Groups version bump (#4561)

Bump the backup version and force a full backup if
there's a backup for teams/groups that has base(s)
from an older version of corso

This will avoid propagating older details formats
forward. Those formats don't have all the data
newer formats do

This is mostly a stop-gap, a more robust solution
can be added later

Manually tested that it forces a full backup

---

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

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

#### Type of change

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

#### Issue(s)

* #4569

#### Test Plan

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

src/internal/kopia/backup_bases.go

@@ -46,6 +46,9 @@ type BackupBases interface {
 	// MinBackupVersion returns the lowest version of all merge backups in the
 	// BackupBases.
 	MinBackupVersion() int
+	// MinAssisttVersion returns the lowest version of all assist backups in the
+	// BackupBases.
+	MinAssistVersion() int
 	// MergeBackupBases takes another BackupBases and merges it's contained assist
 	// and merge bases into this BackupBases. The passed in BackupBases is
 	// considered an older alternative to this BackupBases meaning bases from
@@ -119,6 +122,22 @@ func (bb *backupBases) MinBackupVersion() int {
 	return min
 }
 
+func (bb *backupBases) MinAssistVersion() int {
+	min := version.NoBackup
+
+	if bb == nil {
+		return min
+	}
+
+	for _, base := range bb.assistBases {
+		if min == version.NoBackup || base.Backup.Version < min {
+			min = base.Backup.Version
+		}
+	}
+
+	return min
+}
+
 func (bb backupBases) MergeBases() []BackupBase {
 	return slices.Clone(bb.mergeBases)
 }

src/internal/kopia/backup_bases_test.go

@@ -92,20 +92,23 @@ func TestBackupBasesUnitSuite(t *testing.T) {
 	suite.Run(t, &BackupBasesUnitSuite{Suite: tester.NewUnitSuite(t)})
 }
 
-func (suite *BackupBasesUnitSuite) TestMinBackupVersion() {
+func (suite *BackupBasesUnitSuite) TestBackupBases_minVersions() {
 	table := []struct {
 		name                  string
 		bb                    *backupBases
-		expectedVersion int
+		expectedBackupVersion int
+		expectedAssistVersion int
 	}{
 		{
 			name:                  "Nil BackupBase",
-			expectedVersion: version.NoBackup,
+			expectedBackupVersion: version.NoBackup,
+			expectedAssistVersion: version.NoBackup,
 		},
 		{
 			name:                  "No Backups",
 			bb:                    &backupBases{},
-			expectedVersion: version.NoBackup,
+			expectedBackupVersion: version.NoBackup,
+			expectedAssistVersion: version.NoBackup,
 		},
 		{
 			name: "Unsorted Backups",
@@ -128,7 +131,8 @@ func (suite *BackupBasesUnitSuite) TestMinBackupVersion() {
 					},
 				},
 			},
-			expectedVersion: 0,
+			expectedBackupVersion: 0,
+			expectedAssistVersion: version.NoBackup,
 		},
 		{
 			name: "Only Assist Bases",
@@ -151,12 +155,97 @@ func (suite *BackupBasesUnitSuite) TestMinBackupVersion() {
 					},
 				},
 			},
-			expectedVersion: version.NoBackup,
+			expectedBackupVersion: version.NoBackup,
+			expectedAssistVersion: 0,
+		},
+		{
+			name: "Assist and Merge Bases, min merge",
+			bb: &backupBases{
+				mergeBases: []BackupBase{
+					{
+						Backup: &backup.Backup{
+							Version: 1,
+						},
+					},
+					{
+						Backup: &backup.Backup{
+							Version: 5,
+						},
+					},
+					{
+						Backup: &backup.Backup{
+							Version: 3,
+						},
+					},
+				},
+				assistBases: []BackupBase{
+					{
+						Backup: &backup.Backup{
+							Version: 4,
+						},
+					},
+					{
+						Backup: &backup.Backup{
+							Version: 2,
+						},
+					},
+					{
+						Backup: &backup.Backup{
+							Version: 6,
+						},
+					},
+				},
+			},
+			expectedBackupVersion: 1,
+			expectedAssistVersion: 2,
+		},
+		{
+			name: "Assist and Merge Bases, min assist",
+			bb: &backupBases{
+				mergeBases: []BackupBase{
+					{
+						Backup: &backup.Backup{
+							Version: 7,
+						},
+					},
+					{
+						Backup: &backup.Backup{
+							Version: 5,
+						},
+					},
+					{
+						Backup: &backup.Backup{
+							Version: 3,
+						},
+					},
+				},
+				assistBases: []BackupBase{
+					{
+						Backup: &backup.Backup{
+							Version: 4,
+						},
+					},
+					{
+						Backup: &backup.Backup{
+							Version: 2,
+						},
+					},
+					{
+						Backup: &backup.Backup{
+							Version: 6,
+						},
+					},
+				},
+			},
+			expectedBackupVersion: 3,
+			expectedAssistVersion: 2,
 		},
 	}
 	for _, test := range table {
 		suite.Run(test.name, func() {
-			assert.Equal(suite.T(), test.expectedVersion, test.bb.MinBackupVersion())
+			t := suite.T()
+			assert.Equal(t, test.expectedBackupVersion, test.bb.MinBackupVersion(), "backup")
+			assert.Equal(t, test.expectedAssistVersion, test.bb.MinAssistVersion(), "assist")
 		})
 	}
 }

src/internal/m365/onedrive_test.go

@@ -228,7 +228,7 @@ func (suite *SharePointIntegrationSuite) TestLinkSharesInheritanceRestoreAndBack
 
 func (suite *SharePointIntegrationSuite) TestRestoreFolderNamedFolderRegression() {
 	// No reason why it couldn't work with previous versions, but this is when it got introduced.
-	testRestoreFolderNamedFolderRegression(suite, version.All8MigrateUserPNToID)
+	testRestoreFolderNamedFolderRegression(suite, version.Backup)
 }
 
 // ---------------------------------------------------------------------------
@@ -292,7 +292,7 @@ func (suite *OneDriveIntegrationSuite) TestLinkSharesInheritanceRestoreAndBackup
 
 func (suite *OneDriveIntegrationSuite) TestRestoreFolderNamedFolderRegression() {
 	// No reason why it couldn't work with previous versions, but this is when it got introduced.
-	testRestoreFolderNamedFolderRegression(suite, version.All8MigrateUserPNToID)
+	testRestoreFolderNamedFolderRegression(suite, version.Backup)
 }
 
 // ---------------------------------------------------------------------------

src/internal/m365/service/onedrive/restore_test.go

@@ -24,7 +24,7 @@ func TestRestoreUnitSuite(t *testing.T) {
 func (suite *RestoreUnitSuite) TestAugmentRestorePaths() {
 	// Adding a simple test here so that we can be sure that this
 	// function gets updated whenever we add a new version.
-	require.LessOrEqual(suite.T(), version.Backup, version.All8MigrateUserPNToID, "unsupported backup version")
+	require.LessOrEqual(suite.T(), version.Backup, version.Groups9Update, "unsupported backup version")
 
 	table := []struct {
 		name    string
@@ -216,7 +216,7 @@ func (suite *RestoreUnitSuite) TestAugmentRestorePaths() {
 func (suite *RestoreUnitSuite) TestAugmentRestorePaths_DifferentRestorePath() {
 	// Adding a simple test here so that we can be sure that this
 	// function gets updated whenever we add a new version.
-	require.LessOrEqual(suite.T(), version.Backup, version.All8MigrateUserPNToID, "unsupported backup version")
+	require.LessOrEqual(suite.T(), version.Backup, version.Groups9Update, "unsupported backup version")
 
 	type pathPair struct {
 		storage string

src/internal/m365/service/onedrive/stub/stub.go

@@ -217,7 +217,8 @@ func (c *collection) withFile(name string, fileData []byte, meta MetaData) (*col
 		c.Aux = append(c.Aux, md)
 
 		// v6+ current metadata design
-	case version.OneDrive6NameInMeta, version.OneDrive7LocationRef, version.All8MigrateUserPNToID:
+	case version.OneDrive6NameInMeta, version.OneDrive7LocationRef,
+		version.All8MigrateUserPNToID, version.Groups9Update:
 		item, err := FileWithData(
 			name+metadata.DataFileSuffix,
 			name+metadata.DataFileSuffix,
@@ -251,7 +252,8 @@ func (c *collection) withFile(name string, fileData []byte, meta MetaData) (*col
 func (c *collection) withFolder(name string, meta MetaData) (*collection, error) {
 	switch c.BackupVersion {
 	case 0, version.OneDrive4DirIncludesPermissions, version.OneDrive5DirMetaNoName,
-		version.OneDrive6NameInMeta, version.OneDrive7LocationRef, version.All8MigrateUserPNToID:
+		version.OneDrive6NameInMeta, version.OneDrive7LocationRef,
+		version.All8MigrateUserPNToID, version.Groups9Update:
 		return c, nil
 
 	case version.OneDrive1DataAndMetaFiles, 2, version.OneDrive3IsMetaMarker:

src/internal/operations/backup.go

@@ -371,6 +371,34 @@ func (op *BackupOperation) do(
 		return nil, clues.Wrap(err, "producing manifests and metadata")
 	}
 
+	// Force full backups if the base is an older corso version. Those backups
+	// don't have all the data we want to pull forward.
+	//
+	// TODO(ashmrtn): We can push this check further down the stack to either:
+	//   * the metadata fetch code to disable individual bases (requires a
+	//     function to completely remove a base from the set)
+	//   * the base finder code to skip over older bases (breaks isolation a bit
+	//     by requiring knowledge of good/bad backup versions for different
+	//     services)
+	if op.Selectors.PathService() == path.GroupsService {
+		if mans.MinBackupVersion() != version.NoBackup &&
+			mans.MinBackupVersion() < version.Groups9Update {
+			logger.Ctx(ctx).Info("dropping merge bases due to groups version change")
+
+			mans.DisableMergeBases()
+			mans.DisableAssistBases()
+
+			canUseMetadata = false
+			mdColls = nil
+		}
+
+		if mans.MinAssistVersion() != version.NoBackup &&
+			mans.MinAssistVersion() < version.Groups9Update {
+			logger.Ctx(ctx).Info("disabling assist bases due to groups version change")
+			mans.DisableAssistBases()
+		}
+	}
+
 	ctx = clues.Add(
 		ctx,
 		"can_use_metadata", canUseMetadata,

src/internal/operations/pathtransformer/restore_path_transformer_test.go

@@ -61,6 +61,40 @@ func (suite *RestorePathTransformerUnitSuite) TestGetPaths() {
 		expectErr     assert.ErrorAssertionFunc
 		expected      []expectPaths
 	}{
+		{
+			name: "Groups List Errors v9",
+			// No version bump for the change so we always have to check for this.
+			backupVersion: version.Groups9Update,
+			input: []*details.Entry{
+				{
+					RepoRef:     GroupsRootItemPath.RR.String(),
+					LocationRef: GroupsRootItemPath.Loc.String(),
+					ItemInfo: details.ItemInfo{
+						Groups: &details.GroupsInfo{
+							ItemType: details.SharePointList,
+						},
+					},
+				},
+			},
+			expectErr: assert.Error,
+		},
+		{
+			name: "Groups Page Errors v9",
+			// No version bump for the change so we always have to check for this.
+			backupVersion: version.Groups9Update,
+			input: []*details.Entry{
+				{
+					RepoRef:     GroupsRootItemPath.RR.String(),
+					LocationRef: GroupsRootItemPath.Loc.String(),
+					ItemInfo: details.ItemInfo{
+						Groups: &details.GroupsInfo{
+							ItemType: details.SharePointPage,
+						},
+					},
+				},
+			},
+			expectErr: assert.Error,
+		},
 		{
 			name: "Groups List Errors",
 			// No version bump for the change so we always have to check for this.

src/internal/operations/test/exchange_test.go

@@ -231,6 +231,113 @@ func (suite *ExchangeBackupIntgSuite) TestBackup_Run_exchange() {
 	}
 }
 
+func (suite *ExchangeBackupIntgSuite) TestBackup_Run_exchangeBasic_groups9VersionBump() {
+	t := suite.T()
+
+	ctx, flush := tester.NewContext(t)
+	defer flush()
+
+	var (
+		mb   = evmock.NewBus()
+		sel  = selectors.NewExchangeBackup([]string{suite.its.user.ID})
+		opts = control.DefaultOptions()
+		ws   = deeTD.DriveIDFromRepoRef
+	)
+
+	sel.Include(
+		sel.ContactFolders([]string{api.DefaultContacts}, selectors.PrefixMatch()),
+		// sel.EventCalendars([]string{api.DefaultCalendar}, selectors.PrefixMatch()),
+		sel.MailFolders([]string{api.MailInbox}, selectors.PrefixMatch()))
+
+	bo, bod := prepNewTestBackupOp(
+		t,
+		ctx,
+		mb,
+		sel.Selector,
+		opts,
+		version.All8MigrateUserPNToID)
+	defer bod.close(t, ctx)
+
+	runAndCheckBackup(t, ctx, &bo, mb, false)
+	checkBackupIsInManifests(
+		t,
+		ctx,
+		bod.kw,
+		bod.sw,
+		&bo,
+		bod.sel,
+		bod.sel.ID(),
+		path.EmailCategory)
+
+	_, expectDeets := deeTD.GetDeetsInBackup(
+		t,
+		ctx,
+		bo.Results.BackupID,
+		bod.acct.ID(),
+		bod.sel.ID(),
+		path.ExchangeService,
+		ws,
+		bod.kms,
+		bod.sss)
+	deeTD.CheckBackupDetails(
+		t,
+		ctx,
+		bo.Results.BackupID,
+		ws,
+		bod.kms,
+		bod.sss,
+		expectDeets,
+		false)
+
+	mb = evmock.NewBus()
+	notForcedFull := newTestBackupOp(
+		t,
+		ctx,
+		bod,
+		mb,
+		opts)
+	notForcedFull.BackupVersion = version.Groups9Update
+
+	runAndCheckBackup(t, ctx, &notForcedFull, mb, false)
+	checkBackupIsInManifests(
+		t,
+		ctx,
+		bod.kw,
+		bod.sw,
+		&notForcedFull,
+		bod.sel,
+		bod.sel.ID(),
+		path.EmailCategory)
+
+	_, expectDeets = deeTD.GetDeetsInBackup(
+		t,
+		ctx,
+		notForcedFull.Results.BackupID,
+		bod.acct.ID(),
+		bod.sel.ID(),
+		path.ExchangeService,
+		ws,
+		bod.kms,
+		bod.sss)
+	deeTD.CheckBackupDetails(
+		t,
+		ctx,
+		notForcedFull.Results.BackupID,
+		ws,
+		bod.kms,
+		bod.sss,
+		expectDeets,
+		false)
+
+	// The number of items backed up in the second backup should be less than the
+	// number of items in the original backup.
+	assert.Greater(
+		t,
+		bo.Results.Counts[string(count.PersistedNonCachedFiles)],
+		notForcedFull.Results.Counts[string(count.PersistedNonCachedFiles)],
+		"items written")
+}
+
 func (suite *ExchangeBackupIntgSuite) TestBackup_Run_incrementalExchange() {
 	testExchangeContinuousBackups(suite, control.Toggles{})
 }

src/internal/operations/test/group_test.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"testing"
 
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/suite"
 
 	evmock "github.com/alcionai/corso/src/internal/events/mock"
@@ -13,6 +14,7 @@ import (
 	"github.com/alcionai/corso/src/internal/version"
 	deeTD "github.com/alcionai/corso/src/pkg/backup/details/testdata"
 	"github.com/alcionai/corso/src/pkg/control"
+	"github.com/alcionai/corso/src/pkg/count"
 	"github.com/alcionai/corso/src/pkg/path"
 	"github.com/alcionai/corso/src/pkg/selectors"
 	selTD "github.com/alcionai/corso/src/pkg/selectors/testdata"
@@ -78,6 +80,121 @@ func (suite *GroupsBackupIntgSuite) TestBackup_Run_incrementalGroups() {
 		true)
 }
 
+func (suite *GroupsBackupIntgSuite) TestBackup_Run_groupsBasic_groups9VersionBump() {
+	t := suite.T()
+
+	ctx, flush := tester.NewContext(t)
+	defer flush()
+
+	var (
+		mb      = evmock.NewBus()
+		sel     = selectors.NewGroupsBackup([]string{suite.its.group.ID})
+		opts    = control.DefaultOptions()
+		whatSet = deeTD.CategoryFromRepoRef
+	)
+
+	sel.Include(
+		selTD.GroupsBackupLibraryFolderScope(sel),
+		selTD.GroupsBackupChannelScope(sel))
+
+	bo, bod := prepNewTestBackupOp(
+		t,
+		ctx,
+		mb,
+		sel.Selector,
+		opts,
+		version.All8MigrateUserPNToID)
+	defer bod.close(t, ctx)
+
+	runAndCheckBackup(t, ctx, &bo, mb, false)
+	checkBackupIsInManifests(
+		t,
+		ctx,
+		bod.kw,
+		bod.sw,
+		&bo,
+		bod.sel,
+		bod.sel.ID(),
+		path.ChannelMessagesCategory)
+
+	_, expectDeets := deeTD.GetDeetsInBackup(
+		t,
+		ctx,
+		bo.Results.BackupID,
+		bod.acct.ID(),
+		bod.sel.ID(),
+		path.GroupsService,
+		whatSet,
+		bod.kms,
+		bod.sss)
+	deeTD.CheckBackupDetails(
+		t,
+		ctx,
+		bo.Results.BackupID,
+		whatSet,
+		bod.kms,
+		bod.sss,
+		expectDeets,
+		false)
+
+	mb = evmock.NewBus()
+	forcedFull := newTestBackupOp(
+		t,
+		ctx,
+		bod,
+		mb,
+		opts)
+	forcedFull.BackupVersion = version.Groups9Update
+
+	runAndCheckBackup(t, ctx, &forcedFull, mb, false)
+	checkBackupIsInManifests(
+		t,
+		ctx,
+		bod.kw,
+		bod.sw,
+		&forcedFull,
+		bod.sel,
+		bod.sel.ID(),
+		path.ChannelMessagesCategory)
+
+	_, expectDeets = deeTD.GetDeetsInBackup(
+		t,
+		ctx,
+		forcedFull.Results.BackupID,
+		bod.acct.ID(),
+		bod.sel.ID(),
+		path.GroupsService,
+		whatSet,
+		bod.kms,
+		bod.sss)
+	deeTD.CheckBackupDetails(
+		t,
+		ctx,
+		forcedFull.Results.BackupID,
+		whatSet,
+		bod.kms,
+		bod.sss,
+		expectDeets,
+		false)
+
+	// The number of items backed up in the forced full backup should be roughly
+	// the same as the number of items in the original backup.
+	assert.Equal(
+		t,
+		bo.Results.Counts[string(count.PersistedNonCachedFiles)],
+		forcedFull.Results.Counts[string(count.PersistedNonCachedFiles)],
+		"items written")
+}
+
+func (suite *GroupsBackupIntgSuite) TestBackup_Run_groupsVersion9AssistBases() {
+	sel := selectors.NewGroupsBackup([]string{suite.its.group.ID})
+	sel.Include(
+		selTD.GroupsBackupLibraryFolderScope(sel),
+		selTD.GroupsBackupChannelScope(sel))
+
+	runDriveAssistBaseGroupsUpdate(suite, sel.Selector, false)
+}
+
 func (suite *GroupsBackupIntgSuite) TestBackup_Run_groupsBasic() {
 	t := suite.T()
 

src/internal/operations/test/helper_test.go

@@ -169,6 +169,7 @@ func prepNewTestBackupOp(
 		bod,
 		bus,
 		opts)
+	bo.BackupVersion = backupVersion
 
 	bod.sss = streamstore.NewStreamer(
 		bod.kw,

src/internal/operations/test/onedrive_test.go

@@ -3,6 +3,8 @@ package test_test
 import (
 	"context"
 	"fmt"
+	"io"
+	"sync/atomic"
 	"testing"
 
 	"github.com/alcionai/clues"
@@ -36,6 +38,7 @@ import (
 	"github.com/alcionai/corso/src/pkg/control"
 	ctrlTD "github.com/alcionai/corso/src/pkg/control/testdata"
 	"github.com/alcionai/corso/src/pkg/count"
+	"github.com/alcionai/corso/src/pkg/extensions"
 	"github.com/alcionai/corso/src/pkg/fault"
 	"github.com/alcionai/corso/src/pkg/path"
 	"github.com/alcionai/corso/src/pkg/selectors"
@@ -107,6 +110,118 @@ func (suite *OneDriveBackupIntgSuite) TestBackup_Run_oneDrive() {
 		false)
 }
 
+func (suite *OneDriveBackupIntgSuite) TestBackup_Run_oneDriveBasic_groups9VersionBump() {
+	t := suite.T()
+
+	ctx, flush := tester.NewContext(t)
+	defer flush()
+
+	var (
+		mb     = evmock.NewBus()
+		userID = tconfig.SecondaryM365UserID(t)
+		osel   = selectors.NewOneDriveBackup([]string{userID})
+		ws     = deeTD.DriveIDFromRepoRef
+		opts   = control.DefaultOptions()
+	)
+
+	osel.Include(selTD.OneDriveBackupFolderScope(osel))
+
+	bo, bod := prepNewTestBackupOp(
+		t,
+		ctx,
+		mb,
+		osel.Selector,
+		opts,
+		version.All8MigrateUserPNToID)
+	defer bod.close(t, ctx)
+
+	runAndCheckBackup(t, ctx, &bo, mb, false)
+	checkBackupIsInManifests(
+		t,
+		ctx,
+		bod.kw,
+		bod.sw,
+		&bo,
+		bod.sel,
+		bod.sel.ID(),
+		path.FilesCategory)
+
+	_, expectDeets := deeTD.GetDeetsInBackup(
+		t,
+		ctx,
+		bo.Results.BackupID,
+		bod.acct.ID(),
+		bod.sel.ID(),
+		path.OneDriveService,
+		ws,
+		bod.kms,
+		bod.sss)
+	deeTD.CheckBackupDetails(
+		t,
+		ctx,
+		bo.Results.BackupID,
+		ws,
+		bod.kms,
+		bod.sss,
+		expectDeets,
+		false)
+
+	mb = evmock.NewBus()
+	notForcedFull := newTestBackupOp(
+		t,
+		ctx,
+		bod,
+		mb,
+		opts)
+	notForcedFull.BackupVersion = version.Groups9Update
+
+	runAndCheckBackup(t, ctx, &notForcedFull, mb, false)
+	checkBackupIsInManifests(
+		t,
+		ctx,
+		bod.kw,
+		bod.sw,
+		&notForcedFull,
+		bod.sel,
+		bod.sel.ID(),
+		path.FilesCategory)
+
+	_, expectDeets = deeTD.GetDeetsInBackup(
+		t,
+		ctx,
+		notForcedFull.Results.BackupID,
+		bod.acct.ID(),
+		bod.sel.ID(),
+		path.OneDriveService,
+		ws,
+		bod.kms,
+		bod.sss)
+	deeTD.CheckBackupDetails(
+		t,
+		ctx,
+		notForcedFull.Results.BackupID,
+		ws,
+		bod.kms,
+		bod.sss,
+		expectDeets,
+		false)
+
+	// The number of items backed up in the second backup should be less than the
+	// number of items in the original backup.
+	assert.Greater(
+		t,
+		bo.Results.Counts[string(count.PersistedNonCachedFiles)],
+		notForcedFull.Results.Counts[string(count.PersistedNonCachedFiles)],
+		"items written")
+}
+
+//func (suite *OneDriveBackupIntgSuite) TestBackup_Run_oneDriveVersion9AssistBases() {
+//	sel := selectors.NewOneDriveBackup([]string{tconfig.SecondaryM365UserID(suite.T())})
+//	sel.Include(selTD.OneDriveBackupFolderScope(sel))
+//
+//	runDriveAssistBaseGroupsUpdate(suite, sel.Selector, true)
+//}
+
 func (suite *OneDriveBackupIntgSuite) TestBackup_Run_incrementalOneDrive() {
 	sel := selectors.NewOneDriveRestore([]string{suite.its.user.ID})
 
@@ -806,6 +921,179 @@ func runDriveIncrementalTest(
 	}
 }
 
+var (
+	_ io.ReadCloser                    = &failFirstRead{}
+	_ extensions.CreateItemExtensioner = &createFailFirstRead{}
+)
+
+// failFirstRead fails the first read on a file being uploaded during a
+// snapshot. Only one file is failed during the snapshot even if it the snapshot
+// contains multiple files.
+type failFirstRead struct {
+	firstFile *atomic.Bool
+	io.ReadCloser
+}
+
+func (e *failFirstRead) Read(p []byte) (int, error) {
+	if e.firstFile.CompareAndSwap(true, false) {
+		// This is the first file being read, return an error for it.
+		return 0, clues.New("injected error for testing")
+	}
+
+	return e.ReadCloser.Read(p)
+}
+
+func newCreateSingleFileFailExtension() *createFailFirstRead {
+	firstItem := &atomic.Bool{}
+	firstItem.Store(true)
+
+	return &createFailFirstRead{
+		firstItem: firstItem,
+	}
+}
+
+type createFailFirstRead struct {
+	firstItem *atomic.Bool
+}
+
+func (ce *createFailFirstRead) CreateItemExtension(
+	_ context.Context,
+	r io.ReadCloser,
+	_ details.ItemInfo,
+	_ *details.ExtensionData,
+) (io.ReadCloser, error) {
+	return &failFirstRead{
+		firstFile:  ce.firstItem,
+		ReadCloser: r,
+	}, nil
+}
+
+func runDriveAssistBaseGroupsUpdate(
+	suite tester.Suite,
+	sel selectors.Selector,
+	expectCached bool,
+) {
+	t := suite.T()
+
+	ctx, flush := tester.NewContext(t)
+	defer flush()
+
+	var (
+		whatSet = deeTD.CategoryFromRepoRef
+		mb      = evmock.NewBus()
+		opts    = control.DefaultOptions()
+	)
+
+	opts.ItemExtensionFactory = []extensions.CreateItemExtensioner{
+		newCreateSingleFileFailExtension(),
+	}
+
+	// Creating out here so bod lasts for full test and isn't closed until the
+	// test is compltely done.
+	bo, bod := prepNewTestBackupOp(
+		t,
+		ctx,
+		mb,
+		sel,
+		opts,
+		version.All8MigrateUserPNToID)
+	defer bod.close(t, ctx)
+
+	suite.Run("makeAssistBackup", func() {
+		t := suite.T()
+
+		ctx, flush := tester.NewContext(t)
+		defer flush()
+
+		// Need to run manually cause runAndCheckBackup assumes success for the most
+		// part.
+		err := bo.Run(ctx)
+		assert.Error(t, err, clues.ToCore(err))
+		assert.NotEmpty(t, bo.Results, "backup had non-zero results")
+		assert.NotEmpty(t, bo.Results.BackupID, "backup generated an ID")
+		assert.NotZero(t, bo.Results.ItemsWritten)
+
+		// TODO(ashmrtn): Check that the base is marked as an assist base.
+		t.Logf("base error: %v\n", err)
+	})
+
+	// Don't run the below if we've already failed since it won't make sense
+	// anymore.
+	if suite.T().Failed() {
+		return
+	}
+
+	suite.Run("makeIncrementalBackup", func() {
+		t := suite.T()
+
+		ctx, flush := tester.NewContext(t)
+		defer flush()
+
+		var (
+			mb   = evmock.NewBus()
+			opts = control.DefaultOptions()
+		)
+
+		forcedFull := newTestBackupOp(
+			t,
+			ctx,
+			bod,
+			mb,
+			opts)
+		forcedFull.BackupVersion = version.Groups9Update
+
+		runAndCheckBackup(t, ctx, &forcedFull, mb, false)
+
+		reasons, err := bod.sel.Reasons(bod.acct.ID(), false)
+		require.NoError(t, err, clues.ToCore(err))
+
+		for _, reason := range reasons {
+			checkBackupIsInManifests(
+				t,
+				ctx,
+				bod.kw,
+				bod.sw,
+				&forcedFull,
+				bod.sel,
+				bod.sel.ID(),
+				reason.Category())
+		}
+
+		_, expectDeets := deeTD.GetDeetsInBackup(
+			t,
+			ctx,
+			forcedFull.Results.BackupID,
+			bod.acct.ID(),
+			bod.sel.ID(),
+			bod.sel.PathService(),
+			whatSet,
+			bod.kms,
+			bod.sss)
+		deeTD.CheckBackupDetails(
+			t,
+			ctx,
+			forcedFull.Results.BackupID,
+			whatSet,
+			bod.kms,
+			bod.sss,
+			expectDeets,
+			false)
+
+		// For groups the forced full backup shouldn't have any cached items. For
+		// OneDrive and SharePoint it should since they shouldn't be forcing full
+		// backups.
+		cachedCheck := assert.NotZero
+		if !expectCached {
+			cachedCheck = assert.Zero
+		}
+
+		cachedCheck(
+			t,
+			forcedFull.Results.Counts[string(count.PersistedCachedFiles)],
+			"kopia cached items")
+	})
+}
+
 func (suite *OneDriveBackupIntgSuite) TestBackup_Run_oneDriveOwnerMigration() {
 	t := suite.T()
 

src/internal/operations/test/sharepoint_test.go

@@ -46,6 +46,117 @@ func (suite *SharePointBackupIntgSuite) SetupSuite() {
 	suite.its = newIntegrationTesterSetup(suite.T())
 }
 
+func (suite *SharePointBackupIntgSuite) TestBackup_Run_sharePointBasic_groups9VersionBump() {
+	t := suite.T()
+
+	ctx, flush := tester.NewContext(t)
+	defer flush()
+
+	var (
+		mb   = evmock.NewBus()
+		sel  = selectors.NewSharePointBackup([]string{suite.its.site.ID})
+		opts = control.DefaultOptions()
+		ws   = deeTD.DriveIDFromRepoRef
+	)
+
+	sel.Include(selTD.SharePointBackupFolderScope(sel))
+
+	bo, bod := prepNewTestBackupOp(
+		t,
+		ctx,
+		mb,
+		sel.Selector,
+		opts,
+		version.All8MigrateUserPNToID)
+	defer bod.close(t, ctx)
+
+	runAndCheckBackup(t, ctx, &bo, mb, false)
+	checkBackupIsInManifests(
+		t,
+		ctx,
+		bod.kw,
+		bod.sw,
+		&bo,
+		bod.sel,
+		bod.sel.ID(),
+		path.LibrariesCategory)
+
+	_, expectDeets := deeTD.GetDeetsInBackup(
+		t,
+		ctx,
+		bo.Results.BackupID,
+		bod.acct.ID(),
+		bod.sel.ID(),
+		path.SharePointService,
+		ws,
+		bod.kms,
+		bod.sss)
+	deeTD.CheckBackupDetails(
+		t,
+		ctx,
+		bo.Results.BackupID,
+		ws,
+		bod.kms,
+		bod.sss,
+		expectDeets,
+		false)
+
+	mb = evmock.NewBus()
+	notForcedFull := newTestBackupOp(
+		t,
+		ctx,
+		bod,
+		mb,
+		opts)
+	notForcedFull.BackupVersion = version.Groups9Update
+
+	runAndCheckBackup(t, ctx, &notForcedFull, mb, false)
+	checkBackupIsInManifests(
+		t,
+		ctx,
+		bod.kw,
+		bod.sw,
+		&notForcedFull,
+		bod.sel,
+		bod.sel.ID(),
+		path.LibrariesCategory)
+
+	_, expectDeets = deeTD.GetDeetsInBackup(
+		t,
+		ctx,
+		notForcedFull.Results.BackupID,
+		bod.acct.ID(),
+		bod.sel.ID(),
+		path.SharePointService,
+		ws,
+		bod.kms,
+		bod.sss)
+	deeTD.CheckBackupDetails(
+		t,
+		ctx,
+		notForcedFull.Results.BackupID,
+		ws,
+		bod.kms,
+		bod.sss,
+		expectDeets,
+		false)
+
+	// The number of items backed up in the second backup should be less than the
+	// number of items in the original backup.
+	assert.Greater(
+		t,
+		bo.Results.Counts[string(count.PersistedNonCachedFiles)],
+		notForcedFull.Results.Counts[string(count.PersistedNonCachedFiles)],
+		"items written")
+}
+
+func (suite *SharePointBackupIntgSuite) TestBackup_Run_sharePointVersion9AssistBases() {
+	sel := selectors.NewSharePointBackup([]string{suite.its.site.ID})
+	sel.Include(selTD.SharePointBackupFolderScope(sel))
+
+	runDriveAssistBaseGroupsUpdate(suite, sel.Selector, true)
+}
+
 func (suite *SharePointBackupIntgSuite) TestBackup_Run_incrementalSharePoint() {
 	sel := selectors.NewSharePointRestore([]string{suite.its.site.ID})
 

src/internal/version/backup.go

@@ -1,6 +1,6 @@
 package version
 
-const Backup = 8
+const Backup = Groups9Update
 
 // Various labels to refer to important version changes.
 // Labels don't need 1:1 service:version representation.  Add a new
@@ -46,6 +46,10 @@ const (
 	// All8MigrateUserPNToID marks when we migrated repo refs from the user's
 	// PrincipalName to their ID for stability.
 	All8MigrateUserPNToID = 8
+
+	// Groups9Update marks when we updated the details that groups and teams use.
+	// Older backups don't contain all the info we want in details.
+	Groups9Update = 9
 )
 
 // IsNoBackup returns true if the version implies that no prior backup exists.