serde-save

The most complete serialization tree for [serde].

[Save] represents the entire serde data model, including struct names, field names, and enum variant information. This means that it can intercept structures when they are serialized, before losslessly forwarding them.

[Save] can optionally persist errors in the serialization tree, instead of short-circuiting. This is a zero-cost option - see documentation on [Save::Error] for more.

#[derive(Serialize)]
struct MyStruct {
    system_time: SystemTime,
    path_buf: PathBuf,
    normal_string: String,
}

// These will fail to serialize
let before_unix_epoch = SystemTime::UNIX_EPOCH - Duration::from_secs(1);
let non_utf8_path = PathBuf::from(OsString::from_vec(vec![u8::MAX]));

let my_struct = MyStruct {
    system_time: before_unix_epoch,
    path_buf: non_utf8_path,
    normal_string: String::from("this is a string"), // this is fine
};

// By default errors are short-circuiting
assert_eq!(
    save(&my_struct).unwrap_err().to_string(),
    "SystemTime must be later than UNIX_EPOCH"
);

// But you can persist and inspect them in-tree if you prefer.
assert_eq!(
    save_errors(&my_struct), // use this method instead
    Save::strukt(
        "MyStruct",
        [
            ("system_time",   Save::error("SystemTime must be later than UNIX_EPOCH")),
            ("path_buf",      Save::error("path contains invalid UTF-8 characters")),
            ("normal_string", Save::string("this is a string")),
        ]
    )
)

[Serializer] can also check for incorrect implementations of the serde protocol.

See the documentation on [Save]s variants to see which invariants are checked. You can configure this behaviour.