Include the LICENSE in every crate

[cuviper]

Motivation

The MIT license states:

The above copyright notice and this permission notice
shall be included in all copies or substantial portions
of the Software.

Solution

Therefore the LICENSE files should be present in each crate directory,
so they are included with cargo publish.

[cuviper]

Currently, the LICENSE is only present in the workspace root and in tracing-core/.

Another option is to symlink the same file from the root to each directory, which does get dereferenced when publishing from unix hosts, but I think this has problems from Windows.

[hawkw]

This looks good to me --- thanks for noticing and fixing this!

Another option is to symlink the same file from the root to each directory, which does get dereferenced when publishing from unix hosts, but I think this has problems from Windows.

I think just duplicating it is fine — I don't think any tracing crate has been published from a Windows machine yet, but I'd rather not have to worry about it later if someone does end up publishing from Windows.

Do you happen to know if using the Cargo.toml license-file field with a relative path like

license-file = "../LICENSE"

would result in the actual license file being included into every published crate? If so, that might be a slightly nicer option, but I'm not sure how Cargo handles this.

[cuviper]

Do you happen to know if using the Cargo.toml license-file field with a relative path like

license-file = "../LICENSE"

would result in the actual license file being included into every published crate? If so, that might be a slightly nicer option, but I'm not sure how Cargo handles this.

Ah, it looks like that is a feature since Cargo 1.43:

The license-file file is automatically included during publish, even if it is not explicitly listed in the include list or is in a location outside of the root of the package. #7905

You get a warning if you have both fields:

warning: only one of `license` or `license-file` is necessary

But crates.io calls it "non-standard" if you only have the file, like here on pretty-git-prompt. I'm not sure what it displays if you have both...

edit: looks like "non-standard" only comes up when there's no license field:
https://github.com/rust-lang/crates.io/blob/a251368963d55ff12ecb65249cfe96950deb867b/src/models/version.rs#L252

[hawkw]

Okay, thanks for looking into that. For now, I think just duplicating the license text is the best approach. I'm going to go ahead and merge this.