Check that data_frames have unique names.

Fixes tidyverse#820
krlmlr · Oct 29, 2015 · 3187f86 · 3187f86
1 parent 77dba6b
commit 3187f86
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diff --git a/R/dataframe.R b/R/dataframe.R
@@ -264,6 +264,11 @@ check_data_frame <- function(x) {
     invalid_df("Each variable must be named", x, which(bad_name))
   }
 
+  dups <- duplicated(names_x)
+  if (any(dups)) {
+    invalid_df("Each variable must have a unique name", x, dups)
+  }
+
   # Types
   is_1d <- vapply(x, is_1d, logical(1))
   if (any(!is_1d)) {

diff --git a/tests/testthat/test-data_frame.R b/tests/testthat/test-data_frame.R
@@ -75,3 +75,10 @@ test_that("columns must be named (#1101)", {
     "Each variable must be named"
   )
 })
+
+test_that("names must be unique (#820)", {
+  expect_error(
+    check_data_frame(list(x = 1, x = 2)),
+    "Each variable must have a unique name"
+  )
+})