Hmbown/CodeWhale · error · std::io::Error

config file exceeds the 1 MiB limit

Error message

config file {} exceeds the 1 MiB limit

What it means

The config loader reads config files with a hard cap of MAX_CONFIG_FILE_BYTES (1 MiB), using read(2) with O_NOFOLLOW and take(limit+1) so oversized files are detected without reading them fully into memory unbounded. If the file's byte length exceeds 1 MiB it returns an InvalidData io::Error naming the path. This is a safety guard against absurd/corrupt config files and symlink attacks.

Solutions

1. Inspect the file at the reported path (`ls -lh`, `wc -c`) and trim it under 1 MiB — remove duplicated or commented-out sections
2. Regenerate the config from a known-good template instead of hand-editing the bloated one
3. Check whether scripts/CI write into the config path and bound their output
4. Verify the path is a regular file, not a symlink to something huge

import os
path = "~/.codewhale/config.toml"
if os.path.getsize(os.path.expanduser(path)) > 1024*1024:
    raise SystemExit(f"{path} exceeds 1 MiB; trim before loading")

match std::fs::read(path) {
    Err(e) if e.kind() == std::io::ErrorKind::InvalidData =>
        eprintln!("config too large (>1MiB): regenerate it"),
    other => other,
}

When it happens

Trigger: Loading a config file (via the no-follow hardened reader path) whose size on disk is greater than 1 MiB — the read is capped at MAX_CONFIG_FILE_BYTES + 1 bytes and the length check fires.

Common situations: A config generator or tool concatenated credentials/prompts into the config until it grew past 1 MiB; a symlink or bind-mount pointed the config path at a huge file (the O_NOFOLLOW flag catches plain symlinks); accidental binary/log file placed at the config path.

Understand the failure class

Background: "File too large" / "file size exceeds limit" errors: why libraries cap file sizes and how to fix them — this error's family across 46 libraries.

Related errors

• bundle at is bytes; the limit is bytes
• agent profile provider cannot be empty
• agent profile provider must be a simple provider id
• api_key cannot be empty string
• approval_policy ' ' is not allowed by requirements ( )

AI-assisted analysis of Hmbown/CodeWhale@73e0f67d83 (2026-09-22). Data as JSON: /api/errors/c8b27a2f86a376bf. Report an issue: GitHub.

Appendix: source

Thrown at crates/config/src/lib.rs:6880

    read_string_no_follow(&path)
        .with_context(|| format!("failed to read {label} at {}", path.display()))
}

/// Maximum bytes read from a config file. Configs are kilobytes; anything
/// larger is not a config file.
const MAX_CONFIG_FILE_BYTES: u64 = 1024 * 1024;

#[cfg(unix)]
fn read_string_no_follow(path: &Path) -> std::io::Result<String> {
    let file = fs::OpenOptions::new()
        .read(true)
        .custom_flags(libc::O_NOFOLLOW)
        .open(path)?;
    let mut raw = String::new();
    file.take(MAX_CONFIG_FILE_BYTES + 1)
        .read_to_string(&mut raw)?;
    if raw.len() as u64 > MAX_CONFIG_FILE_BYTES {
        return Err(std::io::Error::new(
            std::io::ErrorKind::InvalidData,
            format!("config file {} exceeds the 1 MiB limit", path.display()),
        ));
    }
    Ok(raw)
}

#[cfg(not(unix))]
fn read_string_no_follow(path: &Path) -> std::io::Result<String> {
    let file = fs::File::open(path)?;
    let mut raw = String::new();
    file.take(MAX_CONFIG_FILE_BYTES + 1)
        .read_to_string(&mut raw)?;
    if raw.len() as u64 > MAX_CONFIG_FILE_BYTES {
        return Err(std::io::Error::new(
            std::io::ErrorKind::InvalidData,
            format!("config file {} exceeds the 1 MiB limit", path.display()),
        ));

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