Fix bug where unassigning a document was too aggressive and deleted relationships where it shouldn't.

src/ifcopenshell-python/ifcopenshell/api/document/unassign_document.py

@@ -58,4 +58,7 @@ class Usecase:
     def execute(self):
         for rel in self.settings["product"].HasAssociations:
             if rel.is_a("IfcRelAssociatesDocument") and rel.RelatingDocument == self.settings["document"]:
-                self.file.remove(rel)
+                if len(rel.RelatedObjects) == 1:
+                    self.file.remove(rel)
+                else:
+                    rel.RelatedObjects = [o for o in rel.RelatedObjects if o != self.settings["product"]]

src/ifcopenshell-python/test/api/document/test_assign_document.py

@@ -0,0 +1,39 @@
+# IfcOpenShell - IFC toolkit and geometry engine
+# Copyright (C) 2023 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of IfcOpenShell.
+#
+# IfcOpenShell is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# IfcOpenShell is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+
+import test.bootstrap
+import ifcopenshell.api
+
+
+class TestAssignDocument(test.bootstrap.IFC4):
+    def test_assigning_a_document(self):
+        element = ifcopenshell.api.run("root.create_entity", self.file, ifc_class="IfcWall")
+        reference = ifcopenshell.api.run("document.add_reference", self.file, information=None)
+        ifcopenshell.api.run("document.assign_document", self.file, product=element, document=reference)
+        assert element.HasAssociations[0].RelatingDocument == reference
+
+    def test_assigning_multiple_documents(self):
+        element = ifcopenshell.api.run("root.create_entity", self.file, ifc_class="IfcWall")
+        element2 = ifcopenshell.api.run("root.create_entity", self.file, ifc_class="IfcWall")
+        reference = ifcopenshell.api.run("document.add_reference", self.file, information=None)
+        ifcopenshell.api.run("document.assign_document", self.file, product=element, document=reference)
+        ifcopenshell.api.run("document.assign_document", self.file, product=element2, document=reference)
+        assert len(self.file.by_type("IfcRelAssociatesDocument")) == 1
+        assert element.HasAssociations[0].RelatingDocument == reference
+        assert element2.HasAssociations[0].RelatingDocument == reference
+        assert element.HasAssociations[0] == element.HasAssociations[0]

src/ifcopenshell-python/test/api/document/test_unassign_document.py

@@ -0,0 +1,40 @@
+# IfcOpenShell - IFC toolkit and geometry engine
+# Copyright (C) 2023 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of IfcOpenShell.
+#
+# IfcOpenShell is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# IfcOpenShell is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+
+import test.bootstrap
+import ifcopenshell.api
+
+
+class TestUnassignDocument(test.bootstrap.IFC4):
+    def test_unassigning_a_document(self):
+        element = ifcopenshell.api.run("root.create_entity", self.file, ifc_class="IfcWall")
+        reference = ifcopenshell.api.run("document.add_reference", self.file, information=None)
+        ifcopenshell.api.run("document.assign_document", self.file, product=element, document=reference)
+        ifcopenshell.api.run("document.unassign_document", self.file, product=element, document=reference)
+        assert not element.HasAssociations
+        assert not len(self.file.by_type("IfcRelAssociatesDocument"))
+
+    def test_unassigning_a_document_used_by_multiple_entities(self):
+        element = ifcopenshell.api.run("root.create_entity", self.file, ifc_class="IfcWall")
+        element2 = ifcopenshell.api.run("root.create_entity", self.file, ifc_class="IfcWall")
+        reference = ifcopenshell.api.run("document.add_reference", self.file, information=None)
+        ifcopenshell.api.run("document.assign_document", self.file, product=element, document=reference)
+        ifcopenshell.api.run("document.assign_document", self.file, product=element2, document=reference)
+        ifcopenshell.api.run("document.unassign_document", self.file, product=element, document=reference)
+        assert not element.HasAssociations
+        assert element2.HasAssociations[0].RelatingDocument == reference