fix(paging): stop calendar and Gmail listing on a repeated page token

listCalendarList now uses collectAllPages. Gmail backup ID listing
rejects a repeated NextPageToken the same way Photos Picker already
does, so a stuck Google token cannot hang --all or backup.

Signed-off-by: Sebastien Tardif <sebtardif@ncf.ca>

Author: SebTardif

internal/backup/gmail/fetch.go

@@ -20,6 +20,7 @@ var (
 	errCacheRequired     = errors.New("gmail backup cache is required")
 	errFetchStopped      = errors.New("gmail backup fetch stopped before completion")
 	errMessageIDMismatch = errors.New("gmail backup source returned a different message ID")
+	errRepeatedPageToken = errors.New("repeated page token")
 )
 
 type CacheStore interface {
@@ -85,6 +86,7 @@ func ListMessageIDs(ctx context.Context, source Source, opts ListOptions) ([]str
 
 	ids := make([]string, 0)
 	seen := make(map[string]struct{})
+	seenTokens := map[string]struct{}{}
 	pageToken := ""
 	if opts.UseCache && !opts.Refresh {
 		state, found, err := opts.Cache.ReadListState(opts.Selection)
@@ -134,7 +136,8 @@ func ListMessageIDs(ctx context.Context, source Source, opts ListOptions) ([]str
 		ids = appendUniqueIDs(ids, seen, page.IDs, opts.Selection.Max)
 		emitEvent(opts.Progress, Event{Phase: EventPhaseList, Done: len(ids)})
 
-		complete := strings.TrimSpace(page.NextPageToken) == "" || reachedSelectionMax(ids, opts.Selection.Max)
+		next := strings.TrimSpace(page.NextPageToken)
+		complete := next == "" || reachedSelectionMax(ids, opts.Selection.Max)
 		if opts.UseCache {
 			nextToken := page.NextPageToken
 			if complete {
@@ -147,6 +150,10 @@ func ListMessageIDs(ctx context.Context, source Source, opts ListOptions) ([]str
 		if complete {
 			break
 		}
+		if _, exists := seenTokens[next]; exists {
+			return nil, fmt.Errorf("list Gmail backup messages: %w %q", errRepeatedPageToken, next)
+		}
+		seenTokens[next] = struct{}{}
 		pageToken = page.NextPageToken
 	}
 	return ids, nil

internal/backup/gmail/fetch_test.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"strings"
 	"sync"
 	"sync/atomic"
 	"testing"
@@ -122,6 +123,31 @@ func TestListMessageIDsMarksMaxedPartialStateComplete(t *testing.T) {
 	}
 }
 
+type stuckPageTokenSource struct{}
+
+func (stuckPageTokenSource) Labels(context.Context) ([]Label, error) {
+	return nil, nil
+}
+
+func (stuckPageTokenSource) ListMessageIDs(context.Context, ListRequest) (ListPage, error) {
+	return ListPage{IDs: []string{"m1"}, NextPageToken: "stuck"}, nil
+}
+
+func (stuckPageTokenSource) RawMessage(context.Context, string) (Message, error) {
+	return Message{}, nil
+}
+
+func TestListMessageIDsRejectsRepeatedPageToken(t *testing.T) {
+	t.Parallel()
+	ctx, cancel := context.WithTimeout(context.Background(), 300*time.Millisecond)
+	defer cancel()
+	_, err := ListMessageIDs(ctx, stuckPageTokenSource{}, ListOptions{})
+	if err == nil || !strings.Contains(err.Error(), `repeated page token "stuck"`) {
+		t.Fatalf("err = %v", err)
+	}
+	t.Logf("err = %v", err)
+}
+
 func TestFetchMessagesPreservesInputOrderAcrossWorkers(t *testing.T) {
 	t.Parallel()
 	source := &fakeSource{

internal/cmd/calendar_list.go

@@ -361,28 +361,18 @@ func resolveCalendarIDs(ctx context.Context, store *config.ConfigStore, svc *cal
 }
 
 func listCalendarList(ctx context.Context, svc *calendar.Service) ([]*calendar.CalendarListEntry, error) {
-	var (
-		items     []*calendar.CalendarListEntry
-		pageToken string
-	)
-	for {
+	fetch := func(pageToken string) ([]*calendar.CalendarListEntry, string, error) {
 		call := svc.CalendarList.List().MaxResults(250).Context(ctx)
 		if pageToken != "" {
 			call = call.PageToken(pageToken)
 		}
 		resp, err := call.Do()
 		if err != nil {
-			return nil, err
-		}
-		if len(resp.Items) > 0 {
-			items = append(items, resp.Items...)
-		}
-		if resp.NextPageToken == "" {
-			break
+			return nil, "", err
 		}
-		pageToken = resp.NextPageToken
+		return resp.Items, resp.NextPageToken, nil
 	}
-	return items, nil
+	return collectAllPages("", fetch)
 }
 
 // sortEventsBy sorts events in place by the given key (start|end|summary|calendar).

internal/cmd/calendar_list_test.go

@@ -6,7 +6,9 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"slices"
+	"strings"
 	"testing"
+	"time"
 
 	"google.golang.org/api/calendar/v3"
 	"google.golang.org/api/option"
@@ -80,3 +82,37 @@ func TestCalendarEventsListCall_EventTypesFilter(t *testing.T) {
 		})
 	}
 }
+
+func TestListCalendarListRejectsRepeatedPageToken(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if !(strings.Contains(r.URL.Path, "calendarList") && r.Method == http.MethodGet) {
+			http.NotFound(w, r)
+			return
+		}
+		w.Header().Set("Content-Type", "application/json")
+		_ = json.NewEncoder(w).Encode(map[string]any{
+			"items": []map[string]any{
+				{"id": "c1", "summary": "One", "accessRole": "owner"},
+			},
+			"nextPageToken": "stuck",
+		})
+	}))
+	defer srv.Close()
+
+	svc, err := calendar.NewService(context.Background(),
+		option.WithHTTPClient(srv.Client()),
+		option.WithEndpoint(srv.URL+"/"),
+		option.WithoutAuthentication(),
+	)
+	if err != nil {
+		t.Fatalf("NewService: %v", err)
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 300*time.Millisecond)
+	defer cancel()
+	_, err = listCalendarList(ctx, svc)
+	if err == nil || !strings.Contains(err.Error(), "repeated page token") {
+		t.Fatalf("err = %v", err)
+	}
+	t.Logf("err = %v", err)
+}