kubernetes/kops · error

error building annotation patch: %v

Error message

error building annotation patch: %v

What it means

SetInstalledVersion builds a JSON strategic-merge patch containing only the annotations map, then applies it to the namespace. This error is thrown if json.Marshal of the in-memory annotationPatch struct fails. Since the struct is simple (map[string]string), this is rare and typically indicates an unexpected serialization problem.

Source

Thrown at channels/pkg/channels/channel_version.go:202

	Annotations map[string]string `json:"annotations,omitempty"`
}

func (c *Channel) SetInstalledVersion(ctx context.Context, k8sClient kubernetes.Interface, version *ChannelVersion) error {
	// Primarily to check it exists
	_, err := k8sClient.CoreV1().Namespaces().Get(ctx, c.Namespace, metav1.GetOptions{})
	if err != nil {
		return fmt.Errorf("error querying namespace %q: %v", c.Namespace, err)
	}

	value, err := version.Encode()
	if err != nil {
		return err
	}

	annotationPatch := &annotationPatch{Metadata: annotationPatchMetadata{Annotations: map[string]string{c.AnnotationName(): value}}}
	annotationPatchJSON, err := json.Marshal(annotationPatch)
	if err != nil {
		return fmt.Errorf("error building annotation patch: %v", err)
	}

	klog.V(2).Infof("sending patch: %q", string(annotationPatchJSON))

	_, err = k8sClient.CoreV1().Namespaces().Patch(ctx, c.Namespace, types.StrategicMergePatchType, annotationPatchJSON, metav1.PatchOptions{})
	if err != nil {
		return fmt.Errorf("error applying annotation to namespace: %v", err)
	}
	return nil
}

View on GitHub (pinned to 4c8573c808)

Solutions

1. Inspect the wrapped %v marshal error to identify the cause.
2. Verify the annotation value produced by version.Encode() is a plain string (no invalid content).
3. Upgrade/patch the library if a serialization bug is confirmed.
4. Report with the full wrapped error if reproducible.

if err := ch.SetInstalledVersion(ctx, k8sClient, version); err != nil {
    if strings.Contains(err.Error(), "error building annotation patch") {
        return fmt.Errorf("patch construction bug: %w", err)
    }
    return err
}

When it happens

Trigger: json.Marshal failing on the annotationPatch struct during SetInstalledVersion — practically only due to a programming-level issue, since the payload contains only strings.

Common situations: Rarely hit in practice; would surface as a bug in the patch construction code rather than a cluster/environment issue.

Understand the failure class

Background: json.Marshal / "failed to marshal" errors in Go: why "unsupported type" happens and how to fix it — this error's family across 22 libraries.

Related errors

• building node patch: %w
• error building node patch: %v
• marshaling to json for %v: %w
• error marshaling into JSON: %v
• error patching needs-update label: %v

AI-assisted analysis of kubernetes/kops@4c8573c808 (2026-09-05). Data as JSON: /api/errors/8409f97c98542193. Report an issue: GitHub.