add non-delta message paging path (#4229)

similar to exchange, there are conditions under
which channel messages are unable to use the
delta api.  In particular, when the channel has no valid email property.  This change ensures that
we enumerate the entire channel under those
conditions, instead of failing out.

Technically, the only situation we know of where
the email property is missing, and thus the channel cannot make delta queries, is when there are
zero messages in the channel already.  However,
there may be unknown cases that we haven't caught, so instead of skipping the channel we're going to
handle non-delta enumeration for future safeguarding.

---

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

- [x] ⛔ No

#### Type of change

- [x] 🐛 Bugfix

#### Issue(s)

* #3989 

#### Test Plan

- [x] ⚡ Unit test
- [x] 💚 E2E

src/internal/common/str/str.go

@@ -80,3 +80,13 @@ func Preview(s string, size int) string {
 
 	return ss
 }
+
+func SliceToMap(ss []string) map[string]struct{} {
+	m := map[string]struct{}{}
+
+	for _, s := range ss {
+		m[s] = struct{}{}
+	}
+
+	return m
+}

src/internal/m365/collection/groups/backup.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/alcionai/corso/src/internal/common/pii"
 	"github.com/alcionai/corso/src/internal/common/ptr"
+	"github.com/alcionai/corso/src/internal/common/str"
 	"github.com/alcionai/corso/src/internal/data"
 	"github.com/alcionai/corso/src/internal/m365/graph"
 	"github.com/alcionai/corso/src/internal/m365/support"
@@ -154,12 +155,19 @@ func populateCollections(
 
 		ictx = clues.Add(ictx, "previous_path", prevPath)
 
-		added, removed, du, err := bh.getChannelMessageIDsDelta(ctx, cID, prevDelta)
+		// if the channel has no email property, it is unable to process delta tokens
+		// and will return an error if a delta token is queried.
+		canMakeDeltaQueries := len(ptr.Val(c.GetEmail())) > 0
+
+		add, rem, du, err := bh.getChannelMessageIDs(ctx, cID, prevDelta, canMakeDeltaQueries)
 		if err != nil {
 			el.AddRecoverable(ctx, clues.Stack(err))
 			continue
 		}
 
+		added := str.SliceToMap(add)
+		removed := str.SliceToMap(rem)
+
 		if len(du.URL) > 0 {
 			deltaURLs[cID] = du.URL
 		} else if !du.Reset {

src/internal/m365/collection/groups/backup_test.go

@@ -40,8 +40,8 @@ var _ backupHandler = &mockBackupHandler{}
 type mockBackupHandler struct {
 	channels      []models.Channelable
 	channelsErr   error
-	messageIDs    map[string]struct{}
-	deletedMsgIDs map[string]struct{}
+	messageIDs    []string
+	deletedMsgIDs []string
 	messagesErr   error
 	messages      map[string]models.ChatMessageable
 	info          map[string]*details.GroupsInfo
@@ -53,10 +53,11 @@ func (bh mockBackupHandler) getChannels(context.Context) ([]models.Channelable,
 	return bh.channels, bh.channelsErr
 }
 
-func (bh mockBackupHandler) getChannelMessageIDsDelta(
+func (bh mockBackupHandler) getChannelMessageIDs(
 	_ context.Context,
 	_, _ string,
-) (map[string]struct{}, map[string]struct{}, api.DeltaUpdate, error) {
+	_ bool,
+) ([]string, []string, api.DeltaUpdate, error) {
 	return bh.messageIDs, bh.deletedMsgIDs, api.DeltaUpdate{}, bh.messagesErr
 }
 
@@ -131,7 +132,7 @@ func (suite *BackupUnitSuite) TestPopulateCollections() {
 			name: "happy path, one container",
 			mock: mockBackupHandler{
 				channels:   testdata.StubChannels("one"),
-				messageIDs: map[string]struct{}{"msg-one": {}},
+				messageIDs: []string{"msg-one"},
 			},
 			expectErr:           require.NoError,
 			expectColls:         2,
@@ -142,7 +143,7 @@ func (suite *BackupUnitSuite) TestPopulateCollections() {
 			name: "happy path, one container, only deleted messages",
 			mock: mockBackupHandler{
 				channels:      testdata.StubChannels("one"),
-				deletedMsgIDs: map[string]struct{}{"msg-one": {}},
+				deletedMsgIDs: []string{"msg-one"},
 			},
 			expectErr:           require.NoError,
 			expectColls:         2,
@@ -153,7 +154,7 @@ func (suite *BackupUnitSuite) TestPopulateCollections() {
 			name: "happy path, many containers",
 			mock: mockBackupHandler{
 				channels:   testdata.StubChannels("one", "two"),
-				messageIDs: map[string]struct{}{"msg-one": {}},
+				messageIDs: []string{"msg-one"},
 			},
 			expectErr:           require.NoError,
 			expectColls:         3,
@@ -291,7 +292,7 @@ func (suite *BackupUnitSuite) TestPopulateCollections_incremental() {
 			name: "non incremental",
 			mock: mockBackupHandler{
 				channels:   testdata.StubChannels("chan"),
-				messageIDs: map[string]struct{}{"msg": {}},
+				messageIDs: []string{"msg"},
 			},
 			deltaPaths:          metadata.DeltaPaths{},
 			expectErr:           require.NoError,
@@ -304,7 +305,7 @@ func (suite *BackupUnitSuite) TestPopulateCollections_incremental() {
 			name: "incremental",
 			mock: mockBackupHandler{
 				channels:      testdata.StubChannels("chan"),
-				deletedMsgIDs: map[string]struct{}{"msg": {}},
+				deletedMsgIDs: []string{"msg"},
 			},
 			deltaPaths: metadata.DeltaPaths{
 				"chan": {
@@ -356,7 +357,7 @@ func (suite *BackupUnitSuite) TestPopulateCollections_incremental() {
 			name: "incremental new and deleted channel",
 			mock: mockBackupHandler{
 				channels:   testdata.StubChannels("chan2"),
-				messageIDs: map[string]struct{}{"msg": {}},
+				messageIDs: []string{"msg"},
 			},
 			deltaPaths: metadata.DeltaPaths{
 				"chan": {

src/internal/m365/collection/groups/channel_handler.go

@@ -36,11 +36,12 @@ func (bh channelsBackupHandler) getChannels(
 	return bh.ac.GetChannels(ctx, bh.protectedResource)
 }
 
-func (bh channelsBackupHandler) getChannelMessageIDsDelta(
+func (bh channelsBackupHandler) getChannelMessageIDs(
 	ctx context.Context,
 	channelID, prevDelta string,
-) (map[string]struct{}, map[string]struct{}, api.DeltaUpdate, error) {
-	return bh.ac.GetChannelMessageIDsDelta(ctx, bh.protectedResource, channelID, prevDelta)
+	canMakeDeltaQueries bool,
+) ([]string, []string, api.DeltaUpdate, error) {
+	return bh.ac.GetChannelMessageIDs(ctx, bh.protectedResource, channelID, prevDelta, canMakeDeltaQueries)
 }
 
 func (bh channelsBackupHandler) includeContainer(

src/internal/m365/collection/groups/handlers.go

@@ -20,11 +20,12 @@ type backupHandler interface {
 		ctx context.Context,
 	) ([]models.Channelable, error)
 
-	// gets all message IDs by delta in the channel
-	getChannelMessageIDsDelta(
+	// gets all message IDs (by delta, if possible) in the channel
+	getChannelMessageIDs(
 		ctx context.Context,
 		channelID, prevDelta string,
-	) (map[string]struct{}, map[string]struct{}, api.DeltaUpdate, error)
+		canMakeDeltaQueries bool,
+	) ([]string, []string, api.DeltaUpdate, error)
 
 	// includeContainer evaluates whether the channel is included
 	// in the provided scope.

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

@@ -3,18 +3,72 @@ package api
 import (
 	"context"
 
+	"github.com/alcionai/clues"
 	"github.com/microsoftgraph/msgraph-sdk-go/models"
 	"github.com/microsoftgraph/msgraph-sdk-go/teams"
 
 	"github.com/alcionai/corso/src/internal/common/ptr"
 	"github.com/alcionai/corso/src/internal/m365/graph"
-	"github.com/alcionai/corso/src/pkg/logger"
 )
 
 // ---------------------------------------------------------------------------
 // channel message pager
 // ---------------------------------------------------------------------------
 
+var _ Pager[models.ChatMessageable] = &channelMessagePageCtrl{}
+
+type channelMessagePageCtrl struct {
+	resourceID, channelID string
+	gs                    graph.Servicer
+	builder               *teams.ItemChannelsItemMessagesRequestBuilder
+	options               *teams.ItemChannelsItemMessagesRequestBuilderGetRequestConfiguration
+}
+
+func (p *channelMessagePageCtrl) SetNextLink(nextLink string) {
+	p.builder = teams.NewItemChannelsItemMessagesRequestBuilder(nextLink, p.gs.Adapter())
+}
+
+func (p *channelMessagePageCtrl) GetPage(
+	ctx context.Context,
+) (NextLinkValuer[models.ChatMessageable], error) {
+	resp, err := p.builder.Get(ctx, p.options)
+	return resp, graph.Stack(ctx, err).OrNil()
+}
+
+func (c Channels) NewChannelMessagePager(
+	teamID, channelID string,
+	selectProps ...string,
+) *channelMessagePageCtrl {
+	builder := c.Stable.
+		Client().
+		Teams().
+		ByTeamIdString(teamID).
+		Channels().
+		ByChannelIdString(channelID).
+		Messages()
+
+	options := &teams.ItemChannelsItemMessagesRequestBuilderGetRequestConfiguration{
+		QueryParameters: &teams.ItemChannelsItemMessagesRequestBuilderGetQueryParameters{},
+		Headers:         newPreferHeaders(preferPageSize(maxNonDeltaPageSize)),
+	}
+
+	if len(selectProps) > 0 {
+		options.QueryParameters.Select = selectProps
+	}
+
+	return &channelMessagePageCtrl{
+		resourceID: teamID,
+		channelID:  channelID,
+		builder:    builder,
+		gs:         c.Stable,
+		options:    options,
+	}
+}
+
+// ---------------------------------------------------------------------------
+// channel message delta pager
+// ---------------------------------------------------------------------------
+
 var _ DeltaPager[models.ChatMessageable] = &channelMessageDeltaPageCtrl{}
 
 type channelMessageDeltaPageCtrl struct {
@@ -65,7 +119,7 @@ func (c Channels) NewChannelMessageDeltaPager(
 
 	options := &teams.ItemChannelsItemMessagesDeltaRequestBuilderGetRequestConfiguration{
 		QueryParameters: &teams.ItemChannelsItemMessagesDeltaRequestBuilderGetQueryParameters{},
-		Headers:         newPreferHeaders(preferPageSize(maxNonDeltaPageSize)),
+		Headers:         newPreferHeaders(preferPageSize(maxDeltaPageSize)),
 	}
 
 	if len(selectProps) > 0 {
@@ -83,44 +137,20 @@ func (c Channels) NewChannelMessageDeltaPager(
 
 // GetChannelMessageIDsDelta fetches a delta of all messages in the channel.
 // returns two maps: addedItems, deletedItems
-func (c Channels) GetChannelMessageIDsDelta(
+func (c Channels) GetChannelMessageIDs(
 	ctx context.Context,
-	teamID, channelID, prevDelta string,
-) (map[string]struct{}, map[string]struct{}, DeltaUpdate, error) {
-	var (
-		added   = map[string]struct{}{}
-		deleted = map[string]struct{}{}
-		// select is not currently allowed on messages
-		// this func will still isolate to the ID, however,
-		// because we need the follow-up get request to gather
-		// all replies to the message.
-		// selectProps      = idAnd()
-		pager = c.NewChannelMessageDeltaPager(teamID, channelID, prevDelta)
-	)
+	teamID, channelID, prevDeltaLink string,
+	canMakeDeltaQueries bool,
+) ([]string, []string, DeltaUpdate, error) {
+	added, removed, du, err := getAddedAndRemovedItemIDs(
+		ctx,
+		c.NewChannelMessagePager(teamID, channelID),
+		c.NewChannelMessageDeltaPager(teamID, channelID, prevDeltaLink),
+		prevDeltaLink,
+		canMakeDeltaQueries,
+		addedAndRemovedByDeletedDateTime)
 
-	results, du, err := deltaEnumerateItems[models.ChatMessageable](ctx, pager, prevDelta)
-	if graph.IsErrInvalidDelta(err) {
-		logger.Ctx(ctx).Infow("delta token not supported", "delta_link", prevDelta)
-
-		added = map[string]struct{}{}
-		deleted = map[string]struct{}{}
-
-		return added, deleted, du, nil
-	}
-
-	if err != nil {
-		return nil, nil, DeltaUpdate{}, graph.Wrap(ctx, err, "extracting channel messages from response")
-	}
-
-	for _, r := range results {
-		if r.GetAdditionalData()[graph.AddtlDataRemoved] == nil {
-			added[ptr.Val(r.GetId())] = struct{}{}
-		} else {
-			deleted[ptr.Val(r.GetId())] = struct{}{}
-		}
-	}
-
-	return added, deleted, du, nil
+	return added, removed, du, clues.Stack(err).OrNil()
 }
 
 // ---------------------------------------------------------------------------

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

@@ -56,28 +56,30 @@ func (suite *ChannelsPagerIntgSuite) TestEnumerateChannelMessages() {
 	ctx, flush := tester.NewContext(t)
 	defer flush()
 
-	addedIDs, _, du, err := ac.GetChannelMessageIDsDelta(
+	addedIDs, _, du, err := ac.GetChannelMessageIDs(
 		ctx,
 		suite.its.group.id,
 		suite.its.group.testContainerID,
-		"")
+		"",
+		true)
 	require.NoError(t, err, clues.ToCore(err))
 	require.NotEmpty(t, addedIDs)
 	require.NotZero(t, du.URL, "delta link")
 	require.True(t, du.Reset, "reset due to empty prev delta link")
 
-	addedIDs, deletedIDs, du, err := ac.GetChannelMessageIDsDelta(
+	addedIDs, deletedIDs, du, err := ac.GetChannelMessageIDs(
 		ctx,
 		suite.its.group.id,
 		suite.its.group.testContainerID,
-		du.URL)
+		du.URL,
+		true)
 	require.NoError(t, err, clues.ToCore(err))
 	require.Empty(t, addedIDs, "should have no new messages from delta")
 	require.Empty(t, deletedIDs, "should have no deleted messages from delta")
 	require.NotZero(t, du.URL, "delta link")
 	require.False(t, du.Reset, "prev delta link should be valid")
 
-	for id := range addedIDs {
+	for _, id := range addedIDs {
 		suite.Run(id+"-replies", func() {
 			testEnumerateChannelMessageReplies(
 				suite.T(),

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

@@ -278,5 +278,6 @@ func (c Contacts) GetAddedAndRemovedItemIDs(
 		pager,
 		deltaPager,
 		prevDeltaLink,
-		canMakeDeltaQueries)
+		canMakeDeltaQueries,
+		addedAndRemovedByAddtlData)
 }

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

@@ -277,5 +277,6 @@ func (c Events) GetAddedAndRemovedItemIDs(
 		pager,
 		deltaPager,
 		prevDeltaLink,
-		canMakeDeltaQueries)
+		canMakeDeltaQueries,
+		addedAndRemovedByAddtlData)
 }

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

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"strings"
+	"time"
 
 	"github.com/alcionai/clues"
 
@@ -172,12 +173,15 @@ func deltaEnumerateItems[T any](
 // shared enumeration runner funcs
 // ---------------------------------------------------------------------------
 
+type addedAndRemovedHandler[T any] func(items []T) ([]string, []string, error)
+
 func getAddedAndRemovedItemIDs[T any](
 	ctx context.Context,
 	pager Pager[T],
 	deltaPager DeltaPager[T],
 	prevDeltaLink string,
 	canMakeDeltaQueries bool,
+	aarh addedAndRemovedHandler[T],
 ) ([]string, []string, DeltaUpdate, error) {
 	if canMakeDeltaQueries {
 		ts, du, err := deltaEnumerateItems[T](ctx, deltaPager, prevDeltaLink)
@@ -186,7 +190,7 @@ func getAddedAndRemovedItemIDs[T any](
 		}
 
 		if err == nil {
-			a, r, err := addedAndRemovedByAddtlData(ts)
+			a, r, err := aarh(ts)
 			return a, r, du, graph.Stack(ctx, err).OrNil()
 		}
 	}
@@ -198,13 +202,19 @@ func getAddedAndRemovedItemIDs[T any](
 		return nil, nil, DeltaUpdate{}, graph.Stack(ctx, err)
 	}
 
-	a, r, err := addedAndRemovedByAddtlData[T](ts)
+	a, r, err := aarh(ts)
 
 	return a, r, du, graph.Stack(ctx, err).OrNil()
 }
 
-type getIDAndAddtler interface {
+type getIDer interface {
 	GetId() *string
+}
+
+// for added and removed by additionalData[@removed]
+
+type getIDAndAddtler interface {
+	getIDer
 	GetAdditionalData() map[string]any
 }
 
@@ -230,3 +240,30 @@ func addedAndRemovedByAddtlData[T any](items []T) ([]string, []string, error) {
 
 	return added, removed, nil
 }
+
+// for added and removed by GetDeletedDateTime()
+
+type getIDAndDeletedDateTimer interface {
+	getIDer
+	GetDeletedDateTime() *time.Time
+}
+
+func addedAndRemovedByDeletedDateTime[T any](items []T) ([]string, []string, error) {
+	added, removed := []string{}, []string{}
+
+	for _, item := range items {
+		giaddt, ok := any(item).(getIDAndDeletedDateTimer)
+		if !ok {
+			return nil, nil, clues.New("item does not provide id and deleted date time getters").
+				With("item_type", fmt.Sprintf("%T", item))
+		}
+
+		if giaddt.GetDeletedDateTime() == nil {
+			added = append(added, ptr.Val(giaddt.GetId()))
+		} else {
+			removed = append(removed, ptr.Val(giaddt.GetId()))
+		}
+	}
+
+	return added, removed, nil
+}

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

@@ -363,7 +363,8 @@ func (suite *PagerUnitSuite) TestGetAddedAndRemovedItemIDs() {
 				test.pagerGetter(t),
 				test.deltaPagerGetter(t),
 				test.prevDelta,
-				test.canDelta)
+				test.canDelta,
+				addedAndRemovedByAddtlData)
 
 			require.NoErrorf(t, err, "getting added and removed item IDs: %+v", clues.ToCore(err))
 			require.EqualValues(t, test.expect.added, added, "added item IDs")

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

@@ -308,5 +308,6 @@ func (c Mail) GetAddedAndRemovedItemIDs(
 		pager,
 		deltaPager,
 		prevDeltaLink,
-		canMakeDeltaQueries)
+		canMakeDeltaQueries,
+		addedAndRemovedByAddtlData)
 }