Remove duplicate vertices

src/main.rs

@@ -2,6 +2,7 @@ use clap::{Parser, Subcommand};
 use openapi_parser::{
     build_tree, parse_schema, parse_schema_fix_example_issue, NodeType, ObjectChild, TreeNode,
 };
+use std::collections::HashSet;
 use std::fmt::Write;
 
 /// Dump the tree structure of a schema element as dot file
@@ -78,7 +79,17 @@ fn main() {
     }
 }
 
-fn recurse_export(node: &TreeNode, parent_name: &str, out: &mut String) {
+fn recurse_export(
+    node: &TreeNode,
+    parent_name: &str,
+    out: &mut String,
+    already_processed: &mut HashSet<String>,
+) {
+    if already_processed.contains(&node.name) {
+        return;
+    }
+    already_processed.insert(node.name.to_string());
+
     if !parent_name.is_empty() && matches!(node.r#type, NodeType::Object { .. }) {
         writeln!(out, "\"{}\" -> \"{}\";", parent_name, node.name).unwrap();
     }
@@ -87,11 +98,11 @@ fn recurse_export(node: &TreeNode, parent_name: &str, out: &mut String) {
         NodeType::Array { item } => {
             let mut item = item.clone();
             item.name.push_str(" []");
-            recurse_export(&item, parent_name, out);
+            recurse_export(&item, parent_name, out, already_processed);
         }
         NodeType::Object { children, .. } => {
             for child in children {
-                recurse_export(&child.node, &node.name, out);
+                recurse_export(&child.node, &node.name, out, already_processed);
             }
         }
 
@@ -102,7 +113,9 @@ fn recurse_export(node: &TreeNode, parent_name: &str, out: &mut String) {
 fn graphviz_export(tree: &TreeNode) -> String {
     let mut out = "digraph G {\n".to_string();
 
-    recurse_export(tree, "", &mut out);
+    let mut already_processed = HashSet::new();
+
+    recurse_export(tree, "", &mut out, &mut already_processed);
 
     out.push_str("}\n");
     out