hjson-rust fails with Rust 1.48 about hjson-rust HOT 4 OPEN

You can avoid the issue with

serde-hjson = { version = "0.9", default-features = false }

this will disable preservation of key order

I made a version that patches the issue (it was and still is UB but it seems to work for now).
https://github.com/Yarn/hjson-rust/tree/unitialized_fix
https://github.com/Yarn/linked-hash-map/tree/hjson_fix

you can use it with

serde-hjson = { git = "https://github.com/Yarn/hjson-rust.git", rev = "ae3a336153d0c4f757beb848d2059123be00cb75" }

My workaround for the older version of serde is to read the file to a serde_hjson::Value then using an old version of serde_json to write json to a string then reading that string using a new version of serde_json

in Cargo.toml

serde-hjson = { git = "https://github.com/Yarn/hjson-rust.git", rev = "ae3a336153d0c4f757beb848d2059123be00cb75" }
serde_json = "1.0"
serde_json_old = { package = "serde_json", version = "0.8.6" }

in your code assuming Thing implements serde 1.0 deserialize

let mut f = std::fs::File::open(path).unwrap();
let a: serde_hjson::Value = serde_hjson::from_reader(f).unwrap();
let b = serde_json_old::to_string(&a).unwrap();
let thing: Thing = serde_json::from_str(&b).unwrap();

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#24

sometimes the solution is in the obvious place

from hjson-rust.

what's the story with your nu_hjson fork, @jonathandturner ? I can't find the source and it looks like it is also on an older version of serde (0.8.23). From the issues list here there seems to be no viable hjson package for rust currently.

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@Nutomic has tried swapping out linked_hash_map (the dead library causing this error) for hashlink (a new, well maintained one). However unfortunately it has this error:

            #[inline]
            fn visit_map<'de, V>(&mut self, visitor: V) -> Result<Value, V::Error>
                where V: de::MapVisitor,
                // where V: de::MapAccess<'de>,
            {
                let values = try!(MapVisitor::default().visit_map(visitor));
                Ok(Value::Object(values))
            }

error:

error[E0599]: no method named `visit_map` found for struct `LinkedHashMapVisitor<_, _>` in the current scope
   --> src/value.rs:442:57
    |
442 |                 let values = try!(MapVisitor::default().visit_map(visitor));
    |                                                         ^^^^^^^^^ method not found in `LinkedHashMapVisitor<_, _>`
    |
    = help: items from traits can only be used if the trait is in scope
    = note: the following trait is implemented but not in scope; perhaps add a `use` for it:
            `use serde::de::Visitor;`

This is because hashlink requires serde::de::MapAccess rather than serde::de::MapVisitor, which unfortunately only newer versions of serde have.

I tried upgrading the serde version from 0.8.0, but it causes ~100 errors that I'm not familiar enough with serde to fix.

edit: [here's the code: Nutomic/hjson-rust#use-hashlink

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