I’m thrilled to announce Serde 0.7.0! It’s been a long time coming, and has a number of long awaited new features, breaking changes, and other notable changes. Serde 0.6.x is now deprecated, and while I’ll try to keep serde_codegen and serde_macros while projects switch over to 0.7, I’m going to shift more to a pull-based approach, so please file a bug ticket if a nightly release has broken you.

On to the list on the major changes!

Serde

• Removed the word Error from serde::de::Error variants.
• Renamed visit_ methods to serialize_ and deserialize_.
• Removed dependency on the deprecated num crate.
• Require that implementations of serde::de::Error implement std::error::Error.
• Added serde::de::Deserializer::deserialize_struct_field hook that allows a Deserializer to know the next value is a struct field.
• Added serde::ser::Error, which allows a Serialize type produce an error if it cannot be serialized.
• Serializing std::path::Path with non-unicode characters will result in a Serde error, rather than a panic.
• Added implementations for std::net types.
• Added serde::de::Error::unknown_variant error message hook.
• Renamed serde::de::Error::syntax to serde::de::Error::custom.

Serde Codegen and Macros

• Serde now by default ignores unknown fields when deserializing. The previous behavior, where Serde will report unknown fields as an error, can be opted in with the container annotation #[serde(deny_unknown_fields)], as in:

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#[serde(deny_unknown_fields)]
struct Point {
    x: usize,
    y: usize,
}

• Added the container annotation #[serde(rename="...")]to rename the container, as in:

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#[serde(rename="point")]
struct Point {
    x: usize,
    y: usize,
}

• Added the variantl annotation #[serde(rename="...")] to rename variants, as in:

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enum Value {
    #[serde(rename="type")]
    Type
}

• Added rename annotation #[serde(rename(serialize="...", deserialize="..."))] that supports crazy schemas like AWS that expect serialized fields with the first character lower case, and the deserialized response with the first character upper cased.
• Removed support for the unused format-specific rename support.
• Added the field annotation #[serde(default="$path")], where $path is a reference to some function that returns a default value for a field if it’s not present when deserializing. For example:

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trait MyDefault {
    fn my_default() -> Self;
}

struct Point<T: MyDefault> {
    x: T,
    #[serde(default="MyDefault::my_default")]
    y: T,
}

• Added the field annotation #[serde(skip_serializing_if="$path")], where $path is a path reference to some function that returns a bool, that if true, should skip serializing the field.

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trait ShouldSkip {
    fn should_skip(&self) -> bool;
}

struct Point<T: ShouldSkip> {
    x: T,
    #[serde(skip_serializing_if="ShouldSkip::should_skip")]
    y: T,
}

• Added the field annotations #[serde(serialize_with="$path")] and #[serde(deserialize_with="$path")], where $path us a path reference to some function that serializes a field, as in:

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trait MySerialization {
    fn serialize_with<S: Serializer>(&self, serializer: &mut S) -> Result<(), S::Error>;

    fn deserialize_with<D: Deserializer>(deserializer: &mut D) -> Result<Self, D::Error>;
}

struct Record {
    #[serde(serialize_with="MySerialization::serialize_with")]
    #[serde(deserialize_with="MySerialization::deserialize_with")]
    timestamp: time::Timespec,
}

Serde JSON

• Added StreamDeserializer, that enables parsing a stream of JSON values optionally separated by whitespace into an iterator of those deserialized values.

Thanks

I’d like to thank everyone that’s helped out over the past few months. Please forgive me if I accidentally left you off the list:

• Craig M. Brandenburg
• Florian Gilcher
• Hans Kristian Flaatten
• Issam Hakimi
• Joe Wilm
• John Heitmann
• Marek Kotewicz
• Ms2ger
• Nathan Lilienthal
• Oliver Schneider
• Paul Woolcock
• Roma Sokolov
• Simon Persson
• Thomas Bahn
• Tom Jakubowski
• thorbenk