Fix bug where DetectFaces would be called with the wrong media.

This happend because the go routine did not capture the media variable,
and so the it would change before the go routine could start
and call the DetectFaces function.

api/graphql/resolvers/user.go

@@ -321,7 +321,7 @@ func (r *mutationResolver) UserRemoveRootAlbum(ctx context.Context, userID int,
 
 	var deletedAlbumIDs []int = nil
 
-	err := r.Database.Transaction(func(tx *gorm.DB) error {
+	transactionError := r.Database.Transaction(func(tx *gorm.DB) error {
 		if err := tx.Raw("DELETE FROM user_albums WHERE user_id = ? AND album_id = ?", userID, albumID).Error; err != nil {
 			return err
 		}
@@ -346,12 +346,12 @@ func (r *mutationResolver) UserRemoveRootAlbum(ctx context.Context, userID int,
 		}
 
 		// Cleanup if no user owns the album anymore
-		var count int
+		var userAlbumCount int
-		if err := tx.Raw("SELECT COUNT(user_id) FROM user_albums WHERE album_id = ?", albumID).Scan(&count).Error; err != nil {
+		if err := tx.Raw("SELECT COUNT(user_id) FROM user_albums WHERE album_id = ?", albumID).Scan(&userAlbumCount).Error; err != nil {
 			return err
 		}
 
-		if count == 0 {
+		if userAlbumCount == 0 {
 			deletedAlbumIDs = append(childAlbumIDs, albumID)
 			childAlbumIDs = nil
 
@@ -360,17 +360,13 @@ func (r *mutationResolver) UserRemoveRootAlbum(ctx context.Context, userID int,
 				deletedAlbumIDs = nil
 				return err
 			}
-
-			if err := face_detection.GlobalFaceDetector.ReloadFacesFromDatabase(tx); err != nil {
-				return err
-			}
 		}
 
 		return nil
 	})
 
-	if err != nil {
+	if transactionError != nil {
-		return nil, err
+		return nil, transactionError
 	}
 
 	if deletedAlbumIDs != nil {
@@ -382,6 +378,11 @@ func (r *mutationResolver) UserRemoveRootAlbum(ctx context.Context, userID int,
 				return nil, err
 			}
 		}
+
+		// Reload faces as media might have been deleted
+		if err := face_detection.GlobalFaceDetector.ReloadFacesFromDatabase(r.Database); err != nil {
+			return nil, err
+		}
 	}
 
 	return &album, nil

api/scanner/face_detection/face_detector.go

@@ -84,8 +84,8 @@ func (fd *FaceDetector) ReloadFacesFromDatabase(db *gorm.DB) error {
 }
 
 // DetectFaces finds the faces in the given image and saves them to the database
-func (fd *FaceDetector) DetectFaces(tx *gorm.DB, media *models.Media) error {
+func (fd *FaceDetector) DetectFaces(db *gorm.DB, media *models.Media) error {
-	if err := tx.Model(media).Preload("MediaURL").First(&media).Error; err != nil {
+	if err := db.Model(media).Preload("MediaURL").First(&media).Error; err != nil {
 		return err
 	}
 
@@ -116,7 +116,7 @@ func (fd *FaceDetector) DetectFaces(tx *gorm.DB, media *models.Media) error {
 	}
 
 	for _, face := range faces {
-		fd.classifyFace(tx, &face, media, thumbnailPath)
+		fd.classifyFace(db, &face, media, thumbnailPath)
 	}
 
 	return nil
@@ -126,7 +126,7 @@ func (fd *FaceDetector) classifyDescriptor(descriptor face.Descriptor) int32 {
 	return int32(fd.rec.ClassifyThreshold(descriptor, 0.2))
 }
 
-func (fd *FaceDetector) classifyFace(tx *gorm.DB, face *face.Face, media *models.Media, imagePath string) error {
+func (fd *FaceDetector) classifyFace(db *gorm.DB, face *face.Face, media *models.Media, imagePath string) error {
 	fd.mutex.Lock()
 	defer fd.mutex.Unlock()
 
@@ -153,18 +153,18 @@ func (fd *FaceDetector) classifyFace(tx *gorm.DB, face *face.Face, media *models
 			ImageFaces: []models.ImageFace{imageFace},
 		}
 
-		if err := tx.Create(&faceGroup).Error; err != nil {
+		if err := db.Create(&faceGroup).Error; err != nil {
 			return err
 		}
 
 	} else {
 		log.Println("Found match")
 
-		if err := tx.First(&faceGroup, int(match)).Error; err != nil {
+		if err := db.First(&faceGroup, int(match)).Error; err != nil {
 			return err
 		}
 
-		if err := tx.Model(&faceGroup).Association("ImageFaces").Append(&imageFace); err != nil {
+		if err := db.Model(&faceGroup).Association("ImageFaces").Append(&imageFace); err != nil {
 			return err
 		}
 	}

api/scanner/scanner_album.go

@@ -75,10 +75,11 @@ func scanAlbum(album *models.Album, cache *AlbumScannerCache, db *gorm.DB) {
 
 	album_has_changes := false
 	for count, media := range albumMedia {
-		// tx, err := db.Begin()
+		processing_was_needed := false
 
 		transactionError := db.Transaction(func(tx *gorm.DB) error {
-			processing_was_needed, err := ProcessMedia(tx, media)
+			log.Printf("Process media transaction enter (%s)", media.Path)
+			processing_was_needed, err = ProcessMedia(tx, media)
 			if err != nil {
 				return errors.Wrapf(err, "failed to process photo (%s)", media.Path)
 			}
@@ -93,22 +94,23 @@ func scanAlbum(album *models.Album, cache *AlbumScannerCache, db *gorm.DB) {
 					Content:  fmt.Sprintf("Processed media at %s", media.Path),
 					Progress: &progress,
 				})
-
-				if media.Type == models.MediaTypePhoto {
-					go func() {
-						if err := face_detection.GlobalFaceDetector.DetectFaces(tx, media); err != nil {
-							ScannerError("Error detecting faces in image (%s): %s", media.Path, err)
-						}
-					}()
-				}
 			}
 
+			log.Printf("Process media transaction exit (%s)", media.Path)
 			return nil
 		})
 
 		if transactionError != nil {
 			ScannerError("Failed to begin database transaction: %s", transactionError)
 		}
+
+		if processing_was_needed && media.Type == models.MediaTypePhoto {
+			go func(media *models.Media) {
+				if err := face_detection.GlobalFaceDetector.DetectFaces(db, media); err != nil {
+					ScannerError("Error detecting faces in image (%s): %s", media.Path, err)
+				}
+			}(media)
+		}
 	}
 
 	cleanup_errors := CleanupMedia(db, album.ID, albumMedia)