fix: writing empty exif tags (#27025)

server/src/repositories/metadata.repository.ts

@@ -119,8 +119,12 @@ export class MetadataRepository {
   }
 
   async writeTags(path: string, tags: Partial<Tags>): Promise<void> {
+    // If exiftool assigns a field with ^= instead of =, empty values will be written too.
+    // Since exiftool-vendored doesn't support an option for this, we append the ^ to the name of the tag instead.
+    // https://exiftool.org/exiftool_pod.html#:~:text=is%20used%20to%20write%20an%20empty%20string
+    const tagsToWrite = Object.fromEntries(Object.entries(tags).map(([key, value]) => [`${key}^`, value]));
     try {
-      await this.exiftool.write(path, tags);
+      await this.exiftool.write(path, tagsToWrite);
     } catch (error) {
       this.logger.warn(`Error writing exif data (${path}): ${error}`);
     }

server/src/services/metadata.service.ts

@@ -467,7 +467,7 @@ export class MetadataService extends BaseService {
         GPSLatitude: latitude,
         GPSLongitude: longitude,
         Rating: rating,
-        TagsList: tags?.length ? tags : undefined,
+        TagsList: tags,
       },
       _.isUndefined,
     );