Return missing when output is length 0

Fixes #254
tidyverse · Mar 4, 2017 · d24d1b5 · d24d1b5
1 parent 8658c40
commit d24d1b5
Show file tree

Hide file tree

Showing 3 changed files with 6 additions and 9 deletions.
diff --git a/NEWS.md b/NEWS.md
@@ -33,7 +33,7 @@
 * Removed `LinkingTo:` dependency on `dplyr` (#247, @krlmlr).
 
 * Recursive index via `as_function()` now returns `missing` when first element
-  is `NULL`
+  is `NULL`, or when the element has length 0 (#254).
 
 * When indexing elements (e.g. `map(x, "field")`), `NULL` values are
   replaced with `.null` (#231).

diff --git a/src/extract.c b/src/extract.c
@@ -103,8 +103,5 @@ SEXP extract_impl(SEXP x, SEXP index, SEXP missing) {
     }
   }
 
-  if (TYPEOF(x) == NILSXP)
-    return missing;
-  else
-    return x;
+  return (Rf_length(x) > 0) ? x : missing;
 }
diff --git a/tests/testthat/test-as-function.R b/tests/testthat/test-as-function.R
@@ -11,13 +11,13 @@ test_that(".null replaces absent values", {
   expect_equal(map_dbl(x, "b", .null = NA), c(2, NA, NA))
 })
 
-test_that(".null replaces actual NULL values", {
+test_that(".null replaces elements with length 0", {
   x <- list(
     list(a = 1),
-    list(a = NULL)
+    list(a = NULL),
+    list(a = numeric())
   )
-
-  expect_equal(map_dbl(x, "a", .null = NA), c(1, NA))
+  expect_equal(map_dbl(x, "a", .null = NA), c(1, NA, NA))
 })