chore: Two small fixes for new engine (#19241)

Author: benclive

pkg/dataobj/metastore/object.go

@@ -693,6 +693,8 @@ func (m *ObjectMetastore) listObjects(ctx context.Context, path string, start, e
 	if err != nil {
 		return nil, err
 	}
+	defer objectReader.Close()
+
 	n, err := buf.ReadFrom(objectReader)
 	if err != nil {
 		return nil, fmt.Errorf("reading metastore object: %w", err)

pkg/engine/engine.go

@@ -48,6 +48,9 @@ func New(opts logql.EngineOpts, cfg metastore.Config, bucket objstore.Bucket, li
 	if opts.BatchSize <= 0 {
 		panic(fmt.Sprintf("invalid batch size for query engine. must be greater than 0, got %d", opts.BatchSize))
 	}
+	if opts.RangeConfig.IsZero() {
+		opts.RangeConfig = rangeio.DefaultConfig
+	}
 
 	return &QueryEngine{
 		logger:    logger,

pkg/util/rangeio/rangeio.go

@@ -106,6 +106,11 @@ func (cfg *Config) RegisterFlags(prefix string, fs *flag.FlagSet) {
 	fs.IntVar(&cfg.MinRangeSize, prefix+"min-range-size", DefaultConfig.MinRangeSize, "Experimental: minimum size of a byte range")
 }
 
+func (cfg *Config) IsZero() bool {
+	var zero Config
+	return cfg == nil || *cfg == zero
+}
+
 // effectiveParallelism returns the effective parallelism limit.
 func (cfg *Config) effectiveParallelism() int {
 	if cfg.MaxParallelism <= 0 {