support 'Pool' objects in dm_from_src

DESCRIPTION

@@ -57,6 +57,7 @@ Imports:
     tidyselect (>= 1.0.1),
     vctrs (>= 0.3.2)
 Suggests: 
+    pool,
     brio,
     covr,
     crayon,

R/dm-from-src.R

@@ -52,6 +52,12 @@ dm_from_src <- function(src = NULL, table_names = NULL, learn_keys = NULL,
     # FIXME: Check empty arguments and ellipsis
     return(empty_dm())
   }
+
+  if (inherits(src, "Pool")) {
+    src <- pool_src <- pool::poolCheckout(src)
+    on.exit(pool::poolReturn(pool_src))
+  }
+
   # both DBI-Connection and {dplyr}-src object are accepted
   src <- src_from_src_or_con(src)
   con <- con_from_src_or_con(src)

tests/testthat/test-pool-support.R

@@ -0,0 +1,7 @@
+test_that("dm_from_src supports 'Pool'", {
+  # expect no error
+  conn <- pool::dbPool(RSQLite::SQLite(), "", timeout = 10)
+  DBI::dbWriteTable(conn, "mtcars", mtcars)
+  dm <- dm::dm_from_src(conn, learn_keys = FALSE)
+  expect_identical(names(dm), "mtcars")
+})