Add test package and lookup fix.

Thanks to Martin Morgan for locating problem

Author: hadley

R/scales-.r

@@ -75,15 +75,15 @@ scales_add_defaults <- function(scales, data, aesthetics, env) {
   )
   new_aesthetics <- intersect(new_aesthetics, names(datacols))
   if (length(datacols) == 0) return()
-  
+
   for(aes in new_aesthetics) {
     disc <- is.discrete(datacols[[aes]])
     type <- if (disc) "discrete" else "continuous"
     scale_name <- paste("scale", aes, type, sep="_")
-    
+
     # Skip aesthetics with no scales (e.g. group, order, etc)
-    if (!exists(scale_name, globalenv())) next
-    scale_f <- get(scale_name, globalenv())
+    scale_f <- find_global(scale_name)
+    if (is.null(scale_f)) next
 
     if (disc) {
       args <- list()
@@ -96,6 +96,21 @@ scales_add_defaults <- function(scales, data, aesthetics, env) {
 
 }
 
+# Look for object first in global 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()))
+  }
+  
+  if (exists(name, "package::ggplot2")) {
+    return(get(name, "package::ggplot2"))
+  }
+  
+  NULL
+}
+
 # Determine default transformation for continuous scales
 trans_type <- function(x) {
   if (inherits(x, "Date")) {

inst/test_ns/DESCRIPTION

@@ -0,0 +1,12 @@
+Package: nstest
+Type: Package
+Title: Test ggplot2 NAMESPACE
+Version: 0.1
+Author: Hadley Wickham <[email protected]>
+Maintainer: Hadley Wickham <[email protected]>
+Description: Check to see if ggplot2 namespace set up correctly.
+Imports:
+    ggplot2
+License: GPL-2
+Collate:
+    'my-plot.r'

inst/test_ns/NAMESPACE

@@ -0,0 +1,2 @@
+export(my_plot)
+import(ggplot2)

inst/test_ns/R/my-plot.r

@@ -0,0 +1,12 @@
+#' Create a plot.
+#'
+#' @export
+#' @import ggplot2
+#' @examples
+#' plot(my_plot())
+my_plot <- function() {
+  df <- data.frame(x = 1:10, y = sample(10), z = runif(1))
+
+  ggplot(df) + geom_point(aes_string(x = "x", y = "y", colour = "z"))
+  
+}

inst/test_ns/man/my_plot.Rd

@@ -0,0 +1,13 @@
+\name{my_plot}
+\alias{my_plot}
+\title{Create a plot.}
+\usage{
+  my_plot()
+}
+\description{
+  Create a plot.
+}
+\examples{
+plot(my_plot())
+}
+