progressr fails to load on R<4

[MichaelChirico]

As seen in GHA (progressr 1.0.0):

https://github.com/Rdatatable/data.table/actions/runs/30377527575/job/90336903587#step:11:1962

** testing if installed package can be loaded from temporary location
Error: Error: package or namespace load failed for ‘progressr’:
 .onLoad failed in loadNamespace() for 'progressr', details:
  call: globalCallingHandlers()
  error: register_global_progression_handler() requires R (>= 4.0.0)

I poked around briefly at the source code and couldn't figure out where .onLoad() makes the call, but it looks like there's supposed to be an optional functionality that is being triggered unconditionally.

[MichaelChirico]

Gemini traced it out for me:

.onLoad():

progressr/R/zzz.R

Line 34 in 36cd0ff

warn_about_rstudio_condition_handlers()

warn_about_rstudio_condition_handlers():

progressr/R/rstudio-console.R

Line 100 in 36cd0ff

affected <- patch_rstudio_console_evidence()

patch_rstudio_console_evidence():

progressr/R/rstudio-console.R

Line 46 in 36cd0ff

handlers <- globalCallingHandlers()

Which is overloaded to an error in pre-4.0 R:

progressr/R/global_progression_handler.R

Lines 324 to 328 in 36cd0ff

	if (getRversion() < "4.0.0") {
	globalCallingHandlers <- function(...) {
	stop("register_global_progression_handler() requires R (>= 4.0.0)")
	}
	}

---

What's left is to understand what the intended behavior is -- should we patch something, or just require R 4.0.0?