From a54eb9c6f9c12816f6befefd3828b78689076549 Mon Sep 17 00:00:00 2001
From: Kevin Newton <kddnewton@gmail.com>
Date: Fri, 8 Dec 2023 09:40:26 -0500
Subject: [PATCH] [ruby/prism] A couple of small dot enhancements

https://github.com/ruby/prism/commit/5642a57f39
---
 prism/templates/lib/prism/dot_visitor.rb.erb | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/prism/templates/lib/prism/dot_visitor.rb.erb b/prism/templates/lib/prism/dot_visitor.rb.erb
index 5e01388c6de242..fc3dd4b2234009 100644
--- a/prism/templates/lib/prism/dot_visitor.rb.erb
+++ b/prism/templates/lib/prism/dot_visitor.rb.erb
@@ -122,13 +122,17 @@ module Prism
         digraph.edge("#{id}:<%= field.name %> -> #{node_id(<%= field.name %>)};")
       end
       <%- when Prism::NodeListField -%>
-      table.field("<%= field.name %>", port: true)
+      if node.<%= field.name %>.any?
+        table.field("<%= field.name %>", port: true)
 
-      waypoint = "#{id}_<%= field.name %>"
-      digraph.waypoint("#{waypoint};")
+        waypoint = "#{id}_<%= field.name %>"
+        digraph.waypoint("#{waypoint};")
 
-      digraph.edge("#{id}:<%= field.name %> -> #{waypoint};")
-      node.<%= field.name %>.each { |child| digraph.edge("#{waypoint} -> #{node_id(child)};") }
+        digraph.edge("#{id}:<%= field.name %> -> #{waypoint};")
+        node.<%= field.name %>.each { |child| digraph.edge("#{waypoint} -> #{node_id(child)};") }
+      else
+        table.field("<%= field.name %>", "[]")
+      end
       <%- when Prism::StringField, Prism::ConstantField, Prism::OptionalConstantField, Prism::UInt8Field, Prism::UInt32Field, Prism::ConstantListField -%>
       table.field("<%= field.name %>", node.<%= field.name %>.inspect)
       <%- when Prism::LocationField -%>