openai/codex · error · anyhow::Error

methods must not contain empty entries

Error message

methods must not contain empty entries

What it means

normalize_methods trims and uppercases each entry of match.methods; an entry that becomes empty afterwards — "" or whitespace-only — is rejected with 'methods must not contain empty entries'. The list itself must also be non-empty, which is a separate check ('match.methods must not be empty').

Source

Thrown at codex-rs/network-proxy/src/mitm_hook.rs:555

    let normalized = normalize_host(host);
    if normalized.is_empty() {
        return Err(anyhow!("host must not be empty"));
    }
    if normalized.contains('*') {
        return Err(anyhow!(
            "MITM hook hosts must be exact hosts and cannot contain wildcards"
        ));
    }
    Ok(normalized)
}

fn normalize_methods(methods: &[String]) -> Result<Vec<String>> {
    methods
        .iter()
        .map(|method| {
            let normalized = method.trim().to_ascii_uppercase();
            if normalized.is_empty() {
                return Err(anyhow!("methods must not contain empty entries"));
            }
            Ok(normalized)
        })
        .collect()
}

fn validate_query_constraints(query: &BTreeMap<String, Vec<String>>) -> Result<()> {
    for (name, values) in query {
        let normalized = normalize_query_name(name)?;
        if normalized.is_empty() {
            return Err(anyhow!("query keys must not be empty"));
        }
        if values.is_empty() {
            return Err(anyhow!(
                "query key {name:?} must list at least one allowed value"
            ));
        }
        let _ = compile_value_matchers(values)

View on GitHub (pinned to 339751715c)

Solutions

1. Remove blank entries from methods
2. Write standard HTTP method names ("GET", "POST", ...); case is normalized automatically
3. If the list ends up empty, that is the separate 'must not be empty' error — keep at least one method

Example fix

# before
methods = ["GET", ""]

# after
methods = ["GET", "POST"]

// Rust — no blank method entries
for (i, hook) in config.mitm_hooks.iter().enumerate() {
    if hook.matcher.methods.iter().any(|m| m.trim().is_empty()) {
        return Err(anyhow!("network.mitm_hooks[{i}].match.methods has an empty entry"));
    }
}

fn methods_have_no_blanks(hook: &MitmHookConfig) -> bool {
    hook.matcher.methods.iter().all(|m| !m.trim().is_empty())
}

match validate_mitm_hook_config(&config) {
    Ok(()) => {}
    Err(err) => eprintln!("{err:#}"), // 'invalid network.mitm_hooks[i].match.methods: methods must not contain empty entries'
}

When it happens

Trigger: methods = [""], or methods = ["GET", " "] in a [[network.mitm_hooks]] entry; methods matching is case-insensitive ('get' normalizes to 'GET'), but blank entries fail.

Common situations: Lists built by string concatenation that emit an empty element; trailing commas parsed as empty entries; editing out one method but leaving its separator.

Understand the failure class

Background: Config validation failed: what "invalid value for {key}" and settings-rejection errors mean across 19 open-source libraries — this error's family across 19 libraries.

Related errors

• network.mitm_hooks[{hook_index}].match.body is reserved for
• network.mitm_hooks[{hook_index}].host must not be empty
• expected exactly one of secret_env_var or secret_file
• path_prefixes must not contain empty entries
• glob pattern must not be empty

AI-assisted analysis of openai/codex@339751715c (2026-08-25). Data as JSON: /api/errors/9a13f6d66bf0092b. Report an issue: GitHub.