From 424fab2e40db52d8f24604e6dfd11ad880c930c5 Mon Sep 17 00:00:00 2001
From: Aryadev Chavali <aryadev@aryadevchavali.com>
Date: Fri, 12 Dec 2025 04:08:01 +0000
Subject: [PATCH] Weird bug in draw_tree

Seems near the 100,000 node mark, the vector craps itself?  I keep
getting "heap use after free" errors here when trying to access the
allocator vector.  Disabling fsan just leads to a segment fault near
the same point.

I think we might need to introduce our own vector :)
---
 src/main.cpp | 27 +++++++++++++++++++--------
 1 file changed, 19 insertions(+), 8 deletions(-)

diff --git a/src/main.cpp b/src/main.cpp
index b98da12..6f53a7c 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -52,7 +52,7 @@ constexpr u64 clamp_to_width(const DrawState &ds, f64 val)
          (val - ds.bounds.lower_val);
 }
 
-void draw_tree(const DrawState &ds)
+void draw_tree(const DrawState &ds, const State &state)
 {
   // Number line
   DrawLine(0, HEIGHT / 2, WIDTH, HEIGHT / 2, WHITE);
@@ -63,18 +63,29 @@ void draw_tree(const DrawState &ds)
   DrawLine(lower_x, LINE_TOP, lower_x, LINE_BOTTOM, WHITE);
   DrawLine(upper_x, LINE_TOP, upper_x, LINE_BOTTOM, WHITE);
 
-  std::stack<cw::node::Node> stack;
-  stack.push(ds.state.allocator.get_val(0));
+  std::stack<std::pair<u64, f64>> stack;
+  cw::node::Node n = state.allocator.get_val(0);
+  stack.push(std::make_pair(0, n.value.norm));
   while (!stack.empty())
   {
-    auto n = stack.top();
+    u64 node_index;
+    f64 norm;
+    std::tie(node_index, norm) = stack.top();
     stack.pop();
-    u64 x = clamp_to_width(ds, n.value.norm);
+    u64 x = clamp_to_width(ds, norm);
     DrawLine(x, LINE_TOP, x, LINE_BOTTOM, RED);
+
+    cw::node::Node n = state.allocator.get_val(node_index);
     if (n.left >= 0)
-      stack.push(ds.state.allocator.get_val(n.left));
+    {
+      cw::node::Node left = state.allocator.get_val(n.left);
+      stack.push(std::make_pair(n.left, left.value.norm));
+    }
     if (n.right >= 0)
-      stack.push(ds.state.allocator.get_val(n.right));
+    {
+      cw::node::Node right = state.allocator.get_val(n.right);
+      stack.push(std::make_pair(n.right, right.value.norm));
+    }
   }
 }
 
@@ -145,7 +156,7 @@ int main(void)
 
     ClearBackground(BLACK);
     BeginDrawing();
-    draw_tree(draw_state);
+    draw_tree(draw_state, state);
     DrawText(format_str.c_str(), WIDTH / 2 - format_str_width / 2, HEIGHT / 8,
              FONT_SIZE, WHITE);
     EndDrawing();