What causes "key can not contain null bytes" in Morganamilo/paru?

Locate the offending [env] entry (e.g. grep -P '\x00' paru.conf) and remove the null byte

Morganamilo/paru · error · anyhow::Error

key can not contain null bytes

Error message

key can not contain null bytes

What it means

parse_env rejects environment variable keys containing NUL ('\0') bytes. NUL bytes are invalid in environment variable names on Unix (execve-style env blocks are NUL-delimited), so any key containing one would be truncated or rejected by the OS. The library raises this to fail early with a clear message.

Solutions

Locate the offending [env] entry (e.g. grep -P '\x00' paru.conf) and remove the null byte
Recreate the config file from a clean copy instead of editing the binary-corrupted file
Validate the config is UTF-8 text: file/iconv check

Defensive patterns

Strategy: validation

Validate before calling

fn valid_env_key(key: &str) -> bool {
    !key.is_empty() && !key.contains('\0')
}

Prevention

Keep config files as clean UTF-8 text
Never write config files with binary tools
Check for NUL bytes with grep -P '\x00' after programmatic edits

When it happens

Trigger: A key string parsed from the config [env] section contains a '\0' character, e.g. from a binary-corrupted config file or bad escaping.

Common situations: Corrupted or machine-generated paru.conf with embedded null bytes; files edited through tools that inserted NULs.

Understand the failure class

Background: "Invalid ... format", "must be in format X", "does not look like a ..." — invalid argument format errors across CLI tools and libraries — this error's family across 17 libraries.

Related errors

AI-assisted analysis of Morganamilo/paru@9ac3578807 (2026-09-12). Data as JSON: /api/errors/3aa69eb04ae1b945. Report an issue: GitHub.

Appendix: source

Thrown at src/config.rs:991

        let repo = self.pkgbuild_repos.repo_mut(repo).unwrap();

        match key {
            "Url" => repo.source.set_url(Url::parse(value?)?),
            "Path" => repo.source.set_path(value?.to_string()),
            "Depth" => repo.depth = value?.parse()?,
            "SkipReview" => repo.skip_review = true,
            "GenerateSrcinfo" => repo.force_srcinfo = true,
            _ => eprintln!("{}", tr!("error: unknown option '{}' in repo", key)),
        }

        Ok(())
    }

    fn parse_env(&mut self, key: &str, value: Option<&str>) -> Result<()> {
        let value = value.context(tr!("key can not be empty"))?;

        ensure!(!key.is_empty(), tr!("key can not be empty"));
        ensure!(!key.contains('\0'), tr!("key can not contain null bytes"));
        ensure!(
            !value.contains('\0'),
            tr!("value can not contain null bytes")
        );

        self.env.push((key.to_owned(), value.to_string()));
        set_var(key, value);
        Ok(())
    }

    fn parse_bin(&mut self, key: &str, value: Option<&str>) -> Result<()> {
        let value = value
            .map(|s| s.to_string())
            .ok_or_else(|| anyhow!(tr!("key can not be empty")))?;

        let split = value.split_whitespace().map(|s| s.to_string());

        match key {

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