Blocker: import_future() won't find re-exports from 'parallelly'

[HenrikBengtsson]

I'm moving lots of functions to the new parallelly package, cf. futureverse/future#432. I'm still re-exporting these functions in future. However, running revdep checks on furrr 0.2.0 gives the following errors:

* checking Rd contents ... OK
  Backtrace:
   1. furrr:::furrr_test_that(...)
   2. furrr:::supported_strategies() checks/furrr/new/furrr.Rcheck/tests/testthat/helper-furrr-test-that.R:8:2
   3. furrr:::import_future("supportsMulticore") checks/furrr/new/furrr.Rcheck/tests/testthat/helper-furrr-test-that.R:27:2
   4. furrr:::import_from(name, default = default, package = "future")
  
  ── 7. Error: (unknown) (@test-future-modify.R#4)  ──────────────────────────────
  No such 'future' function: supportsMulticore()
  Backtrace:
   1. furrr:::furrr_test_that(...)
   2. furrr:::supported_strategies() checks/furrr/new/furrr.Rcheck/tests/testthat/helper-furrr-test-that.R:8:2
   3. furrr:::import_future("supportsMulticore") checks/furrr/new/furrr.Rcheck/tests/testthat/helper-furrr-test-that.R:27:2
   4. furrr:::import_from(name, default = default, package = "future")
  
  ── 8. Error: (unknown) (@test-future-pmap.R#4)  ────────────────────────────────
  No such 'future' function: supportsMulticore()
  Backtrace:
   1. furrr:::furrr_test_that(...)
   2. furrr:::supported_strategies() checks/furrr/new/furrr.Rcheck/tests/testthat/helper-furrr-test-that.R:8:2
   3. furrr:::import_future("supportsMulticore") checks/furrr/new/furrr.Rcheck/tests/testthat/helper-furrr-test-that.R:27:2
   4. furrr:::import_from(name, default = default, package = "future")
  
  ── 9. Error: (unknown) (@test-future-walk.R#1)  ────────────────────────────────
  No such 'future' function: supportsMulticore()
  Backtrace:
   1. furrr:::furrr_test_that(...)
   2. furrr:::supported_strategies() checks/furrr/new/furrr.Rcheck/tests/testthat/helper-furrr-test-that.R:8:2
   3. furrr:::import_future("supportsMulticore") checks/furrr/new/furrr.Rcheck/tests/testthat/helper-furrr-test-that.R:27:2
   4. furrr:::import_from(name, default = default, package = "future")
  
  ══ testthat results  ═══════════════════════════════════════════════════════════
  [ OK: 44 | SKIPPED: 1 | WARNINGS: 0 | FAILED: 9 ]

These errors will prevent me from going ahead with the new, trimmed future release. The fix is to update import_from(), which I guess you've got from future.apply, to use the less conservative inherits = TRUE;

furrr:::import_from
function (name, default = NULL, package) 
{
    ns <- getNamespace(package)
    if (exists(name, mode = "function", envir = ns, inherits = TRUE)) {
        get(name, mode = "function", envir = ns, inherits = TRUE)
    }
    else if (!is.null(default)) {
        default
    }
    else {
        stop(sprintf("No such '%s' function: %s()", package, 
            name))
    }
}

OTH, why not just do a regular import or use future::supportsMulticore() here?

[DavisVaughan]

@HenrikBengtsson furrr 0.2.1 is on CRAN with the fix!

[HenrikBengtsson]

Awesome. A quick check gives that it now works with the feature/parallelly branch of future. Thanks for the quick turnaround.