Migrating from `serde_yml` to `noyalib`

serde_yml was a continuation fork of serde_yaml after upstream archival. The serde_yml repo was itself archived 2025-09-03; 0.0.13 (2024-08-25) is the last published release. The fork inherits the full serde_yaml 0.9 API shape including the 7-variant Value and the with::singleton_map* family.

noyalib is a clean-room reimplementation of YAML 1.2 with the same serde data model, no unsafe code, and no libyaml C dependency.

Crates.io / docs.rs state verified 2026-09-05 (every function this guide names still exists on docs.rs). If the upstream API has shifted since, file an issue and we’ll update.

TL;DR

-[dependencies]
-serde_yml = "0.0"
+[dependencies]
+noyalib = "0.0"

-use serde_yml::Value;
-let v: Value = serde_yml::from_str(input)?;
-let s        = serde_yml::to_string(&v)?;
+use noyalib::Value;
+let v: Value = noyalib::from_str(input)?;
+let s        = noyalib::to_string(&v)?;

That is the entire migration for the typical call site — serde_yml’s public surface mirrors serde_yaml’s function-for-function and noyalib’s does the same.

Function-by-function mapping

`serde_yml` 0.0	`noyalib`
`serde_yml::from_str::<T>`	`noyalib::from_str::<T>`
`serde_yml::from_slice::<T>`	`noyalib::from_slice::<T>`
`serde_yml::from_reader::<R, T>`	`noyalib::from_reader::<R, T>`
`serde_yml::from_value::<T>`	`noyalib::from_value::<T>`
`serde_yml::to_string`	`noyalib::to_string`
`serde_yml::to_writer`	`noyalib::to_writer`
`serde_yml::to_value`	`noyalib::to_value`
`serde_yml::Value`	`noyalib::Value` (same 7 variants)
`serde_yml::Mapping`	`noyalib::Mapping`
`serde_yml::Number`	`noyalib::Number`
`serde_yml::Error`	`noyalib::Error`
`serde_yml::Deserializer`	`noyalib::Deserializer`
`serde_yml::Serializer`	`noyalib::Serializer`
`serde_yml::with::singleton_map`	`noyalib::with::singleton_map`
`serde_yml::with::singleton_map_recursive`	`noyalib::with::singleton_map_recursive`
`serde_yml::with::singleton_map_optional`	`noyalib::with::singleton_map_optional`
`serde_yml::with::singleton_map_with`	`noyalib::with::singleton_map_with`
(n/a)	`noyalib::from_str_strict::<T>` — error on unknown keys
(n/a)	`noyalib::Spanned<T>` — source-location wrapper
(n/a)	`noyalib::cst::Document` — lossless byte-faithful edits
(n/a)	`noyalib::ParserConfig` — explicit resource limits

serde_yml’s Value enum has the same 7 variants as serde_yaml’s and noyalib’s — Null, Bool, Number, String, Sequence, Mapping, Tagged(Box<TaggedValue>). No match-arm changes are required.

Behavioural differences worth knowing

The same three behavioural notes that apply to the serde_yaml migration apply here. See MIGRATION-FROM-SERDE-YAML.md for the full discussion; the headlines:

Value::Tagged is preserved through the Value data path. noyalib::from_str::<Value>("!Custom 'hi'\n") returns Value::Tagged(t) (t.tag() == "!Custom", t.value() == Value::String("hi")), not the transparent-unwrapped Value::String("hi"). serde_yml’s behaviour matched serde_yaml’s pre-Tagged behaviour. To get the unwrapped string, call value.untag().as_str().
YAML 1.2 strict booleans by default. country: NO parses as Value::String("NO"), not Value::Bool(false). Opt into YAML 1.1 boolean recognition via ParserConfig::new().legacy_booleans(true) if you need the old behaviour for round-trip compatibility with legacy files.
Multi-doc streams use load_all_as. serde_yml’s Deserializer::from_str(...).map(...) pattern maps to noyalib::load_all_as::<T>(input)? returning Vec<T>.

Drop-in compatibility shim

Because serde_yml’s API is a verbatim mirror of serde_yaml’s, the same compat shim works:

[dependencies]
noyalib = { version = "0.0", features = ["compat-serde-yaml"] }

-use serde_yml::{from_str, to_string, Value, Mapping, Number};
+use noyalib::compat::serde_yaml::{from_str, to_string, Value, Mapping, Number};

The shim re-exports noyalib-native types under noyalib::compat::serde_yaml::* — no transitive dependency on the archived serde_yaml 0.9 nor serde_yml 0.0.

Migration checklist

Replace serde_yml = "0.0" → noyalib = "0.0" (or noyalib = { version = "0.0", features = ["compat-serde-yaml"] } for the shim path).
Replace use serde_yml::*; → use noyalib::*; (or use noyalib::compat::serde_yaml::*;).
If you exhaustively match Value, the 7 variant arms are already correct — no shape change.
Decide YAML 1.1-vs-1.2 boolean handling: stay on YAML 1.2 strict (the safer default) or opt into legacy_booleans(true).
Run cargo audit. The migration removes any transitive serde_yaml 0.9 advisory exposure.
Run your existing test suite. Failures almost always trace to one of the three behavioural notes above.

If you hit a snag, file an issue at https://github.com/sebastienrousseau/noyalib/issues with the input that misbehaves.

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