add warning when orientation is ambiguous fixes #4250

Author: sierrajohnson

R/stat-boxplot.R

@@ -23,7 +23,13 @@ StatBoxplot <- ggproto("StatBoxplot", Stat,
   setup_params = function(self, data, params) {
     params$flipped_aes <- has_flipped_aes(data, params, main_is_orthogonal = TRUE,
                                           group_has_equal = TRUE,
-                                          main_is_optional = TRUE)
+                                          main_is_optional = TRUE,
+                                        default = NA)
+    
+    if (is.na(params$flipped_aes)) {
+      cli::cli_warn("Warning: Orientation is not uniquely specified when both the x and y aesthetics are continuous. Picking default orientation 'x'.")
+      params$flipped_aes <- FALSE
+    }
     data <- flip_data(data, params$flipped_aes)
 
     has_x <- !(is.null(data$x) && is.null(params$x))

R/utilities.R

@@ -562,7 +562,7 @@ has_flipped_aes <- function(data, params = list(), main_is_orthogonal = NA,
     }
   }
 
-  isTRUE(default)
+  default
 }
 #' @rdname bidirection
 #' @export

tests/testthat/_snaps/geom-boxplot.md

@@ -1,17 +1,14 @@
 # geom_boxplot for continuous x gives warning if more than one x (#992)
 
-    Continuous x aesthetic
-    i did you forget `aes(group = ...)`?
+    Warning: Orientation is not uniquely specified when both the x and y aesthetics are continuous. Picking default orientation 'x'.
 
 ---
 
-    Continuous x aesthetic
-    i did you forget `aes(group = ...)`?
+    Warning: Orientation is not uniquely specified when both the x and y aesthetics are continuous. Picking default orientation 'x'.
 
 ---
 
-    Continuous x aesthetic
-    i did you forget `aes(group = ...)`?
+    Warning: Orientation is not uniquely specified when both the x and y aesthetics are continuous. Picking default orientation 'x'.
 
 # boxplots with a group size >1 error