From d0ef32de0f6677319074d61af59b2c0179d4cee6 Mon Sep 17 00:00:00 2001
From: "R. Timothy Edwards" <tim@opencircuitdesign.com>
Date: Thu, 5 Mar 2026 10:17:29 -0500
Subject: [PATCH] Tracked down a DRC issue found recently where spurious errors
 get drawn outside the area being worked on.  Tracked it down to a missing
 check for an invalid rectangle.  Fixed now.

---
 drc/DRCsubcell.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drc/DRCsubcell.c b/drc/DRCsubcell.c
index d328c4b0..73030298 100644
--- a/drc/DRCsubcell.c
+++ b/drc/DRCsubcell.c
@@ -826,6 +826,7 @@ DRCInteractionCheck(def, area, erasebox, func, cdarg)
 		 */
 		subArea = *erasebox;
 		GeoClip(&subArea, &cliparea);
+		if (GEO_RECTNULL(&subArea)) continue;
 		GEO_EXPAND(&subArea, DRCTechHalo, &intArea);
 
 		errorSaveType = DRCErrorType;