From ab11ac53387b4e15ccd5212576ac5e99b6c7f6b0 Mon Sep 17 00:00:00 2001
From: Thomas Krijnen <t.krijnen@gmail.com>
Date: Tue, 9 Jun 2026 21:35:40 +0200
Subject: [PATCH] Catch decomposition errors #8149

---
 src/ifcgeom/mapping/mapping.cpp | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/ifcgeom/mapping/mapping.cpp b/src/ifcgeom/mapping/mapping.cpp
index a44ef1a57a..fe6ebab56a 100644
--- a/src/ifcgeom/mapping/mapping.cpp
+++ b/src/ifcgeom/mapping/mapping.cpp
@@ -198,8 +198,14 @@ aggregate_of_instance::ptr mapping::find_openings(const IfcUtil::IfcBaseEntity*
                 // Only aggregation, not nesting is considered.
                 break;
             }
-            IfcSchema::IfcObjectDefinition* rel_obdef = (*decomposes->begin())->as<IfcSchema::IfcRelAggregates>()->RelatingObject();
-            if (rel_obdef->as<IfcSchema::IfcElement>() && !rel_obdef->as<IfcSchema::IfcFeatureElementSubtraction>()) {
+            IfcSchema::IfcObjectDefinition* rel_obdef = nullptr;
+            try {
+                rel_obdef = (*decomposes->begin())->as<IfcSchema::IfcRelAggregates>()->RelatingObject();
+            } catch (const std::exception&) {
+                // exception already logged as part of handling of placement
+                break;
+            }
+            if (rel_obdef && rel_obdef->as<IfcSchema::IfcElement>() && !rel_obdef->as<IfcSchema::IfcFeatureElementSubtraction>()) {
                 IfcSchema::IfcElement* element = rel_obdef->as<IfcSchema::IfcElement>();
                 auto rels = element->HasOpenings();
                 for (auto& rel : *rels) {