src/download/index.ts

@@ -361,8 +361,8 @@ const openPart = async (
 // written unpacked: each part is named `destination` with the extension
 // replaced by its own entry's, and the two must differ ignoring case. When the
 // file records a hash, `<imageHash>:<videoHash>` must match it, each over that
-// part's own bytes. Only then is whatever was at `destination` removed and the
-// image, then the video, renamed into place; on any failure neither is stored.
+// part's own bytes. Only then are the image, then the video, renamed into
+// place; on any failure neither is stored.
 //
 // The ZIP is chosen by its uploader and may expand enormously, so each part is
 // written as it decompresses and never held, and the ZIP is refused once the
@@ -486,7 +486,6 @@ const decryptLivePhoto = async (
             await part.handle.sync();
             await part.handle.close();
         }
-        await rm(destination, { force: true });
         await rename(image.tmpPath, path);
         try {
             await rename(video.tmpPath, videoPath);
@@ -570,8 +569,7 @@ const fetchAndDecrypt = async (
     }, api.getRetryOptions());
 
 // Write `file`'s original to `outPath`. A live photo is written as its image
-// and its video beside `outPath` instead, and whatever was at `outPath` is
-// removed (see `decryptLivePhoto`).
+// and its video beside `outPath` instead (see `decryptLivePhoto`).
 export const downloadFile = async (
     api: ApiClient,
     file: EnteFile,

src/library/content.ts

@@ -687,7 +687,10 @@ export class ContentCache implements PhotoContent, ThumbnailsAPI {
                     await this.touch(cached.path);
                 return { ...cached, bytes: size, cached: true };
             }
-            // A recorded file that has since gone re-fetches below.
+            // A recorded file that has since gone re-fetches below. So does a
+            // live photo recorded with no video: the cache opened before the
+            // library's records said it is a live photo, while its image and
+            // video had no JSON file beside them yet.
             known.delete(fileID);
         }
 

test/download/download.test.ts

@@ -1883,15 +1883,6 @@ describe("downloadFile live photos", () => {
         expect(readdirSync(t.dir).sort()).toEqual(["f.JPG", "f.bin"]);
     });
 
-    it("replaces what was at the destination", async () => {
-        const t = setup(livePhotoZip(), livePhoto);
-        writeFileSync(t.outPath, livePhotoZip());
-
-        await t.run();
-
-        expect(readdirSync(t.dir).sort()).toEqual(["f.heic", "f.mov"]);
-    });
-
     it("renames the image and then the video into place, each from its own temp file", async () => {
         const t = setup(livePhotoZip(), livePhoto);
 

test/library/content.test.ts

@@ -596,6 +596,36 @@ describe("ContentCache live photos", () => {
         expect(second!.pathsFor(5)).toEqual({});
     });
 
+    it("fetches a live photo's image and video again when the cache opened before knowing it is a live photo and no JSON file names them", async () => {
+        const { file: live, body } = await asLivePhoto(file(5, "IMG_5.HEIC"));
+        mkdirSync(originals(), { recursive: true });
+        writeFileSync(join(originals(), "5.heic"), "an image");
+        writeFileSync(join(originals(), "5.mov"), "a video");
+        const cache = cacheOf([live], new Map([[5, body]]));
+        // Opened without being told that file 5 is a live photo, the cache
+        // records one of the two files as its original, with no video.
+        await cache.open();
+
+        const events: string[] = [];
+        const result = await cache.original(5, {
+            onProgress: (e) => events.push(e.status),
+        });
+
+        expect(events.at(-1)).toBe("done");
+        expect(result).toEqual({
+            path: join(originals(), "5.heic"),
+            videoPath: join(originals(), "5.mov"),
+            bytes: IMAGE.length,
+        });
+        expect(readFileSync(result.path)).toEqual(Buffer.from(IMAGE));
+        expect(readFileSync(result.videoPath!)).toEqual(Buffer.from(VIDEO));
+        expect(
+            JSON.parse(
+                readFileSync(join(originals(), "5.livephoto.json"), "utf-8"),
+            ),
+        ).toEqual({ image: "5.heic", video: "5.mov" });
+    });
+
     it.each(["missing", "empty"])(
         "fetches a live photo again when the video its JSON file names is %s",
         async (state) => {