BoundaryML/baml · error

failed to create collector

Error message

failed to create collector: %w

What it means

Wraps errors from raw_objects.NewRawObject when constructing the OBJECT_COLLECTOR in BamlRuntime.NewCollector (rawobjects_constructors.go:22). The native runtime refused or failed to create the collector object from the encoded kwargs.

Solutions

1. Read the wrapped NewRawObject error for the runtime-side cause.
2. Use a unique collector name and valid kwargs.
3. Reinstall matched BAML Go client + native binaries and retry.

Example fix

// before
collector, _ := rt.NewCollector("run-1")
// after
collector, err := rt.NewCollector("run-1")
if err != nil {
	return nil, fmt.Errorf("collector init failed: %w", err)
}

if rt == nil { return errors.New("runtime not initialized") }
if strings.TrimSpace(name) == "" { return errors.New("collector name required") }

collector, err := rt.NewCollector(name)
if err != nil {
	var root error = err
	for errors.Unwrap(root) != nil { root = errors.Unwrap(root) }
	return fmt.Errorf("collector creation failed (%v): %w", root, err)
}

When it happens

Trigger: BamlRuntime.NewCollector(name) where the C++ runtime's collector construction fails — e.g. duplicate collector name at runtime, invalid kwargs, or runtime-side construction panic surfaced through FFI.

Common situations: Runtime rejecting constructor args after a version upgrade; creating collectors during runtime shutdown; native binary incompatibility.

Related errors

• failed to clear
• failed to get last log
• failed to get log by id
• failed to get logs
• failed to get name

AI-assisted analysis of BoundaryML/baml@bd85ce9dee (2026-09-12). Data as JSON: /api/errors/139cc2e7ad0e2685. Report an issue: GitHub.

Appendix: source

Thrown at engine/language_client_go/pkg/rawobjects_constructors.go:22

	"fmt"

	"github.com/boundaryml/baml/engine/language_client_go/baml_go/raw_objects"
	"github.com/boundaryml/baml/engine/language_client_go/baml_go/serde"
	"github.com/boundaryml/baml/engine/language_client_go/pkg/cffi"
)

// / Construct Collector
func (r *BamlRuntime) NewCollector(name string) (Collector, error) {
	kwargs, err := serde.EncodeMapEntries(map[string]any{
		"name": name,
	}, "collector constructor args")
	if err != nil {
		return nil, fmt.Errorf("failed to encode kwargs: %w", err)
	}

	ptr, err := raw_objects.NewRawObject(r.runtime, cffi.BamlObjectType_OBJECT_COLLECTOR, kwargs)
	if err != nil {
		return nil, fmt.Errorf("failed to create collector: %w", err)
	}

	as_collector, ok := ptr.(*collector)
	if !ok {
		return nil, fmt.Errorf("unexpected type for collector creation: %T", ptr)
	}

	return as_collector, nil
}

func (r *BamlRuntime) newMediaFromUrl(mediaType MediaType, url string, mimeType *string) (media, error) {
	kwargs, err := serde.EncodeMapEntries(map[string]any{
		"mime_type": mimeType,
		"url":       url,
	}, "media constructor args")
	if err != nil {
		return nil, fmt.Errorf("failed to encode kwargs: %w", err)
	}

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