if a trace has fillcolor, but no fill attribute, it always has fill; otherwise, the fill attribute has to be something other than 'none'

Author: cpsievert

R/plotly_build.R

@@ -1006,5 +1006,12 @@ supplyUserPalette <- function(default, user) {
 # helper functions
 array_ok <- function(attr) isTRUE(tryNULL(attr$arrayOk))
 has_fill <- function(trace) {
-  has_attr(trace$type %||% "scatter", "fillcolor")
+  trace_type <- trace[["type"]] %||% "scatter"
+  # if trace type has fillcolor, but no fill attribute, then fill is always relevant
+  has_fillcolor <- has_attr(trace_type, "fillcolor")
+  has_fill <- has_attr(trace_type, "fill")
+  if (has_fillcolor && !has_fill) return(TRUE)
+  fill <- trace[["fill"]] %||% "none"
+  if (has_fillcolor && isTRUE(fill != "none")) return(TRUE)
+  FALSE
 }