Using `lwd` parameter in geom_line() produces `size` warning

[sarmapar]

I recently updated ggplot and found I am getting the "Using size aesthetic for lines was deprecated in ggplot2 3.4.0." warning for my lines of code where I use the lwd parameter. Is lwd also being deprecated? I think a more clear/informative warning would be helpful, because it took me a while to find the source since I didn't explicitly use size anywhere.

Simplified example that produces the warning:

library(ggplot2)

ggplot(economics, aes(date, unemploy)) + 
   geom_line(lwd = 0.25)

[clauswilke]

Good point. I think it's an oversight, lwd should be mapped onto the new linewidth aesthetic, and not onto size. This happens here:

ggplot2/R/ggplot-global.R

Line 37 in 759c63c

"lwd" = "size",

In general, though, I think it's better to not use these base-R terms at all but rather use the correct ggplot2 aesthetic.

[thomasp85]

Agree with @clauswilke on all accounts. This was an oversight by me