Deprecate the size argument of if_else() (#7722)

* Deprecate the `size` argument of `if_else()`

* NEWS bullet

Author: DavisVaughan

NEWS.md

@@ -1,5 +1,7 @@
 # dplyr (development version)
 
+* Passing `size` to `if_else()` is now deprecated. The output size is always taken from the `condition` (#7722).
+
 * `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).

R/if-else.R

@@ -23,8 +23,9 @@
 #' @param ptype An optional prototype declaring the desired output type. If
 #'   supplied, this overrides the common type of `true`, `false`, and `missing`.
 #'
-#' @param size An optional size declaring the desired output size. If supplied,
-#'   this overrides the size of `condition`.
+#' @param size `r lifecycle::badge("deprecated")`
+#'
+#'   Output size is always taken from `condition`.
 #'
 #' @return
 #' A vector with the same size as `condition` and the same type as the common
@@ -57,10 +58,14 @@ if_else <- function(
   missing = NULL,
   ...,
   ptype = NULL,
-  size = NULL
+  size = deprecated()
 ) {
   check_dots_empty0(...)
 
+  if (!is_missing(size)) {
+    lifecycle::deprecate_warn("1.2.0", "if_else(size = )")
+  }
+
   # Assert early since we `!` the `condition`
   check_logical(condition)
 
@@ -81,7 +86,6 @@ if_else <- function(
     default = missing,
     default_arg = "missing",
     ptype = ptype,
-    size = size,
     call = current_env()
   )
 }

man/if_else.Rd

@@ -66,11 +66,11 @@
       ! Can't convert from `false` <double> to <integer> due to loss of precision.
       * Locations: 1
 
-# `size` overrides the `condition` size
+# `size` is deprecated
 
     Code
-      if_else(TRUE, 1, 2, size = 2)
+      x <- if_else(c(TRUE, FALSE), 1, 2, size = 2)
     Condition
-      Error in `if_else()`:
-      ! `condition` must have size 2, not size 1.
+      Warning:
+      The `size` argument of `if_else()` is deprecated as of dplyr 1.2.0.
 

tests/testthat/_snaps/if-else.md

@@ -103,11 +103,9 @@ test_that("`ptype` overrides the common type", {
   })
 })
 
-test_that("`size` overrides the `condition` size", {
-  expect_identical(if_else(c(TRUE, FALSE), 1, 2, size = 2), c(1, 2))
-
-  # Note that `condition` is used as the name in the error message
-  expect_snapshot(error = TRUE, {
-    if_else(TRUE, 1, 2, size = 2)
+test_that("`size` is deprecated", {
+  expect_snapshot({
+    x <- if_else(c(TRUE, FALSE), 1, 2, size = 2)
   })
+  expect_identical(x, c(1, 2))
 })