[RFC] Move cache outside of node_modules

[jaredpalmer]

Describe the feature you'd like to request

node_modules is a bad default place for the cache because most CI/CDs will blow out node_modules whenever the lockfile changes. The cache also currently grows in an unbounded manner.

Describe the solution you'd like

Use tmp directory

On macOS and Linux consider using tmp.

• Pro: automatically clean up and not let the cache grow unbounded
• Con: hard to inspect from VSCode
• Con: hard to cache, will require custom flag to change position in CI so it is cacheable (--cache-dir=.turbo)

Use .turbo at the root

• Pro: easy to inspect locally
• Pro: no needed to change location in ci w/flag

Hybrid of both?

Use tmp on macOS when run in interactive shell, use .turbo in CI?

Describe alternatives you've considered

n/a

[fz6m]

I think ${root}/.turbo is better

1. In github actions: .turbo can be easily cached (see next.js)

2. Local check: When there is a problem with the cache, can delete it for check

[jlarmstrongiv]

Agree with @fz6m keep the turbo cache in the project folder please

[belgattitude]

Some thoughts, I'd prefer a .cache/turbo. But .turbo is fantastic

[weyert]

I would prefer the root of the project or an optional to configure where it should go

[miszo]

I would opt for the Use .turbo at the root option. It is easier to inspect locally and cache on CI.

[kevin-secrist]

Would be nice to specify the cache directory in turbo.json, in a similar way that yarn/npm allow you to change the package cache location in their config files. Seems like this would be a reasonable way to implement the feature without causing a breaking change. For caching in CI I've had to put --cache-dir .turbo in all calls to turbo, but it would be nice to avoid that by either specifying an env var or (preferably) putting it in the config file so it also applies to local development.

[anthonyshew]

Shipped in 2.0: #8126