Migrating from serde_yaml — the one-line version

# Cargo.toml — the whole migration:
serde_yaml = { package = "noyalib-serde-yaml", version = "=0.0.58" }

Every use serde_yaml::… in your codebase keeps compiling and behaving. That is the entire recipe; the rest of this page is what “behaving” means and where the edges are.

What is guaranteed

The shim parses under the core’s ParserConfig::serde_yaml_compat() profile and renders errors upstream-style. The 18-case contract suite in the core repository (crates/noyalib/tests/serde_yaml_contract.rs) pins — with expectations captured live from serde_yaml 0.9.34+deprecated — values, error Display text, and location() line/column/index for: anchors and aliases, merge keys, scalar and composite keys, YAML 1.1 boolean spellings, octal/binary/sexagesimal numbers, null and date scalars, Unicode/CRLF/emoji, malformed-input locations, built-in and custom tags, duplicate keys, non-finite and overflowing numbers, integer boundaries, and alias resource limits.

The edges

• Custom tags under deserialize_any refuse with upstream’s message, but anchor the location at the value rather than the tag.
• Error wording beyond the pinned classes may use noyalib’s own phrasing — upstream’s message set is unbounded; the classes real code pins (per the contract corpus) are matched.
• Spec-vs-libyaml acceptance gaps exist in both directions (libyaml rejects spec-legal anchor names like &\L; empty implicit keys; etc.). noyalib follows the spec — it passes 406/406 of the official YAML test suite.

When you outgrow drop-in

The same engine offers YAML 1.2 strict resolution, byte-exact lossless editing (noyalib::cst), source spans, streaming deserialisation, and schema validation. Depend on noyalib directly (optionally with features = ["compat-serde-yaml"] to keep the shim during a gradual migration), and see the core’s docs/MIGRATION-FROM-SERDE-YAML.md for the full function-by-function mapping.