Test: lib.backup() takes no new original once onProgress has thrown or its lock is lost

The onProgress test now runs eight photos with a pool of five and holds
only the first five downloads, so a backup that went on after the throw
would download and store the other three. The end-to-end test of a
removed backup.lock expects the backup to stop after its three originals,
before it fetches ML data.

Model: opus-5-5

test/cli/backup-concurrency.test.ts

@@ -397,19 +397,33 @@ describe("lib.backup()", () => {
     });
 
     // A throw from `onProgress` fails the backup: `lib.backup()` rejects with
-    // it. It rejects only once it has finished with every original it was
-    // working on, so nothing is written into the backup after it has ended
-    // and removed its lock. Here, with a content pool of eight, all eight
-    // downloads wait at once. Photo 103's is let go first and answered 404,
-    // and the line reporting that failure throws while the other seven wait.
-    it("when onProgress throws, rejects only once the originals it was working on are in place", async () => {
+    // it. From then on the backup starts no further original. It finishes the
+    // ones it is working on, and rejects only once they are in place, so
+    // nothing is written into the backup after it has ended and removed its
+    // lock. Here the first five downloads wait. Photo 103's is let go first
+    // and answered 404, and the line reporting that failure throws while the
+    // other four wait. Only those five downloads are held: a backup that went
+    // on would store the other three photos.
+    it("when onProgress throws, starts no further original, and rejects once the originals it was working on are in place", async () => {
         const dir = mkdtempSync(join(root, "backup-"));
-        const holding = holdingServer(103);
-        const lib = await openLibrary(
-            dir,
-            holding.fetch,
-            new RequestPools({ contentConcurrency: 8 }),
-        );
+        const downloads: number[] = [];
+        const held: { id: number; release: () => void }[] = [];
+        const fetch: typeof globalThis.fetch = async (input, init) => {
+            const id = downloadOf(input);
+            if (id !== undefined) {
+                downloads.push(id);
+                if (downloads.length <= 5) {
+                    await new Promise<void>((release) =>
+                        held.push({ id, release }),
+                    );
+                }
+                if (id === 103) {
+                    return new Response("not found", { status: 404 });
+                }
+            }
+            return server(input, init);
+        };
+        const lib = await openLibrary(dir, fetch);
         const lines: string[] = [];
         try {
             const backup = lib.backup({
@@ -432,12 +446,12 @@ describe("lib.backup()", () => {
                 return err;
             });
 
-            await vi.waitFor(() => expect(holding.held).toHaveLength(8), {
+            await vi.waitFor(() => expect(held).toHaveLength(5), {
                 interval: 5,
                 timeout: 5000,
             });
-            const at103 = holding.held.findIndex((h) => h.id === 103);
-            holding.held.splice(at103, 1)[0]!.release();
+            const at103 = held.findIndex((h) => h.id === 103);
+            held.splice(at103, 1)[0]!.release();
             await vi.waitFor(
                 () =>
                     expect(
@@ -445,14 +459,13 @@ describe("lib.backup()", () => {
                     ).toBe(true),
                 { interval: 5, timeout: 5000 },
             );
-            for (const download of holding.held) download.release();
+            for (const download of held) download.release();
 
             expect(await rejection).toEqual(
                 new Error("the progress output is closed"),
             );
-            expect(storedWhenRejected).toEqual(
-                PHOTO_IDS.filter((id) => id !== 103),
-            );
+            expect(downloads.sort()).toEqual([101, 102, 103, 104, 105]);
+            expect(storedWhenRejected).toEqual([101, 102, 104, 105]);
             expect(lockedWhenRejected).toBe(false);
         } finally {
             await lib.close();

test/cli/backup-end-to-end.test.ts

@@ -705,9 +705,10 @@ describe("a backup whose lock is lost", () => {
     };
 
     // The backup downloads up to five originals at once, so all three are
-    // under way when the lock is lost, and beach.jpg is stored. `quak backup`
-    // prints why as one line, with no stack trace, and exits 1.
-    it("stops quak backup before its next file when backup.lock is removed, and exits 1", async () => {
+    // under way when the lock is lost, and beach.jpg is stored. The backup
+    // then stops before it fetches ML data. `quak backup` prints why as one
+    // line, with no stack trace, and exits 1.
+    it("stops quak backup before it fetches ML data when backup.lock is removed, and exits 1", async () => {
         const result = backup(dir, {}, fetch);
         await heldRequested;
         rmSync(lockPath, { recursive: true });
@@ -722,7 +723,6 @@ describe("a backup whose lock is lost", () => {
                 "Fetching original beach.jpg (100)...\n" +
                 "Fetching original IMG_0002.HEIC (300)...\n" +
                 "Fetching original toast.mp4 (200)...\n" +
-                "Fetching ML data...\n" +
                 `quak: lost the lock on ${dir}: ENOENT: no such file or directory, stat '${lockPath}'\n`,
         );
         expect(downloads.sort()).toEqual([100, 200, 300]);