fix: return total number of docs when sync has no update (#18255)

### Summary

As title

---------

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

internal/dao/sync_task.go

@@ -333,7 +333,7 @@ func (d *SyncTaskDAO) CompleteSyncTask(ctx context.Context, taskContext SyncTask
 			"status":             SyncStatusDone,
 			"poll_range_end":     entity.FlexibleTime(pollRangeEnd),
 			"new_docs_indexed":   newDocs,
-			"total_docs_indexed": gorm.Expr("total_docs_indexed + ?", totalDocs),
+			"total_docs_indexed": totalDocs,
 			"error_msg":          errorMsg,
 			"error_count":        errorCount,
 		})

internal/handler/connector.go

@@ -434,7 +434,7 @@ func (h *ConnectorHandler) RebuildConnector(c *gin.Context) {
 	common.SuccessWithData(c, ok, "success")
 }
 
-// ResumeFailedSync resumes a failed connector sync task from checkpoint.
+// ResumeFailedSync resumes a failed connector sync task from checkpoint. (when network outage)
 // @Summary Resume Failed Connector Sync
 // @Description Resume a failed connector sync task from its saved checkpoint
 // @Tags connector

internal/router/router.go

@@ -626,7 +626,6 @@ func (r *Router) Setup(engine *gin.Engine) {
 			{
 				connectors.GET("", r.connectorHandler.ListConnectors)
 				connectors.POST("", r.connectorHandler.CreateConnector)
-				// Sync logs for the current user, optionally filtered by dataset.
 				connectors.GET("/sync_logs", r.connectorHandler.ListSyncLogs)
 				connectors.POST("/google/oauth/web/start", r.connectorHandler.StartGoogleWebOAuth)
 				connectors.POST("/google/oauth/web/result", r.connectorHandler.PollGoogleWebOAuthResult)

internal/service/sync_task_service.go

@@ -143,7 +143,7 @@ func (s *SyncTaskService) HandleTransientFailure(ctx context.Context, taskID, co
 // CompleteSync commits a successful SYNC task and schedules the next one.
 func (s *SyncTaskService) CompleteSync(ctx context.Context, taskContext SyncTaskContext, pollRangeEnd time.Time, stats SyncStats) (string, error) {
 	changed := stats.Added + stats.Updated
-	return s.taskDAO.CompleteSyncTask(ctx, taskContext, pollRangeEnd, changed, changed, stats.ErrorCount, stats.ErrorMsg)
+	return s.taskDAO.CompleteSyncTask(ctx, taskContext, pollRangeEnd, stats.Added, changed, stats.ErrorCount, stats.ErrorMsg)
 }
 
 // CompletePrune commits a successful PRUNE task and schedules the next one.

internal/syncer/connector/registry.go

@@ -25,7 +25,7 @@ import (
 // Factory creates a connector for a task context.
 type Factory func(ctx context.Context, taskContext any) (Connector, error)
 
-// Registry maps Python connector source names to Go connector factories.
+// Registry connector source names to Go connector factories.
 type Registry struct {
 	mu        sync.RWMutex
 	factories map[string]Factory

internal/syncer/syncer_test.go

@@ -794,7 +794,12 @@ func TestHash128MatchesPythonGolden(t *testing.T) {
 func TestFingerprintSkipsUnchangedDocument(t *testing.T) {
 	db := setupSyncerDB(t)
 	insertTaskContext(t, db, "conn-1", "kb-1", "task-1", dao.TaskTypeSync)
-	_ = db.Model(&entity.SyncLogs{}).Where("id = ?", "task-1").Update("status", dao.SyncStatusRunning).Error
+	if err := db.Model(&entity.SyncLogs{}).Where("id = ?", "task-1").Updates(map[string]any{
+		"status":             dao.SyncStatusRunning,
+		"total_docs_indexed": int64(1),
+	}).Error; err != nil {
+		t.Fatalf("set running task: %v", err)
+	}
 	taskService := service.NewSyncTaskService(dao.NewSyncTaskDAO(db))
 	legacyID := service.Hash128("conn-1:source-1")
 	store := fakeStore{ids: map[string]struct{}{legacyID: {}}, fingerprints: map[string]string{legacyID: "fp-1"}}
@@ -808,6 +813,20 @@ func TestFingerprintSkipsUnchangedDocument(t *testing.T) {
 	if sink.callCount() != 0 {
 		t.Fatalf("sink calls = %d, want 0", sink.callCount())
 	}
+	var completed entity.SyncLogs
+	if err := db.First(&completed, "id = ?", "task-1").Error; err != nil {
+		t.Fatalf("load completed task: %v", err)
+	}
+	if completed.NewDocsIndexed != 0 || completed.TotalDocsIndexed != 0 {
+		t.Fatalf("completed stats new/total = %d/%d, want 0/0", completed.NewDocsIndexed, completed.TotalDocsIndexed)
+	}
+	var next entity.SyncLogs
+	if err := db.Where("id <> ? AND connector_id = ? AND kb_id = ? AND task_type = ? AND status = ?", "task-1", "conn-1", "kb-1", dao.TaskTypeSync, dao.SyncStatusSchedule).First(&next).Error; err != nil {
+		t.Fatalf("load next scheduled task: %v", err)
+	}
+	if next.TotalDocsIndexed != 1 {
+		t.Fatalf("next scheduled total docs indexed = %d, want 1", next.TotalDocsIndexed)
+	}
 }
 
 // TestAutoParseFlagFlowsToSink verifies connector2kb.auto_parse is preserved.