fix: locking

mount.go

@@ -377,6 +377,8 @@ type lazyByIDNode struct {
 	client *DocspellClient
 	query  string
 	limit  int
+	mu     sync.Mutex
+	shards map[string]*lazyByIDShardNode
 }
 
 type lazyByIDShardNode struct {
@@ -511,11 +513,21 @@ func (d *lazyByIDNode) Lookup(ctx context.Context, name string) (fs.Node, error)
 	if !isDocspellIDPrefix(name) {
 		return nil, fuse.ENOENT
 	}
-	return &lazyByIDShardNode{
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	if d.shards == nil {
+		d.shards = map[string]*lazyByIDShardNode{}
+	}
+	shard, ok := d.shards[name]
+	if !ok {
+		shard = &lazyByIDShardNode{
 			query:  combineItemQueries(d.query, "id:"+name+"*"),
 			client: d.client,
 			limit:  d.limit,
-	}, nil
+		}
+		d.shards[name] = shard
+	}
+	return shard, nil
 }
 
 func (d *lazyByIDNode) ReadDirAll(ctx context.Context) ([]fuse.Dirent, error) {

mount_test.go

@@ -104,6 +104,16 @@ func TestLazyByIDShardFetchesMatchingPrefix(t *testing.T) {
 	if _, err := shard.(*lazyByIDShardNode).Lookup(context.Background(), "it-item-1.pdf"); err != nil {
 		t.Fatal(err)
 	}
+	lookupAgain, err := byID.(*lazyByIDNode).Lookup(context.Background(), "it")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if lookupAgain != shard {
+		t.Fatal("expected repeated shard lookup to return its cached node")
+	}
+	if _, err := lookupAgain.(*lazyByIDShardNode).Lookup(context.Background(), "it-item-1.pdf"); err != nil {
+		t.Fatal(err)
+	}
 	if len(queries) != 2 || queries[0] != "id:it*" || queries[1] != "id:it*" {
 		t.Fatalf("unexpected queries: %v", queries)
 	}