Update to update_*_defaults() (reviving #5781) (#5846)

* Update to `update_*_defaults()` (#5781)

* unify updating mechanism

* add tests

* redocument

* add news bullet

* add review suggestion

* move news bullet

Author: teunbrand

NEWS.md

@@ -1,5 +1,7 @@
 # ggplot2 (development version)
 
+* `update_geom_defaults()` and `update_stat_defaults()` have a reset mechanism
+  when using `new = NULL` and invisible return the previous defaults (#4993).
 * Fixed regression in axes where `breaks = NULL` caused the axes to disappear
   instead of just rendering the axis line (@teunbrand, #5816).
 * `geom_point()` can be dodged vertically by using 

R/geom-defaults.R

@@ -3,7 +3,9 @@
 #' @param stat,geom Name of geom/stat to modify (like `"point"` or
 #'   `"bin"`), or a Geom/Stat object (like `GeomPoint` or
 #'   `StatBin`).
-#' @param new Named list of aesthetics.
+#' @param new One of the following:
+#'  * A named list of aesthetics to serve as new defaults.
+#'  * `NULL` to reset the defaults.
 #' @keywords internal
 #' @export
 #' @examples
@@ -16,7 +18,7 @@
 #' ggplot(mtcars, aes(mpg, wt)) + geom_point()
 #'
 #' # reset default
-#' update_geom_defaults("point", aes(color = "black"))
+#' update_geom_defaults("point", NULL)
 #'
 #'
 #' # updating a stat's default aesthetic settings
@@ -29,27 +31,45 @@
 #'   geom_function(fun = dnorm, color = "red")
 #'
 #' # reset default
-#' update_stat_defaults("bin", aes(y = after_stat(count)))
+#' update_stat_defaults("bin", NULL)
 #'
 #' @rdname update_defaults
 update_geom_defaults <- function(geom, new) {
-  g <- check_subclass(geom, "Geom", env = parent.frame())
-  old <- g$default_aes
-  new <- rename_aes(new)
-  new_names_order <- unique(c(names(old), names(new)))
-  new <- defaults(new, old)[new_names_order]
-  g$default_aes[names(new)] <- new
-  invisible()
+  update_defaults(geom, "Geom", new, env = parent.frame())
 }
 
 #' @rdname update_defaults
 #' @export
 update_stat_defaults <- function(stat, new) {
-  g <- check_subclass(stat, "Stat", env = parent.frame())
-  old <- g$default_aes
-  new <- rename_aes(new)
-  new_names_order <- unique(c(names(old), names(new)))
-  new <- defaults(new, old)[new_names_order]
-  g$default_aes[names(new)] <- new
-  invisible()
+  update_defaults(stat, "Stat", new, env = parent.frame())
+}
+
+cache_defaults <- new_environment()
+
+update_defaults <- function(name, subclass, new, env = parent.frame()) {
+  obj   <- check_subclass(name, subclass, env = env)
+  index <- snake_class(obj)
+
+  if (is.null(new)) { # Reset from cache
+
+    old <- cache_defaults[[index]]
+    if (!is.null(old)) {
+      new <- update_defaults(name, subclass, new = old, env = env)
+    }
+    invisible(new)
+
+  } else { # Update default aesthetics
+
+    old <- obj$default_aes
+    # Only update cache the first time defaults are changed
+    if (!exists(index, envir = cache_defaults)) {
+      cache_defaults[[index]] <- old
+    }
+    new <- rename_aes(new)
+    name_order <- unique(c(names(old), names(new)))
+    new <- defaults(new, old)[name_order]
+    obj$default_aes[names(new)] <- new
+    invisible(old)
+
+  }
 }

man/update_defaults.Rd

@@ -6,7 +6,21 @@ test_that("aesthetic checking in geom throws correct errors", {
   expect_snapshot_error(check_aesthetics(aes, 4))
 })
 
-
+test_that("geom defaults can be set and reset", {
+  l <- geom_point()
+  test <- l$geom$use_defaults(data_frame0())
+  expect_equal(test$colour, "black")
+
+  inv <- update_geom_defaults("point", list(colour = "red"))
+  test <- l$geom$use_defaults(data_frame0())
+  expect_equal(test$colour, "red")
+  expect_equal(inv$colour, "black")
+
+  inv <- update_geom_defaults("point", NULL)
+  test <- l$geom$use_defaults(data_frame0())
+  expect_equal(test$colour, "black")
+  expect_equal(inv$colour, "red")
+})
 
 test_that("updating geom aesthetic defaults preserves class and order", {
 
@@ -23,7 +37,7 @@ test_that("updating geom aesthetic defaults preserves class and order", {
 
   expect_equal(updated_defaults, intended_defaults)
 
-  update_geom_defaults("point", original_defaults)
+  update_geom_defaults("point", NULL)
 
 })
 
@@ -46,6 +60,6 @@ test_that("updating stat aesthetic defaults preserves class and order", {
 
   expect_equal(updated_defaults, intended_defaults)
 
-  update_stat_defaults("bin", original_defaults)
+  update_stat_defaults("bin", NULL)
 
 })