From e4e4f31d2090da0183df82b2cef8b2d4d1a901a7 Mon Sep 17 00:00:00 2001
From: Thomas Krijnen <t.krijnen@gmail.com>
Date: Tue, 13 Jan 2026 08:45:04 +0100
Subject: [PATCH] Defer deletion so that traversal still works

---
 src/ifcparse/IfcParse.cpp | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/ifcparse/IfcParse.cpp b/src/ifcparse/IfcParse.cpp
index dc820d8439..aca36af03d 100644
--- a/src/ifcparse/IfcParse.cpp
+++ b/src/ifcparse/IfcParse.cpp
@@ -2022,6 +2022,7 @@ void IfcFile::removeEntity(const express::Base& entity) {
         batch_deletion_ids_.push_back(id);
     } else {
         process_deletion_(entity);
+        byid_.erase(entity.id());
     }
 }
 
@@ -2112,9 +2113,6 @@ void IfcFile::process_deletion_(const express::Base& entity) {
             ++it;
         }
     }
-
-    // This now frees the shared_ptr
-    byid_.erase(entity.id());
 }
 
 void IfcParse::impl::in_memory_file_storage::process_deletion_inverse(const express::Base& entity) {
@@ -2613,6 +2611,10 @@ void IfcParse::IfcFile::unbatch() {
     for (auto& id : batch_deletion_ids_) {
         process_deletion_(instance_by_id(id));
     }
+    // keep in memory until all deletions are processed
+    for (auto& id : batch_deletion_ids_) {
+        byid_.erase(id);
+    }
     batch_mode_ = false;
     batch_deletion_ids_.clear();
 }