feat(cli): add sync command for working with external projects

[NullVoxPopuli]

Reason why: It's hard/impossible to have dependencies automatically injected by default due limitations on hard-links , this PR (for adding sync) aims to provide a low-level utility for tools such as turborepo to manage this automatic syncing for us. This is important because when a project starts using peerDependencies, it's unavoidable to have the need for dependenciesMeta.*.injected: true, yet due to the aforementioned limitations of hard-links, has some major DX downsides -- which this PR and the combination of turborepo (or nx) can 100% alleviate, allowing the average dev to not even know about the problem or the history around these injected issues. Later, it may make sense to have a flag to inject all in-monorepo deps by default, and then rely on this command to fix the hard-link limitations (and this may be required for the feature to be totally transparent to the average dev).

Related: #6088
Unblocks: CrowdStrike/ember-headless-table#145

[NullVoxPopuli]

@zkochan hello! It's my first time contributing anything other than an error message to pnpm, so if anything looks super wonkey / wrong -- lemme know -- I haven't written tests yet, and the PR is still marked as draft, but I wanted to ping you for early review so that you may have a chance to look at this before I end up spending too much time going down a wrong direction.

This file is < 100 lines 🤷 if that helps prioritization (this is a very busy project!)

[NullVoxPopuli]

this is something I'm not sure about -- should I add this package, resolve-package-path to the package.json? or does pnpm have an existing util for finding the install location for where injected files should go?

[zkochan]

This is where sync currently happens:

pnpm/exec/lifecycle/src/runLifecycleHooksConcurrently.ts

Lines 58 to 84 in e570adc

	if (targetDirs == null || targetDirs.length === 0 || !isBuilt) return
	const filesResponse = await fetchFromDir(rootDir, { resolveSymlinks: opts.resolveSymlinksInInjectedDirs })
	await Promise.all(
	targetDirs.map(async (targetDir) => {
	const targetModulesDir = path.join(targetDir, 'node_modules')
	const nodeModulesIndex = {}
	if (fs.existsSync(targetModulesDir)) {
	// If the target directory contains a node_modules directory
	// (it may happen when the hoisted node linker is used)
	// then we need to preserve this node_modules.
	// So we scan this node_modules directory and pass it as part of the new package.
	await scanDir('node_modules', targetModulesDir, targetModulesDir, nodeModulesIndex)
	}
	return opts.storeController.importPackage(targetDir, {
	filesResponse: {
	fromStore: false,
	...filesResponse,
	filesIndex: {
	...filesResponse.filesIndex,
	...nodeModulesIndex,
	},
	},
	force: false,
	})
	})
	)
	}

[NullVoxPopuli]

@zkochan I took a brief look at this again today, and I don't really grok what's going on in the code you linked.
My path forward will be to create an external package, https://github.com/NullVoxPopuli/pnpm-sync-dependencies-meta-injected
I've started with copying from the CrowdStrike repos (which currently have this code as a private package) -- over the coming days, I'll be pulling in code from this PR so that the behavior is more robust, and less "secret conventions" specific.

I implemented this here: universal-ember/ember-primitives#7

[octogonz]

📌 This problem can also be solved using https://github.com/tiktok/pnpm-sync