From aa053bd52c87af28a7b30a6fa4c60948f7a6d976 Mon Sep 17 00:00:00 2001
From: Ghesselink <geert.hess@gmail.com>
Date: Mon, 4 May 2026 15:33:34 +0000
Subject: [PATCH] unblock voxel schema loading, add test for express

---
 .../ifcopenshell/express/schema_class.py      | 17 +++-
 .../test/test_express_aggregate_bounds.py     | 80 +++++++++++++++++++
 2 files changed, 95 insertions(+), 2 deletions(-)
 create mode 100644 src/ifcopenshell-python/test/test_express_aggregate_bounds.py

diff --git a/src/ifcopenshell-python/ifcopenshell/express/schema_class.py b/src/ifcopenshell-python/ifcopenshell/express/schema_class.py
index 4dd5e9d450..9547e7047e 100644
--- a/src/ifcopenshell-python/ifcopenshell/express/schema_class.py
+++ b/src/ifcopenshell-python/ifcopenshell/express/schema_class.py
@@ -401,7 +401,13 @@ class SchemaClass(codegen.Base):
 
             if isinstance(type, nodes.AggregationType):
                 aggr_type = type.aggregate_type
-                make_bound = lambda b: -1 if b == "?" else int(b)
+                def make_bound(b):
+                    # `?` and non-literal bounds (attribute references, arithmetic expressions) collapse to -1.
+                    # 
+                    try:
+                        return int(b)
+                    except (TypeError, ValueError):
+                        return -1
                 bound1, bound2 = map(make_bound, (type.bounds.lower, type.bounds.upper))
                 decl_type = get_declared_type(type.type, emitted_names)
                 return x.aggregation_type(aggr_type, bound1, bound2, decl_type)
@@ -528,7 +534,14 @@ class SchemaClass(codegen.Base):
                 inv_attrs = []
                 for attr in type.inverse:
                     if attr.bounds:
-                        make_bound = lambda b: -1 if b == "?" else int(b)
+                        def make_bound(b):
+                            # `?` and non-literal bounds (attribute references, arithmetic
+                            # expressions) collapse to -1 (unbounded) — the C++ runtime has
+                            # no third state for "dynamic cardinality".
+                            try:
+                                return int(b)
+                            except (TypeError, ValueError):
+                                return -1
                         bound1, bound2 = map(make_bound, (attr.bounds.lower, attr.bounds.upper))
                     else:
                         bound1, bound2 = -1, -1
diff --git a/src/ifcopenshell-python/test/test_express_aggregate_bounds.py b/src/ifcopenshell-python/test/test_express_aggregate_bounds.py
new file mode 100644
index 0000000000..030c301a78
--- /dev/null
+++ b/src/ifcopenshell-python/test/test_express_aggregate_bounds.py
@@ -0,0 +1,80 @@
+import os
+import sys
+import tempfile
+import unittest
+
+import ifcopenshell.express
+
+sys.path.insert(0, os.path.dirname(ifcopenshell.express.__file__))
+
+
+def _parse(schema_text):
+    with tempfile.NamedTemporaryFile(mode="w", suffix=".exp", delete=False) as f:
+        f.write(schema_text)
+        path = f.name
+    try:
+        return ifcopenshell.express.parse(path)
+    finally:
+        os.unlink(path)
+        cache = path + ".cache.dat"
+        if os.path.exists(cache):
+            os.unlink(cache)
+
+
+class TestAggregateBounds(unittest.TestCase):
+    def test_literal_bounds_preserved(self):
+        """After loading [1;3] -> (1, 3)?"""
+        s = _parse(
+            "SCHEMA t; ENTITY E; v : ARRAY [1:3] OF REAL; END_ENTITY; END_SCHEMA;"
+        )
+        agg = (
+            next(d for d in s.schema.declarations() if d.name() == "E")
+            .attributes()[0]
+            .type_of_attribute()
+            .as_aggregation_type()
+        )
+        self.assertEqual((agg.bound1(), agg.bound2()), (1, 3))
+        s.disown()
+
+    def test_unbounded_marker(self):
+        """ [0:?] -> (0, -1)?"""
+        s = _parse(
+            "SCHEMA t; ENTITY E; v : LIST [0:?] OF REAL; END_ENTITY; END_SCHEMA;"
+        )
+        agg = (
+            next(d for d in s.schema.declarations() if d.name() == "E")
+            .attributes()[0]
+            .type_of_attribute()
+            .as_aggregation_type()
+        )
+        # import pdb; pdb.set_trace()
+        self.assertEqual((agg.bound1(), agg.bound2()), (0, -1))
+        s.disown()
+
+    def test_voxel_grid_with_dynamic_bound_loads(self):
+        """ 
+        Array that is an expression :  [1:dim_x*dim_y*dim_z]
+        Parsing must not crash, Bbund must be (1, -1)
+        """
+        s = _parse(
+            """
+            SCHEMA t;
+            TYPE IfcBoolean = BOOLEAN; END_TYPE;
+
+            ENTITY IfcVoxelHolder;
+              NumberOfVoxelsX : INTEGER;
+              NumberOfVoxelsY : INTEGER;
+              NumberOfVoxelsZ : INTEGER;
+              Voxels : ARRAY [1:NumberOfVoxelsX*NumberOfVoxelsY*NumberOfVoxelsZ] OF IfcBoolean;
+            END_ENTITY;
+            END_SCHEMA;
+            """
+        )
+        holder = next(d for d in s.schema.declarations() if d.name() == "IfcVoxelHolder")
+        voxels = holder.attributes()[-1].type_of_attribute().as_aggregation_type()
+        self.assertEqual((voxels.bound1(), voxels.bound2()), (1, -1))
+        s.disown()
+
+
+if __name__ == "__main__":
+    unittest.main()