geom_density error when all groups are dropped

[stla]

Hello,

library(ggplot2)
dat <- structure(list(include = c(TRUE, TRUE, TRUE, TRUE, TRUE, TRUE
), Petal_Width = c(0.1234567, 1.4321, 1.5, 1.5, 1.3, 1.5), Species = c("setosa", 
"versicolor", "versicolor", "versicolor", "versicolor", "versicolor"
), Date = structure(c(1484524800, 1484611200, 1484697600, 1484784000, 
1484870400, 1485043200), class = c("POSIXct", "POSIXt"), tzone = "UTC")), .Names = c("include", 
"Petal_Width", "Species", "Date"), class = c("tbl_df", "tbl", 
"data.frame"), row.names = c(NA, -6L))
ggplot(dat, aes(x=Petal_Width)) + geom_density() + facet_wrap("Date")

This generates this error:

Error: Discrete value supplied to continuous scale
In addition: Warning messages:
1: Groups with fewer than two data points have been dropped. 
2: Groups with fewer than two data points have been dropped. 
3: Groups with fewer than two data points have been dropped. 
4: Groups with fewer than two data points have been dropped. 
5: Groups with fewer than two data points have been dropped. 
6: Groups with fewer than two data points have been dropped.

In fact, all groups are dropped. Then I think the error message is not very appropriate.

[karawoo]

In your example all of the groups (dates) only have a single data point, so I think the warning messages are accurate.

[stla]

Yes, exactly, the warnings are accurate, but not the error message.

[hadley]

Thanks for providing some code that illustrates the problem — it's a great start 😄 However, your code is currently a bit too complicated: there's quite a bit of extraneous stuff in there that doesn't seem directly related to the problem. Can you please try and simplify your example some more? The more minimal you can make the reprex, the faster I can identify the problem and fix it.

[hadley]

Minimal reprex:

df <- data.frame(x = 1)
ggplot(df, aes(x)) + geom_density()

[hadley]

Fixed in 49619b7