geom_line becomes invisible when color aesthetic applied

I am attempting to apply a gradient color scale to a line in a ggplot object. When I create the plotly chart, the plotted line is not visible. Hovering over the plot area shows the values of the variables if the cursor is where the line is located, even though the line is not visible.

If I do not apply a color aesthetic, the line is visible.

I have download the most recent plotly package from Github.

Here is some example code of the issue:

library(tidyverse)

df <- tibble(
x = rnorm(100, 7, 1),
y = rnorm(100, 4, 1),
z = rnorm(100, 5, 1))

plot <- ggplot(df) +
geom_line(aes(x, y, color = z),
lwd = 1.5) +
scale_color_gradient(low = "red",
high = "blue")

plot

plotly::plotly_build(plot)

ggplot:

首先使用 ggplot2、geom_line()、scale_color_gradient() 和 plotly::plotly_build(plot) 运行 issue 中的 R 示例，并将其与不使用颜色美学映射的版本进行比较。跟踪有颜色的 ggplot 线转换为 Plotly 图表的过程；当线条可见且保留其渐变色和悬停值时，即表示完成。