BUG: Tagged enum serialization => deserialization produces error with certain crate layout

[folex]

Hi! First, thank for your amazing work. Serde is a gem!

rustup info

active toolchain
----------------
nightly-x86_64-apple-darwin (default)
rustc 1.53.0-nightly (07e0e2ec2 2021-03-24)

Affected versions:

serde: 1.0.118 - 1.0.125
serde_json:: 1.0.57 - 1.0.64

Minimal example

I've stumbled upon a pretty strange issue. I managed to minify the example to 3 dependencies https://github.com/folex/serde_bug_report and minimal lines of code in tests/test.rs.

What happened

I have a tagged enum. I serialize it, then deserialize, and get an error

Error("invalid type: map, expected u64", line: 0, column: 0)

The code is as follows. Define struct, tagged enum wrapper, serialize it to bytes via serde_json, and then deserialize. Pretty usual deal. There's just one strange detail to it, see after the code snippet.

use serde::{Deserialize, Serialize};
use serde_json

#[test]
fn deserialize() {
    let msg = FooMessage::Particle(<_>::default());
    let bytes = serde_json::to_vec(&msg).unwrap();
    let test_msg: Result<FooMessage, _> = serde_json::from_slice(&bytes);
    println!("{:?}", test_msg);
    test_msg.unwrap();
}

#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Default)]
pub struct FooParticle {
    pub timestamp: u64,
}

#[derive(Serialize, Deserialize, Debug, Clone, PartialEq)]
#[serde(tag = "action")]
pub enum FooMessage {
    Particle(FooParticle),
}

Stranger things

For the error to happen, 2 things must take place:

1. tracing-bunyan-formatter should be in the dependencies
2. one of the fields must be named timestamp

Cargo.toml:

[dependencies]
serde = { version = "1.0.125", features = ["derive"] }
serde_json = "1.0.64"
tracing-bunyan-formatter = "0.2.0"

I couldn't figure out why on earth this tracing dependency breaks things, but for me it certainly does. I can avoid using this crate, but maybe this is a symptom of a bigger issue? It was pretty hard to debug and I'd appreciate if you have any suggestions and ideas on the possible reasons.

Thanks!

[thekuom]

I am also seeing this issue albeit with a different example. My minimal example is here: https://github.com/thekuom/serde_json_tracing_bunyan_formatter_bug_report and fails while using #[serde(flatten)]

[thekuom]

@folex, I think this is a result of #505

You should be able to fix this by changing your deps to

tracing-bunyan-formatter = { version = "0.2.0", default-features = false }

or using the workaround mentioned here: #505 (comment)

tracing-bunyan-formatter has the arbitrary-precision feature turned on by default