Migrating from `yaml_serde` to `noyalib`

yaml_serde (also resolvable as yaml-serde) is the actively maintained fork of serde_yaml under the yaml org. 0.10.7 (2026-08-18) is the current release. The fork advertises itself as a true drop-in for serde_yaml and documents a Cargo package = rename so existing use serde_yaml::*; imports keep compiling without touching call sites.

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]
-yaml_serde = "0.10"
+[dependencies]
+noyalib = "0.0"

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

If you adopted yaml_serde via the Cargo package-rename trick (keeping use serde_yaml::*; in source), drop the rename:

-[dependencies]
-serde_yaml = { package = "yaml_serde", version = "0.10" }
+[dependencies]
+noyalib = "0.0"

-use serde_yaml::{from_str, to_string, Value};
+use noyalib::{from_str, to_string, Value};

Function-by-function mapping

yaml_serde mirrors serde_yaml 0.9 exactly. Every entry below holds for both spellings; substitute your import path.

`yaml_serde` 0.10	`noyalib`
`yaml_serde::from_str::<T>`	`noyalib::from_str::<T>`
`yaml_serde::from_slice::<T>`	`noyalib::from_slice::<T>`
`yaml_serde::from_reader::<R, T>`	`noyalib::from_reader::<R, T>`
`yaml_serde::from_value::<T>`	`noyalib::from_value::<T>`
`yaml_serde::to_string`	`noyalib::to_string`
`yaml_serde::to_writer`	`noyalib::to_writer`
`yaml_serde::to_value`	`noyalib::to_value`
`yaml_serde::Value`	`noyalib::Value` (same 7 variants)
`yaml_serde::Mapping`	`noyalib::Mapping`
`yaml_serde::Number`	`noyalib::Number`
`yaml_serde::Error`	`noyalib::Error`
`yaml_serde::Deserializer`	`noyalib::Deserializer`
`yaml_serde::Serializer`	`noyalib::Serializer`
`yaml_serde::with::singleton_map`	`noyalib::with::singleton_map`
`yaml_serde::with::singleton_map_recursive`	`noyalib::with::singleton_map_recursive`
`yaml_serde::with::singleton_map_optional`	`noyalib::with::singleton_map_optional`
`yaml_serde::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

yaml_serde::Value is the same 7-variant enum as serde_yaml::Value and noyalib::Value: Null, Bool, Number, String, Sequence, Mapping, Tagged(Box<TaggedValue>).

Behavioural differences worth knowing

The three behavioural notes that apply to the serde_yaml migration apply here. The full discussion lives in MIGRATION-FROM-SERDE-YAML.md; 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")). To get the unwrapped inner, call value.untag().as_str().
YAML 1.2 strict booleans by default. country: NO stays Value::String("NO"). Opt into legacy YAML 1.1 boolean recognition via ParserConfig::new().legacy_booleans(true).
Multi-doc streams use load_all_as. noyalib::load_all_as::<T>(input) returns Vec<T> directly.

Drop-in compatibility shim

If you adopted yaml_serde to keep use serde_yaml::*; imports compiling and you can’t change call sites at all, the noyalib compat shim does the same:

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

-use serde_yaml::{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 dep on either upstream.

Migration checklist

Replace yaml_serde = "0.10" (or the package-rename pattern under serde_yaml = { package = "yaml_serde" }) → noyalib = "0.0".
Replace use yaml_serde::*; → use noyalib::*; (or use noyalib::compat::serde_yaml::*; for the shim path).
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 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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