Morganamilo/paru · error

invalid value ' ' for key ' ', expected

Error message

invalid value '{val}' for key '{key}', expected: {exp}

What it means

This is an enum-deserialization failure raised from ConfigEnum::from_str (src/config.rs), a generic validation helper used when a config value must map onto a fixed set of enum variants. The helper looks the raw string up in VALUE_LOOKUP (a static table of accepted name -> variant pairs); when the name is absent, it builds the '|'-joined list of valid names from the same table and bails with this error. It fires while loading or validating the configuration file: the input at fault is the string value assigned to the given key, which is neither a recognized variant name (case is compared exactly) nor otherwise convertible. The message deliberately includes the expected alternatives so the user can correct the config without reading the source.

Solutions

  1. Use one of the values listed after 'expected:' in the error message
  2. Fix the spelling/case of the value in the config file or CLI flag
  3. Check documentation for the valid enum values for the key

Example fix

// before
SortBy = popularity  // invalid
// after
SortBy = votes  // one of the values in the 'expected:' list
Defensive patterns

Strategy: validation

Validate before calling

function validate_enum(key: string, value: string, lookup: readonly string[]): string | null {
  return lookup.includes(value) ? null : `invalid value '${value}' for '${key}', expected: ${lookup.join('|')}`;
}

Type guard

function isValidSortBy(v: string): v is 'name' | 'votes' | 'popularity' | 'modified' {
  return ['name', 'votes', 'popularity', 'modified'].includes(v);
}

Try / catch

match ConfigEnum::from_str(key, value) {
    Err(e) if e.to_string().contains("invalid value") => {
        eprintln!("{} — fix the value in paru.conf", e);
        std::process::exit(1);
    }
    Err(e) => return Err(e),
    Ok(v) => apply(v),
}

Prevention

When it happens

Trigger: Setting a config key (or `--sortby`/`--searchby` option) to an unrecognized string, e.g. `--searchby slug` when only name/desc/etc. are valid, or `SortBy = downloads` in paru.conf with a misspelled value.

Common situations: Typoed values in paru.conf; values copied from other AUR helpers with different vocabularies; case-sensitivity issues (`Name` vs `name`).

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

AI-assisted analysis of Morganamilo/paru@9ac3578807 (2026-09-12). Data as JSON: /api/errors/57bcbe4001f15f83. Report an issue: GitHub.

Appendix: source

Thrown at src/config.rs:178

    fn default_or(self, key: &str, value: Option<&str>) -> Result<Self> {
        value.map_or(Ok(self), |value| ConfigEnum::from_str(key, value))
    }

    fn from_str(key: &str, value: &str) -> Result<Self> {
        let val = Self::VALUE_LOOKUP
            .iter()
            .find(|(name, _)| name == &value)
            .map(|(_, res)| *res);

        if let Some(val) = val {
            Ok(val)
        } else {
            let okvalues = Self::VALUE_LOOKUP
                .iter()
                .map(|v| v.0)
                .collect::<Vec<&str>>()
                .join("|");
            bail!(tr!(
                "invalid value '{val}' for key '{key}', expected: {exp}",
                val = value,
                key = key,
                exp = okvalues
            ))
        }
    }
}

type ConfigEnumValues<T> = &'static [(&'static str, T)];

#[derive(Debug, SmartDefault, PartialEq, Eq)]
pub enum Sign {
    #[default]
    No,
    Yes,
    Key(String),
}

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