go-kratos/kratos · error

metadata: AppendToClientContext got an odd number of input p

Error message

metadata: AppendToClientContext got an odd number of input pairs for metadata: %d

What it means

Error "metadata: AppendToClientContext got an odd number of input pairs for metadata: %d" thrown in go-kratos/kratos.

Source

Thrown at metadata/metadata.go:108

type clientMetadataKey struct{}

// NewClientContext creates a new context with client md attached.
func NewClientContext(ctx context.Context, md Metadata) context.Context {
	return context.WithValue(ctx, clientMetadataKey{}, md)
}

// FromClientContext returns the client metadata in ctx if it exists.
func FromClientContext(ctx context.Context) (Metadata, bool) {
	md, ok := ctx.Value(clientMetadataKey{}).(Metadata)
	return md, ok
}

// AppendToClientContext returns a new context with the provided kv merged
// with any existing metadata in the context.
func AppendToClientContext(ctx context.Context, kv ...string) context.Context {
	if len(kv)%2 == 1 {
		panic(fmt.Sprintf("metadata: AppendToClientContext got an odd number of input pairs for metadata: %d", len(kv)))
	}
	md, _ := FromClientContext(ctx)
	md = md.Clone()
	for i := 0; i < len(kv); i += 2 {
		md.Set(kv[i], kv[i+1])
	}
	return NewClientContext(ctx, md)
}

// MergeToClientContext merge new metadata into ctx.
func MergeToClientContext(ctx context.Context, cmd Metadata) context.Context {
	md, _ := FromClientContext(ctx)
	md = md.Clone()
	for k, v := range cmd {
		md[k] = v
	}
	return NewClientContext(ctx, md)
}

View on GitHub (pinned to 668db92c2c)

When it happens

Trigger: Thrown at metadata/metadata.go:108 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of go-kratos/kratos@668db92c2c (2026-08-16). Data as JSON: /api/errors/191fd44993813137. Report an issue: GitHub.