glanceapp/glance · error

orderedMap: decoding key: %v

Error message

orderedMap: decoding key: %v

What it means

The orderedYAMLMap unmarshaler failed while decoding a mapping key into the generic key type K. The key node in the YAML document could not be converted to the expected Go type (typically string), for example a complex node (sequence/mapping) where a scalar key was expected. The underlying go-yaml decode error is included via %v.

Source

Thrown at internal/glance/config.go:620

func (om *orderedYAMLMap[K, V]) UnmarshalYAML(node *yaml.Node) error {
	if node.Kind != yaml.MappingNode {
		return fmt.Errorf("orderedMap: expected mapping node, got %d", node.Kind)
	}

	if len(node.Content)%2 != 0 {
		return fmt.Errorf("orderedMap: expected even number of content items, got %d", len(node.Content))
	}

	om.keys = make([]K, len(node.Content)/2)
	om.data = make(map[K]V, len(node.Content)/2)

	for i := 0; i < len(node.Content); i += 2 {
		keyNode := node.Content[i]
		valueNode := node.Content[i+1]

		var key K
		if err := keyNode.Decode(&key); err != nil {
			return fmt.Errorf("orderedMap: decoding key: %v", err)
		}

		if _, ok := om.data[key]; ok {
			return fmt.Errorf("orderedMap: duplicate key %v", key)
		}

		var value V
		if err := valueNode.Decode(&value); err != nil {
			return fmt.Errorf("orderedMap: decoding value: %v", err)
		}

		(*om).keys[i/2] = key
		(*om).data[key] = value
	}

	return nil
}

View on GitHub (pinned to 91324e8de7)

Solutions

1. Find the mapping named in the wrapping error and make every key a plain scalar (string)
2. If keys must be non-strings, verify the target orderedYAMLMap key type actually matches the YAML scalars (quotes: `"1"` vs `1`)
3. Re-run and read the nested go-yaml error for the exact line/column, then fix that spot

Example fix

# before
theme:
  presets:
    - my-theme:
        color-scheme: dark
# after
theme:
  presets:
    my-theme:
      color-scheme: dark

// Walk the YAML tree and assert every key in relevant mappings is a scalar
func keysAreScalars(n *yaml.Node) error {
    if n.Kind != yaml.MappingNode { return nil }
    for i := 0; i < len(n.Content); i += 2 {
        if n.Content[i].Kind != yaml.ScalarNode {
            return fmt.Errorf("non-scalar key at line %d", n.Content[i].Line)
        }
    }
    return nil
}

Wrap config decode; on 'orderedMap: decoding key' print the node line from the chained error and reject the file with an actionable message.

When it happens

Trigger: Decoding a YAML mapping into orderedYAMLMap[string, X] where a key is itself a sequence or mapping node (e.g. `[a, b]: value`), or a typed key field (int/bool alias) receiving an incompatible scalar.

Common situations: Copy-pasted YAML where a list was accidentally placed at the key position; YAML anchors/merge keys used as keys; indenting a list under a map so that list items become keys.

Related errors

• orderedMap: decoding value: %v
• URL is required
• nested groups are not supported
• split columns inside of groups are not supported
• source is required

AI-assisted analysis of glanceapp/glance@91324e8de7 (2026-08-15). Data as JSON: /api/errors/dc77fcbbfa5cf3b5. Report an issue: GitHub.