allow reporter = "silent" for specific tar_targets

[stemangiola]

Prework

• [ x] I understand and agree to help guide.
• [ x] I understand and agree to contributing guide.
• [ x] New features take time and effort to create, and they take even more effort to maintain. So if the purpose of the feature is to resolve a struggle you are encountering personally, please consider first posting a "trouble" or "other" issue so we can discuss your use case and search for existing solutions first.

Proposal

We are using Targets to make scalable APIs (HPCell). This pipeline is decided by the user, and we build a custom pipeline from the API calls, of this sort.

step_1() > step_2() |> step_3() |> ...

or

step_1() > step_3() |> ...

Sometime, targets are not defined, and it simplifies the implementation to create dummy targets (=NULL) anyway. However the messaging of a target (that should not exist) being build is confusing for the user.

it would be beneficial to have

tar_target(normalisation, NULL, reporter = "silent")

so that such a target gets built but in the background.

Thanks.

[wlandau]

I don't have plans to redesign the reporter infrastructure to make this work there, but as long as you are developing a custom API, you could make use of tar_progress() and other functions in https://docs.ropensci.org/targets/reference/index.html#progress and filter out the NULL targets.