Goals

Currently the documentation states the following:

Because a long-running process won't exit, tasks that would depend on it would never run. Once you've labeled the task as persistent, turbo will throw an error if other tasks depend on it.

This option is most useful for development servers or other "watch" tasks.

I think long-running process should be able to depend on other long-running process.
If your starting a task, which itself is marked as persistent task, and it depends on another task that is also marked as persistent then it should simply just start both tasks in parallell.

I originally laid out my argument in this issue as I felt the current logic was so unlogical as to be a bug.

Non-goals

No response

Background

Using mprocs I could run two persistent tasks at the same time:

pnpm mprocs 'pnpm --filter package-a dev' 'pnpm --filter package-b dev'

With turborepo's new persistent mode it should be possible to simply run (assuming that package-b depends on package-a):

pnpm turbo watch --filter package-b dev

Without this functionality persistent mode makes zero sense. The whole reason people use turborepo in the first place is because they have a monorepo, if tasks can't depend on other tasks then there is no reason to use turborepo.

pnpm and mprocs already lets me solve this, but mprocs have no understanding of the dependency tree like turbo does. So if the persistent-model in turbo where to make sense then it should work with dependencies.

Proposal

Simply remove the warning and let persistent tasks depend on other persistent tasks (thereby running them in parallell).