new_scale_*() throws an error in ggplot2 3.5.0

[alhenry]

The function new_scale_*() throws the following error in ggplot2 3.5.0:

Error in scale$guide == "none" : 
  comparison (==) is possible only for atomic and list types

Presumably this is something related to the new behaviour of guides & scales in ggplot?

[eliocamp]

This is supposed to be fixed by #57, which is included in the latest release. All tests pass with the current ggplot2 version. Make sure you're running the latest ggnewscale version. If the problem persists, please submit a reproducible example so I can investigate further.

[alhenry]

I've tested with the latest version of ggplot2 and ggnewscale on CRAN and no longer found the issue. Will close this for now. Sorry for the false alarm!

[eliocamp]

Good to know! Do report any other issue, though.

[bennotkin]

_Edit: I wrote all of this and then realized the ggplot 3.5 now allows for guide = "colorsteps", not just guide = guide_colorsteps(). With the former, I get the desired behavior. Editing, rather than deleting, this comment for anyone who may find this helpful._

---

I continue to have the same error, when I set guide = guide_colorsteps().

Here's a reproducible example:

ggplot(mpg) +
  geom_point(aes(x = cty, y = hwy, color = displ)) +
  scale_color_stepsn(
    colors = c("yellow", "red"),
    guide = guide_colorsteps()) +
  ggnewscale::new_scale_color()
# Error in scale$guide == "none" : 
#   comparison (==) is possible only for atomic and list types

I don't get the error if I don't include guide = guide_colorsteps()[^1], nor if `guide = "legend". Both of the following work:

[^1]: Normally, one wouldn't include guide = guide_colorsteps() in scale_color_stepsn, as it is the default behavior; however, in my non-reprex usage I sometimes set guide = "legend": guide = if (diff(lengths(list(params$labels, params$breaks))) == 1) "legend" else guide_colorsteps()

ggplot(mpg) +
  geom_point(aes(x = cty, y = hwy, color = displ)) +
  scale_color_stepsn(colors = c("yellow", "red")) +
  ggnewscale::new_scale_color()

ggplot(mpg) +
  geom_point(aes(x = cty, y = hwy, color = displ)) +
  scale_color_stepsn(
    colors = c("yellow", "red"),
    guide = "legend") +
  ggnewscale::new_scale_color()

If, rather than setting the guide in scale_color_stepsn but in guides(), there is no error with ggnewscale::new_scale_color(), but the guide setting persists after ggnewscale::new_scale_color(), and that causes a different error when the guide type is different in the next plot:

ggplot(mpg) +
  geom_point(aes(x = cty, y = hwy, color = displ)) +
  scale_color_stepsn(colors = c("yellow", "red")) +
  guides(color = guide_colorsteps()) +
  ggnewscale::new_scale_color() +
  # Shifting x and y so they are obviously separate from previous layer
  geom_point(aes(x = cty + 10, y = 50 - hwy, color = class), shape = 1)
# Error in `parse_binned_breaks()`:
# ! Breaks are not formatted correctly for a bin legend.
# ℹ Use `(<lower>, <upper>]` format to indicate bins.
# Run `rlang::last_trace()` to see where the error occurred.
# Warning message:
# In parse_binned_breaks(scale, breaks) : NAs introduced by coercion