Ensure complete themes never inherit defaults

Fills in missing theme_void() components revealed by the fix.

Closes #2080. Fixes #2058. Fixes #2079. Written by @has2k1

NEWS.md

@@ -1,5 +1,8 @@
 # ggplot2 2.2.1.9000
 
+* Complete themes now always override all elements of the default theme
+  (@has2k1, #2058, #2079)
+
 * Alternative syntax for calculated aesthetics. Instead of using 
   `aes(y = ..count..)` you can (and should!) now use `aes(y = calc(count))`.
   `calc()` is a real function with documentation which hopefully will make

R/labeller.r

@@ -554,7 +554,9 @@ build_strip <- function(label_df, labeller, theme, horizontal) {
       clip = "on"
     )
 
-    theme$strip.text.y$angle <- adjust_angle(theme$strip.text.y$angle)
+    if (inherits(theme$strip.text.y, "element_text")) {
+      theme$strip.text.y$angle <- adjust_angle(theme$strip.text.y$angle)
+    }
 
     grobs_left <- grobs
 

R/theme-defaults.r

@@ -221,7 +221,7 @@ theme_linedraw <- function(base_size = 11, base_family = "",
                            base_line_size = base_size / 22,
                            base_rect_size = base_size / 22) {
   half_line <- base_size / 2
-  
+
   # Starts with theme_bw and then modify some parts
   # = replace all greys with pure black or white
   theme_bw(
@@ -260,7 +260,7 @@ theme_light <- function(base_size = 11, base_family = "",
                         base_line_size = base_size / 22,
                         base_rect_size = base_size / 22) {
   half_line <- base_size / 2
-  
+
   # Starts with theme_grey and then modify some parts
   theme_grey(
     base_size = base_size,
@@ -302,7 +302,7 @@ theme_dark <- function(base_size = 11, base_family = "",
                        base_line_size = base_size / 22,
                        base_rect_size = base_size / 22) {
   half_line <- base_size / 2
-  
+
   # Starts with theme_grey and then modify some parts
   theme_grey(
     base_size = base_size,
@@ -398,10 +398,9 @@ theme_void <- function(base_size = 11, base_family = "",
                        base_line_size = base_size / 22,
                        base_rect_size = base_size / 22) {
   half_line <- base_size / 2
-
+
+  # Only keep indispensable text: legend and plot titles
   theme(
-    # Use only inherited elements and make almost everything blank
-    # Only keep indispensable text
     line =               element_blank(),
     rect =               element_blank(),
     text =               element_text(
@@ -410,27 +409,47 @@ theme_void <- function(base_size = 11, base_family = "",
                             lineheight = 0.9, hjust = 0.5, vjust = 0.5, angle = 0,
                             margin = margin(), debug = FALSE
                          ),
-    axis.text =        element_blank(),
-    axis.title =       element_blank(),
+    axis.text =          element_blank(),
+    axis.title =         element_blank(),
+    axis.ticks.length =  unit(0, "pt"),
+    legend.key.size =    unit(1.2, "lines"),
+    legend.position =    "right",
     legend.text =        element_text(size = rel(0.8)),
     legend.title =       element_text(hjust = 0),
-    strip.text =         element_text(
-                           size = rel(0.8),
-                           margin = margin(half_line, half_line, half_line, half_line)
-                         ),
+    strip.text =         element_text(size = rel(0.8)),
+    strip.switch.pad.grid = unit(0.1, "cm"),
+    strip.switch.pad.wrap = unit(0.1, "cm"),
+    panel.ontop =        FALSE,
+    panel.spacing =      unit(half_line, "pt"),
     plot.margin =        unit(c(0, 0, 0, 0), "lines"),
+    plot.title =         element_text(
+                           size = rel(1.2),
+                           hjust = 0, vjust = 1,
+                           margin = margin(t = half_line * 1.2)
+                         ),
+    plot.subtitle =      element_text(
+                           size = rel(0.9),
+                           hjust = 0, vjust = 1,
+                           margin = margin(t = half_line * 0.9)
+                         ),
+    plot.caption =       element_text(
+                           size = rel(0.9),
+                           hjust = 1, vjust = 1,
+                           margin = margin(t = half_line * 0.9)
+                         ),
 
     complete = TRUE
   )
 }
 
+
 #' @export
 #' @rdname ggtheme
 theme_test <- function(base_size = 11, base_family = "",
                        base_line_size = base_size / 22,
                        base_rect_size = base_size / 22) {
   half_line <- base_size / 2
-  
+
   theme(
     line =               element_line(
                            colour = "black", size = base_line_size,

R/theme.r

@@ -413,10 +413,17 @@ theme <- function(line,
   )
 }
 
+is_theme_complete <- function(x) isTRUE(attr(x, "complete"))
+
 
 # Combine plot defaults with current theme to get complete theme for a plot
-plot_theme <- function(x) {
-  defaults(x$theme, theme_get())
+plot_theme <- function(x, default = theme_get()) {
+  theme <- x$theme
+  if (is_theme_complete(theme)) {
+    theme
+  } else {
+    defaults(theme, default)
+  }
 }
 
 #' Modify properties of an element in a theme object
@@ -456,7 +463,7 @@ add_theme <- function(t1, t2, t2name) {
   }
 
   # If either theme is complete, then the combined theme is complete
-  attr(t1, "complete") <- attr(t1, "complete") || attr(t2, "complete")
+  attr(t1, "complete") <- is_theme_complete(t1) || is_theme_complete(t2)
   t1
 }
 
@@ -486,7 +493,7 @@ add_theme <- function(t1, t2, t2name) {
 update_theme <- function(oldtheme, newtheme) {
   # If the newtheme is a complete one, don't bother searching
   # the default theme -- just replace everything with newtheme
-  if (attr(newtheme, "complete"))
+  if (is_theme_complete(newtheme))
     return(newtheme)
 
   # These are elements in newtheme that aren't already set in oldtheme.

tests/testthat/test-theme.r

@@ -224,6 +224,16 @@ test_that("Elements can be merged", {
   )
 })
 
+test_that("complete plot themes shouldn't inherit from default", {
+  default_theme <- theme_gray() + theme(axis.text.x = element_text(colour = "red"))
+  base <- qplot(1, 1)
+
+  ptheme <- plot_theme(base + theme(axis.text.x = element_text(colour = "blue")), default_theme)
+  expect_equal(ptheme$axis.text.x$colour, "blue")
+
+  ptheme <- plot_theme(base + theme_void(), default_theme)
+  expect_null(ptheme$axis.text.x)
+})
 
 # Visual tests ------------------------------------------------------------
 
@@ -315,4 +325,4 @@ test_that("axes can be styled independently", {
       axis.line.y.right = element_line(colour = 'yellow')
     )
   vdiffr::expect_doppelganger("axes_styling", plot)
-})
+})