throw warning when only one of two variables is AsIs

Author: teunbrand

R/coord-.R

@@ -284,3 +284,24 @@ check_coord_limits <- function(
   check_object(limits, is_vector, "a vector", arg = arg, call = call)
   check_length(limits, 2L, arg = arg, call = call)
 }
+
+is_transform_immune <- function(data, coord_name) {
+  x <- inherits(data$x, "AsIs")
+  y <- inherits(data$y, "AsIs")
+  if (!(x || y)) {
+    # Neither variable is AsIs, so we need to transform
+    return(FALSE)
+  }
+  if (x && y) {
+    # Both variables are AsIs, so no need to transform
+    return(TRUE)
+  }
+  # We're now in the `xor(x, y)` case
+  var <- if (x) "x" else "y"
+  alt <- if (x) "y" else "x"
+  cli::cli_warn(
+    "{.fn {coord_name}} cannot respect the {.cls AsIs} class of {.var {var}} \\
+    when {.var {alt}} is not also {.cls AsIs}."
+  )
+  return(FALSE)
+}

R/coord-polar.R

@@ -180,7 +180,7 @@ CoordPolar <- ggproto("CoordPolar", Coord,
   },
 
   transform = function(self, data, panel_params) {
-    if (inherits(data$x, "AsIs") && inherits(data$y, "AsIs")) {
+    if (is_transform_immune(data, snake_class(self))) {
       return(data)
     }
 

R/coord-radial.R

@@ -275,7 +275,7 @@ CoordRadial <- ggproto("CoordRadial", Coord,
   },
 
   transform = function(self, data, panel_params) {
-    if (inherits(data$x, "AsIs") && inherits(data$y, "AsIs")) {
+    if (is_transform_immune(data, snake_class(self))) {
       return(data)
     }
 

R/coord-sf.R

@@ -77,7 +77,7 @@ CoordSf <- ggproto("CoordSf", CoordCartesian,
   },
 
   transform = function(self, data, panel_params) {
-    if (inherits(data$x, "AsIs") && inherits(data$y, "AsIs")) {
+    if (is_transform_immune(data, snake_class(self))) {
       return(data)
     }
 

tests/testthat/_snaps/coord-polar.md

@@ -12,3 +12,7 @@
     No appropriate placement found for `r_axis_inside`.
     i Axis will be placed at panel edge.
 
+# when both x and y are AsIs, they are not transformed
+
+    `coord_name()` cannot respect the <AsIs> class of `x` when `y` is not also <AsIs>.
+

tests/testthat/test-coord-polar.R

@@ -170,6 +170,15 @@ test_that("when both x and y are AsIs, they are not transformed", {
   location <- c(as.numeric(grob$x), as.numeric(grob$y))
   expect_equal(location, c(0.75, 0.25))
 
+  # Check warning is thrown if only one is AsIs
+  p <- ggplot() +
+    annotate("text", x = I(0.75), y = 2.5, label = "foo") +
+    scale_x_continuous(limits = c(0, 10)) +
+    scale_y_continuous(limits = c(0, 10)) +
+    coord_radial()
+
+  expect_snapshot_warning(ggplotGrob(p))
+
 })
 
 # Visual tests ------------------------------------------------------------