Simplify scales$add_default (#5409)

Author: thomasp85

NEWS.md

@@ -1,5 +1,7 @@
 # ggplot2 (development version)
 
+* `stage()` now works correctly, even with aesthetics that do not have scales 
+  (#5408)
 * `labeller()` now handles unspecified entries from lookup tables
   (@92amartins, #4599).
 

R/aes-evaluation.R

@@ -311,9 +311,10 @@ strip_stage <- function(expr) {
   if (is_call(uq_expr, c("after_stat", "after_scale"))) {
     uq_expr[[2]]
   } else if (is_call(uq_expr, "stage")) {
+    uq_expr <- call_match(uq_expr, stage)
     # Prefer stat mapping if present, otherwise original mapping (fallback to
     # scale mapping) but there should always be two arguments to stage()
-    uq_expr$after_stat %||% uq_expr$start %||% (if (is.null(uq_expr$after_scale)) uq_expr[[3]]) %||% uq_expr[[2]]
+    uq_expr$after_stat %||% uq_expr$start %||% uq_expr$after_scale
   } else {
     expr
   }

R/layer.R

@@ -268,13 +268,13 @@ Layer <- ggproto("Layer", NULL,
       aesthetics[["group"]] <- self$aes_params$group
     }
 
-    plot$scales$add_defaults(data, aesthetics, plot$plot_env)
-
     # Evaluate aesthetics
     env <- child_env(baseenv(), stage = stage)
     evaled <- lapply(aesthetics, eval_tidy, data = data, env = env)
     evaled <- compact(evaled)
 
+    plot$scales$add_defaults(evaled, plot$plot_env)
+
     # Check for discouraged usage in mapping
     warn_for_aes_extract_usage(aesthetics, data[setdiff(names(data), "PANEL")])
 
@@ -376,7 +376,7 @@ Layer <- ggproto("Layer", NULL,
     stat_data <- data_frame0(!!!compact(stat_data))
 
     # Add any new scales, if needed
-    plot$scales$add_defaults(data, new, plot$plot_env)
+    plot$scales$add_defaults(stat_data, plot$plot_env)
     # Transform the values, if the scale say it's ok
     # (see stat_spoke for one exception)
     if (self$stat$retransform) {

R/scales-.R

@@ -141,23 +141,15 @@ ScalesList <- ggproto("ScalesList", NULL,
 
   # `aesthetics` is a list of aesthetic-variable mappings. The name of each
   # item is the aesthetic, and the value of each item is the variable in data.
-  add_defaults = function(self, data, aesthetics, env) {
-    if (is.null(aesthetics)) {
-      return()
-    }
-    names(aesthetics) <- unlist(lapply(names(aesthetics), aes_to_scale))
-
-    new_aesthetics <- setdiff(names(aesthetics), self$input())
+  add_defaults = function(self, data, env) {
+    new_aesthetics <- setdiff(names(data), self$input())
     # No new aesthetics, so no new scales to add
     if (is.null(new_aesthetics)) {
       return()
     }
 
-    data_cols <- lapply(aesthetics[new_aesthetics], eval_tidy, data = data)
-    data_cols <- compact(data_cols)
-
-    for (aes in names(data_cols)) {
-      self$add(find_scale(aes, data_cols[[aes]], env))
+    for (aes in new_aesthetics) {
+      self$add(find_scale(aes, data[[aes]], env))
     }
   },