Binaries are not set globally when using `directories.bin`

[felipecrs]

Binaries can also be set using directories.bin and not only bin. bats is an example of it.

https://docs.npmjs.com/cli/v7/configuring-npm/package-json#directoriesbin

To reproduce:

❯ volta --version
1.0.4
❯ npm --version
7.11.1
❯ npm install --global bats

added 1 package, and audited 2 packages in 2s

found 0 vulnerabilities
❯ which bats
bats not found
❯ docker run --rm -it node:14 bash -xc 'npm install --global bats && bats --version'
+ npm install --global bats
/usr/local/bin/bats -> /usr/local/lib/node_modules/bats/bin/bats
+ bats@1.3.0
added 1 package from 1 contributor in 0.353s
+ bats --version
Bats 1.3.0

The above works fine when not using volta.

References bats-core/bats-core#430.

[charlespierce]

Hi @felipecrs thanks for reporting! That does appear to be a use-case that we missed!

[felipecrs]

Just to add, this should probably be fixed somewhere in between this code:

volta/crates/volta-core/src/tool/package/metadata.rs

Lines 203 to 210 in 1ad3d7c

	// If the bin list contains only an empty string, that means `bin` was a string value,
	// rather than a map. In that case, to match `npm`s behavior, we use the name of the package
	// as the bin name.
	// Note: For a scoped package, we should remove the scope and only use the package name
	if manifest.bin == [""] {
	manifest.bin.pop();
	manifest.bin.push(default_binary_name(&manifest.name));
	}

The directories.bin key in package.json needs to be taken into account, and, if set, Volta should look for all files under the directory specified by directories.bin and add them to the manifest.bin list before exiting this function.