sxyazi/yazi · error

not a string

Error message

not a string

What it means

The TryFrom<DataKey> for String conversion only succeeds when the DataKey is the String variant; any other key variant (integer, number, etc.) bails with "not a string". It signals a caller assumption that a dynamic data value is textual when it is not.

Source

Thrown at yazi-shared/src/data/key.rs:81

}

impl From<usize> for DataKey {
	fn from(value: usize) -> Self { Self::Integer(value as i64) }
}

impl From<&'static str> for DataKey {
	fn from(value: &'static str) -> Self { Self::String(Cow::Borrowed(value)) }
}

impl From<String> for DataKey {
	fn from(value: String) -> Self { Self::String(Cow::Owned(value)) }
}

impl TryFrom<DataKey> for String {
	type Error = anyhow::Error;

	fn try_from(value: DataKey) -> Result<Self, Self::Error> {
		let DataKey::String(s) = value else { bail!("not a string") };
		Ok(s.into_owned())
	}
}

impl_into_integer!(DataKey, i8, i16, i32, i64, isize, u8, u16, u32, u64, usize, crate::id::Id);
impl_into_number!(DataKey, f32, f64);

View on GitHub (pinned to 8ebf930f17)

Solutions

1. Match on the DataKey and handle non-string variants explicitly instead of force-converting.
2. Convert with the appropriate TryFrom impl (e.g. integer impls) for the actual variant.
3. At the producer side, ensure the value is emitted as DataKey::String (e.g. tostring in Lua before passing across).

Example fix

// before
let s = String::try_from(key)?;
// after
let s = match key {
    DataKey::String(s) => s.into_owned(),
    DataKey::Integer(i) => i.to_string(),
    other => bail!("unexpected key: {other:?}"),
};

if !matches!(key, DataKey::String(_)) { bail!("expected string key"); }

fn as_str_key(key: &DataKey) -> Option<&str> { match key { DataKey::String(s) => Some(s), _ => None } }

// use match instead of TryFrom to avoid the panic-prone conversion
let s = as_str_key(&key).ok_or_else(|| anyhow!("expected string key"))?;

When it happens

Trigger: `String::try_from(data_key)` (or `?`/`.unwrap()` on such a conversion) where the DataKey holds a numeric or other non-string value.

Common situations: Reading dynamic data (e.g. from Lua-bound data or fetch results) and assuming a field is a string when it was produced as a number; indexing data maps with mixed-type keys.

Understand the failure class

Background: Type mismatch errors: IllegalArgumentException, TypeError and type guards across 150 open-source libraries — this error's family across 150 libraries.

Related errors

• not a dict
• Failed to downcast Data into {}
• not a number
• not a File
• Invalid value for the name property

AI-assisted analysis of sxyazi/yazi@8ebf930f17 (2026-09-09). Data as JSON: /api/errors/f6bc8595ade09392. Report an issue: GitHub.