[RFC] Respect "engines" in package.json

[ObliviousHarmony]

Describe the feature you'd like to request

There is precedent in using the "engines" property of package.json files to ensure that globally installed tools of the wrong version cannot be run on a package. Turborepo should support an engines.turbo version constraint that prevents the globally installed turbo command from running when it does not match.

Describe the solution you'd like

When running a turbo command globally it should read the root package.json file's engines property and check the version constraint of engines.turbo against it's own version. If it does not match it should provide an error and stop executing.

Describe alternatives you've considered

1. When using pnpm, the best way to execute turbo commands is using pnpm exec. Using pnpm turbo is error-prone since pnpm will eat the --filter argument. This leads to pnpm turbo run build --filter={package} and pnpm turbo run build -- --filter={package} having very different results. Our solution is to globally install turbo, however, this can lead to version mismatches with the installed package.
2. Another option could be for turbo global commands to execute the local turbo command when one is present. This would be convenient but might result in some ambiguous behavior as opposed to a nice clean error. Even at that though, it's probably still nice to respect engines.turbo to clearly define what is expected here.

[nathanhammond]

Cross-linking a post on the PR: #1361 (comment)

As a quick ergonomics fix: pnpm -- turbo run build --filter=docs is what you're looking for.

[ObliviousHarmony]

I didn't realize you could call files in ./node_modules/.bin after the double dash. I guess it probably adds it to the PATH for the execution, eh? Thanks for that, it's much shorter.

[jlarmstrongiv]

Agreed, I had to write a bash script to maintain global turbo versions.

#!/usr/bin/env bash
set -euo pipefail

# usage ./global_install turbo

package_json_path="./package.json"

# loop https://stackoverflow.com/a/255913
for dependency in "$@"; do
    # extract from package.json https://unix.stackexchange.com/questions/480481/grep-the-name-from-package-json-file#comment1308267_691616
    version="$(grep -o "\"$dependency\"\s*:\s*\"[^\"]*" "$package_json_path" | grep -o '[^"]*$')"
    # install check https://stackoverflow.com/questions/6480549/install-dependencies-globally-and-locally-using-package-json#comment24765904_10813149
    npm list "$dependency@$version" --global > /dev/null 2>&1 || npm install "$dependency@$version" --no-audit --global
done

Ideally, everything would work with the local project version of turbo using npx turbo

[anthonyshew]

Globally installed turbo executes the version of Turborepo that is installed in your repository's devDependencies. So this is already taken care of!