removing arrowheads in legend

[schochastics]

Is there a way to remove arrowheads in the legend? Something like the below would be nice (the guides part)

library(igraph)
library(ggraph)

set.seed(538)
g <- sample_gnp(n = 30,p = 0.1,directed = T)
E(g)$type <- sample(c(F,T),ecount(g),replace = T)

ggraph(g,layout = "kk")+
  geom_edge_link(aes(col = type),
                 arrow = arrow(type = "closed",length = unit(12,"pt")),
                 end_cap = circle(5,"pt"))+
  geom_node_point(size = 5)+
  theme_graph()+
  guides(edge_colour = guide_legend(override.aes = list(arrow = NULL))) 

What works is overwriting the draw_key function of GeomEdgePath ( link to similar solution for ggplot):

draw_key_line <- function(data, params, size) {
  grid::segmentsGrob(0.1, 0.5, 0.9, 0.5, 
                     gp = grid::gpar(col = alpha(data$edge_colour, data$edge_alpha), 
                               lwd = data$edge_width * .pt, 
                               lty = data$edge_linetype, 
                               lineend = "butt"), arrow = NULL)
}

# override legend drawing function for GeomEdgePath
GeomEdgePath$draw_key <- draw_key_line

Don't think that this should be the preferred solution

[thomasp85]

This should really be fixed at the ggplot2 level. The problem is that arrow is kind of a special aesthetic not part of gpar()