Make error on missing task definition ignorable

[Alfred-Mountfield]

Which project is this feature idea for?

Turborepo

Describe the feature you'd like to request

When you call turbo <TASK>, if turbo can't find the task definition it returns an error:

$ turbo my-task
 ERROR  run failed: error preparing engine: Could not find the following tasks in project: my-task
Turbo error: error preparing engine: Could not find the following tasks in project: my-task

This makes sense as default behaviour, but can be frustrating if you want to use it within a monorepo to call tasks on postinstall (for example) but then also wish to utilise turbo prune.

How I wish to use this:

• I have some packages that include Python
• I wish to have package.json scripts within them to setup and install their Python dependencies in their venvs
• I wish to call those scripts in postinstall in the root
• When building a docker image of an unrelated package, I'd like to call turbo prune other-package
• When trying to build that package, it now fails on postinstall with the above message.

Describe the solution you'd like

An argument you can provide to turbo to ignore missing task definitions. Perhaps --ignore-missing or something like that. Or perhaps better than that, an environment variable so you can set it in certain circumstances (such as after a turbo prune) without it being in your package.json all the time.

Describe alternatives you've considered

I'm unsure what way to get around this other than somehow grepping the output which doesn't seem ideal, or creating a no-op equivalent script in every package.

[mehulkar]

Can you provide a small reproduction I can play around with? The postinstall usage is an interesting use case, but I'm not exactly sure how it's setup. If the packages aren't in the prune output, I would expect that turbo run would be able to ignore them.

[Megamannen]

A workaround is to add a no-op postinstall in the ones that doesn't need one

"postinstall": "echo 'No postinstall'"