Make type.character error for NA_character_

R/modifiers.R

@@ -202,6 +202,22 @@ type.stringr_fixed <- function(x, error_call = caller_env()) {
 }
 #' @export
 type.character <- function(x, error_call = caller_env()) {
+  if (length(x) == 1) {
+    if(is.na(x)) {
+      cli::cli_abort(
+        tr_("{.arg pattern} must be a string, not {.obj_type_friendly {x}}."),
+        call = error_call
+      )
+    }
+  }
+
+  if (any(is.na(x))) {
+    cli::cli_abort(
+      tr_("{.arg pattern} must be a string that does not contain NAs."),
+      call = error_call
+    )
+  }
+
   if (identical(x, "")) "empty" else "regex"
 }
 

tests/testthat/_snaps/modifiers.md

@@ -24,3 +24,19 @@
       Error:
       ! `pattern` must be a string, not an integer vector.
 
+# useful error message for NA_character_
+
+    Code
+      type(NA_character_)
+    Condition
+      Error:
+      ! `pattern` must be a string, not a character `NA`.
+
+# useful error message for vector that includes NAs
+
+    Code
+      type(c("a", "b", NA_character_, "c"))
+    Condition
+      Error:
+      ! `pattern` must be a string that does not contain NAs.
+

tests/testthat/test-modifiers.R

@@ -36,3 +36,15 @@ test_that("subsetting preserves class and options", {
   x <- regex("a", multiline = TRUE)
   expect_equal(x[], x)
 })
+
+test_that("useful error message for NA_character_", {
+  expect_snapshot(error = TRUE, {
+    type(NA_character_)
+  })
+})
+
+test_that("useful error message for vector that includes NAs", {
+  expect_snapshot(error = TRUE, {
+    type(c("a", "b", NA_character_, "c"))
+  })
+})