`usethis` does not recognize R projects created with Positron "Create R Project"

[CorradoLanera]

usethis does not recognize R projects created using Positron's "Create R Project" feature.

For example, when I try to run:

usethis::edit_r_environ("project")

I get the following error (in a folder created via Positron → New Project → R Project):

Error in `proj_set()`:
✖ Path C:/path/to/my/positron-project/ does not
  appear to be inside a project or package.
ℹ Read more in the help for `usethis::proj_get()`.

Notes:

• I don't know whether this is a bug/feature to implement in Positron (the way the project is created) or in usethis (project detection logic), so I'm opening the issue here for further investigation.

Steps to reproduce:

1. Open Positron, create a new R project.
2. In the project directory, open R and run usethis::edit_r_environ("project").

Expected behavior:
usethis should recognize the directory as a valid R project and allow, e.g., editing of the project .Renviron.

Actual behavior:
usethis reports that the directory is not a project or package.

[jennybc]

The best explanation of what's going on is this:

https://positron.posit.co/rstudio-rproj-file.html

A workspace does not necessarily get marked with some characteristic file. Positron and VS Code will place an explicit file at .vscode/settings.json if (and only if) the user does some configuration that’s specific to the project.

Since there is no absolute guarantee that every project folder has a .vscode/settings.json file, we need to rethink some of our project-oriented workflows. There is no exact equivalent of the Rproj file.

The immediate takeaway is that you should make some explicit gesture to give this folder project-hood. For me, this would almost always be making it a git repo. The absolute lightest-weight move is to create a empty file named .here.

It's an open question whether Positron would start to do that automatically. So far, we have not.