Rename a field to a word consists of capitals only

[ANtlord]

🐛 Bug description

Parsing finishes with error Error::MissingValue if I rename a field of parsed structure to a word consists of capitals only.

🤔 Expected Behavior

Should be parsed without errors.

👟 Steps to reproduce

Define structure for parsing

#[derive(Deserialize, Debug)]
pub struct DB {
    #[serde(rename="DB_USER")]
    pub user: String,
    #[serde(rename="DB_PASS")]
    pub pass: String,
    #[serde(rename="DB_NAME")]
    pub name: String,
    #[serde(default="host", rename="DB_HOST")]
    pub host: String,
    #[serde(default="port", rename="DB_PORT")]
    pub port: u16,
}

let db_config = envy::from_env::<settings::DB>().unwrap();

Make export DB_USER=postgres before running, run and get panic value: MissingValue("DB_USER")

🌍 Your environment

Archlinux

envy version:
0.4.0

So. I see this code in lib.rs

impl<Iter: Iterator<Item = (String, String)>> Iterator for Vars<Iter> {
    type Item = (VarName, Val);

    fn next(&mut self) -> Option<Self::Item> {
        self.0
            .next()
            .map(|(k, v)| (VarName(k.to_lowercase()), Val(k, v)))
    }
}

So I understand why the k is got lowercased. I get the expected behavior if I remove this conversion but it's not a solution because I lose feature of automatic comparison of a field of parsed structure and an environment variable. So my question is how to determine if a field has Serde tag rename? I can use the determining in order to prevent the conversion only for "renamed" fields.

[tosti007]

I experience the same issue. A different Steps to reproduce would be to copy the example of the README.md and add a rename attribute to any of the variables, e.g.#[serde(rename="baz")] to the baz variable.

[ANtlord]

The issue is opened 9 months ago. I suppose it's not easy to fix it. I tried another library which doesn't have issue but has another one which is resolved in this one. Well, I fixed both of the issues in my fork of that library.

[ardyfeb]

this library doesn't work anymore