# Function absolute_submodule_url

Source

    fn absolute_submodule_url<'s>(
        base_url: &str,
        submodule_url: &'s str,
    ) -> CargoResult<Cow<'s, str>>

Expand description

Constructs an absolute URL for a child submodule URL with its parent base URL.

Git only assumes a submodule URL is a relative path if it starts with `./` or `../` 1. To fetch the correct repo, we need to construct an absolute submodule URL.

At this moment it comes with some limitations:

- GitHub doesn’t accept non-normalized URLs with relative paths. (`ssh://git@github.com/rust-lang/cargo.git/relative/..` is invalid)
- `url` crate cannot parse SCP-like URLs. (`git@github.com:rust-lang/cargo.git` is not a valid WHATWG URL)

To overcome these, this patch always tries `Url::parse` first to normalize the path. If it couldn’t, append the relative path as the last resort and pray the remote git service supports non-normalized URLs.

See also rust-lang/cargo#12404 and rust-lang/cargo#12295.

1. https://git-scm.com/docs/git-submodule ↩