)
+	}
+
+	return resp, nil
+}
+
+func (p *contactPager) setNext(nextLink string) {
+	p.builder = users.NewItemContactFoldersItemContactsRequestBuilder(nextLink, p.gs.Adapter())
+}
+
+// non delta pagers don't need reset
+func (p *contactPager) reset(context.Context) {}
+
+func (p *contactPager) valuesIn(pl api.PageLinker) ([]getIDAndAddtler, error) {
+	return toValues[models.Contactable](pl)
+}
+
+// ---------------------------------------------------------------------------
+// delta item pager
+// ---------------------------------------------------------------------------
+
+var _ itemPager = &contactDeltaPager{}
+
+type contactDeltaPager struct {
+	gs          graph.Servicer
+	user        string
+	directoryID string
+	builder     *users.ItemContactFoldersItemContactsDeltaRequestBuilder
+	options     *users.ItemContactFoldersItemContactsDeltaRequestBuilderGetRequestConfiguration
+}
+
+func getContactDeltaBuilder(
+	ctx context.Context,
+	gs graph.Servicer,
+	user string,
+	directoryID string,
+	options *users.ItemContactFoldersItemContactsDeltaRequestBuilderGetRequestConfiguration,
+) *users.ItemContactFoldersItemContactsDeltaRequestBuilder {
+	builder := gs.Client().UsersById(user).ContactFoldersById(directoryID).Contacts().Delta()
+	if len(os.Getenv("CORSO_URL_LOGGING")) > 0 {
+		gri, err := builder.ToGetRequestInformation(ctx, options)
+		if err != nil {
+			logger.CtxErr(ctx, err).Error("getting builder info")
+		} else {
+			logger.Ctx(ctx).
+				Infow("builder path-parameters", "path_parameters", gri.PathParameters)
+		}
+	}
+
+	return builder
+}
+
+func NewContactDeltaPager(
+	ctx context.Context,
+	gs graph.Servicer,
+	user, directoryID, deltaURL string,
+	immutableIDs bool,
+) (itemPager, error) {
+	selecting, err := buildOptions([]string{"parentFolderId"}, fieldsForContacts)
+	if err != nil {
+		return nil, err
+	}
+
+	requestParameters := &users.ItemContactFoldersItemContactsDeltaRequestBuilderGetQueryParameters{
+		Select: selecting,
+	}
+
+	options := &users.ItemContactFoldersItemContactsDeltaRequestBuilderGetRequestConfiguration{
+		QueryParameters: requestParameters,
+		Headers:         buildPreferHeaders(true, immutableIDs),
+	}
+
+	if err != nil {
+		return &contactDeltaPager{}, err
+	}
+
+	var builder *users.ItemContactFoldersItemContactsDeltaRequestBuilder
+	if deltaURL != "" {
+		builder = users.NewItemContactFoldersItemContactsDeltaRequestBuilder(deltaURL, gs.Adapter())
+	} else {
+		builder = getContactDeltaBuilder(ctx, gs, user, directoryID, options)
+	}
+
+	return &contactDeltaPager{gs, user, directoryID, builder, options}, nil
+}
+
+func (p *contactDeltaPager) getPage(ctx context.Context) (api.PageLinker, error) {
+	resp, err := p.builder.Get(ctx, p.options)
+	if err != nil {
+		return nil, graph.Stack(ctx, err)
+	}
+
+	return resp, nil
+}
+
+func (p *contactDeltaPager) setNext(nextLink string) {
+	p.builder = users.NewItemContactFoldersItemContactsDeltaRequestBuilder(nextLink, p.gs.Adapter())
+}
+
+func (p *contactDeltaPager) reset(ctx context.Context) {
+	p.builder = getContactDeltaBuilder(ctx, p.gs, p.user, p.directoryID, p.options)
+}
+
+func (p *contactDeltaPager) valuesIn(pl api.PageLinker) ([]getIDAndAddtler, error) {
+	return toValues[models.Contactable](pl)
+}
+
+func (c Contacts) GetAddedAndRemovedItemIDs(
+	ctx context.Context,
+	user, directoryID, oldDelta string,
+	immutableIDs bool,
+	canMakeDeltaQueries bool,
+) ([]string, []string, DeltaUpdate, error) {
+	service, err := c.service()
+	if err != nil {
+		return nil, nil, DeltaUpdate{}, graph.Stack(ctx, err)
+	}
+
+	ctx = clues.Add(
+		ctx,
+		"category", selectors.ExchangeContact,
+		"container_id", directoryID)
+
+	pager, err := NewContactPager(ctx, service, user, directoryID, immutableIDs)
+	if err != nil {
+		return nil, nil, DeltaUpdate{}, graph.Wrap(ctx, err, "creating non-delta pager")
+	}
+
+	deltaPager, err := NewContactDeltaPager(ctx, service, user, directoryID, oldDelta, immutableIDs)
+	if err != nil {
+		return nil, nil, DeltaUpdate{}, graph.Wrap(ctx, err, "creating delta pager")
+	}
+
+	return getAddedAndRemovedItemIDs(ctx, service, pager, deltaPager, oldDelta, canMakeDeltaQueries)
 }
 
 // ---------------------------------------------------------------------------

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

@@ -254,23 +254,47 @@ func (c Events) EnumerateContainers(
 	return el.Failure()
 }
 
+const (
+	eventBetaDeltaURLTemplate = "https://graph.microsoft.com/beta/users/%s/calendars/%s/events/delta"
+)
+
 // ---------------------------------------------------------------------------
 // item pager
 // ---------------------------------------------------------------------------
 
 var _ itemPager = &eventPager{}
 
-const (
-	eventBetaDeltaURLTemplate = "https://graph.microsoft.com/beta/users/%s/calendars/%s/events/delta"
-)
-
 type eventPager struct {
 	gs      graph.Servicer
-	builder *users.ItemCalendarsItemEventsDeltaRequestBuilder
+	builder *users.ItemCalendarsItemEventsRequestBuilder
-	options *users.ItemCalendarsItemEventsDeltaRequestBuilderGetRequestConfiguration
+	options *users.ItemCalendarsItemEventsRequestBuilderGetRequestConfiguration
 }
 
-func (p *eventPager) getPage(ctx context.Context) (api.DeltaPageLinker, error) {
+func NewEventPager(
+	ctx context.Context,
+	gs graph.Servicer,
+	user, calendarID string,
+	immutableIDs bool,
+) (itemPager, error) {
+	options := &users.ItemCalendarsItemEventsRequestBuilderGetRequestConfiguration{
+		Headers: buildPreferHeaders(true, immutableIDs),
+	}
+
+	builder := gs.Client().UsersById(user).CalendarsById(calendarID).Events()
+	if len(os.Getenv("CORSO_URL_LOGGING")) > 0 {
+		gri, err := builder.ToGetRequestInformation(ctx, options)
+		if err != nil {
+			logger.CtxErr(ctx, err).Error("getting builder info")
+		} else {
+			logger.Ctx(ctx).
+				Infow("builder path-parameters", "path_parameters", gri.PathParameters)
+		}
+	}
+
+	return &eventPager{gs, builder, options}, nil
+}
+
+func (p *eventPager) getPage(ctx context.Context) (api.PageLinker, error) {
 	resp, err := p.builder.Get(ctx, p.options)
 	if err != nil {
 		return nil, graph.Stack(ctx, err)
@@ -280,54 +304,58 @@ func (p *eventPager) getPage(ctx context.Context) (api.DeltaPageLinker, error) {
 }
 
 func (p *eventPager) setNext(nextLink string) {
-	p.builder = users.NewItemCalendarsItemEventsDeltaRequestBuilder(nextLink, p.gs.Adapter())
+	p.builder = users.NewItemCalendarsItemEventsRequestBuilder(nextLink, p.gs.Adapter())
 }
 
-func (p *eventPager) valuesIn(pl api.DeltaPageLinker) ([]getIDAndAddtler, error) {
+// non delta pagers don't need reset
+func (p *eventPager) reset(context.Context) {}
+
+func (p *eventPager) valuesIn(pl api.PageLinker) ([]getIDAndAddtler, error) {
 	return toValues[models.Eventable](pl)
 }
 
-func (c Events) GetAddedAndRemovedItemIDs(
+// ---------------------------------------------------------------------------
-	ctx context.Context,
+// delta item pager
-	user, calendarID, oldDelta string,
+// ---------------------------------------------------------------------------
-	immutableIDs bool,
+
-) ([]string, []string, DeltaUpdate, error) {
+var _ itemPager = &eventDeltaPager{}
-	service, err := c.service()
+
-	if err != nil {
+type eventDeltaPager struct {
-		return nil, nil, DeltaUpdate{}, err
+	gs         graph.Servicer
+	user       string
+	calendarID string
+	builder    *users.ItemCalendarsItemEventsDeltaRequestBuilder
+	options    *users.ItemCalendarsItemEventsDeltaRequestBuilderGetRequestConfiguration
 }
 
-	var (
+func NewEventDeltaPager(
-		resetDelta bool
+	ctx context.Context,
-		opts       = &users.ItemCalendarsItemEventsDeltaRequestBuilderGetRequestConfiguration{
+	gs graph.Servicer,
+	user, calendarID, deltaURL string,
+	immutableIDs bool,
+) (itemPager, error) {
+	options := &users.ItemCalendarsItemEventsDeltaRequestBuilderGetRequestConfiguration{
 		Headers: buildPreferHeaders(true, immutableIDs),
 	}
-	)
 
-	ctx = clues.Add(
+	var builder *users.ItemCalendarsItemEventsDeltaRequestBuilder
-		ctx,
-		"container_id", calendarID)
 
-	if len(oldDelta) > 0 {
+	if deltaURL == "" {
-		var (
+		builder = getEventDeltaBuilder(ctx, gs, user, calendarID, options)
-			builder = users.NewItemCalendarsItemEventsDeltaRequestBuilder(oldDelta, service.Adapter())
+	} else {
-			pgr     = &eventPager{service, builder, opts}
+		builder = users.NewItemCalendarsItemEventsDeltaRequestBuilder(deltaURL, gs.Adapter())
-		)
-
-		added, removed, deltaURL, err := getItemsAddedAndRemovedFromContainer(ctx, pgr)
-		// note: happy path, not the error condition
-		if err == nil {
-			return added, removed, DeltaUpdate{deltaURL, false}, nil
-		}
-		// 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) {
-			return nil, nil, DeltaUpdate{}, graph.Stack(ctx, err)
 	}
 
-		resetDelta = true
+	return &eventDeltaPager{gs, user, calendarID, builder, options}, nil
 }
 
+func getEventDeltaBuilder(
+	ctx context.Context,
+	gs graph.Servicer,
+	user string,
+	calendarID string,
+	options *users.ItemCalendarsItemEventsDeltaRequestBuilderGetRequestConfiguration,
+) *users.ItemCalendarsItemEventsDeltaRequestBuilder {
 	// Graph SDK only supports delta queries against events on the beta version, so we're
 	// manufacturing use of the beta version url to make the call instead.
 	// See: https://learn.microsoft.com/ko-kr/graph/api/event-delta?view=graph-rest-beta&tabs=http
@@ -337,11 +365,10 @@ func (c Events) GetAddedAndRemovedItemIDs(
 	// Likewise, the NextLink and DeltaLink odata tags carry our hack forward, so the rest of the code
 	// works as intended (until, at least, we want to _not_ call the beta anymore).
 	rawURL := fmt.Sprintf(eventBetaDeltaURLTemplate, user, calendarID)
-	builder := users.NewItemCalendarsItemEventsDeltaRequestBuilder(rawURL, service.Adapter())
+	builder := users.NewItemCalendarsItemEventsDeltaRequestBuilder(rawURL, gs.Adapter())
-	pgr := &eventPager{service, builder, opts}
 
 	if len(os.Getenv("CORSO_URL_LOGGING")) > 0 {
-		gri, err := builder.ToGetRequestInformation(ctx, nil)
+		gri, err := builder.ToGetRequestInformation(ctx, options)
 		if err != nil {
 			logger.CtxErr(ctx, err).Error("getting builder info")
 		} else {
@@ -350,13 +377,56 @@ func (c Events) GetAddedAndRemovedItemIDs(
 		}
 	}
 
-	added, removed, deltaURL, err := getItemsAddedAndRemovedFromContainer(ctx, pgr)
+	return builder
+}
+
+func (p *eventDeltaPager) getPage(ctx context.Context) (api.PageLinker, error) {
+	resp, err := p.builder.Get(ctx, p.options)
+	if err != nil {
+		return nil, graph.Stack(ctx, err)
+	}
+
+	return resp, nil
+}
+
+func (p *eventDeltaPager) setNext(nextLink string) {
+	p.builder = users.NewItemCalendarsItemEventsDeltaRequestBuilder(nextLink, p.gs.Adapter())
+}
+
+func (p *eventDeltaPager) reset(ctx context.Context) {
+	p.builder = getEventDeltaBuilder(ctx, p.gs, p.user, p.calendarID, p.options)
+}
+
+func (p *eventDeltaPager) valuesIn(pl api.PageLinker) ([]getIDAndAddtler, error) {
+	return toValues[models.Eventable](pl)
+}
+
+func (c Events) GetAddedAndRemovedItemIDs(
+	ctx context.Context,
+	user, calendarID, oldDelta string,
+	immutableIDs bool,
+	canMakeDeltaQueries bool,
+) ([]string, []string, DeltaUpdate, error) {
+	service, err := c.service()
 	if err != nil {
 		return nil, nil, DeltaUpdate{}, err
 	}
 
-	// Events don't have a delta endpoint so just return an empty string.
+	ctx = clues.Add(
-	return added, removed, DeltaUpdate{deltaURL, resetDelta}, nil
+		ctx,
+		"container_id", calendarID)
+
+	pager, err := NewEventPager(ctx, service, user, calendarID, immutableIDs)
+	if err != nil {
+		return nil, nil, DeltaUpdate{}, graph.Wrap(ctx, err, "creating non-delta pager")
+	}
+
+	deltaPager, err := NewEventDeltaPager(ctx, service, user, calendarID, oldDelta, immutableIDs)
+	if err != nil {
+		return nil, nil, DeltaUpdate{}, graph.Wrap(ctx, err, "creating delta pager")
+	}
+
+	return getAddedAndRemovedItemIDs(ctx, service, pager, deltaPager, oldDelta, canMakeDeltaQueries)
 }
 
 // ---------------------------------------------------------------------------

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

@@ -20,6 +20,10 @@ import (
 	"github.com/alcionai/corso/src/pkg/selectors"
 )
 
+const (
+	mailFoldersBetaURLTemplate = "https://graph.microsoft.com/beta/users/%s/mailFolders"
+)
+
 // ---------------------------------------------------------------------------
 // controller
 // ---------------------------------------------------------------------------
@@ -241,6 +245,43 @@ func (c Mail) GetItem(
 	return mail, MailInfo(mail, size), nil
 }
 
+type mailFolderPager struct {
+	service graph.Servicer
+	builder *users.ItemMailFoldersRequestBuilder
+}
+
+func NewMailFolderPager(service graph.Servicer, user string) mailFolderPager {
+	// v1.0 non delta /mailFolders endpoint does not return any of the nested folders
+	rawURL := fmt.Sprintf(mailFoldersBetaURLTemplate, user)
+	builder := users.NewItemMailFoldersRequestBuilder(rawURL, service.Adapter())
+
+	return mailFolderPager{service, builder}
+}
+
+func (p *mailFolderPager) getPage(ctx context.Context) (api.PageLinker, error) {
+	page, err := p.builder.Get(ctx, nil)
+	if err != nil {
+		return nil, graph.Stack(ctx, err)
+	}
+
+	return page, nil
+}
+
+func (p *mailFolderPager) setNext(nextLink string) {
+	p.builder = users.NewItemMailFoldersRequestBuilder(nextLink, p.service.Adapter())
+}
+
+func (p *mailFolderPager) valuesIn(pl api.PageLinker) ([]models.MailFolderable, error) {
+	// Ideally this should be `users.ItemMailFoldersResponseable`, but
+	// that is not a thing as stable returns different result
+	page, ok := pl.(models.MailFolderCollectionResponseable)
+	if !ok {
+		return nil, clues.New("converting to ItemMailFoldersResponseable")
+	}
+
+	return page.GetValue(), nil
+}
+
 // EnumerateContainers iterates through all of the users current
 // mail folders, converting each to a graph.CacheFolder, and calling
 // fn(cf) on each one.
@@ -258,22 +299,25 @@ func (c Mail) EnumerateContainers(
 	}
 
 	el := errs.Local()
-	builder := service.Client().
+
-		UsersById(userID).
+	pgr := NewMailFolderPager(service, userID)
-		MailFolders().
-		Delta()
 
 	for {
 		if el.Failure() != nil {
 			break
 		}
 
-		resp, err := builder.Get(ctx, nil)
+		page, err := pgr.getPage(ctx)
 		if err != nil {
 			return graph.Stack(ctx, err)
 		}
 
-		for _, v := range resp.GetValue() {
+		resp, err := pgr.valuesIn(page)
+		if err != nil {
+			return graph.Stack(ctx, err)
+		}
+
+		for _, v := range resp {
 			if el.Failure() != nil {
 				break
 			}
@@ -290,12 +334,12 @@ func (c Mail) EnumerateContainers(
 			}
 		}
 
-		link, ok := ptr.ValOK(resp.GetOdataNextLink())
+		link, ok := ptr.ValOK(page.GetOdataNextLink())
 		if !ok {
 			break
 		}
 
-		builder = users.NewItemMailFoldersDeltaRequestBuilder(link, service.Adapter())
+		pgr.setNext(link)
 	}
 
 	return el.Failure()
@@ -309,77 +353,35 @@ var _ itemPager = &mailPager{}
 
 type mailPager struct {
 	gs      graph.Servicer
-	builder *users.ItemMailFoldersItemMessagesDeltaRequestBuilder
+	builder *users.ItemMailFoldersItemMessagesRequestBuilder
-	options *users.ItemMailFoldersItemMessagesDeltaRequestBuilderGetRequestConfiguration
+	options *users.ItemMailFoldersItemMessagesRequestBuilderGetRequestConfiguration
 }
 
-func (p *mailPager) getPage(ctx context.Context) (api.DeltaPageLinker, error) {
+func NewMailPager(
-	page, err := p.builder.Get(ctx, p.options)
-	if err != nil {
-		return nil, graph.Stack(ctx, err)
-	}
-
-	return page, nil
-}
-
-func (p *mailPager) setNext(nextLink string) {
-	p.builder = users.NewItemMailFoldersItemMessagesDeltaRequestBuilder(nextLink, p.gs.Adapter())
-}
-
-func (p *mailPager) valuesIn(pl api.DeltaPageLinker) ([]getIDAndAddtler, error) {
-	return toValues[models.Messageable](pl)
-}
-
-func (c Mail) GetAddedAndRemovedItemIDs(
 	ctx context.Context,
-	user, directoryID, oldDelta string,
+	gs graph.Servicer,
+	user, directoryID string,
 	immutableIDs bool,
-) ([]string, []string, DeltaUpdate, error) {
+) (itemPager, error) {
-	service, err := c.service()
+	selecting, err := buildOptions([]string{"isRead"}, fieldsForMessages)
 	if err != nil {
-		return nil, nil, DeltaUpdate{}, err
+		return nil, err
 	}
 
-	var (
+	requestParameters := &users.ItemMailFoldersItemMessagesRequestBuilderGetQueryParameters{
-		deltaURL   string
+		Select: selecting,
-		resetDelta bool
+	}
-	)
 
-	ctx = clues.Add(
+	options := &users.ItemMailFoldersItemMessagesRequestBuilderGetRequestConfiguration{
-		ctx,
+		QueryParameters: requestParameters,
-		"category", selectors.ExchangeMail,
+		Headers:         buildPreferHeaders(true, immutableIDs),
-		"container_id", directoryID)
+	}
 
-	options, err := optionsForFolderMessagesDelta([]string{"isRead"}, immutableIDs)
 	if err != nil {
-		return nil,
+		return &mailPager{}, err
-			nil,
-			DeltaUpdate{},
-			graph.Wrap(ctx, err, "setting contact folder options")
 	}
 
-	if len(oldDelta) > 0 {
+	builder := gs.Client().UsersById(user).MailFoldersById(directoryID).Messages()
-		var (
-			builder = users.NewItemMailFoldersItemMessagesDeltaRequestBuilder(oldDelta, service.Adapter())
-			pgr     = &mailPager{service, builder, options}
-		)
-
-		added, removed, deltaURL, err := getItemsAddedAndRemovedFromContainer(ctx, pgr)
-		// note: happy path, not the error condition
-		if err == nil {
-			return added, removed, DeltaUpdate{deltaURL, false}, err
-		}
-		// 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) {
-			return nil, nil, DeltaUpdate{}, err
-		}
-
-		resetDelta = true
-	}
-
-	builder := service.Client().UsersById(user).MailFoldersById(directoryID).Messages().Delta()
-	pgr := &mailPager{service, builder, options}
 
 	if len(os.Getenv("CORSO_URL_LOGGING")) > 0 {
 		gri, err := builder.ToGetRequestInformation(ctx, options)
@@ -391,12 +393,158 @@ func (c Mail) GetAddedAndRemovedItemIDs(
 		}
 	}
 
-	added, removed, deltaURL, err := getItemsAddedAndRemovedFromContainer(ctx, pgr)
+	return &mailPager{gs, builder, options}, nil
+}
+
+func (p *mailPager) getPage(ctx context.Context) (api.PageLinker, error) {
+	page, err := p.builder.Get(ctx, p.options)
+	if err != nil {
+		return nil, graph.Stack(ctx, err)
+	}
+
+	return page, nil
+}
+
+func (p *mailPager) setNext(nextLink string) {
+	p.builder = users.NewItemMailFoldersItemMessagesRequestBuilder(nextLink, p.gs.Adapter())
+}
+
+// non delta pagers don't have reset
+func (p *mailPager) reset(context.Context) {}
+
+func (p *mailPager) valuesIn(pl api.PageLinker) ([]getIDAndAddtler, error) {
+	return toValues[models.Messageable](pl)
+}
+
+// ---------------------------------------------------------------------------
+// delta item pager
+// ---------------------------------------------------------------------------
+
+var _ itemPager = &mailDeltaPager{}
+
+type mailDeltaPager struct {
+	gs          graph.Servicer
+	user        string
+	directoryID string
+	builder     *users.ItemMailFoldersItemMessagesDeltaRequestBuilder
+	options     *users.ItemMailFoldersItemMessagesDeltaRequestBuilderGetRequestConfiguration
+}
+
+func getMailDeltaBuilder(
+	ctx context.Context,
+	gs graph.Servicer,
+	user string,
+	directoryID string,
+	options *users.ItemMailFoldersItemMessagesDeltaRequestBuilderGetRequestConfiguration,
+) *users.ItemMailFoldersItemMessagesDeltaRequestBuilder {
+	builder := gs.Client().UsersById(user).MailFoldersById(directoryID).Messages().Delta()
+
+	if len(os.Getenv("CORSO_URL_LOGGING")) > 0 {
+		gri, err := builder.ToGetRequestInformation(ctx, options)
+		if err != nil {
+			logger.CtxErr(ctx, err).Error("getting builder info")
+		} else {
+			logger.Ctx(ctx).
+				Infow("builder path-parameters", "path_parameters", gri.PathParameters)
+		}
+	}
+
+	return builder
+}
+
+func NewMailDeltaPager(
+	ctx context.Context,
+	gs graph.Servicer,
+	user, directoryID, oldDelta string,
+	immutableIDs bool,
+) (itemPager, error) {
+	selecting, err := buildOptions([]string{"isRead"}, fieldsForMessages)
+	if err != nil {
+		return nil, err
+	}
+
+	requestParameters := &users.ItemMailFoldersItemMessagesDeltaRequestBuilderGetQueryParameters{
+		Select: selecting,
+	}
+
+	options := &users.ItemMailFoldersItemMessagesDeltaRequestBuilderGetRequestConfiguration{
+		QueryParameters: requestParameters,
+		Headers:         buildPreferHeaders(true, immutableIDs),
+	}
+
+	if err != nil {
+		return &mailDeltaPager{}, err
+	}
+
+	var builder *users.ItemMailFoldersItemMessagesDeltaRequestBuilder
+
+	if len(oldDelta) > 0 {
+		builder = users.NewItemMailFoldersItemMessagesDeltaRequestBuilder(oldDelta, gs.Adapter())
+	} else {
+		builder = getMailDeltaBuilder(ctx, gs, user, directoryID, options)
+	}
+
+	return &mailDeltaPager{gs, user, directoryID, builder, options}, nil
+}
+
+func (p *mailDeltaPager) getPage(ctx context.Context) (api.PageLinker, error) {
+	page, err := p.builder.Get(ctx, p.options)
+	if err != nil {
+		return nil, graph.Stack(ctx, err)
+	}
+
+	return page, nil
+}
+
+func (p *mailDeltaPager) setNext(nextLink string) {
+	p.builder = users.NewItemMailFoldersItemMessagesDeltaRequestBuilder(nextLink, p.gs.Adapter())
+}
+
+func (p *mailDeltaPager) reset(ctx context.Context) {
+	p.builder = p.gs.Client().UsersById(p.user).MailFoldersById(p.directoryID).Messages().Delta()
+
+	if len(os.Getenv("CORSO_URL_LOGGING")) > 0 {
+		gri, err := p.builder.ToGetRequestInformation(ctx, p.options)
+		if err != nil {
+			logger.CtxErr(ctx, err).Error("getting builder info")
+		} else {
+			logger.Ctx(ctx).
+				Infow("builder path-parameters", "path_parameters", gri.PathParameters)
+		}
+	}
+}
+
+func (p *mailDeltaPager) valuesIn(pl api.PageLinker) ([]getIDAndAddtler, error) {
+	return toValues[models.Messageable](pl)
+}
+
+func (c Mail) GetAddedAndRemovedItemIDs(
+	ctx context.Context,
+	user, directoryID, oldDelta string,
+	immutableIDs bool,
+	canMakeDeltaQueries bool,
+) ([]string, []string, DeltaUpdate, error) {
+	service, err := c.service()
 	if err != nil {
 		return nil, nil, DeltaUpdate{}, err
 	}
 
-	return added, removed, DeltaUpdate{deltaURL, resetDelta}, nil
+	ctx = clues.Add(
+		ctx,
+		"category", selectors.ExchangeMail,
+		"container_id", directoryID)
+
+	pager, err := NewMailPager(ctx, service, user, directoryID, immutableIDs)
+	if err != nil {
+		return nil, nil, DeltaUpdate{}, graph.Wrap(ctx, err, "creating delta pager")
+	}
+
+	deltaPager, err := NewMailDeltaPager(ctx, service, user, directoryID, oldDelta, immutableIDs)
+	if err != nil {
+		return nil, nil, DeltaUpdate{}, graph.Wrap(ctx, err, "creating delta pager")
+	}
+
+	return getAddedAndRemovedItemIDs(ctx, service, pager, deltaPager, oldDelta, canMakeDeltaQueries)
 }
 
 // ---------------------------------------------------------------------------

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

@@ -75,27 +75,6 @@ const (
 // which reduces the overall latency of complex calls
 // -----------------------------------------------------------------------
 
-func optionsForFolderMessagesDelta(
-	moreOps []string,
-	immutableIDs bool,
-) (*users.ItemMailFoldersItemMessagesDeltaRequestBuilderGetRequestConfiguration, error) {
-	selecting, err := buildOptions(moreOps, fieldsForMessages)
-	if err != nil {
-		return nil, err
-	}
-
-	requestParameters := &users.ItemMailFoldersItemMessagesDeltaRequestBuilderGetQueryParameters{
-		Select: selecting,
-	}
-
-	options := &users.ItemMailFoldersItemMessagesDeltaRequestBuilderGetRequestConfiguration{
-		QueryParameters: requestParameters,
-		Headers:         buildPreferHeaders(true, immutableIDs),
-	}
-
-	return options, nil
-}
-
 // optionsForCalendars places allowed options for exchange.Calendar object
 // @param moreOps should reflect elements from fieldsForCalendars
 // @return is first call in Calendars().GetWithRequestConfigurationAndResponseHandler
@@ -180,27 +159,6 @@ func optionsForMailFoldersItem(
 	return options, nil
 }
 
-func optionsForContactFoldersItemDelta(
-	moreOps []string,
-	immutableIDs bool,
-) (*users.ItemContactFoldersItemContactsDeltaRequestBuilderGetRequestConfiguration, error) {
-	selecting, err := buildOptions(moreOps, fieldsForContacts)
-	if err != nil {
-		return nil, err
-	}
-
-	requestParameters := &users.ItemContactFoldersItemContactsDeltaRequestBuilderGetQueryParameters{
-		Select: selecting,
-	}
-
-	options := &users.ItemContactFoldersItemContactsDeltaRequestBuilderGetRequestConfiguration{
-		QueryParameters: requestParameters,
-		Headers:         buildPreferHeaders(true, immutableIDs),
-	}
-
-	return options, nil
-}
-
 // optionsForContactChildFolders builds a contacts child folders request.
 func optionsForContactChildFolders(
 	moreOps []string,

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

@@ -18,9 +18,16 @@ import (
 // ---------------------------------------------------------------------------
 
 type itemPager interface {
-	getPage(context.Context) (api.DeltaPageLinker, error)
+	// getPage get a page with the specified options from graph
+	getPage(context.Context) (api.PageLinker, error)
+	// setNext is used to pass in the next url got from graph
 	setNext(string)
-	valuesIn(api.DeltaPageLinker) ([]getIDAndAddtler, error)
+	// reset is used to clear delta url in delta pagers. When
+	// reset is called, we reset the state(delta url) that we
+	// currently have and start a new delta query without the token.
+	reset(context.Context)
+	// valuesIn gets us the values in a page
+	valuesIn(api.PageLinker) ([]getIDAndAddtler, error)
 }
 
 type getIDAndAddtler interface {
@@ -56,6 +63,54 @@ func toValues[T any](a any) ([]getIDAndAddtler, error) {
 	return r, nil
 }
 
+func getAddedAndRemovedItemIDs(
+	ctx context.Context,
+	service graph.Servicer,
+	pager itemPager,
+	deltaPager itemPager,
+	oldDelta string,
+	canMakeDeltaQueries bool,
+) ([]string, []string, DeltaUpdate, error) {
+	var (
+		pgr        itemPager
+		resetDelta bool
+	)
+
+	if canMakeDeltaQueries {
+		pgr = deltaPager
+		resetDelta = len(oldDelta) == 0
+	} else {
+		pgr = pager
+		resetDelta = true
+	}
+
+	added, removed, deltaURL, err := getItemsAddedAndRemovedFromContainer(ctx, pgr)
+	// note: happy path, not the error condition
+	if err == nil {
+		return added, removed, DeltaUpdate{deltaURL, resetDelta}, err
+	}
+
+	// If we already tried with a non-delta url, we can return
+	if !canMakeDeltaQueries {
+		return nil, nil, DeltaUpdate{}, err
+	}
+
+	// return error if invalid not delta error or oldDelta was empty
+	if !graph.IsErrInvalidDelta(err) || len(oldDelta) == 0 {
+		return nil, nil, DeltaUpdate{}, err
+	}
+
+	// reset deltaPager
+	pgr.reset(ctx)
+
+	added, removed, deltaURL, err = getItemsAddedAndRemovedFromContainer(ctx, pgr)
+	if err != nil {
+		return nil, nil, DeltaUpdate{}, err
+	}
+
+	return added, removed, DeltaUpdate{deltaURL, true}, nil
+}
+
 // generic controller for retrieving all item ids in a container.
 func getItemsAddedAndRemovedFromContainer(
 	ctx context.Context,
@@ -65,6 +120,8 @@ func getItemsAddedAndRemovedFromContainer(
 		addedIDs   = []string{}
 		removedIDs = []string{}
 		deltaURL   string
+		nextLink   string
+		deltaLink  string
 	)
 
 	itemCount := 0
@@ -104,10 +161,20 @@ func getItemsAddedAndRemovedFromContainer(
 			}
 		}
 
-		nextLink, delta := api.NextAndDeltaLink(resp)
+		dresp, ok := resp.(api.DeltaPageLinker)
+		if ok {
+			nextLink, deltaLink = api.NextAndDeltaLink(dresp)
+		} else {
+			nextLink = api.NextLink(resp)
+			deltaLink = "" // to make sure we don't use an old value
+		}
+
 		if len(os.Getenv("CORSO_URL_LOGGING")) > 0 {
-			if !api.IsNextLinkValid(nextLink) || api.IsNextLinkValid(delta) {
+			if !api.IsNextLinkValid(nextLink) || !api.IsNextLinkValid(deltaLink) {
-				logger.Ctx(ctx).Infof("Received invalid link from M365:\nNext Link: %s\nDelta Link: %s\n", nextLink, delta)
+				logger.Ctx(ctx).
+					With("next_link", graph.LoggableURL(nextLink)).
+					With("delta_link", graph.LoggableURL(deltaLink)).
+					Info("invalid link from M365")
 			}
 		}
 
@@ -115,8 +182,8 @@ func getItemsAddedAndRemovedFromContainer(
 		// once we run through pages of nextLinks, the last query will
 		// produce a deltaLink instead (if supported), which we'll use on
 		// the next backup to only get the changes since this run.
-		if len(delta) > 0 {
+		if len(deltaLink) > 0 {
-			deltaURL = delta
+			deltaURL = deltaLink
 		}
 
 		// the nextLink is our page cursor within this query.

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

@@ -0,0 +1,256 @@
+package api
+
+import (
+	"context"
+	"testing"
+
+	"github.com/microsoftgraph/msgraph-sdk-go/models/odataerrors"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"github.com/stretchr/testify/suite"
+
+	"github.com/alcionai/corso/src/internal/connector/graph"
+	"github.com/alcionai/corso/src/internal/connector/graph/api"
+	"github.com/alcionai/corso/src/internal/tester"
+)
+
+type testPagerValue struct {
+	id      string
+	removed bool
+}
+
+func (v testPagerValue) GetId() *string { return &v.id } //revive:disable-line:var-naming
+func (v testPagerValue) GetAdditionalData() map[string]any {
+	if v.removed {
+		return map[string]any{graph.AddtlDataRemoved: true}
+	}
+
+	return map[string]any{}
+}
+
+type testPage struct{}
+
+func (p testPage) GetOdataNextLink() *string {
+	next := "" // no next, just one page
+	return &next
+}
+
+var _ itemPager = &testPager{}
+
+type testPager struct {
+	t          *testing.T
+	added      []string
+	removed    []string
+	errorCode  string
+	needsReset bool
+}
+
+func (p *testPager) getPage(ctx context.Context) (api.PageLinker, error) {
+	if p.errorCode != "" {
+		ierr := odataerrors.NewMainError()
+		ierr.SetCode(&p.errorCode)
+
+		err := odataerrors.NewODataError()
+		err.SetError(ierr)
+
+		return nil, err
+	}
+
+	return testPage{}, nil
+}
+func (p *testPager) setNext(string) {}
+func (p *testPager) reset(context.Context) {
+	if !p.needsReset {
+		require.Fail(p.t, "reset should not be called")
+	}
+
+	p.needsReset = false
+	p.errorCode = ""
+}
+
+func (p *testPager) valuesIn(pl api.PageLinker) ([]getIDAndAddtler, error) {
+	items := []getIDAndAddtler{}
+
+	for _, id := range p.added {
+		items = append(items, testPagerValue{id: id})
+	}
+
+	for _, id := range p.removed {
+		items = append(items, testPagerValue{id: id, removed: true})
+	}
+
+	return items, nil
+}
+
+type SharedAPIUnitSuite struct {
+	tester.Suite
+}
+
+func TestSharedAPIUnitSuite(t *testing.T) {
+	suite.Run(t, &SharedAPIUnitSuite{Suite: tester.NewUnitSuite(t)})
+}
+
+func (suite *SharedAPIUnitSuite) TestGetAddedAndRemovedItemIDs() {
+	tests := []struct {
+		name                string
+		pagerGetter         func(context.Context, graph.Servicer, string, string, bool) (itemPager, error)
+		deltaPagerGetter    func(context.Context, graph.Servicer, string, string, string, bool) (itemPager, error)
+		added               []string
+		removed             []string
+		deltaUpdate         DeltaUpdate
+		delta               string
+		canMakeDeltaQueries bool
+	}{
+		{
+			name: "no prev delta",
+			pagerGetter: func(
+				ctx context.Context,
+				gs graph.Servicer,
+				user string,
+				directory string,
+				immutableIDs bool,
+			) (itemPager, error) {
+				// this should not be called
+				return nil, assert.AnError
+			},
+			deltaPagerGetter: func(
+				ctx context.Context,
+				gs graph.Servicer,
+				user string,
+				directory string,
+				delta string,
+				immutableIDs bool,
+			) (itemPager, error) {
+				return &testPager{
+					t:       suite.T(),
+					added:   []string{"uno", "dos"},
+					removed: []string{"tres", "quatro"},
+				}, nil
+			},
+			added:               []string{"uno", "dos"},
+			removed:             []string{"tres", "quatro"},
+			deltaUpdate:         DeltaUpdate{Reset: true},
+			canMakeDeltaQueries: true,
+		},
+		{
+			name: "with prev delta",
+			pagerGetter: func(
+				ctx context.Context,
+				gs graph.Servicer,
+				user string,
+				directory string,
+				immutableIDs bool,
+			) (itemPager, error) {
+				// this should not be called
+				return nil, assert.AnError
+			},
+			deltaPagerGetter: func(
+				ctx context.Context,
+				gs graph.Servicer,
+				user string,
+				directory string,
+				delta string,
+				immutableIDs bool,
+			) (itemPager, error) {
+				return &testPager{
+					t:       suite.T(),
+					added:   []string{"uno", "dos"},
+					removed: []string{"tres", "quatro"},
+				}, nil
+			},
+			added:               []string{"uno", "dos"},
+			removed:             []string{"tres", "quatro"},
+			delta:               "delta",
+			deltaUpdate:         DeltaUpdate{Reset: false},
+			canMakeDeltaQueries: true,
+		},
+		{
+			name: "delta expired",
+			pagerGetter: func(
+				ctx context.Context,
+				gs graph.Servicer,
+				user string,
+				directory string,
+				immutableIDs bool,
+			) (itemPager, error) {
+				// this should not be called
+				return nil, assert.AnError
+			},
+			deltaPagerGetter: func(
+				ctx context.Context,
+				gs graph.Servicer,
+				user string,
+				directory string,
+				delta string,
+				immutableIDs bool,
+			) (itemPager, error) {
+				return &testPager{
+					t:          suite.T(),
+					added:      []string{"uno", "dos"},
+					removed:    []string{"tres", "quatro"},
+					errorCode:  "SyncStateNotFound",
+					needsReset: true,
+				}, nil
+			},
+			added:               []string{"uno", "dos"},
+			removed:             []string{"tres", "quatro"},
+			delta:               "delta",
+			deltaUpdate:         DeltaUpdate{Reset: true},
+			canMakeDeltaQueries: true,
+		},
+		{
+			name: "quota exceeded",
+			pagerGetter: func(
+				ctx context.Context,
+				gs graph.Servicer,
+				user string,
+				directory string,
+				immutableIDs bool,
+			) (itemPager, error) {
+				return &testPager{
+					t:       suite.T(),
+					added:   []string{"uno", "dos"},
+					removed: []string{"tres", "quatro"},
+				}, nil
+			},
+			deltaPagerGetter: func(
+				ctx context.Context,
+				gs graph.Servicer,
+				user string,
+				directory string,
+				delta string,
+				immutableIDs bool,
+			) (itemPager, error) {
+				return &testPager{errorCode: "ErrorQuotaExceeded"}, nil
+			},
+			added:               []string{"uno", "dos"},
+			removed:             []string{"tres", "quatro"},
+			deltaUpdate:         DeltaUpdate{Reset: true},
+			canMakeDeltaQueries: false,
+		},
+	}
+
+	for _, tt := range tests {
+		suite.Run(tt.name, func() {
+			ctx, flush := tester.NewContext()
+			defer flush()
+
+			pager, _ := tt.pagerGetter(ctx, graph.Service{}, "user", "directory", false)
+			deltaPager, _ := tt.deltaPagerGetter(ctx, graph.Service{}, "user", "directory", tt.delta, false)
+
+			added, removed, deltaUpdate, err := getAddedAndRemovedItemIDs(
+				ctx,
+				graph.Service{},
+				pager,
+				deltaPager,
+				tt.delta,
+				tt.canMakeDeltaQueries,
+			)
+
+			require.NoError(suite.T(), err, "getting added and removed item IDs")
+			require.EqualValues(suite.T(), tt.added, added, "added item IDs")
+			require.EqualValues(suite.T(), tt.removed, removed, "removed item IDs")
+			require.Equal(suite.T(), tt.deltaUpdate, deltaUpdate, "delta update")
+		})
+	}
+}

src/internal/connector/exchange/data_collections.go

@@ -41,7 +41,7 @@ func (dps DeltaPaths) AddDelta(k, d string) {
 		dp = DeltaPath{}
 	}
 
-	dp.delta = d
+	dp.Delta = d
 	dps[k] = dp
 }
 
@@ -51,13 +51,13 @@ func (dps DeltaPaths) AddPath(k, p string) {
 		dp = DeltaPath{}
 	}
 
-	dp.path = p
+	dp.Path = p
 	dps[k] = dp
 }
 
 type DeltaPath struct {
-	delta string
+	Delta string
-	path  string
+	Path  string
 }
 
 // ParseMetadataCollections produces a map of structs holding delta
@@ -148,7 +148,7 @@ func parseMetadataCollections(
 	// complete backup on the next run.
 	for _, dps := range cdp {
 		for k, dp := range dps {
-			if len(dp.delta) == 0 || len(dp.path) == 0 {
+			if len(dp.Path) == 0 {
 				delete(dps, k)
 			}
 		}

src/internal/connector/exchange/data_collections_test.go

@@ -68,7 +68,12 @@ func (suite *DataCollectionsUnitSuite) TestParseMetadataCollections() {
 			data: []fileValues{
 				{graph.PreviousPathFileName, "prev-path"},
 			},
-			expect:      map[string]DeltaPath{},
+			expect: map[string]DeltaPath{
+				"key": {
+					Delta: "delta-link",
+					Path:  "prev-path",
+				},
+			},
 			expectError: assert.NoError,
 		},
 		{
@@ -87,8 +92,8 @@ func (suite *DataCollectionsUnitSuite) TestParseMetadataCollections() {
 			},
 			expect: map[string]DeltaPath{
 				"key": {
-					delta: "delta-link",
+					Delta: "delta-link",
-					path:  "prev-path",
+					Path:  "prev-path",
 				},
 			},
 			expectError: assert.NoError,
@@ -108,7 +113,12 @@ func (suite *DataCollectionsUnitSuite) TestParseMetadataCollections() {
 				{graph.DeltaURLsFileName, ""},
 				{graph.PreviousPathFileName, "prev-path"},
 			},
-			expect:      map[string]DeltaPath{},
+			expect: map[string]DeltaPath{
+				"key": {
+					Delta: "delta-link",
+					Path:  "prev-path",
+				},
+			},
 			expectError: assert.NoError,
 		},
 		{
@@ -119,8 +129,8 @@ func (suite *DataCollectionsUnitSuite) TestParseMetadataCollections() {
 			},
 			expect: map[string]DeltaPath{
 				"key": {
-					delta: "`!@#$%^&*()_[]{}/\"\\",
+					Delta: "`!@#$%^&*()_[]{}/\"\\",
-					path:  "prev-path",
+					Path:  "prev-path",
 				},
 			},
 			expectError: assert.NoError,
@@ -133,8 +143,8 @@ func (suite *DataCollectionsUnitSuite) TestParseMetadataCollections() {
 			},
 			expect: map[string]DeltaPath{
 				"key": {
-					delta: "\\n\\r\\t\\b\\f\\v\\0\\\\",
+					Delta: "\\n\\r\\t\\b\\f\\v\\0\\\\",
-					path:  "prev-path",
+					Path:  "prev-path",
 				},
 			},
 			expectError: assert.NoError,
@@ -150,8 +160,8 @@ func (suite *DataCollectionsUnitSuite) TestParseMetadataCollections() {
 			},
 			expect: map[string]DeltaPath{
 				"key": {
-					delta: "\\n",
+					Delta: "\\n",
-					path:  "prev-path",
+					Path:  "prev-path",
 				},
 			},
 			expectError: assert.NoError,
@@ -191,8 +201,8 @@ func (suite *DataCollectionsUnitSuite) TestParseMetadataCollections() {
 			assert.Len(t, emails, len(test.expect))
 
 			for k, v := range emails {
-				assert.Equal(t, v.delta, emails[k].delta, "delta")
+				assert.Equal(t, v.Delta, emails[k].Delta, "delta")
-				assert.Equal(t, v.path, emails[k].path, "path")
+				assert.Equal(t, v.Path, emails[k].Path, "path")
 			}
 		})
 	}
@@ -248,6 +258,7 @@ func (suite *DataCollectionsIntegrationSuite) TestMailFetch() {
 		name                string
 		scope               selectors.ExchangeScope
 		folderNames         map[string]struct{}
+		canMakeDeltaQueries bool
 	}{
 		{
 			name: "Folder Iterative Check Mail",
@@ -258,6 +269,18 @@ func (suite *DataCollectionsIntegrationSuite) TestMailFetch() {
 			folderNames: map[string]struct{}{
 				DefaultMailFolder: {},
 			},
+			canMakeDeltaQueries: true,
+		},
+		{
+			name: "Folder Iterative Check Mail Non-Delta",
+			scope: selectors.NewExchangeBackup(users).MailFolders(
+				[]string{DefaultMailFolder},
+				selectors.PrefixMatch(),
+			)[0],
+			folderNames: map[string]struct{}{
+				DefaultMailFolder: {},
+			},
+			canMakeDeltaQueries: false,
 		},
 	}
 
@@ -265,13 +288,16 @@ func (suite *DataCollectionsIntegrationSuite) TestMailFetch() {
 		suite.Run(test.name, func() {
 			t := suite.T()
 
+			ctrlOpts := control.Defaults()
+			ctrlOpts.ToggleFeatures.DisableDelta = !test.canMakeDeltaQueries
+
 			collections, err := createCollections(
 				ctx,
 				acct,
 				inMock.NewProvider(userID, userID),
 				test.scope,
 				DeltaPaths{},
-				control.Defaults(),
+				ctrlOpts,
 				func(status *support.ConnectorOperationStatus) {},
 				fault.New(true))
 			require.NoError(t, err, clues.ToCore(err))

src/internal/connector/exchange/service_iterators.go

@@ -23,6 +23,7 @@ type addedAndRemovedItemIDsGetter interface {
 		ctx context.Context,
 		user, containerID, oldDeltaToken string,
 		immutableIDs bool,
+		canMakeDeltaQueries bool,
 	) ([]string, []string, api.DeltaUpdate, error)
 }
 
@@ -85,8 +86,8 @@ func filterContainersAndFillCollections(
 
 		var (
 			dp          = dps[cID]
-			prevDelta   = dp.delta
+			prevDelta   = dp.Delta
-			prevPathStr = dp.path // do not log: pii; log prevPath instead
+			prevPathStr = dp.Path // do not log: pii; log prevPath instead
 			prevPath    path.Path
 			ictx        = clues.Add(
 				ctx,
@@ -119,7 +120,8 @@ func filterContainersAndFillCollections(
 			qp.ResourceOwner.ID(),
 			cID,
 			prevDelta,
-			ctrlOpts.ToggleFeatures.ExchangeImmutableIDs)
+			ctrlOpts.ToggleFeatures.ExchangeImmutableIDs,
+			!ctrlOpts.ToggleFeatures.DisableDelta)
 		if err != nil {
 			if !graph.IsErrDeletedInFlight(err) {
 				el.AddRecoverable(clues.Stack(err).Label(fault.LabelForceNoBackupCreation))
@@ -243,7 +245,7 @@ func makeTombstones(dps DeltaPaths) map[string]string {
 	r := make(map[string]string, len(dps))
 
 	for id, v := range dps {
-		r[id] = v.path
+		r[id] = v.Path
 	}
 
 	return r

src/internal/connector/exchange/service_iterators_test.go

@@ -30,7 +30,10 @@ import (
 var _ addedAndRemovedItemIDsGetter = &mockGetter{}
 
 type (
-	mockGetter        map[string]mockGetterResults
+	mockGetter struct {
+		noReturnDelta bool
+		results       map[string]mockGetterResults
+	}
 	mockGetterResults struct {
 		added    []string
 		removed  []string
@@ -43,18 +46,24 @@ func (mg mockGetter) GetAddedAndRemovedItemIDs(
 	ctx context.Context,
 	userID, cID, prevDelta string,
 	_ bool,
+	_ bool,
 ) (
 	[]string,
 	[]string,
 	api.DeltaUpdate,
 	error,
 ) {
-	results, ok := mg[cID]
+	results, ok := mg.results[cID]
 	if !ok {
 		return nil, nil, api.DeltaUpdate{}, clues.New("mock not found for " + cID)
 	}
 
-	return results.added, results.removed, results.newDelta, results.err
+	delta := results.newDelta
+	if mg.noReturnDelta {
+		delta.URL = ""
+	}
+
+	return results.added, results.removed, delta, results.err
 }
 
 var _ graph.ContainerResolver = &mockResolver{}
@@ -171,9 +180,11 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections() {
 	}{
 		{
 			name: "happy path, one container",
-			getter: map[string]mockGetterResults{
+			getter: mockGetter{
+				results: map[string]mockGetterResults{
 					"1": commonResult,
 				},
+			},
 			resolver:            newMockResolver(container1),
 			scope:               allScope,
 			expectErr:           assert.NoError,
@@ -182,10 +193,12 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections() {
 		},
 		{
 			name: "happy path, many containers",
-			getter: map[string]mockGetterResults{
+			getter: mockGetter{
+				results: map[string]mockGetterResults{
 					"1": commonResult,
 					"2": commonResult,
 				},
+			},
 			resolver:            newMockResolver(container1, container2),
 			scope:               allScope,
 			expectErr:           assert.NoError,
@@ -194,10 +207,12 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections() {
 		},
 		{
 			name: "no containers pass scope",
-			getter: map[string]mockGetterResults{
+			getter: mockGetter{
+				results: map[string]mockGetterResults{
 					"1": commonResult,
 					"2": commonResult,
 				},
+			},
 			resolver:            newMockResolver(container1, container2),
 			scope:               selectors.NewExchangeBackup(nil).MailFolders(selectors.None())[0],
 			expectErr:           assert.NoError,
@@ -206,9 +221,11 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections() {
 		},
 		{
 			name: "err: deleted in flight",
-			getter: map[string]mockGetterResults{
+			getter: mockGetter{
+				results: map[string]mockGetterResults{
 					"1": deletedInFlightResult,
 				},
+			},
 			resolver:              newMockResolver(container1),
 			scope:                 allScope,
 			expectErr:             assert.NoError,
@@ -218,9 +235,11 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections() {
 		},
 		{
 			name: "err: other error",
-			getter: map[string]mockGetterResults{
+			getter: mockGetter{
+				results: map[string]mockGetterResults{
 					"1": errorResult,
 				},
+			},
 			resolver:            newMockResolver(container1),
 			scope:               allScope,
 			expectErr:           assert.NoError,
@@ -229,10 +248,12 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections() {
 		},
 		{
 			name: "half collections error: deleted in flight",
-			getter: map[string]mockGetterResults{
+			getter: mockGetter{
+				results: map[string]mockGetterResults{
 					"1": deletedInFlightResult,
 					"2": commonResult,
 				},
+			},
 			resolver:              newMockResolver(container1, container2),
 			scope:                 allScope,
 			expectErr:             assert.NoError,
@@ -242,10 +263,12 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections() {
 		},
 		{
 			name: "half collections error: other error",
-			getter: map[string]mockGetterResults{
+			getter: mockGetter{
+				results: map[string]mockGetterResults{
 					"1": errorResult,
 					"2": commonResult,
 				},
+			},
 			resolver:            newMockResolver(container1, container2),
 			scope:               allScope,
 			expectErr:           assert.NoError,
@@ -254,10 +277,12 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections() {
 		},
 		{
 			name: "half collections error: deleted in flight, fail fast",
-			getter: map[string]mockGetterResults{
+			getter: mockGetter{
+				results: map[string]mockGetterResults{
 					"1": deletedInFlightResult,
 					"2": commonResult,
 				},
+			},
 			resolver:              newMockResolver(container1, container2),
 			scope:                 allScope,
 			failFast:              control.FailFast,
@@ -268,10 +293,12 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections() {
 		},
 		{
 			name: "half collections error: other error, fail fast",
-			getter: map[string]mockGetterResults{
+			getter: mockGetter{
+				results: map[string]mockGetterResults{
 					"1": errorResult,
 					"2": commonResult,
 				},
+			},
 			resolver:            newMockResolver(container1, container2),
 			scope:               allScope,
 			failFast:            control.FailFast,
@@ -281,12 +308,24 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections() {
 		},
 	}
 	for _, test := range table {
-		suite.Run(test.name, func() {
+		for _, canMakeDeltaQueries := range []bool{true, false} {
+			name := test.name
+
+			if canMakeDeltaQueries {
+				name += "-delta"
+			} else {
+				name += "-non-delta"
+			}
+
+			suite.Run(name, func() {
 				t := suite.T()
 
 				ctx, flush := tester.NewContext()
 				defer flush()
 
+				ctrlOpts := control.Options{FailureHandling: test.failFast}
+				ctrlOpts.ToggleFeatures.DisableDelta = !canMakeDeltaQueries
+
 				collections, err := filterContainersAndFillCollections(
 					ctx,
 					qp,
@@ -295,7 +334,7 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections() {
 					test.resolver,
 					test.scope,
 					dps,
-				control.Options{FailureHandling: test.failFast},
+					ctrlOpts,
 					fault.New(test.failFast == control.FailFast))
 				test.expectErr(t, err, clues.ToCore(err))
 
@@ -327,7 +366,7 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections() {
 				assert.Equal(t, test.expectDoNotMergeColls, doNotMerges, "doNotMerge collections")
 
 				// items in collections assertions
-			for k, expect := range test.getter {
+				for k, expect := range test.getter.results {
 					coll := collections[k]
 
 					if coll == nil {
@@ -354,6 +393,7 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections() {
 			})
 		}
 	}
+}
 
 func checkMetadata(
 	t *testing.T,
@@ -488,74 +528,80 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_Dupli
 	}{
 		{
 			name: "1 moved to duplicate",
-			getter: map[string]mockGetterResults{
+			getter: mockGetter{
+				results: map[string]mockGetterResults{
 					"1": result1,
 					"2": result2,
 				},
+			},
 			resolver: newMockResolver(container1, container2),
 			inputMetadata: func(t *testing.T, cat path.CategoryType) DeltaPaths {
 				return DeltaPaths{
 					"1": DeltaPath{
-						delta: "old_delta",
+						Delta: "old_delta",
-						path:  oldPath1(t, cat).String(),
+						Path:  oldPath1(t, cat).String(),
 					},
 					"2": DeltaPath{
-						delta: "old_delta",
+						Delta: "old_delta",
-						path:  idPath2(t, cat).String(),
+						Path:  idPath2(t, cat).String(),
 					},
 				}
 			},
 			expectMetadata: func(t *testing.T, cat path.CategoryType) DeltaPaths {
 				return DeltaPaths{
 					"1": DeltaPath{
-						delta: "delta_url",
+						Delta: "delta_url",
-						path:  idPath1(t, cat).String(),
+						Path:  idPath1(t, cat).String(),
 					},
 					"2": DeltaPath{
-						delta: "delta_url2",
+						Delta: "delta_url2",
-						path:  idPath2(t, cat).String(),
+						Path:  idPath2(t, cat).String(),
 					},
 				}
 			},
 		},
 		{
 			name: "both move to duplicate",
-			getter: map[string]mockGetterResults{
+			getter: mockGetter{
+				results: map[string]mockGetterResults{
 					"1": result1,
 					"2": result2,
 				},
+			},
 			resolver: newMockResolver(container1, container2),
 			inputMetadata: func(t *testing.T, cat path.CategoryType) DeltaPaths {
 				return DeltaPaths{
 					"1": DeltaPath{
-						delta: "old_delta",
+						Delta: "old_delta",
-						path:  oldPath1(t, cat).String(),
+						Path:  oldPath1(t, cat).String(),
 					},
 					"2": DeltaPath{
-						delta: "old_delta",
+						Delta: "old_delta",
-						path:  oldPath2(t, cat).String(),
+						Path:  oldPath2(t, cat).String(),
 					},
 				}
 			},
 			expectMetadata: func(t *testing.T, cat path.CategoryType) DeltaPaths {
 				return DeltaPaths{
 					"1": DeltaPath{
-						delta: "delta_url",
+						Delta: "delta_url",
-						path:  idPath1(t, cat).String(),
+						Path:  idPath1(t, cat).String(),
 					},
 					"2": DeltaPath{
-						delta: "delta_url2",
+						Delta: "delta_url2",
-						path:  idPath2(t, cat).String(),
+						Path:  idPath2(t, cat).String(),
 					},
 				}
 			},
 		},
 		{
 			name: "both new",
-			getter: map[string]mockGetterResults{
+			getter: mockGetter{
+				results: map[string]mockGetterResults{
 					"1": result1,
 					"2": result2,
 				},
+			},
 			resolver: newMockResolver(container1, container2),
 			inputMetadata: func(t *testing.T, cat path.CategoryType) DeltaPaths {
 				return DeltaPaths{}
@@ -564,27 +610,29 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_Dupli
 			expectMetadata: func(t *testing.T, cat path.CategoryType) DeltaPaths {
 				return DeltaPaths{
 					"1": DeltaPath{
-						delta: "delta_url",
+						Delta: "delta_url",
-						path:  idPath1(t, cat).String(),
+						Path:  idPath1(t, cat).String(),
 					},
 					"2": DeltaPath{
-						delta: "delta_url2",
+						Delta: "delta_url2",
-						path:  idPath2(t, cat).String(),
+						Path:  idPath2(t, cat).String(),
 					},
 				}
 			},
 		},
 		{
 			name: "add 1 remove 2",
-			getter: map[string]mockGetterResults{
+			getter: mockGetter{
+				results: map[string]mockGetterResults{
 					"1": result1,
 				},
+			},
 			resolver: newMockResolver(container1),
 			inputMetadata: func(t *testing.T, cat path.CategoryType) DeltaPaths {
 				return DeltaPaths{
 					"2": DeltaPath{
-						delta: "old_delta",
+						Delta: "old_delta",
-						path:  idPath2(t, cat).String(),
+						Path:  idPath2(t, cat).String(),
 					},
 				}
 			},
@@ -593,8 +641,8 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_Dupli
 			expectMetadata: func(t *testing.T, cat path.CategoryType) DeltaPaths {
 				return DeltaPaths{
 					"1": DeltaPath{
-						delta: "delta_url",
+						Delta: "delta_url",
-						path:  idPath1(t, cat).String(),
+						Path:  idPath1(t, cat).String(),
 					},
 				}
 			},
@@ -649,7 +697,7 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_Dupli
 					assert.Equal(t, 1, metadatas, "metadata collections")
 
 					// items in collections assertions
-					for k, expect := range test.getter {
+					for k, expect := range test.getter.results {
 						coll := collections[k]
 
 						if coll == nil {
@@ -690,12 +738,14 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_repea
 	}{
 		{
 			name: "repeated adds",
-			getter: map[string]mockGetterResults{
+			getter: mockGetter{
+				results: map[string]mockGetterResults{
 					"1": {
 						added:    []string{"a1", "a2", "a3", "a1"},
 						newDelta: newDelta,
 					},
 				},
+			},
 			expectAdded: map[string]struct{}{
 				"a1": {},
 				"a2": {},
@@ -705,12 +755,14 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_repea
 		},
 		{
 			name: "repeated removes",
-			getter: map[string]mockGetterResults{
+			getter: mockGetter{
+				results: map[string]mockGetterResults{
 					"1": {
 						removed:  []string{"r1", "r2", "r3", "r1"},
 						newDelta: newDelta,
 					},
 				},
+			},
 			expectAdded: map[string]struct{}{},
 			expectRemoved: map[string]struct{}{
 				"r1": {},
@@ -720,13 +772,15 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_repea
 		},
 		{
 			name: "remove for same item wins",
-			getter: map[string]mockGetterResults{
+			getter: mockGetter{
+				results: map[string]mockGetterResults{
 					"1": {
 						added:    []string{"i1", "a2", "a3"},
 						removed:  []string{"i1", "r2", "r3"},
 						newDelta: newDelta,
 					},
 				},
+			},
 			expectAdded: map[string]struct{}{
 				"a2": {},
 				"a3": {},
@@ -806,7 +860,7 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_repea
 			assert.Zero(t, doNotMerges, "doNotMerge collections")
 
 			// items in collections assertions
-			for k := range test.getter {
+			for k := range test.getter.results {
 				coll := collections[k]
 				if !assert.NotNilf(t, coll, "missing collection for path %s", k) {
 					continue
@@ -822,7 +876,7 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_repea
 	}
 }
 
-func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_incrementals() {
+func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_incrementals_nondelta() {
 	var (
 		userID   = "user_id"
 		tenantID = suite.creds.AzureTenantID
@@ -865,12 +919,15 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_incre
 		resolver              graph.ContainerResolver
 		dps                   DeltaPaths
 		expect                map[string]endState
+		skipWhenForcedNoDelta bool
 	}{
 		{
 			name: "new container",
-			getter: map[string]mockGetterResults{
+			getter: mockGetter{
+				results: map[string]mockGetterResults{
 					"1": commonResults,
 				},
+			},
 			resolver: newMockResolver(mockContainer{
 				id:          strPtr("1"),
 				displayName: strPtr("new"),
@@ -884,9 +941,11 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_incre
 		},
 		{
 			name: "not moved container",
-			getter: map[string]mockGetterResults{
+			getter: mockGetter{
+				results: map[string]mockGetterResults{
 					"1": commonResults,
 				},
+			},
 			resolver: newMockResolver(mockContainer{
 				id:          strPtr("1"),
 				displayName: strPtr("not_moved"),
@@ -895,8 +954,8 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_incre
 			}),
 			dps: DeltaPaths{
 				"1": DeltaPath{
-					delta: "old_delta_url",
+					Delta: "old_delta_url",
-					path:  prevPath(suite.T(), "1", "not_moved").String(),
+					Path:  prevPath(suite.T(), "1", "not_moved").String(),
 				},
 			},
 			expect: map[string]endState{
@@ -905,9 +964,11 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_incre
 		},
 		{
 			name: "moved container",
-			getter: map[string]mockGetterResults{
+			getter: mockGetter{
+				results: map[string]mockGetterResults{
 					"1": commonResults,
 				},
+			},
 			resolver: newMockResolver(mockContainer{
 				id:          strPtr("1"),
 				displayName: strPtr("moved"),
@@ -916,8 +977,8 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_incre
 			}),
 			dps: DeltaPaths{
 				"1": DeltaPath{
-					delta: "old_delta_url",
+					Delta: "old_delta_url",
-					path:  prevPath(suite.T(), "1", "prev").String(),
+					Path:  prevPath(suite.T(), "1", "prev").String(),
 				},
 			},
 			expect: map[string]endState{
@@ -926,12 +987,14 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_incre
 		},
 		{
 			name: "deleted container",
-			getter:   map[string]mockGetterResults{},
+			getter: mockGetter{
+				results: map[string]mockGetterResults{},
+			},
 			resolver: newMockResolver(),
 			dps: DeltaPaths{
 				"1": DeltaPath{
-					delta: "old_delta_url",
+					Delta: "old_delta_url",
-					path:  prevPath(suite.T(), "1", "deleted").String(),
+					Path:  prevPath(suite.T(), "1", "deleted").String(),
 				},
 			},
 			expect: map[string]endState{
@@ -940,9 +1003,11 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_incre
 		},
 		{
 			name: "one deleted, one new",
-			getter: map[string]mockGetterResults{
+			getter: mockGetter{
+				results: map[string]mockGetterResults{
 					"2": commonResults,
 				},
+			},
 			resolver: newMockResolver(mockContainer{
 				id:          strPtr("2"),
 				displayName: strPtr("new"),
@@ -951,8 +1016,8 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_incre
 			}),
 			dps: DeltaPaths{
 				"1": DeltaPath{
-					delta: "old_delta_url",
+					Delta: "old_delta_url",
-					path:  prevPath(suite.T(), "1", "deleted").String(),
+					Path:  prevPath(suite.T(), "1", "deleted").String(),
 				},
 			},
 			expect: map[string]endState{
@@ -962,9 +1027,11 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_incre
 		},
 		{
 			name: "one deleted, one new, same path",
-			getter: map[string]mockGetterResults{
+			getter: mockGetter{
+				results: map[string]mockGetterResults{
 					"2": commonResults,
 				},
+			},
 			resolver: newMockResolver(mockContainer{
 				id:          strPtr("2"),
 				displayName: strPtr("same"),
@@ -973,8 +1040,8 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_incre
 			}),
 			dps: DeltaPaths{
 				"1": DeltaPath{
-					delta: "old_delta_url",
+					Delta: "old_delta_url",
-					path:  prevPath(suite.T(), "1", "same").String(),
+					Path:  prevPath(suite.T(), "1", "same").String(),
 				},
 			},
 			expect: map[string]endState{
@@ -984,10 +1051,12 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_incre
 		},
 		{
 			name: "one moved, one new, same path",
-			getter: map[string]mockGetterResults{
+			getter: mockGetter{
+				results: map[string]mockGetterResults{
 					"1": commonResults,
 					"2": commonResults,
 				},
+			},
 			resolver: newMockResolver(
 				mockContainer{
 					id:          strPtr("1"),
@@ -1004,8 +1073,8 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_incre
 			),
 			dps: DeltaPaths{
 				"1": DeltaPath{
-					delta: "old_delta_url",
+					Delta: "old_delta_url",
-					path:  prevPath(suite.T(), "1", "prev").String(),
+					Path:  prevPath(suite.T(), "1", "prev").String(),
 				},
 			},
 			expect: map[string]endState{
@@ -1015,9 +1084,11 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_incre
 		},
 		{
 			name: "bad previous path strings",
-			getter: map[string]mockGetterResults{
+			getter: mockGetter{
+				results: map[string]mockGetterResults{
 					"1": commonResults,
 				},
+			},
 			resolver: newMockResolver(mockContainer{
 				id:          strPtr("1"),
 				displayName: strPtr("not_moved"),
@@ -1026,12 +1097,12 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_incre
 			}),
 			dps: DeltaPaths{
 				"1": DeltaPath{
-					delta: "old_delta_url",
+					Delta: "old_delta_url",
-					path:  "1/fnords/mc/smarfs",
+					Path:  "1/fnords/mc/smarfs",
 				},
 				"2": DeltaPath{
-					delta: "old_delta_url",
+					Delta: "old_delta_url",
-					path:  "2/fnords/mc/smarfs",
+					Path:  "2/fnords/mc/smarfs",
 				},
 			},
 			expect: map[string]endState{
@@ -1040,9 +1111,11 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_incre
 		},
 		{
 			name: "delta expiration",
-			getter: map[string]mockGetterResults{
+			getter: mockGetter{
+				results: map[string]mockGetterResults{
 					"1": expiredResults,
 				},
+			},
 			resolver: newMockResolver(mockContainer{
 				id:          strPtr("1"),
 				displayName: strPtr("same"),
@@ -1051,23 +1124,26 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_incre
 			}),
 			dps: DeltaPaths{
 				"1": DeltaPath{
-					delta: "old_delta_url",
+					Delta: "old_delta_url",
-					path:  prevPath(suite.T(), "1", "same").String(),
+					Path:  prevPath(suite.T(), "1", "same").String(),
 				},
 			},
 			expect: map[string]endState{
 				"1": {data.NotMovedState, true},
 			},
+			skipWhenForcedNoDelta: true, // this is not a valid test for non-delta
 		},
 		{
 			name: "a little bit of everything",
-			getter: map[string]mockGetterResults{
+			getter: mockGetter{
+				results: map[string]mockGetterResults{
 					"1": commonResults,  // new
 					"2": commonResults,  // notMoved
 					"3": commonResults,  // moved
 					"4": expiredResults, // moved
 					// "5" gets deleted
 				},
+			},
 			resolver: newMockResolver(
 				mockContainer{
 					id:          strPtr("1"),
@@ -1096,20 +1172,20 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_incre
 			),
 			dps: DeltaPaths{
 				"2": DeltaPath{
-					delta: "old_delta_url",
+					Delta: "old_delta_url",
-					path:  prevPath(suite.T(), "2", "not_moved").String(),
+					Path:  prevPath(suite.T(), "2", "not_moved").String(),
 				},
 				"3": DeltaPath{
-					delta: "old_delta_url",
+					Delta: "old_delta_url",
-					path:  prevPath(suite.T(), "3", "prev").String(),
+					Path:  prevPath(suite.T(), "3", "prev").String(),
 				},
 				"4": DeltaPath{
-					delta: "old_delta_url",
+					Delta: "old_delta_url",
-					path:  prevPath(suite.T(), "4", "prev").String(),
+					Path:  prevPath(suite.T(), "4", "prev").String(),
 				},
 				"5": DeltaPath{
-					delta: "old_delta_url",
+					Delta: "old_delta_url",
-					path:  prevPath(suite.T(), "5", "deleted").String(),
+					Path:  prevPath(suite.T(), "5", "deleted").String(),
 				},
 			},
 			expect: map[string]endState{
@@ -1119,15 +1195,45 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_incre
 				"4": {data.MovedState, true},
 				"5": {data.DeletedState, false},
 			},
+			skipWhenForcedNoDelta: true,
 		},
 	}
 	for _, test := range table {
-		suite.Run(test.name, func() {
+		for _, deltaBefore := range []bool{true, false} {
+			for _, deltaAfter := range []bool{true, false} {
+				name := test.name
+
+				if deltaAfter {
+					name += "-delta"
+				} else {
+					if test.skipWhenForcedNoDelta {
+						suite.T().Skip("intentionally skipped non-delta case")
+					}
+					name += "-non-delta"
+				}
+
+				suite.Run(name, func() {
 					t := suite.T()
 
 					ctx, flush := tester.NewContext()
 					defer flush()
 
+					ctrlOpts := control.Defaults()
+					ctrlOpts.ToggleFeatures.DisableDelta = !deltaAfter
+
+					getter := test.getter
+					if !deltaAfter {
+						getter.noReturnDelta = false
+					}
+
+					dps := test.dps
+					if !deltaBefore {
+						for k, dp := range dps {
+							dp.Delta = ""
+							dps[k] = dp
+						}
+					}
+
 					collections, err := filterContainersAndFillCollections(
 						ctx,
 						qp,
@@ -1136,7 +1242,7 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_incre
 						test.resolver,
 						allScope,
 						test.dps,
-				control.Defaults(),
+						ctrlOpts,
 						fault.New(true))
 					assert.NoError(t, err, clues.ToCore(err))
 
@@ -1167,3 +1273,5 @@ func (suite *ServiceIteratorsSuite) TestFilterContainersAndFillCollections_incre
 				})
 			}
 		}
+	}
+}

src/internal/connector/graph/errors.go

@@ -36,6 +36,7 @@ const (
 	mailboxNotEnabledForRESTAPI errorCode = "MailboxNotEnabledForRESTAPI"
 	malwareDetected             errorCode = "malwareDetected"
 	requestResourceNotFound     errorCode = "Request_ResourceNotFound"
+	quotaExceeded               errorCode = "ErrorQuotaExceeded"
 	resourceNotFound            errorCode = "ResourceNotFound"
 	resyncRequired              errorCode = "ResyncRequired" // alt: resyncRequired
 	syncFolderNotFound          errorCode = "ErrorSyncFolderNotFound"
@@ -111,6 +112,10 @@ func IsErrInvalidDelta(err error) bool {
 		errors.Is(err, ErrInvalidDelta)
 }
 
+func IsErrQuotaExceeded(err error) bool {
+	return hasErrorCode(err, quotaExceeded)
+}
+
 func IsErrExchangeMailFolderNotFound(err error) bool {
 	return hasErrorCode(err, resourceNotFound, mailboxNotEnabledForRESTAPI)
 }

src/internal/connector/graph/errors_test.go

@@ -161,6 +161,45 @@ func (suite *GraphErrorsUnitSuite) TestIsErrInvalidDelta() {
 	}
 }
 
+func (suite *GraphErrorsUnitSuite) TestIsErrQuotaExceeded() {
+	table := []struct {
+		name   string
+		err    error
+		expect assert.BoolAssertionFunc
+	}{
+		{
+			name:   "nil",
+			err:    nil,
+			expect: assert.False,
+		},
+		{
+			name:   "non-matching",
+			err:    assert.AnError,
+			expect: assert.False,
+		},
+		{
+			name:   "as",
+			err:    ErrInvalidDelta,
+			expect: assert.False,
+		},
+		{
+			name:   "non-matching oDataErr",
+			err:    odErr("fnords"),
+			expect: assert.False,
+		},
+		{
+			name:   "quota-exceeded oDataErr",
+			err:    odErr("ErrorQuotaExceeded"),
+			expect: assert.True,
+		},
+	}
+	for _, test := range table {
+		suite.Run(test.name, func() {
+			test.expect(suite.T(), IsErrQuotaExceeded(test.err))
+		})
+	}
+}
+
 func (suite *GraphErrorsUnitSuite) TestIsErrUserNotFound() {
 	table := []struct {
 		name   string

src/internal/operations/backup_integration_test.go

@@ -708,9 +708,15 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_exchange() {
 	}
 }
 
-// TestBackup_Run ensures that Integration Testing works
-// for the following scopes: Contacts, Events, and Mail
 func (suite *BackupOpIntegrationSuite) TestBackup_Run_incrementalExchange() {
+	testExchangeContinuousBackups(suite, control.Toggles{})
+}
+
+func (suite *BackupOpIntegrationSuite) TestBackup_Run_nonIncrementalExchange() {
+	testExchangeContinuousBackups(suite, control.Toggles{DisableDelta: true})
+}
+
+func testExchangeContinuousBackups(suite *BackupOpIntegrationSuite, toggles control.Toggles) {
 	ctx, flush := tester.NewContext()
 	defer flush()
 
@@ -719,7 +725,6 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_incrementalExchange() {
 	var (
 		t          = suite.T()
 		acct       = tester.NewM365Account(t)
-		ffs        = control.Toggles{}
 		mb         = evmock.NewBus()
 		now        = dttm.Now()
 		service    = path.ExchangeService
@@ -860,7 +865,7 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_incrementalExchange() {
 		}
 	}
 
-	bo, acct, kw, ms, ss, gc, sels, closer := prepNewTestBackupOp(t, ctx, mb, sel.Selector, ffs, version.Backup)
+	bo, acct, kw, ms, ss, gc, sels, closer := prepNewTestBackupOp(t, ctx, mb, sel.Selector, toggles, version.Backup)
 	defer closer()
 
 	// run the initial backup
@@ -947,14 +952,18 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_incrementalExchange() {
 		name string
 		// performs the incremental update required for the test.
 		updateUserData       func(t *testing.T)
-		itemsRead      int
+		deltaItemsRead       int
-		itemsWritten   int
+		deltaItemsWritten    int
+		nonDeltaItemsRead    int
+		nonDeltaItemsWritten int
 	}{
 		{
-			name:           "clean incremental, no changes",
+			name:                 "clean, no changes",
 			updateUserData:       func(t *testing.T) {},
-			itemsRead:      0,
+			deltaItemsRead:       0,
-			itemsWritten:   0,
+			deltaItemsWritten:    0,
+			nonDeltaItemsRead:    8,
+			nonDeltaItemsWritten: 0, // unchanged items are not counted towards write
 		},
 		{
 			name: "move an email folder to a subfolder",
@@ -979,8 +988,10 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_incrementalExchange() {
 				newLoc := expectDeets.MoveLocation(cat.String(), from.locRef, to.locRef)
 				from.locRef = newLoc
 			},
-			itemsRead:    0, // zero because we don't count container reads
+			deltaItemsRead:       0, // zero because we don't count container reads
-			itemsWritten: 2,
+			deltaItemsWritten:    2,
+			nonDeltaItemsRead:    8,
+			nonDeltaItemsWritten: 2,
 		},
 		{
 			name: "delete a folder",
@@ -1003,8 +1014,10 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_incrementalExchange() {
 					expectDeets.RemoveLocation(category.String(), d.dests[container2].locRef)
 				}
 			},
-			itemsRead:    0,
+			deltaItemsRead:       0,
-			itemsWritten: 0, // deletions are not counted as "writes"
+			deltaItemsWritten:    0, // deletions are not counted as "writes"
+			nonDeltaItemsRead:    4,
+			nonDeltaItemsWritten: 0,
 		},
 		{
 			name: "add a new folder",
@@ -1053,8 +1066,10 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_incrementalExchange() {
 					}
 				}
 			},
-			itemsRead:    4,
+			deltaItemsRead:       4,
-			itemsWritten: 4,
+			deltaItemsWritten:    4,
+			nonDeltaItemsRead:    8,
+			nonDeltaItemsWritten: 4,
 		},
 		{
 			name: "rename a folder",
@@ -1111,10 +1126,12 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_incrementalExchange() {
 					}
 				}
 			},
-			itemsRead: 0, // containers are not counted as reads
+			deltaItemsRead: 0, // containers are not counted as reads
 			// Renaming a folder doesn't cause kopia changes as the folder ID doesn't
 			// change.
-			itemsWritten: 0,
+			deltaItemsWritten:    0, // two items per category
+			nonDeltaItemsRead:    8,
+			nonDeltaItemsWritten: 0,
 		},
 		{
 			name: "add a new item",
@@ -1165,8 +1182,10 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_incrementalExchange() {
 					}
 				}
 			},
-			itemsRead:    2,
+			deltaItemsRead:       2,
-			itemsWritten: 2,
+			deltaItemsWritten:    2,
+			nonDeltaItemsRead:    10,
+			nonDeltaItemsWritten: 2,
 		},
 		{
 			name: "delete an existing item",
@@ -1177,7 +1196,7 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_incrementalExchange() {
 
 					switch category {
 					case path.EmailCategory:
-						ids, _, _, err := ac.Mail().GetAddedAndRemovedItemIDs(ctx, uidn.ID(), containerID, "", false)
+						ids, _, _, err := ac.Mail().GetAddedAndRemovedItemIDs(ctx, uidn.ID(), containerID, "", false, true)
 						require.NoError(t, err, "getting message ids", clues.ToCore(err))
 						require.NotEmpty(t, ids, "message ids in folder")
 
@@ -1190,7 +1209,7 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_incrementalExchange() {
 							ids[0])
 
 					case path.ContactsCategory:
-						ids, _, _, err := ac.Contacts().GetAddedAndRemovedItemIDs(ctx, uidn.ID(), containerID, "", false)
+						ids, _, _, err := ac.Contacts().GetAddedAndRemovedItemIDs(ctx, uidn.ID(), containerID, "", false, true)
 						require.NoError(t, err, "getting contact ids", clues.ToCore(err))
 						require.NotEmpty(t, ids, "contact ids in folder")
 
@@ -1203,7 +1222,7 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_incrementalExchange() {
 							ids[0])
 
 					case path.EventsCategory:
-						ids, _, _, err := ac.Events().GetAddedAndRemovedItemIDs(ctx, uidn.ID(), containerID, "", false)
+						ids, _, _, err := ac.Events().GetAddedAndRemovedItemIDs(ctx, uidn.ID(), containerID, "", false, true)
 						require.NoError(t, err, "getting event ids", clues.ToCore(err))
 						require.NotEmpty(t, ids, "event ids in folder")
 
@@ -1217,16 +1236,19 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_incrementalExchange() {
 					}
 				}
 			},
-			itemsRead:    2,
+			deltaItemsRead:       2,
-			itemsWritten: 0, // deletes are not counted as "writes"
+			deltaItemsWritten:    0, // deletes are not counted as "writes"
+			nonDeltaItemsRead:    8,
+			nonDeltaItemsWritten: 0,
 		},
 	}
+
 	for _, test := range table {
 		suite.Run(test.name, func() {
 			var (
 				t     = suite.T()
 				incMB = evmock.NewBus()
-				incBO = newTestBackupOp(t, ctx, kw, ms, gc, acct, sels, incMB, ffs, closer)
+				incBO = newTestBackupOp(t, ctx, kw, ms, gc, acct, sels, incMB, toggles, closer)
 				atid  = m365.AzureTenantID
 			)
 
@@ -1243,8 +1265,14 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_incrementalExchange() {
 
 			// do some additional checks to ensure the incremental dealt with fewer items.
 			// +4 on read/writes to account for metadata: 1 delta and 1 path for each type.
-			assert.Equal(t, test.itemsWritten+4, incBO.Results.ItemsWritten, "incremental items written")
+			if !toggles.DisableDelta {
-			assert.Equal(t, test.itemsRead+4, incBO.Results.ItemsRead, "incremental items read")
+				assert.Equal(t, test.deltaItemsRead+4, incBO.Results.ItemsRead, "incremental items read")
+				assert.Equal(t, test.deltaItemsWritten+4, incBO.Results.ItemsWritten, "incremental items written")
+			} else {
+				assert.Equal(t, test.nonDeltaItemsRead+4, incBO.Results.ItemsRead, "non delta items read")
+				assert.Equal(t, test.nonDeltaItemsWritten+4, incBO.Results.ItemsWritten, "non delta items written")
+			}
+
 			assert.NoError(t, incBO.Errors.Failure(), "incremental non-recoverable error", clues.ToCore(incBO.Errors.Failure()))
 			assert.Empty(t, incBO.Errors.Recovered(), "incremental recoverable/iteration errors")
 			assert.Equal(t, 1, incMB.TimesCalled[events.BackupStart], "incremental backup-start events")

src/pkg/backup/details/details.go

@@ -626,11 +626,9 @@ const (
 func UpdateItem(item *ItemInfo, newLocPath *path.Builder) {
 	// Only OneDrive and SharePoint have information about parent folders
 	// contained in them.
-	var updatePath func(newLocPath *path.Builder)
-
 	// Can't switch based on infoType because that's been unstable.
 	if item.Exchange != nil {
-		updatePath = item.Exchange.UpdateParentPath
+		item.Exchange.UpdateParentPath(newLocPath)
 	} else if item.SharePoint != nil {
 		// SharePoint used to store library items with the OneDriveItem ItemType.
 		// Start switching them over as we see them since there's no point in
@@ -639,14 +637,10 @@ func UpdateItem(item *ItemInfo, newLocPath *path.Builder) {
 			item.SharePoint.ItemType = SharePointLibrary
 		}
 
-		updatePath = item.SharePoint.UpdateParentPath
+		item.SharePoint.UpdateParentPath(newLocPath)
 	} else if item.OneDrive != nil {
-		updatePath = item.OneDrive.UpdateParentPath
+		item.OneDrive.UpdateParentPath(newLocPath)
-	} else {
-		return
 	}
-
-	updatePath(newLocPath)
 }
 
 // ItemInfo is a oneOf that contains service specific

src/pkg/control/options.go

@@ -101,6 +101,14 @@ type Toggles struct {
 	// DisableIncrementals prevents backups from using incremental lookups,
 	// forcing a new, complete backup of all data regardless of prior state.
 	DisableIncrementals bool `json:"exchangeIncrementals,omitempty"`
+	// DisableDelta prevents backups from using delta based lookups,
+	// forcing a backup by enumerating all items. This is different
+	// from DisableIncrementals in that this does not even makes use of
+	// delta endpoints with or without a delta token. This is necessary
+	// when the user has filled up the mailbox storage available to the
+	// user as Microsoft prevents the API from being able to make calls
+	// to delta endpoints.
+	DisableDelta bool `json:"exchangeDelta,omitempty"`
 	// ExchangeImmutableIDs denotes whether Corso should store items with
 	// immutable Exchange IDs. This is only safe to set if the previous backup for
 	// incremental backups used immutable IDs or if a full backup is being done.

src/pkg/services/m365/api/users.go

@@ -58,6 +58,7 @@ type MailboxInfo struct {
 	Language                   Language
 	WorkingHours               WorkingHours
 	ErrGetMailBoxSetting       []error
+	QuotaExceeded              bool
 }
 
 type AutomaticRepliesSettings struct {
@@ -109,6 +110,12 @@ func (ui *UserInfo) ServiceEnabled(service path.ServiceType) bool {
 	return ok
 }
 
+// Returns if we can run delta queries on a mailbox. We cannot run
+// them if the mailbox is full which is indicated by QuotaExceeded.
+func (ui *UserInfo) CanMakeDeltaQueries() bool {
+	return !ui.Mailbox.QuotaExceeded
+}
+
 // ---------------------------------------------------------------------------
 // methods
 // ---------------------------------------------------------------------------
@@ -260,7 +267,8 @@ func (c Users) GetInfo(ctx context.Context, userID string) (*UserInfo, error) {
 		QueryParameters: &requestParameters,
 	}
 
-	if _, err := c.GetMailFolders(ctx, userID, options); err != nil {
+	mfs, err := c.GetMailFolders(ctx, userID, options)
+	if err != nil {
 		if graph.IsErrUserNotFound(err) {
 			logger.CtxErr(ctx, err).Error("user not found")
 			return nil, graph.Stack(ctx, clues.Stack(graph.ErrResourceOwnerNotFound, err))
@@ -295,6 +303,32 @@ func (c Users) GetInfo(ctx context.Context, userID string) (*UserInfo, error) {
 
 	userInfo.Mailbox = mbxInfo
 
+	// TODO: This tries to determine if the user has hit their mailbox
+	// limit by trying to fetch an item and seeing if we get the quota
+	// exceeded error. Ideally(if available) we should convert this to
+	// pull the user's usage via an api and compare if they have used
+	// up their quota.
+	if mfs != nil {
+		mf := mfs.GetValue()[0] // we will always have one
+		options := &users.ItemMailFoldersItemMessagesDeltaRequestBuilderGetRequestConfiguration{
+			QueryParameters: &users.ItemMailFoldersItemMessagesDeltaRequestBuilderGetQueryParameters{
+				Top: ptr.To[int32](1), // just one item is enough
+			},
+		}
+		_, err = c.stable.Client().
+			UsersById(userID).
+			MailFoldersById(ptr.Val(mf.GetId())).
+			Messages().
+			Delta().
+			Get(ctx, options)
+
+		if err != nil && !graph.IsErrQuotaExceeded(err) {
+			return nil, err
+		}
+
+		userInfo.Mailbox.QuotaExceeded = graph.IsErrQuotaExceeded(err)
+	}
+
 	return userInfo, nil
 }