(JavaScript) Throw a more descriptive error when the package name is missing

[krishnan-chandra]

Closes #20859.

While this is a simple fix and addresses the linked issue, there is an interesting edge case to discuss:

Internal packages do not necessarily have a name field in package.json (see wireapp/wire-desktop#1692, facebook/react#13107 for examples). The JavaScript backend in Pants does require that each package.json define a name, but I'm not so sure that's necessarily the right behavior.

It's worth considering whether we should make names optional in Pants, given that larger JavaScript monorepos may have internal packages that are not meant to be published. Furthermore, different JS package managers handle this situation differently -

• Bun doesn't handle package.json files without a name
• npm assigns the parent directory name as the name

[tobni]

LGTM!

The reason for requiring it is that it makes it easier for pants to "talk about the packages", we use it to name targets, match for dep-inference, workspace invocations use package names, and also in logs and the like.

We could auto-generate a "description" and use that instead for logs and targets, but I suspect it'll be easier for users to know what pants is talking about if they named the thing.

There are also package manager commands that fail when packages lack names (depends on versions and what fallbacks are in place but workspaces are name based).

The argument of a package being private is valid, but there's a "private": true attribute for that.

[krishnan-chandra]

Yeah, it doesn't really seem that there is agreement around the ecosystem about how to deal with this issue, so the safest option is probably to require the package to have a name and call it a day 🤷‍♂️

That's good enough for me, ty for the explanation!