Every public entry point on DeploymentArtifact took ReadOnlySpan<byte> and did
JsonDocument.Parse(blob.ToArray()) — a full copy plus a full document build per
call — so one apply paid ~8-11 full parses of the same bytes (the scoped
ParseComposition alone parsed three times: scope, composition, BuildClusterSets).
DeploymentArtifact.Open(byte[]) now parses once into ParsedDeploymentArtifact,
which owns the JsonDocument and exposes an instance method mirroring each static
entry point. The moved bodies operate on Root; BuildClusterSets takes JsonElement
instead of re-parsing the blob; ResolveClusterScope is memoized per node id, since
every consumer of one apply asks about the same node.
Every static is now a thin wrapper (Open + delegate + dispose) keeping its
ReadOnlySpan<byte> signature and its lenient empty/malformed contract — the
wrapper pays the one copy and owns the JsonException catch, so output shapes are
unchanged. Hot callers migrate to Open() separately.
ParsedDeploymentArtifactTests pins same-bytes-same-output through both doors for
all six entry points over a rich multi-cluster artifact (raw chain + UNS refs +
scripts + keys + ACLs), with falsifiability controls proving the fixture actually
scopes, plus memoization and after-dispose-use coverage.
Joseph Doherty
59202017cd