# `Opsmaru.Incus.NativeYaml`
[🔗](https://github.com/upmaru/opsmaru-incus/blob/v0.1.0/lib/opsmaru/incus/native_yaml.ex#L1)

Strict-subset YAML decoding for native ConfigMap/DevicesMap values.

Contract: every accepted document decodes to exactly what the pinned
go-yaml v4 `UnmarshalYAML` produces; everything else is rejected. Input
outside the subset is rejected even when the native decoder would accept it.

Supported: one document holding a block or flow mapping (ConfigMap values
are scalars; DevicesMap values are mappings of scalars), string keys,
quoted/block scalars as strings, plain scalars resolved with go-yaml v4
rules, anchors on scalars and block mappings, aliases, and `<<` merge keys
(alias, mapping or sequence of those) with native precedence.

Rejected: explicit tags, directives, additional documents, sequences other
than merge lists, nesting deeper than four collections, anchors inside flow
collections or on keys, non-string plain keys, date-like plain scalars, more
than 100 alias expansions and numeric forms outside the mirrored resolver.
yamerl stops at the first rejected token, so pathological input is cheap.

# `decode`

Decodes `yaml` for `:config_map` or `:devices_map` merged into `existing`.
Returns `{:ok, map | nil}` or `:error`; never raises.

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*Consult [api-reference.md](api-reference.md) for complete listing*