Progress bars behind callr processes

[wlandau]

I'm really enjoying cli progress bars, but I'm struggling with an edge case. For ropensci/targets#1442, I need to run the progress bar behind a non-interactive callr process. Unfortunately, the non-interactivity seems to make the progress bar slightly less responsive, and it seems to spill over into multiple lines. This is the desired behavior when writing to a fixed log file, but it's counterintuitive when the parent session is interactive. Are there any workarounds etc.?

out <- callr::r(
  \() {
    library(cli)
    clean <- function() {
      options(cli.num_colors = 256)
      cli_progress_bar("Cleaning data", total = 100)
      for (i in 1:100) {
        Sys.sleep(5/100)
        cli_progress_update()
      }
      cli_progress_done()
    }
    clean()
  },
  show = TRUE,
  stderr = "2>&1"
)
#> Cleaning data ■■■■■■■                           19% | ETA:  4s
#> Cleaning data ■■■■■■■■■■■■■■■■■                 55% | ETA:  2s
#> Cleaning data ■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■  100% | #> ETA:  0s

[gaborcsardi]

Set the cli.dynamic = TRUE option in the subprocess.

[wlandau]

Thanks! Works great on my end.