More robust shim for new setup_layer() ggplot2:::Layer method

See also #1481

and tidyverse/ggplot2#2875

Author: cpsievert

R/ggplotly.R

@@ -238,10 +238,10 @@ gg2list <- function(p, width = NULL, height = NULL,
 
   # ggplot2 3.1.0.9000 introduced a Layer method named setup_layer() 
   # currently, LayerSf is the only core-ggplot2 Layer that makes use
-  # of it https://github.com/tidyverse/ggplot2/pull/2875
+  # of it https://github.com/tidyverse/ggplot2/pull/2875#issuecomment-438708426
   data <- layer_data
   if (packageVersion("ggplot2") > "3.1.0") {
-    data <- by_layer(function(l, d) l$setup_layer(d, plot))
+    data <- by_layer(function(l, d) if (is.function(l$setup_layer)) l$setup_layer(d, plot) else d)
   }
 
   # Initialise panels, add extra data for margins & missing facetting