As a dev, I want to check if there are function that download and inform the dev

[statnmap]

As a user, I'd like to know what to do if my package uses a function that requires an Internet connection.

Validation

• [ ] There is a check function that detects the use of functions downloading some things on Internet
• [ ] The output of this function inform the user about what to do to avoid CRAN rejection

Technical

• [ ] Maybe, there is the possibility to simulate the absence of Internet connection to detect errors like this ?

  ══ Failed tests ════════════════════════════════════════════════════════════════
   ── Error ('test-dock_from_desc.R:39'): dock_from_desc works ────────────────────
   Error in `utils::download.file(url, path, mode = "wb", quiet = quiet)`: cannot open URL 'https://sysreqs.r-hub.io/pkg/R6,askpass,attempt,base64enc,brio,bslib,cachem,callr,cli,clipr,covr,crayon,credentials,curl,desc,diffobj,digest,ellipsis,evaluate,fansi,fastmap,fs,gert,gh,gitcreds,glue,highr,htmltools,httr,ini/linux-x86_64-debian-gcc'
   Backtrace:
   ▆
   1. └─dockerfiler::dock_from_desc(file.path(descdir, "DESCRIPTION")) at test-dock_from_desc.R:39:4
   2. ├─base::unique(get_sysreqs(packages = packages))
   3. └─dockerfiler::get_sysreqs(packages = packages)
   4. ├─base::sort(...)
   5. ├─base::unique(...)
   6. ├─base::unname(...)
   7. ├─base::unlist(...)
   8. └─base::lapply(...)
   9. └─dockerfiler (local) FUN(X[[i]], ...)
   10. └─dockerfiler:::get_batch_sysreqs(.x, quiet = quiet)
   11. └─utils::download.file(url, path, mode = "wb", quiet = quiet)