juicedata/juicefs · error

first key should be test, but got %s

Error message

first key should be test, but got %s

What it means

Raised in the objbench 'list objects' filesystem case: the second listed entry must be the test object under `key` ('test'), but a different key was returned. The message text says 'first key' but actually checks objs[1] — the key that objbench just Put. This validates that the list returns the newly written object in the expected position.

Source

Thrown at cmd/objbench.go:902

		br := []byte("hello")
		if err := blob.Put(ctx, key, bytes.NewReader(br)); err != nil {
			return fmt.Errorf("put object failed: %s", err)
		}
		defer blob.Delete(ctx, key) //nolint:errcheck
		if isFileSystem {
			objs, err := listAll(ctx, blob, "", "", 2)
			if err == nil {
				if len(objs) != 2 {
					return fmt.Errorf("list should return 2 keys, but got %d", len(objs))
				}
				if objs[0].Key() != "" {
					return fmt.Errorf("first key should be empty string, but got %s", objs[0].Key())
				}
				if objs[0].Size() != 0 {
					return fmt.Errorf("first object size should be 0, but got %d", objs[0].Size())
				}
				if objs[1].Key() != key {
					return fmt.Errorf("first key should be test, but got %s", objs[1].Key())
				}
				if objs[1].Size() != 5 {
					return fmt.Errorf("size of first key shold be 5, but got %v", objs[1].Size())
				}
				now := time.Now()
				if objs[1].Mtime().Before(now.Add(-30*time.Second)) || objs[1].Mtime().After(now.Add(time.Second*30)) {
					return fmt.Errorf("mtime of key should be within 30 seconds, but got %s", objs[1].Mtime().Sub(now))
				}
			} else {
				return fmt.Errorf("list failed: %s", err)
			}

			objs, err = listAll(ctx, blob, "", "test2", 1)
			if err != nil {
				return fmt.Errorf("list failed: %s", err)
			} else if len(objs) != 0 {
				return fmt.Errorf("list should not return anything, but got %d", len(objs))
			}

View on GitHub (pinned to c9a67b23e8)

Solutions

1. Remove leftover files/keys from the test directory/prefix and rerun.
2. Check how the backend normalizes keys in List vs Put (trailing/leading slashes).
3. Verify ordering matches the reference file:// implementation.
4. Clear any entry caches on filesystem-backed stores before rerunning.
5. Upgrade/align JuiceFS versions if backend and CLI differ.

Example fix

// before: backend returns key "/test" for put key "test"
return &entry{key: "/" + rel, ...}
// after: keep keys consistent with Put
return &entry{key: rel, ...}

// ensure the test key exists and prefix is clean before listing
objs, _ := listAll(ctx, blob, "", "", 10)
keys := make([]string, 0, len(objs))
for _, o := range objs { keys = append(keys, o.Key()) }
// expect keys == ["", key]

if objs[1].Key() != key {
    log.Printf("got %q, want %q; check key normalization and leftovers", objs[1].Key(), key)
}

When it happens

Trigger: listAll(ctx, blob, "", "", 2) returned 2 entries whose first is "" but whose second entry's Key() != key — caused by leftover objects in the test prefix, incorrect ordering, or the backend returning a differently-normalized key (e.g. leading slash).

Common situations: Dirty test directory containing other files that shift entry positions; backend key normalization adding/removing separators; backend sorting that misplaces the new object; stale caches in a custom implementation.

Understand the failure class

Background: "invalid response format", "malformed payload", "missing data field": when an API returns 200 but the response shape is wrong — this error's family across 23 libraries.

Related errors

• list should return 2 keys, but got %d
• first key should be empty string, but got %s
• first object size should be 0, but got %d
• size of first key shold be 5, but got %v
• list failed: %s

AI-assisted analysis of juicedata/juicefs@c9a67b23e8 (2026-09-06). Data as JSON: /api/errors/955aa2f6ef5df021. Report an issue: GitHub.