Add allow_empty to check_logical() and check_character()

R/standalone-types-check.R

@@ -1,14 +1,18 @@
 # ---
 # repo: r-lib/rlang
 # file: standalone-types-check.R
-# last-updated: 2023-03-13
+# last-updated: 2024-08-18
 # license: https://unlicense.org
 # dependencies: standalone-obj-type.R
 # imports: rlang (>= 1.1.0)
 # ---
 #
 # ## Changelog
 #
+# 2025-09-19
+# - `check_logical()` and `check_character()` gain `allow_empty` to disallow
+#    `logical(0)` and `character(0)` respectively.
+#
 # 2025-09-19:
 # - `check_logical()` gains an `allow_na` argument (@jonthegeek, #1724)
 #
@@ -505,14 +509,16 @@ check_formula <- function(
 check_character <- function(
   x,
   ...,
+  allow_empty = TRUE,
   allow_na = TRUE,
   allow_null = FALSE,
   arg = caller_arg(x),
   call = caller_env()
 ) {
   if (!missing(x)) {
-    if (is_character(x)) {
-      if (!allow_na && any(is.na(x))) {
+    problematic <- !allow_empty && length(x) == 0L
+    if (!problematic && is_character(x)) {
+      if (!allow_na && anyNA(x)) {
         abort(
           sprintf("`%s` can't contain NA values.", arg),
           arg = arg,
@@ -541,13 +547,16 @@ check_character <- function(
 check_logical <- function(
   x,
   ...,
+  allow_empty = TRUE,
   allow_na = TRUE,
   allow_null = FALSE,
   arg = caller_arg(x),
   call = caller_env()
 ) {
   if (!missing(x)) {
-    if (is_logical(x)) {
+    problematic <- !allow_empty && length(x) == 0
+
+    if (!problematic && is_logical(x)) {
       if (!allow_na && any(is.na(x))) {
         abort(
           sprintf("`%s` can't contain NA values.", arg),

tests/testthat/_snaps/standalone-types-check.md

@@ -456,6 +456,12 @@
       <error/rlang_error>
       Error in `checker()`:
       ! `foo` can't contain NA values.
+    Code
+      err(checker(character(0), check_character, allow_empty = FALSE))
+    Output
+      <error/rlang_error>
+      Error in `checker()`:
+      ! `foo` must be a character vector, not an empty character vector.
 
 # `check_logical()` checks
 
@@ -489,6 +495,12 @@
       <error/rlang_error>
       Error in `checker()`:
       ! `foo` must be a logical vector or `NULL`, not a list.
+    Code
+      err(checker(logical(0), check_logical, allow_empty = FALSE))
+    Output
+      <error/rlang_error>
+      Error in `checker()`:
+      ! `foo` must be a logical vector, not an empty logical vector.
     Code
       err(checker(NA, check_logical, allow_na = FALSE))
     Output

tests/testthat/test-standalone-types-check.R

@@ -162,7 +162,7 @@ test_that("`check_character()` checks", {
   expect_null(check_character(chr()))
   expect_null(check_character("foo"))
   expect_null(check_character(letters))
-  expect_null(check_character(NULL, allow_null = TRUE))
+  expect_null(check_character(NULL, allow_null = TRUE, allow_empty = FALSE))
 
   expect_snapshot({
     err(checker(, check_character))
@@ -171,6 +171,7 @@ test_that("`check_character()` checks", {
     err(checker(1, check_character))
     err(checker(list("foo", "bar"), check_character, allow_null = TRUE))
     err(checker(c("a", NA), check_character, allow_na = FALSE))
+    err(checker(character(0), check_character, allow_empty = FALSE))
   })
 })
 
@@ -180,14 +181,15 @@ test_that("`check_logical()` checks", {
   expect_null(check_logical(na_lgl))
   expect_null(check_logical(lgl()))
   expect_null(check_logical(c(TRUE, FALSE, NA)))
-  expect_null(check_logical(NULL, allow_null = TRUE))
+  expect_null(check_logical(NULL, allow_null = TRUE, allow_empty = FALSE))
 
   expect_snapshot({
     err(checker(, check_logical))
     err(checker(NULL, check_logical))
     err(checker(NA_integer_, check_logical))
     err(checker(1, check_logical))
     err(checker(list("foo", "bar"), check_logical, allow_null = TRUE))
+    err(checker(logical(0), check_logical, allow_empty = FALSE))
     err(checker(NA, check_logical, allow_na = FALSE))
   })
 })