How to prevent from running `npm install` in pnpm or yarn projects?

[zanminkian]

Since corepack does not support npm, it's always possible to run a npm command within a project configured to be used with another package manager.
For example, a package.json has been configured "packageManager":"pnpm@10.0.0". People can stil run npm install in this project.

I know @antfu/ni and #650 can help. I also know corepack is going to completely remove ALL code about npm. However, for a better development experience, it is widely expected to throw an error when running npm install in pnpm/yarn projects.

Any solutions?

[legobeat]

Do I understand right if you wish to prevent developers from running installation with anything but your specified package manager? If so it doesn't seem like anything core pack could support per se as the entrypoint in case is npm. corepack is primarily a package-manager bridge, not a script executor.

How about a preinstall script which bails unless your conditions are met? if nothing else, you should be able to look at environment variables to detect initiating package manager(s).

[aduh95]

You can use "devEngines": https://docs.npmjs.com/cli/v11/configuring-npm/package-json#devengines

[zanminkian]

You can use "devEngines"

It can help. Thanks. But...still looks weird. This propery is not widely supported by yarn and pnpm. A package.json containing both packageManager and devEngines looks verbose 🤦

[aduh95]

Unfortunately npm team made it very clear they would always disregard the packageManager field, and that's how the devEngines proposal got traction. Technically you could use only devEngines with latest Corepack.
I've suggested in #668 to move the packageManager field to a separate file, but I didn't receive much support for this idea, so currently that's not an option.

[zanminkian]

Npm do not and won't support packageManager field. So I suggest corepack support devEngines when packageManager is not present. For example, a package.json contains devEngines but not packageManager. Running pnpm and yarn should respect devEngines, but currently it will automactically insert a packageManager field.

[aduh95]

So I suggest corepack support devEngines when packageManager is not present. For example, a package.json contains devEngines but not packageManager

That's already the case, see https://github.com/nodejs/corepack?tab=readme-ov-file#devenginespackagemanager

currently it will automactically insert a packageManager field.

Only if devEngines doesn't specify a specific version

[zanminkian]

@aduh95 Awsome. I forgot I am using corepack v0.31.0. Thanks!

Since corepack released v0.32.0, I think we can deprecate packageManager field now. Using devEngines works well under both npm(>=10.9.0) and corepack(>=0.32.0).

[arcanis]

I think we can deprecate packageManager field now.

Certainly not. We have no plan to add support for devEngines in Yarn.

[zanminkian]

FYI, I use yarn or pnpm via corepack. So personally, I don't need packageManager field since npm and corepack support devEngines.

Deprecating something that has already documented in official Node website is a serious thing.