find_global looks in better places for scales

Author: hadley

R/scales-.r

@@ -81,20 +81,20 @@ scales_add_defaults <- function(scales, data, aesthetics, env) {
     scale_name <- paste("scale", aes, type, sep="_")
 
     # Skip aesthetics with no scales (e.g. group, order, etc)
-    scale_f <- find_global(scale_name)
+    scale_f <- find_global(scale_name, env)
     if (is.null(scale_f)) next
 
     scales$add(scale_f())
   }
 
 }
 
-# Look for object first in global environment and if not found, then in 
+# Look for object first in parent environment and if not found, then in 
 # ggplot2 package environment.  This makes it possible to override default
-# scales by setting them in the default environment.
-find_global <- function(name) {
-  if (exists(name, globalenv())) {
-    return(get(name, globalenv()))
+# scales by setting them in the parent environment.
+find_global <- function(name, env) {
+  if (exists(name, env)) {
+    return(get(name, env))
   }
 
   if (exists(name, "package:ggplot2")) {

inst/tests/test-scales.r

@@ -126,3 +126,23 @@ test_that("oob affects position values", {
 
 })
 
+test_that("scales looked for in appropriate place", {
+  xlabel <- function(x) ggplot_build(x)$panel$x_scales[[1]]$name
+  p0 <- qplot(mpg, wt, data = mtcars) + scale_x_continuous("0")
+  expect_equal(xlabel(p0), "0")
+
+  scale_x_continuous <- function(...) ggplot2::scale_x_continuous("1")
+  p1 <- qplot(mpg, wt, data = mtcars)
+  expect_equal(xlabel(p1), "1")
+
+  f <- function() {
+    scale_x_continuous <- function(...) ggplot2::scale_x_continuous("2")
+    qplot(mpg, wt, data = mtcars)
+  }
+  p2 <- f()
+  expect_equal(xlabel(p2), "2")
+
+  rm(scale_x_continuous)
+  p4 <- qplot(mpg, wt, data = mtcars)
+  expect_equal(xlabel(p4), NULL)
+})