Using scale_fill_continuous(breaks=NULL) results in error

[wch]

Some of the visual tests in visual_test/scale-breaks.r now throw errors. This was introduced by e6594a1, where the colorbar guide started being used as the default.

Here are the two bad tests:

dat <- data.frame(x=1:3, y=1:3)

ggplot(dat, aes(x=1, y=y, fill=x)) + geom_point(shape=21) + scale_fill_continuous(breaks=NULL)

ggplot(dat, aes(x=1, y=y, colour=x)) + geom_point() + scale_colour_continuous(breaks=NULL)

We should also have some unit tests for this...

[kohske]

0.9.1 also results in error.
And legend guide also induce a warning.
What is the expected behavior if breaks = NULL for non-positional scales?

[wch]

The error in master (1df1e82) is this:

dat <- data.frame(x=1:3, y=1:3)
ggplot(dat, aes(x=1, y=y, fill=x)) + geom_point(shape=21) + scale_fill_continuous(breaks=NULL)
# Error in names(guide$key) <- c(output, ".label", ".value") : 
#   'names' attribute [3] must be the same length as the vector [2]

ggplot(dat, aes(x=1, y=y, colour=x)) + geom_point() + scale_colour_continuous(breaks=NULL)
# Error in names(guide$key) <- c(output, ".label", ".value") : 
#  'names' attribute [3] must be the same length as the vector [2]

Also, this gives a warning:

ggplot(dat, aes(x=1, y=y, size=x)) + geom_point() + scale_size_continuous(breaks=NULL)
# Warning message:
# In is.na(breaks) : is.na() applied to non-(list or vector) of type 'NULL'

[kohske]

I mean that these errors and warnings also happen in the released version 0.9.1.

I'm sure why this error happens.
But I'm not sure how it should be. The breaks = NULL for non-positional scales would be meaningless.

Should it be simply ignored, with some warning message?

[wch]

In 0.9.1, I get warnings only, but no errors.

ggplot(dat, aes(x=1, y=y, colour=x)) + geom_point() + scale_colour_continuous(breaks=NULL)
# Warning message:
# In is.na(breaks) : is.na() applied to non-(list or vector) of type 'NULL'

Maybe it should not show the legend when breaks=NULL? I think that is the existing behavior in 0.9.1.

[kohske]

@wch

yes, but in 0.9.1,

> ggplot(dat, aes(x=1, y=y, colour=x)) + geom_point() + scale_colour_continuous(breaks=NULL, guide = "colorbar")
Error in names(guide$key) <- c(output, ".label", ".value") : 
  'names' attribute [3] must be the same length as the vector [2]

So the bug(?) is not due to changing the colorbar as default.

Maybe it should not show the legend when breaks=NULL?

I agree. Do you think there is a situation where someone want to show colorbar without tick/lables?

[kohske]

So possible solution for break = NULL for the non-positional scale is either,

1. Surpress showing guide, with some warning messages.
2. Use default breaks (waiver()) instead, with some warning messages.

The warning message should be like:

breaks = NULL for non-spatial scale is meaningless so the guide is not displayed.

[wch]

Oh, I see what you mean. Yes, the bug is in colorbar.

[kohske]

ah..., if the branch referring the issue is merged on github, those who commit the branch will close the issue, I understand.
A bit surprising because I was sleeping at that time...