Fix weird legend bug

Author: hadley

NEWS

@@ -36,3 +36,4 @@ ggplot2 0.8.5 (2009-XX-XX) ----------------------------------------
   have formatter argument to match scale_continuous
 * legends will only merge if both the title and all labels are the same.
   (Fixes #16)
+* Fix for bug #19: Legend with three constraints doesn't work 

R/guides-legend.r

@@ -75,7 +75,6 @@ guide_legends <- function(scales, layers, default_mapping, theme) {
     } else {
       keys <- keys[[1]]
     }
-    
     build_legend(title, keys, layers, default_mapping, theme)
   })
 }
@@ -166,7 +165,7 @@ build_legend <- function(name, mapping, layers, default_mapping, theme) {
 build_legend_data <- function(layer, mapping, default_mapping) {
   all <- names(c(layer$mapping, default_mapping, layer$stat$default_aes()))
   geom <- c(layer$geom$required_aes, names(layer$geom$default_aes()))
-  
+ 
   matched <- intersect(intersect(all, geom), names(mapping))
   matched <- setdiff(matched, names(layer$geom_params))
 

R/layer.r

@@ -84,10 +84,12 @@ Layer <- proto(expr = {
   clone <- function(.) as.proto(.$as.list(all.names=TRUE))
 
   use_defaults <- function(., data) {
-    df <- aesdefaults(data, .$geom$default_aes(), compact(.$mapping))
+    mapped_vars <- .$mapping[!sapply(.$mapping, is.character)]
+    df <- aesdefaults(data, .$geom$default_aes(), mapped_vars)
 
     # Override mappings with parameters
     gp <- intersect(c(names(df), .$geom$required_aes), names(.$geom_params))
+
     if (length(.$geom_params[gp])) 
       gp <- gp[sapply(.$geom_params[gp], is.atomic)]
     df[gp] <- .$geom_params[gp]