Java projects can get complex and editors (like IntelliJ can provide much better tooling when configured).

At my last job we had a mono-repo with the .idea directory (for IntelliJ) commited. For Java projects IntelliJ needs to sometimes be directed to understand what folders are “resources” to allow better autocompletion and highlighting. For example specifying custom java faces components directory that will be used once the application is packaged into a war file, so IntelliJ knows they are accessible from JSP html files, and will autocomplete and show you what attributes you can modify on the component.

It’s definitely not a never situation. You can commit only certain files from the configuration (project settings not editor preferences)

So... are you also against having any hints as to how to set up a working local dev environment in the README.md file? Because that's also not necessary to run the project, but it's a courtesy to contributors.

Also, the idea that there is some universal rule of 'what should be checked in to source control' that applies to EVERYTHING from personal projects to corporate internal monorepos to open source projects to undergrad joint coding projects to video games is... absurd.

No, because that's documentation, but I think that was obvious.

Well, no it's not obvious.

If I can provide machine readable documentation on how to get your VSCode environment set up (in the form of a .vscode/extensions.json file), isn't that strictly better than merely human-readable documentation in README.md under a 'Recommended VSCode Extensions to work with this project' header?

No, because that doesn't translate to other IDEs and one user programmatically changing things to suit themselves causes fluff in PRs and diffs. You also can't guarantee every environment is going to respond correctly.

One user programmatically changing things to suit themselves is supposed to do so in their user settings, which has precedence over the checked-in copy. That way, you have the best of both worlds: easy set-up for everyone who wants it but you can override it without touching the VCS.

Update: turns out the precedence rules are a little more subtle than I thought.

See also: https://code.visualstudio.com/docs/getstarted/settings#_sett...

Can you override user settings at the project level?

Yes, project-level (aka workspace) settings generally override user settings.

But then again, language-specific settings will trump all other settings. And that’s one way to override workspace-level settings in your user settings if you want.

Here’s a detailed list of all levels of settings in VS Code, ordered by precedence: https://code.visualstudio.com/docs/getstarted/settings#_sett...