From 8eb2371ce15670e0cbc41c3caf347970051ec978 Mon Sep 17 00:00:00 2001
From: Jared Miller <jared@smell.flowers>
Date: Mon, 9 Feb 2026 21:05:27 -0500
Subject: [PATCH] Add stack and local_vars to ZStackBottom sentinel

ZStackBottom lacked attributes that normal stack operations need when
returning from a subroutine to the top level. Zork 1 hit this on the
first subroutine return during startup.
---
 src/mudlib/zmachine/zstackmanager.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/mudlib/zmachine/zstackmanager.py b/src/mudlib/zmachine/zstackmanager.py
index a986733..df7350f 100644
--- a/src/mudlib/zmachine/zstackmanager.py
+++ b/src/mudlib/zmachine/zstackmanager.py
@@ -96,6 +96,8 @@ class ZRoutine:
 class ZStackBottom:
     def __init__(self):
         self.program_counter = 0  # used as a cache only
+        self.stack = []
+        self.local_vars = [0 for _ in range(15)]
 
 
 class ZStackManager: