src/library/read.ts

@@ -44,8 +44,8 @@ const byNewestAlbum = (a: AlbumRecord, b: AlbumRecord): number =>
 
 // A single photo. Field access mirrors `PhotoRecord`; `record()` returns the
 // underlying plain record for callers that need the IPC-safe value. `file` is
-// the file the record was made from, so the save path stays known after a
-// refresh removes the file from the library.
+// the membership the record is read from, so the save path carries the date of
+// `takenAt` and stays known after a refresh removes the file from the library.
 export class Photo {
     constructor(
         private readonly rec: PhotoRecord,

src/library/records.ts

@@ -86,9 +86,9 @@ export interface LibraryChange {
 export interface DerivedRecords {
     albums: Map<number, AlbumRecord>;
     photos: Map<number, PhotoRecord>;
-    // One membership of each photo's file, for its `Photo`'s save path. It
-    // holds the file's key, so it stays in this process: no snapshot or change
-    // carries it.
+    // The membership each photo's record is read from, for its `Photo`'s save
+    // path. It holds the file's key, so it stays in this process: no snapshot
+    // or change carries it.
     files: Map<number, EnteFile>;
 }
 
@@ -113,10 +113,20 @@ export const takenAtOf = (file: EnteFile): number =>
             file.metadata.creationTime,
     );
 
+// The membership a file's record is read from: the most recently synced, lowest
+// collection id to break ties.
+const representative = (memberships: EnteFile[]): EnteFile =>
+    memberships.reduce((best, m) =>
+        m.updationTime > best.updationTime ||
+        (m.updationTime === best.updationTime &&
+            m.collectionID < best.collectionID)
+            ? m
+            : best,
+    );
+
 // Build one PhotoRecord from every membership of a file. The memberships share
-// the same underlying file, so metadata is read from a single representative
-// (the most recently synced, lowest collection id to break ties); `albumIDs`
-// gathers them all.
+// the same underlying file, so metadata is read from a single representative;
+// `albumIDs` gathers them all.
 const toPhotoRecord = (
     fileID: number,
     memberships: EnteFile[],
@@ -124,13 +134,7 @@ const toPhotoRecord = (
     const albumIDs = memberships
         .map((m) => m.collectionID)
         .sort((a, b) => a - b);
-    const rep = memberships.reduce((best, m) =>
-        m.updationTime > best.updationTime ||
-        (m.updationTime === best.updationTime &&
-            m.collectionID < best.collectionID)
-            ? m
-            : best,
-    );
+    const rep = representative(memberships);
 
     const pub = rep.pubMagicMetadata ?? {};
     const priv = rep.magicMetadata ?? {};
@@ -221,7 +225,7 @@ export const deriveRecords = (
                 record.thumbnailPath = paths.thumbnailPath;
         }
         photos.set(fileID, record);
-        photoFiles.set(fileID, memberships[0]!);
+        photoFiles.set(fileID, representative(memberships));
         takenAtByFile.set(fileID, record.takenAt);
     }
 

test/library/content-library.test.ts

@@ -416,6 +416,50 @@ describe("Photo save path, local copy, content and EXIF", () => {
         await lib.close();
     });
 
+    it("dates the save path by the membership its takenAt comes from", async () => {
+        // One file in two albums. The date edited in Ente has reached album 2's
+        // copy, synced later, but album 1 still has an earlier edit.
+        const older = file(1, 1);
+        older.pubMagicMetadata = {
+            editedTime: new Date(2026, 1, 1, 12).getTime() * 1000,
+        };
+        const newer = file(1, 2);
+        newer.updationTime = 2;
+        newer.pubMagicMetadata = {
+            editedTime: new Date(2026, 3, 15, 12).getTime() * 1000,
+        };
+        const client = {
+            whoami: () => ({ email: "u@example.com", userID: USER_ID }),
+            collectionsSince: async (): Promise<CollectionsPage> => ({
+                collections: [collection(1), collection(2)],
+                deleted: [],
+                cursor: 1,
+            }),
+            filesSince: async (args: {
+                collectionID: number;
+            }): Promise<FilesPage> => ({
+                files: [args.collectionID === 1 ? older : newer],
+                deleted: [],
+                cursor: 1,
+            }),
+        };
+        const lib = await open({ client });
+        const photo = lib.photos.byID({ fileID: 1 })!;
+
+        expect(photo.takenAt).toBe(new Date(2026, 3, 15, 12).getTime());
+        expect(photo.savePath).toBe(
+            join(
+                root,
+                "backup",
+                "2026",
+                "2026-04",
+                "2026-04-15",
+                "2026-04-15.1.jpg",
+            ),
+        );
+        await lib.close();
+    });
+
     it("has a save path, and is not local, without a content source", async () => {
         const lib = await open({ contentSource: undefined });
         const photo = lib.photos.byID({ fileID: 1 })!;