Rust: project 3 `trait KvsEngine`'s `fn remove`

Author: thanhnguyen2187Created Jan 6, 2025Updated Jan 6, 2025

Labelstype/enhancement

Now, the trait is:

rust

pub trait KvsEngine: Send + Sync {
    fn set(&mut self, key: String, value: String) -> Result<()>;
    fn get(&self, key: String) -> Result<Option<String>>;
    fn remove(&mut self, key: String) -> Result<()>;
}

I think Result<()> of remove is not good typing, as it groups both key not found and other errors into one type. The signature of get is much better, as we can infer from the returned result:

Result(Some(...)): a corresponding value is found
Result(None): there is no corresponding value
Error(...): error happened

My proposal is to have remove returns the same type as get:

rust

pub trait KvsEngine: Send + Sync {
    fn set(&mut self, key: String, value: String) -> Result<()>;
    fn get(&self, key: String) -> Result<Option<String>>;
    fn remove(&mut self, key: String) -> Result<Option<String>>;
}

Source: pingcap/talent-plan

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