rust-lang/cargo · error

couldn't find repository name

Error message

couldn't find repository name

What it means

GitHub fast path expects exactly two path segments (`user/repo`). After successfully reading the username segment, the next `pieces.next()` returned `None`, meaning the URL path had only one segment (e.g. `https://github.com/user` with no repository).

Solutions

1. Append the repository name to the URL: `https://github.com/<user>/<repo>`.
2. Verify the URL by opening it in a browser before committing.
3. Add a CI lint that rejects git URLs without at least two path segments.

Example fix

# before
[dependencies]
x = { git = "https://github.com/rust-lang" }

# after
[dependencies]
x = { git = "https://github.com/rust-lang/cargo" }

fn require_two_segments(u: &url::Url) -> Result<(&str, &str), anyhow::Error> {
    let mut s = u.path_segments().ok_or_else(|| anyhow::"no path"))?;
    let user = s.next().filter(|x| !x.is_empty()).ok_or_else(|| anyhow!("no user"))?;
    let repo = s.next().filter(|x| !x.is_empty()).ok_or_else(|| anyhow!("no repo"))?;
    Ok((user, repo))
}

fn url_has_user_and_repo(u: &url::Url) -> bool {
    u.path_segments().map_or(false, |mut s| s.next().is_some() && s.next().is_some())
}

let repository = match pieces.next() { Some(r) if !r.is_empty() => r, _ => return Ok(FastPathRev::Indeterminate) };

When it happens

Trigger: A git dependency URL of the form `https://github.com/<user>` (or with `.git` omitted and only one path component) reaching the GitHub fast path.

Common situations: Copy-paste of a GitHub profile URL instead of a repo URL; trailing slash manipulation that dropped the repo segment; misconfigured registry pointing at a user root.

Related errors

• couldn't find username
• no path segments on url
• too many segments on URL
• attempting to update a git repository, but
• can't checkout from ' ': you are in the offline mode ( )

AI-assisted analysis of rust-lang/cargo@495c385d08 (2026-08-11). Data as JSON: /api/errors/beaec307325387d9. Report an issue: GitHub.

Appendix: source

Thrown at src/sources/git/utils.rs:1819

                rev
            } else {
                debug!("can't use github fast path with `rev = \"{}\"`", rev);
                return Ok(FastPathRev::Indeterminate);
            }
        }
    };

    // This expects GitHub urls in the form `github.com/user/repo` and nothing
    // else
    let mut pieces = url
        .path_segments()
        .ok_or_else(|| anyhow!("no path segments on url"))?;
    let username = pieces
        .next()
        .ok_or_else(|| anyhow!("couldn't find username"))?;
    let repository = pieces
        .next()
        .ok_or_else(|| anyhow!("couldn't find repository name"))?;
    if pieces.next().is_some() {
        anyhow::bail!("too many segments on URL");
    }

    // Trim off the `.git` from the repository, if present, since that's
    // optional for GitHub and won't work when we try to use the API as well.
    let repository = repository.strip_suffix(".git").unwrap_or(repository);

    let url = format!(
        "https://api.github.com/repos/{}/{}/commits/{}",
        username, repository, github_branch_name,
    );
    debug!("attempting GitHub fast path for {}", url);
    let mut request =
        Request::get(url).header(http::header::ACCEPT, "application/vnd.github.3.sha");
    if let Some(local_object) = local_object {
        request = request.header(http::header::IF_NONE_MATCH, &format!("\"{local_object}\""));
    }

View on GitHub (pinned to 495c385d08)