Merge branch 'master' of github.com:tidyverse/ggplot2

Author: hadley

NEWS.md

@@ -1,4 +1,5 @@
 # ggplot2 2.2.1.9000
+To be released as 2.3.0
 
 ## Breaking changes
 

R/plot-build.r

@@ -159,7 +159,7 @@ ggplot_gtable.ggplot_built <- function(data) {
   plot_table <- layout$render(geom_grobs, data, theme, plot$labels)
 
   # Legends
-  position <- theme$legend.position
+  position <- theme$legend.position %||% "right"
   if (length(position) == 2) {
     position <- "manual"
   }

R/plot-construction.r

@@ -38,6 +38,12 @@
 #' # This can be useful to return from a function.
 #' base + list(subset(mpg, fl == "p"), geom_smooth())
 "+.gg" <- function(e1, e2) {
+  if (missing(e2)) {
+    stop("Cannot use `+.gg()` with a single argument. ",
+         "Did you accidentally put + on a new line?",
+         call. = FALSE)
+  }
+
   # Get the name of what was passed in as e2, and pass along so that it
   # can be displayed in error messages
   e2name <- deparse(substitute(e2))

revdep/email.yml

@@ -1,4 +1,4 @@
-release_date: ???
-rel_release_date: ???
-my_news_url: ???
-release_version: ???
+release_date: June 25
+rel_release_date: one month
+my_news_url: https://github.com/tidyverse/ggplot2/blob/master/NEWS.md#ggplot2-2219000
+release_version: 2.3.0

tests/testthat/test-error.R

@@ -0,0 +1,18 @@
+context("error")
+
+test_that("various misuses of +.gg (#2638)", {
+  expect_error(
+    {
+      ggplot(mtcars, aes(hwy, displ))
+      + geom_point()
+    },
+    "Cannot use `+.gg()` with a single argument. Did you accidentally put + on a new line?",
+    fixed = TRUE
+  )
+
+  expect_error(
+    geom_point() + geom_point(),
+    "Cannot add ggproto objects together. Did you forget to add this object to a ggplot object?",
+    fixed = TRUE
+  )
+})