Always retain valid names in bind_rows(.id = ) (#7719)

* `.id` bug in `bind_rows()`

* Update R/bind-rows.R

Co-authored-by: Davis Vaughan <[email protected]>

* Update tests/testthat/test-bind-rows.R

Co-authored-by: Davis Vaughan <[email protected]>

* update `NEWS.md`

* grammar fix

* Update tests/testthat/test-bind-rows.R

Co-authored-by: Davis Vaughan <[email protected]>

* Tweak NEWS

* Remove `rlang::`

---------

Co-authored-by: Davis Vaughan <[email protected]>

Author: Meghansaha

NEWS.md

@@ -1,5 +1,7 @@
 # dplyr (development version)
 
+* `bind_rows()` now replaces empty (or `NA`) element names in a list with its numeric index while preserving existing names (#7719, @Meghansaha).
+
 * New `slice_sample()` example showing how to use it to shuffle rows (#7707, @Hzanib).
 
 * Updated `across()` examples to include an example using `everything()` (#7621, @JBrandenburg02).

R/bind-rows.R

@@ -65,7 +65,11 @@ bind_rows <- function(..., .id = NULL) {
     check_string(.id)
 
     if (!is_named(dots)) {
-      names(dots) <- seq_along(dots)
+      # Replace `NA` or `""` names with their index,
+      # but leave existing names in place (#7100)
+      dots_with_names <- have_name(dots)
+      dots_without_names <- which(!dots_with_names)
+      names(dots)[dots_without_names] <- as.character(dots_without_names)
     }
   } else {
     # Don't let `vec_rbind(.id = NULL)` promote input names to row names

tests/testthat/test-bind-rows.R

@@ -145,6 +145,16 @@ test_that("bind_rows() handles named list", {
   expect_equal(bind_rows(x), tibble(x = 1, y = 2, z = 3))
 })
 
+test_that("bind_rows() handles empty names in a list (#7100)", {
+  x <- rep(list(data.frame(x = 1)), times = 5)
+  names(x) <- paste0("id_", 1:5)
+  names(x)[c(3, 5)] <- NA_character_
+  x <- bind_rows(x, .id = "id")
+
+  # If names are missing, bind_rows will replace with index
+  expect_identical(x$id, c("id_1", "id_2", "3", "id_4", "5"))
+})
+
 test_that("bind_rows() validates lists (#5417)", {
   out <- bind_rows(list(x = 1), list(x = 1, y = 1:2))
   expect_equal(out, tibble(x = c(1, 1, 1), y = c(NA, 1:2)))