Tests: an album or file quak cannot decrypt must not stop a backup

Failing tests for #181, against a
stand-in Ente server with real encryption: the client leaves out a row it
cannot decrypt or parse and reports it, and quak backup stores every other
file, records each such file in failures.json, names each such album, exits
1 while any remain, and drops each once it decrypts or is deleted.

Model: opus-5-5

test/cli/backup-undecryptable.test.ts

@@ -0,0 +1,424 @@
+/**
+ * `quak backup` over an account holding an album or a file quak cannot decrypt
+ * (issue 181).
+ *
+ * The server sends every album and file encrypted, and a refresh decrypts each
+ * one it fetches. A record whose key no key of the account opens, or whose
+ * metadata is not JSON, must not fail the refresh: a refresh that fails commits
+ * nothing, so `quak backup` would store nothing, on every run, until the
+ * server's copy changed. Instead the refresh leaves that record out, and the
+ * library keeps a list of what it left out in its cache. It has to: the next
+ * refresh asks the server only for what changed since the last one, so it will
+ * not see the record again.
+ *
+ * The backup stores every other file. It records each file it could not
+ * decrypt in `failures.json`, prints one line for each album it could not
+ * decrypt, and exits 1 while any remain. Once the server sends a copy that
+ * decrypts, or deletes the record, the next run drops it and can exit 0. The
+ * read commands answer from what did decrypt.
+ *
+ * These tests run the commands with a real saved session over a stand-in Ente
+ * server, which serves albums, files and originals encrypted with libsodium as
+ * the real server does. A record is broken the way a corrupt one arrives: its
+ * key replaced by bytes no key opens, or its metadata text that is not JSON.
+ */
+
+import { existsSync, mkdtempSync, readFileSync, rmSync } from "node:fs";
+import { join } from "node:path";
+import { tmpdir } from "node:os";
+import sodium from "libsodium-wrappers-sumo";
+import { afterEach, beforeAll, beforeEach, describe, expect, it } from "vitest";
+
+import {
+    backupCommand,
+    collectionsCommand,
+    filesCommand,
+    saveSession,
+    type CliContext,
+} from "../../src/cli-commands.js";
+import { loadSession } from "../../src/cli-session.js";
+import type { ClientSnapshot } from "../../src/client.js";
+import { encryptBlob, init, toBase64 } from "../../src/crypto/index.js";
+
+const USER_ID = 42;
+
+// Every file is taken at noon local time on 2026-03-01, in microseconds as Ente
+// stores times, so its original is saved in the folder `DAY` whatever the time
+// zone of the machine running the tests.
+const TAKEN = new Date(2026, 2, 1, 12).getTime() * 1000;
+const DAY = join("2026", "2026-03", "2026-03-01");
+
+type Row = { id: number; updationTime: number } & Record<string, unknown>;
+
+// `plaintext` sealed under `key` with a fresh nonce, both base64, as Ente
+// sends a key or an album name.
+const secretbox = (
+    plaintext: Uint8Array,
+    key: Uint8Array,
+): { ciphertext: string; nonce: string } => {
+    const nonce = sodium.randombytes_buf(sodium.crypto_secretbox_NONCEBYTES);
+    return {
+        ciphertext: toBase64(
+            sodium.crypto_secretbox_easy(plaintext, nonce, key),
+        ),
+        nonce: toBase64(nonce),
+    };
+};
+
+// What a corrupt row carries in place of its sealed key: random bytes of the
+// same length, which no key opens.
+const corruptKey = (): string =>
+    toBase64(
+        sodium.randombytes_buf(
+            sodium.crypto_secretbox_KEYBYTES + sodium.crypto_secretbox_MACBYTES,
+        ),
+    );
+
+const json = (body: unknown): Response =>
+    new Response(JSON.stringify(body), {
+        status: 200,
+        headers: { "content-type": "application/json" },
+    });
+
+// A stand-in Ente server for one account. It holds each album, and each file in
+// an album, as the row `/collections/v2` and `/collections/v2/diff` serve, and
+// answers a request with the rows whose `updationTime` is past the request's
+// `sinceTime`, as the real server does. A change to a file also moves its
+// album's `updationTime`, which is what tells a client to list the album's
+// files again. Originals are served by file ID, as the files CDN serves them.
+class FakeEnte {
+    private readonly masterKey = sodium.crypto_secretbox_keygen();
+    private readonly keyPair = sodium.crypto_box_keypair();
+    private readonly albums = new Map<number, Row>();
+    private readonly albumKeys = new Map<number, Uint8Array>();
+    // Each album's file rows, by album ID and then file ID.
+    private readonly files = new Map<number, Map<number, Row>>();
+    // Each file's key and its original as served, by file ID. A file in two
+    // albums is one original under one key, sealed under each album's key.
+    private readonly originals = new Map<
+        number,
+        { key: Uint8Array; header: string; body: Uint8Array }
+    >();
+
+    // The session `quak login` would have saved for the account.
+    snapshot(): ClientSnapshot {
+        return {
+            email: "user@example.com",
+            userID: USER_ID,
+            token: "token",
+            masterKey: toBase64(this.masterKey),
+            secretKey: toBase64(this.keyPair.privateKey),
+            publicKey: toBase64(this.keyPair.publicKey),
+        };
+    }
+
+    // Album `id`, named `name`, as of time `t`. With `corrupt`, its key cannot
+    // be decrypted. An album keeps its key from one call to the next, so its
+    // files' rows still decrypt once it is put back without `corrupt`.
+    putAlbum(id: number, name: string, t: number, corrupt = false): void {
+        const key = this.albumKeys.get(id) ?? sodium.crypto_secretbox_keygen();
+        this.albumKeys.set(id, key);
+        const sealedKey = secretbox(key, this.masterKey);
+        const sealedName = secretbox(new TextEncoder().encode(name), key);
+        this.albums.set(id, {
+            id,
+            owner: { id: USER_ID },
+            encryptedKey: corrupt ? corruptKey() : sealedKey.ciphertext,
+            keyDecryptionNonce: sealedKey.nonce,
+            encryptedName: sealedName.ciphertext,
+            nameDecryptionNonce: sealedName.nonce,
+            type: "album",
+            updationTime: t,
+        });
+        if (!this.files.has(id)) this.files.set(id, new Map());
+    }
+
+    // File `id`, titled `photo-<id>.jpg`, in album `albumID` as of time `t`.
+    // With `corruptKey`, its key cannot be decrypted. With `metadata`, its
+    // metadata decrypts to that text instead of the JSON a client uploads.
+    putFile(
+        albumID: number,
+        id: number,
+        t: number,
+        opts: { corruptKey?: boolean; metadata?: string } = {},
+    ): void {
+        const original = this.originalOf(id);
+        const sealedKey = secretbox(original.key, this.albumKeys.get(albumID)!);
+        const metadata =
+            opts.metadata ??
+            JSON.stringify({
+                title: `photo-${id}.jpg`,
+                fileType: 0,
+                creationTime: TAKEN,
+                modificationTime: TAKEN,
+            });
+        const sealedMetadata = encryptBlob(
+            new TextEncoder().encode(metadata),
+            original.key,
+        );
+        this.files.get(albumID)!.set(id, {
+            id,
+            collectionID: albumID,
+            ownerID: USER_ID,
+            encryptedKey: opts.corruptKey ? corruptKey() : sealedKey.ciphertext,
+            keyDecryptionNonce: sealedKey.nonce,
+            metadata: {
+                encryptedData: toBase64(sealedMetadata.ciphertext),
+                decryptionHeader: toBase64(sealedMetadata.header),
+            },
+            file: { decryptionHeader: original.header },
+            thumbnail: { decryptionHeader: original.header },
+            updationTime: t,
+        });
+        this.moveAlbum(albumID, t);
+    }
+
+    deleteFile(albumID: number, id: number, t: number): void {
+        this.files
+            .get(albumID)!
+            .set(id, { id, updationTime: t, isDeleted: true });
+        this.moveAlbum(albumID, t);
+    }
+
+    deleteAlbum(id: number, t: number): void {
+        this.albums.set(id, { id, updationTime: t, isDeleted: true });
+    }
+
+    readonly fetch = (async (input: string | URL | Request) => {
+        const url = new URL(input instanceof Request ? input.url : input);
+        const since = Number(url.searchParams.get("sinceTime"));
+        const changed = (rows: Iterable<Row>): Row[] =>
+            [...rows].filter((row) => row.updationTime > since);
+        switch (url.pathname) {
+            case "/collections/v2":
+                return json({ collections: changed(this.albums.values()) });
+            case "/collections/v2/diff": {
+                const albumID = Number(url.searchParams.get("collectionID"));
+                const rows = this.files.get(albumID)?.values() ?? [];
+                return json({ diff: changed(rows), hasMore: false });
+            }
+            case "/files/data/fetch":
+                // No file has ML data.
+                return json({ data: [] });
+            default: {
+                const fileID = Number(url.searchParams.get("fileID"));
+                const original = this.originals.get(fileID);
+                return original
+                    ? new Response(original.body)
+                    : new Response("not found", { status: 404 });
+            }
+        }
+    }) as typeof globalThis.fetch;
+
+    private originalOf(id: number): {
+        key: Uint8Array;
+        header: string;
+        body: Uint8Array;
+    } {
+        const known = this.originals.get(id);
+        if (known) return known;
+        const key = sodium.crypto_secretbox_keygen();
+        const { header, ciphertext } = encryptBlob(
+            new TextEncoder().encode(`original of ${id}`),
+            key,
+        );
+        const original = { key, header: toBase64(header), body: ciphertext };
+        this.originals.set(id, original);
+        return original;
+    }
+
+    private moveAlbum(albumID: number, t: number): void {
+        this.albums.set(albumID, {
+            ...this.albums.get(albumID)!,
+            updationTime: t,
+        });
+    }
+}
+
+// Album 1, "Trip", holds file 10, which decrypts, file 11, whose key does not,
+// and file 12, whose metadata is not JSON. Album 2, "Family", holds file 20,
+// but the album's own key does not decrypt. All of it as of time 1.
+const brokenAccount = (): FakeEnte => {
+    const ente = new FakeEnte();
+    ente.putAlbum(1, "Trip", 1);
+    ente.putFile(1, 10, 1);
+    ente.putFile(1, 11, 1, { corruptKey: true });
+    ente.putFile(1, 12, 1, { metadata: "not json" });
+    ente.putAlbum(2, "Family", 1, true);
+    ente.putFile(2, 20, 1);
+    return ente;
+};
+
+// Collects everything written to it.
+class Output {
+    text = "";
+    write(text: string): void {
+        this.text += text;
+    }
+}
+
+let root: string;
+let stdout: Output;
+let stderr: Output;
+
+beforeAll(async () => {
+    await init();
+    await sodium.ready;
+});
+
+beforeEach(() => {
+    root = mkdtempSync(join(tmpdir(), "quak-undecryptable-"));
+});
+
+afterEach(() => {
+    rmSync(root, { recursive: true, force: true });
+});
+
+// A context for one command, with fresh output, whose saved session talks to
+// `ente`. Every run shares one cache directory, as runs of `quak` do.
+const context = (ente: FakeEnte): CliContext => {
+    stdout = new Output();
+    stderr = new Output();
+    saveSession(join(root, "session"), ente.snapshot());
+    return {
+        stdout,
+        stderr,
+        sessionDir: join(root, "session"),
+        cacheDir: join(root, "cache"),
+        loadSession: (path) =>
+            loadSession(path, { fetch: ente.fetch, retry: { attempts: 1 } }),
+        login: async () => {
+            throw new Error("login not expected");
+        },
+        prompt: async () => {
+            throw new Error("prompt not expected");
+        },
+        promptSecret: async () => {
+            throw new Error("prompt not expected");
+        },
+    };
+};
+
+const backupDir = (): string => join(root, "backup");
+
+// Runs `quak backup` into the backup directory and returns its exit code.
+const backup = (ente: FakeEnte, opts: { json?: boolean } = {}) =>
+    backupCommand(context(ente), backupDir(), opts);
+
+// The backup's `failures.json` entries by file ID, or {} when it has none.
+const failures = (): Record<string, { error: string; attempts: number }> => {
+    const path = join(backupDir(), "failures.json");
+    return existsSync(path)
+        ? JSON.parse(readFileSync(path, "utf-8")).files
+        : {};
+};
+
+// Whether file `id`'s original is at its save path in the backup.
+const stored = (id: number): boolean =>
+    existsSync(join(backupDir(), DAY, `2026-03-01.${id}.jpg`));
+
+describe("quak backup with records it cannot decrypt", () => {
+    it("backs up every other file, records each file it cannot decrypt in failures.json, names each such album, and exits 1", async () => {
+        expect(await backup(brokenAccount())).toBe(1);
+
+        expect(stored(10)).toBe(true);
+        // Without its album's key, file 20 cannot even be listed.
+        expect(stored(20)).toBe(false);
+        expect(failures()).toEqual({
+            "11": expect.objectContaining({
+                fileID: 11,
+                error: expect.stringMatching(
+                    /^could not be decrypted: .*wrong secret key/,
+                ),
+            }),
+            "12": expect.objectContaining({
+                fileID: 12,
+                error: expect.stringMatching(/^could not be decrypted: .*JSON/),
+            }),
+        });
+        expect(stderr.text).toMatch(
+            /^FAILED album 2: could not be decrypted: .*wrong secret key/m,
+        );
+        expect(stderr.text).toContain("  Failed:      2\n");
+    });
+
+    it("names each album it cannot decrypt in the --json result", async () => {
+        expect(await backup(brokenAccount(), { json: true })).toBe(1);
+
+        expect(JSON.parse(stdout.text)).toMatchObject({
+            downloaded: 1,
+            failed: 2,
+            undecryptableAlbums: [2],
+        });
+    });
+
+    it("still reports them on the next run, though the server does not send them again", async () => {
+        const ente = brokenAccount();
+        await backup(ente);
+
+        // Nothing changed on the server, so this run's refresh gets no rows at
+        // all. What it reports, it remembered from the first run.
+        expect(await backup(ente)).toBe(1);
+
+        expect(Object.keys(failures())).toEqual(["11", "12"]);
+        expect(failures()["11"]!.attempts).toBe(2);
+        expect(stderr.text).toMatch(/^FAILED album 2: could not be decrypted/m);
+    });
+
+    it("drops each once the server sends a copy that decrypts, and then exits 0", async () => {
+        const ente = brokenAccount();
+        await backup(ente);
+
+        // At time 2 files 11 and 12 and album 2 change on the server, and now
+        // each decrypts. Album 2 brings file 20 with it.
+        ente.putFile(1, 11, 2);
+        ente.putFile(1, 12, 2);
+        ente.putAlbum(2, "Family", 2);
+        expect(await backup(ente)).toBe(0);
+
+        expect([11, 12, 20].map(stored)).toEqual([true, true, true]);
+        expect(existsSync(join(backupDir(), "failures.json"))).toBe(false);
+        expect(stderr.text).not.toContain("FAILED");
+    });
+
+    it("drops each once the server deletes it, and then exits 0", async () => {
+        const ente = brokenAccount();
+        await backup(ente);
+
+        ente.deleteFile(1, 11, 2);
+        ente.deleteFile(1, 12, 2);
+        ente.deleteAlbum(2, 2);
+        expect(await backup(ente)).toBe(0);
+
+        expect(existsSync(join(backupDir(), "failures.json"))).toBe(false);
+        expect(stderr.text).not.toContain("FAILED");
+    });
+
+    it("backs up a file that does not decrypt in one album but does in another, and does not report it", async () => {
+        // File 30 is in albums 1 and 3, each holding its key sealed under the
+        // album's own key. In album 1 that is corrupt; in album 3 it is not,
+        // and one copy that decrypts is all the backup needs.
+        const ente = new FakeEnte();
+        ente.putAlbum(1, "Trip", 1);
+        ente.putFile(1, 30, 1, { corruptKey: true });
+        ente.putAlbum(3, "Favorites", 1);
+        ente.putFile(3, 30, 1);
+
+        expect(await backup(ente)).toBe(0);
+
+        expect(stored(30)).toBe(true);
+        expect(failures()).toEqual({});
+    });
+});
+
+describe("the read commands with records quak cannot decrypt", () => {
+    it("quak collections and quak files answer from what decrypts", async () => {
+        const ente = brokenAccount();
+
+        expect(await collectionsCommand(context(ente), {})).toBe(0);
+        expect(stdout.text).toBe("1\talbum\tTrip\n");
+
+        expect(await filesCommand(context(ente), { collection: "1" })).toBe(0);
+        expect(stdout.text).toBe("10\timage\tphoto-10.jpg\n");
+    });
+});

test/client/enumeration.test.ts

@@ -10,7 +10,9 @@
  * The return shape keeps live records and tombstones apart — `collections` /
  * `files` are decrypted live records, `deleted` is a plain list of the ids the
  * server tombstoned. A tombstone carries no decryptable key or metadata, so it
- * is a bare id rather than a hollowed-out `Collection` / `EnteFile`.
+ * is a bare id rather than a hollowed-out `Collection` / `EnteFile`. A live row
+ * that does not decrypt, or whose metadata is not JSON, is listed under
+ * `undecryptable` with the reason, so one bad row does not fail the call.
  *
  * All tests inject a fake `fetch` and drive a real `Client` (built with
  * `Client.fromJSON`) so the decryption path runs for real. Live rows are built
@@ -91,27 +93,38 @@ const ownedCollectionRow = (
     };
 };
 
-/** A live file row inside a collection, keyed under that collection's key. */
+/**
+ * A live file row inside a collection, keyed under that collection's key. Its
+ * metadata decrypts to `metadata` when given, otherwise to the JSON a client
+ * uploads for `title`.
+ */
 const fileRow = (
     collectionKey: Uint8Array,
-    opts: { id: number; title: string; updationTime: number },
+    opts: {
+        id: number;
+        title: string;
+        updationTime: number;
+        metadata?: string;
+    },
 ): Record<string, unknown> => {
     const fileKey = sodium.crypto_secretbox_keygen();
     const { ciphertext: encFileKey, nonce: fileKeyNonce } = secretboxEncrypt(
         fileKey,
         collectionKey,
     );
-    const metadata = {
-        title: opts.title,
-        fileType: 0,
-        creationTime: opts.updationTime,
-        modificationTime: opts.updationTime,
-    };
+    const metadata =
+        opts.metadata ??
+        JSON.stringify({
+            title: opts.title,
+            fileType: 0,
+            creationTime: opts.updationTime,
+            modificationTime: opts.updationTime,
+        });
     const push =
         sodium.crypto_secretstream_xchacha20poly1305_init_push(fileKey);
     const encMeta = sodium.crypto_secretstream_xchacha20poly1305_push(
         push.state,
-        new TextEncoder().encode(JSON.stringify(metadata)),
+        new TextEncoder().encode(metadata),
         null,
         sodium.crypto_secretstream_xchacha20poly1305_TAG_FINAL,
     );
@@ -131,6 +144,21 @@ const fileRow = (
     };
 };
 
+/**
+ * `row` with its sealed key replaced by random bytes of the same length, as a
+ * corrupt row arrives: no key opens it, so the row cannot be decrypted.
+ */
+const withCorruptKey = (
+    row: Record<string, unknown>,
+): Record<string, unknown> => ({
+    ...row,
+    encryptedKey: toBase64(
+        sodium.randombytes_buf(
+            sodium.crypto_secretbox_KEYBYTES + sodium.crypto_secretbox_MACBYTES,
+        ),
+    ),
+});
+
 /** A tombstone row. Never decrypted, so only these fields are ever read. */
 const tombstoneRow = (
     id: number,
@@ -278,6 +306,58 @@ describe("Client.filesSince", () => {
         // It gave up after the first page rather than looping.
         expect(sinceTimes).toEqual(["50"]);
     });
+
+    it("leaves out each file it cannot decrypt or parse, with the reason, and decrypts the rest", async () => {
+        const keys = buildKeys();
+        const collectionKey = sodium.crypto_secretbox_keygen();
+
+        // File 1002's key is sealed under no key quak holds, and file 1003's
+        // metadata decrypts to text that is not JSON. Neither may cost the
+        // caller file 1001: each is left out of `files` and reported under
+        // `undecryptable` with the reason instead of failing the call.
+        const { fetch } = recordingFetch(
+            jsonResponse({
+                diff: [
+                    fileRow(collectionKey, {
+                        id: 1001,
+                        title: "fine.jpg",
+                        updationTime: 100,
+                    }),
+                    withCorruptKey(
+                        fileRow(collectionKey, {
+                            id: 1002,
+                            title: "bad-key.jpg",
+                            updationTime: 200,
+                        }),
+                    ),
+                    fileRow(collectionKey, {
+                        id: 1003,
+                        title: "bad-metadata.jpg",
+                        updationTime: 300,
+                        metadata: "not json",
+                    }),
+                ],
+                hasMore: false,
+            }),
+        );
+        const client = Client.fromJSON(snapshotFor(keys), { fetch });
+
+        const { files, undecryptable, cursor } = await client.filesSince({
+            collectionID: 1,
+            collectionKey,
+            sinceTime: 0,
+        });
+
+        expect(files.map((f) => f.id)).toEqual([1001]);
+        expect(undecryptable).toEqual([
+            { id: 1002, error: expect.stringContaining("wrong secret key") },
+            { id: 1003, error: expect.stringContaining("JSON") },
+        ]);
+        // The cursor moves past the two left out, as past any other row, so
+        // the server does not send them again until its copy changes. The
+        // caller has to keep what it was told here.
+        expect(cursor).toBe(300);
+    });
 });
 
 describe("Client.collectionsSince", () => {
@@ -331,6 +411,42 @@ describe("Client.collectionsSince", () => {
         expect(result.cursor).toBe(150);
         expect(sinceTimes).toEqual(["150"]);
     });
+
+    it("leaves out an album it cannot decrypt, with the reason, and decrypts the rest", async () => {
+        const keys = buildKeys();
+
+        // Album 2's key is sealed under no key quak holds. Without its key
+        // neither its name nor its files can be read, so it is left out and
+        // reported under `undecryptable`; album 1 is unaffected.
+        const { fetch } = recordingFetch(
+            jsonResponse({
+                collections: [
+                    ownedCollectionRow(keys.masterKey, {
+                        id: 1,
+                        name: "Vacation",
+                        updationTime: 100,
+                    }),
+                    withCorruptKey(
+                        ownedCollectionRow(keys.masterKey, {
+                            id: 2,
+                            name: "Broken",
+                            updationTime: 200,
+                        }),
+                    ),
+                ],
+            }),
+        );
+        const client = Client.fromJSON(snapshotFor(keys), { fetch });
+
+        const { collections, undecryptable, cursor } =
+            await client.collectionsSince({ sinceTime: 0 });
+
+        expect(collections.map((c) => c.name)).toEqual(["Vacation"]);
+        expect(undecryptable).toEqual([
+            { id: 2, error: expect.stringContaining("wrong secret key") },
+        ]);
+        expect(cursor).toBe(200);
+    });
 });
 
 describe("Client list wrappers still hide deletions", () => {