rust-lang/cargo · error · anyhow::Error

multiple packages found at `{src}`: {} To disambiguate,

Error message

multiple packages found at `{src}`:
    {}
To disambiguate, run `cargo add --git {src} <package>`

What it means

When a git source is given *without* an explicit crate spec, `infer_package_for_git_source` is asked to pick the single package. If the repo contains more than one package, cargo cannot guess which one, so it bails at mod.rs:1057 listing all package names and showing the disambiguating command `cargo add --git <src> <package>`.

Source

Thrown at src/ops/cargo_add/mod.rs:1057

}

fn infer_package_for_git_source(
    mut packages: Vec<Package>,
    src: &dyn std::fmt::Display,
) -> CargoResult<Package> {
    let package = match packages.len() {
        0 => unreachable!(
            "this function should only be called with packages from `GitSource::read_packages` \
            and that call should error for us when there are no packages"
        ),
        1 => packages.pop().expect("match ensured element is present"),
        _ => {
            let mut names: Vec<_> = packages
                .iter()
                .map(|p| p.name().as_str().to_owned())
                .collect();
            names.sort_unstable();
            anyhow::bail!(
                "multiple packages found at `{src}`:\n    {}\nTo disambiguate, run `cargo add --git {src} <package>`",
                names
                    .iter()
                    .map(|s| s.to_string())
                    .coalesce(|x, y| if x.len() + y.len() < 78 {
                        Ok(format!("{x}, {y}"))
                    } else {
                        Err((x, y))
                    })
                    .into_iter()
                    .format("\n    "),
            );
        }
    };
    Ok(package)
}

fn populate_dependency(mut dependency: Dependency, arg: &DepOp) -> Dependency {

View on GitHub (pinned to 0e07a15537)

Solutions

Re-run with the exact package name from the printed list: `cargo add --git <url> <package>`.
Inspect the repo's workspace members first (e.g. via the repo's root `Cargo.toml`) to pick the right name.
If you only ever need one crate from that repo, script the disambiguated command into a wrapper.

Example fix

# before
cargo add --git https://example/repo.git
# error: multiple packages found: crate-a, crate-b

# after
cargo add --git https://example/repo.git crate-a

Defensive patterns

Strategy: validation

Validate before calling

// Probe the git repo's package list before invoking cargo add without a name.
fn list_git_packages(url: &str) -> Vec<String> {
    // e.g. shallow clone + parse root [workspace].members, or use `cargo git-list`-style metadata
    unimplemented!()
}
// let pkgs = list_git_packages(url);
// assert_eq!(pkgs.len(), 1, "disambiguate with: cargo add --git {url} <one-of:{pkgs:?}>");

Prevention

Always pass an explicit package name when adding from multi-package git repos.
Cache the repo's package list in your dependency tooling.
Prefer registry crates or published versions when a git repo has many crates.

When it happens

Trigger: `cargo add --git <url>` against a monorepo/workspace with several crates and no positional package name.

Common situations: Adding a crate from a multi-crate git workspace (common for libraries that ship multiple sub-crates). The user expects a default but cargo requires an explicit choice.

Related errors

AI-assisted analysis of rust-lang/cargo@0e07a15537 (2026-08-06). Data as JSON: /data/errors/e21b17b8ae30fa3c.json. Report an issue: GitHub.