From 335ee1a1bb80922e4a96e3a92a27671ea92b60d7 Mon Sep 17 00:00:00 2001
From: Ryan Schultz <ryan@openingdesign.com>
Date: Thu, 28 May 2026 12:14:23 -0500
Subject: [PATCH] Fix negative zero in imperial feet-inches parser

When the user enters `-0' - 10"`, Python parses feet as -0.0.
The check `feet < 0` is False for negative zero, so the sign was
silently dropped. Use math.copysign to detect it correctly.

Generated with the assistance of an AI coding tool.
---
 src/bonsai/bonsai/tool/unit.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/bonsai/bonsai/tool/unit.py b/src/bonsai/bonsai/tool/unit.py
index 4c3e45b794..5bef7feae1 100644
--- a/src/bonsai/bonsai/tool/unit.py
+++ b/src/bonsai/bonsai/tool/unit.py
@@ -199,8 +199,8 @@ class Unit(bonsai.core.tool.Unit):
                 if inches is None:
                     inches = 0
 
-                # If feet is negative, inches should also be negative (subtractive)
-                if feet < 0:
+                # If feet is negative (including -0), inches should also be negative (subtractive)
+                if math.copysign(1, feet) < 0:
                     inches = -inches
 
                 # Convert to meters