I would be OK with "Option 1" (installing all dependencies, when NODE_ENV is set to `production). I don't know what @pnpm/collaborators think.

The reason this works like this currently is that npm CLI does it like this. Yarn seems to install everything. We can do it in v10 if we decide it soon.

Also, the args are a bit confusing --prod and --dev and their combinations. Maybe it is better to remove them.

Since the possible default behavior will be to install all dependencies pnpm can have --skip-prod-deps and --skip-dev-deps args with false values by default (without detecting NODE_ENV), just to leave the possibility to install only specific set of dependencies

Personally, I'm not particularly satisfied with either option. I checked the documentation for npm and yarn. They are consistent in handling NODE_ENV=production:

npm/Yarn will not install any package listed in devDependencies if the NODE_ENV environment variable is set to production

Ref:

• https://classic.yarnpkg.com/lang/en/docs/cli/install/#toc-yarn-install-production-true-false
• https://docs.npmjs.com/cli/v8/commands/npm-install#description

The handling method of npm and yarn is: If you want to install all dependencies after setting NODE_ENV=production, you can add a flag: --prod=false or --production=false

My main concerns are:

1. This could cause destructive changes (potentially affecting many projects using pnpm).
2. This is inconsistent with the behavior of other package managers, making it difficult for some projects to migrate from npm/yarn to pnpm.
3. Although there is currently no package manager RFC in the open-source community, I believe we should align more closely with npm/yarn to avoid further fragmentation.

I just tried to run NODE_ENV=production yarn install and the dev deps have been installed, strange. Yarn version 1.22.22. Maybe I am missing something?

I am currently migrating from yarn to pnpm, and that was the reason for creating this issue, I do not remember that yarn didn't install dev dependencies on CI or docker when NODE_ENV is production.

UPD: Looks like dev deps in package json has been install, but probably by possible mistake in some prod deps where i.e. webpack was not in dev deps and by hoisting I were able to see webpack in node_modules and didn't notice NODE_ENV=production behavior during install

So yeah, looks like yarn doesn't install dev deps under NODE_ENV=production condition

I checked with the latest Yarn and it installed dev deps.

Yes, looks like latest Yarn version installs dev deps under NODE_ENV=production

If the behavior of yarn is to install everything, then I prefer option 1.

I think option 1 makes more sense.

Normally, I would prefer pnpm to not behave differently from Yarn and NPM, but Yarn and NPM are behaving differently themselves.

In this case, installing everything including dev dependencies rarely break anyone's workflow (unless they don't have enough disk space), so I prefer option 1.

What about the arguments, maybe it is only me, but the fact that pnpm install --prod=false command installs all dependencies including production just blows my mind.

Also, their combination is not clean from the first glance, like pnpm install --prod=false --dev=true will install only dev deps, pnpm install --prod=true --dev=true will install only prod deps and pnpm install --prod=false --dev=false will install all deps