Inconsistent pretty string

[sigoden]

If the string contains newlines, it should be formatted as a multi-line string with |.

However, when the string has a space before \n, it does not work.

use serde::Serialize;

#[derive(Serialize, Debug)]
struct Foo {
    v1: String,
    v2: String,
}

fn main() {
    let a = Foo {
        v1: "a\nc".to_string(),
        v2: "a \nc".to_string(),
    };
    let yaml = serde_yaml_ng::to_string(&a).unwrap();
    println!("{}", yaml);
}

v1: |-
  a
  c
v2: "a \nc"

[acatton]

serde-yaml-ng, like the original serde-yaml wraps unsafe-libyaml which is itself a transpilation from C to Rust of the libyaml.

It is unclear to me who is responsible for this "issue". And I'm not fluent in enough libyaml to give you a definite answer.

All I can say is that the libyaml was originally written for Python. And there is a similar behavior there:

>>> import yaml
>>> print(yaml.dump({'v1': 'a\nc', 'v2': 'a \nc'}))
v1: 'a

  c'
v2: "a \nc"

So I suspect, that the culprit is the libyaml. Either way, this won't get fixed for two reasons: I'm not going to recompile the libyaml to Rust, because I find it to be an heresy. And, I actually want to migrate to libyaml-safer as mentioned in #5. I've been working slowly on this as there is a lot of refactoring necessary for this move.

But regardless of the move, I am unsure how this is a bug. Yeah, it doesn't look neat, I'll grant you this. But deserialize(serialize(data)) = data is still valid, right? This is valid YAML being generated. And one could argue that the current serialization makes it obvious that there are trailing spaces, right?

I'll leave this issue open as documentation, and see what we can do once we fix #5.