BUG: Odd interaction with BatchJobs package

[HenrikBengtsson]

So, although this is unlikely to happen, here it goes:

This works:

library(future)
plan(future.batchtools::batchtools_local)
options(future.debug = TRUE)
f <- future(42)

But not this:

library(future)
loadNamespace("BatchJobs")
plan(future.batchtools::batchtools_local)
options(future.debug = TRUE)
f <- future(42)

which gives:

[12:10:52.163] getGlobalsAndPackages() ...
[12:10:52.164] Searching for globals...
[12:10:52.165] 
[12:10:52.166] Searching for globals ... DONE
[12:10:52.166] - globals: [0] <none>
[12:10:52.166] getGlobalsAndPackages() ... DONE
No readable configuration file found
Created registry in '/home/hb/repositories/future.batchtools/.future/20190622_121007-qn0hej/batchtools_978006181' using cluster functions 'Interactive'
Error in dbDoQuery(reg, query) : 
  Error while etablishing the connection: Error in do.call(reg$db.driver, list()) : 
  'what' must be a function or character string
[12:10:52.431] batchtools::waitForJobs() ...
[12:10:52.447] - batchtools::waitForJobs(): TRUE
[12:10:52.461] - status(): 'defined', 'finished', 'started', 'submitted'
[12:10:52.462] batchtools::waitForJobs() ... done
[12:10:52.462] Results:
[12:10:52.484] List of 7
[12:10:52.484]  $ value         : num 42
[12:10:52.484]  $ stdout        : chr ""
[12:10:52.484]  $ conditions    : list()
[12:10:52.484]  $ started       : POSIXct[1:1], format: "2019-06-22 12:10:09"
[12:10:52.484]  $ finished      : POSIXct[1:1], format: "2019-06-22 12:10:09"
[12:10:52.484]  $ version       : chr "1.8"
[12:10:52.484]  $ batchtools_log: chr [1:9] "### [bt]: This is batchtools v0.9.11" "### [bt]: Starting calculation of 1 jobs" "### [bt]: Setting working directory to '/home/hb/repositories/future.batchtools'" "### [bt]: Memory measurement disabled" ...
[12:10:52.484]  - attr(*, "class")= chr "FutureResult"
[12:10:52.497] delete(): Option 'future.delete = '<NULL>'
Removing 1 jobs ...
Removing user function ...
Removing 1 obsolete result files ...
Removing 1 obsolete log files ...
Recursively removing files in '/home/hb/repositories/future.batchtools/.future/20190622_121007-qn0hej/batchtools_607848383' ...
[12:10:52.543] delete(): batchtools registry deleted: '/home/hb/repositories/future.batchtools/.future/20190622_121007-qn0hej/batchtools_607848383'

Enter a frame number, or 0 to exit   

 1: future(42)
 2: .makeFuture(expr, substitute = FALSE, envir = envir, globals = globals, pac
 3: makeFuture(...)
 4: BatchtoolsFuture(expr = expr, envir = envir, substitute = FALSE, globals = 
 5: mprint(reg)
 6: message(paste(now(), capture.output(print(...)), sep = "", collapse = "\n")
 7: paste(now(), capture.output(print(...)), sep = "", collapse = "\n")
 8: capture.output(print(...))
 9: evalVis(expr)
10: withVisible(eval(expr, pf))
11: eval(expr, pf)
12: eval(expr, pf)
13: print(...)
14: print.Registry(...)
15: cat("  Number of jobs: ", dbGetJobCount(x), "\n")
16: dbGetJobCount(x)
17: dbDoQuery(reg, query)
18: stopf("Error while etablishing the connection: %s", as.character(con))
19: stop(obj)
20: (function () 
{
    replicate(sink.number(), sink(NULL))
    if (interactiv