0.31.0 breaks newtype serialization

[realsama]

Hello there,

I made an upgrade from 0.30.0 -> 0.31.0 but this breaks my code. The below is a reproducible prototype.

use quick_xml::se::to_string;

use serde::{Deserialize, Serialize};

#[derive(Serialize, Deserialize, Debug)]
#[serde(rename = "document")]
pub struct Document {
    #[serde(rename = "@type")]
    pub _type: String,
    pub section: Option<Section>,
}

#[derive(Serialize, Deserialize, Debug)]
pub struct Section {
    #[serde(rename = "@name")]
    pub name: String,
    #[serde(default)]
    pub child: Vec<SectionChild>,
}

#[derive(Serialize, Deserialize, Debug)]
pub enum SectionChild {
    #[serde(rename = "domain")]
    Domain(Domain),
}

#[derive(Serialize, Deserialize, Debug)]
pub struct Domain {
    #[serde(rename = "@name")]
    pub name: String,
}

pub fn main() {
    let doc = Document {
        _type: "document".to_string(),
        section: Some(Section {
            name: "section".to_string(),
            child: vec![SectionChild::Domain(Domain {
                name: "domain".to_string(),
            })],
        }),
    };

    let xml = to_string(&doc).unwrap();
    println!("{}", xml);
}

Running the above will produce an error.

called `Result::unwrap()` on an `Err` value: Unsupported("cannot serialize enum newtype variant `SectionChild::domain`")

[Mingun]

Yes, this is consequences of #630. Unfortunately, serge made a breaking change so we had to change our enum representation policy in incompatible way. You should add rename = "$value" to child member:

 #[derive(Serialize, Deserialize, Debug)]
 pub struct Section {
     #[serde(rename = "@name")]
     pub name: String,
-    #[serde(default)]
+    #[serde(default, rename = "$value")]
     pub child: Vec<SectionChild>,
 }

That representation in any case is more correct and also works in 0.30.

Your example in 0.31

[realsama]

Worked. Thank you for your response!