theme_set() breaks theme_void() if axis.text.x or axis.text.y is modified

[crsh]

Hi, I'm having trouble with one of my custom themes since a recent update (I have tried with version 2.2.1 and the current snapshot from this repository). When I change the settings of axis.text.x or
axis.text.y in a theme that is set as default using theme_set(), theme_void() throws an error. This causes trouble when I try to use cowplot::plot_grid() (see my previous bug report).

library("ggplot2")

df <- data.frame(
    gp = factor(rep(letters[1:3], each = 10))
    , y = rnorm(30)
)
theme_set(theme_classic() + theme(axis.text.x = element_text()))

test <- ggplot(df, aes(gp, y)) + geom_point()

test # works
test + theme_void() # doesn't work

Error in element_grob.element_text(el, ...) : 
  Text element requires non-NULL value for 'angle'.

If I set angle and debug in element_text() it works.

test + theme_void() + theme(axis.text.x = element_text(angle = 0, debug = FALSE)) # works

Is this intended behavior?

[thomasp85]

I don't really think this is a bug - you need to specify the angle the text should be written in. Usually this is derived from the root text element but since this is element_blank in theme_void() you'll need to specify it when you modify child elements...

[crsh]

What is very surprising to me is that I don't make any changes to theme_void(). I modify theme_classic() and set that modified version as default. Still this causes problems with theme_void(). I came across this behavior working with a custom theme of my own where I modify axis text margins. I don't make any changes to the angle and I don't touch theme_void().

Moreover, if I nevertheless set angle to any value, I get the following error

Error in if (debug) { : Argument has length 0

which is why in my continued example I also set debug = FALSE.

Also, I played a little more with this and when I make changes to, e.g., axis.title.x I get the same angle-error, but when I do set angle explicitly I get a new error:

theme_set(theme_classic() + theme(axis.title.x = element_text(angle = 0)))

test <- ggplot(df, aes(gp, y)) + geom_point()

test # works
test + theme_void() # doesn't work

Error in unit(rep(xp, n), "npc") : 'x' and 'units' must have length > 0

[has2k1]

I think it is a bug. theme_void() is a complete theme so whatever the default theme (the one set with theme_set) is should not affect it.

[thomasp85]

Yeah, I can see that now. I'll look into it

[gilliganondata]

I've run into this a couple of times and wind up back on this issue each time. The thing I keep forgetting is that this does not cause an issue if simply axis.title() is set. It only seems to come into play (for me) when I'm trying to set axis.title.x() or axis.title.y() explicitly. With that in mind, I've been able to find various workarounds.

[crsh]

Hooray for the fix. Thanks!