fix(encapsulate): address data table bug (#144)

Author: sebffischer

R/encapsulate.R

@@ -196,12 +196,14 @@ encapsulate = function(method, .f, .args = list(), .opts = list(), .pkgs = chara
   }
   if (nrow(log)) {
     # classes for messages are not really useful, so we save some memory
-    log[, condition := map(condition, function(x) {
+    # data.table list columns with 1 row are no fun :(
+    conds = map(log$condition, function(x) {
       if (inherits(x, "message")) {
         return(trimws(conditionMessage(x)))
       }
       x
-    })]
+    })
+    log$condition = if (length(conds) == 1L) list(conds) else conds
   }
 
   log$class = factor(log$class, levels = c("output", "warning", "error"), ordered = TRUE)

man/mlr_callbacks.Rd

@@ -227,4 +227,18 @@ test_that("condition objects are stored", {
     expect_equal(res$log$condition[[2]], simpleWarning("b"))
     expect_equal(res$log$condition[[3]], simpleError("c"))
   }
+
+  # data.table with 1 row
+  fun = function() {
+    mlr3misc::stopf("c")
+  }
+
+  for (method in c("evaluate", "callr", "mirai", "try")) {
+    if (!requireNamespace(method, quietly = TRUE)) {
+      next
+    }
+    res = encapsulate(method, fun)
+    expect_equal(as.character(res$log$class), "error")
+    expect_equal(res$log$condition[[1]], tryCatch(stopf("c"), error = identity))
+  }
 })