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.