append_asset - keep preexisting contexts valid #4280

issue occurred with ifcpatch ExtractElements - it was adding project from other ifc file (with the contexts) and then adding some elements from it using `append_asset`. During `append_asset` it was considering existing context with the duplicated one and was partially purging it.

src/ifcopenshell-python/ifcopenshell/api/project/append_asset.py

@@ -84,12 +84,12 @@ class Usecase:
             # Now we can easily append our wall type from our libary
             wall_type = ifcopenshell.api.run("project.append_asset", model, library=library, element=wall_type)
         """
-        self.file = file
+        self.file: ifcopenshell.file = file
         self.settings = {"library": library, "element": element}
 
     def execute(self):
         # mapping of old element ids to new elements
-        self.added_elements:dict[int, ifcopenshell.entity_instance] = {}
+        self.added_elements: dict[int, ifcopenshell.entity_instance] = {}
         self.whitelisted_inverse_attributes = {}
         if self.settings["element"].is_a("IfcTypeProduct"):
             self.target_class = "IfcTypeProduct"
@@ -268,6 +268,7 @@ class Usecase:
 
     def reuse_existing_contexts(self):
         added_contexts = set([e for e in self.added_elements.values() if e.is_a("IfcGeometricRepresentationContext")])
+        added_contexts -= set(self.existing_contexts)
         for added_context in added_contexts:
             equivalent_existing_context = self.get_equivalent_existing_context(added_context)
             if not equivalent_existing_context:

src/ifcopenshell-python/test/api/project/test_append_asset.py

@@ -44,6 +44,26 @@ class TestAppendAsset(test.bootstrap.IFC4):
         ifcopenshell.api.run("project.append_asset", self.file, library=library, element=element)
         assert len(self.file.by_type("IfcWallType")) == 1
 
+    def test_reuse_an_existing_context_if_it_was_added_from_library_previously(self):
+        library = ifcopenshell.api.run("project.create_file")
+        project = ifcopenshell.api.run("root.create_entity", library, ifc_class="IfcProject")
+        lib_context = ifcopenshell.api.run("context.add_context", library, context_type="Model")
+
+        self.file.add(project)  # will add project and it's contexts
+
+        material = ifcopenshell.api.run("material.add_material", library, name="Material")
+        style = ifcopenshell.api.run("style.add_style", library)
+        ifcopenshell.api.run(
+            "style.assign_material_style", library, material=material, style=style, context=lib_context
+        )
+
+        ifcopenshell.api.run("project.append_asset", self.file, library=library, element=material)
+        assert len(self.file.by_type("IfcMaterial")) == 1
+        assert len(self.file.by_type("IfcGeometricRepresentationContext")) == 1
+        context = self.file.by_type("IfcMaterial")[0].HasRepresentation[0].Representations[0].ContextOfItems
+        # make sure it's still valid
+        assert context.WorldCoordinateSystem
+
     def test_append_a_single_type_product_even_though_an_inverse_material_relationship_is_shared(self):
         library = ifcopenshell.api.run("project.create_file")
         element = ifcopenshell.api.run("root.create_entity", library, ifc_class="IfcWallType")
@@ -202,24 +222,40 @@ class TestAppendAsset(test.bootstrap.IFC4):
         style = ifcopenshell.api.run("style.add_style", library)
         context = ifcopenshell.api.run("context.add_context", library, context_type="Model")
         ifcopenshell.api.run("style.assign_material_style", library, material=material, style=style, context=context)
+
         ifcopenshell.api.run("project.append_asset", self.file, library=library, element=material)
         assert len(self.file.by_type("IfcMaterial")) == 1
         assert len(self.file.by_type("IfcGeometricRepresentationContext")) == 1
         context = self.file.by_type("IfcMaterial")[0].HasRepresentation[0].Representations[0].ContextOfItems
         assert context == file_context
+        # make sure it's still valid
         assert context.WorldCoordinateSystem
 
     def test_append_a_material_with_a_representation_and_reuse_an_existing_subcontext(self):
         ifcopenshell.api.run("root.create_entity", self.file, ifc_class="IfcProject")
         file_context = ifcopenshell.api.run("context.add_context", self.file, context_type="Model")
-        file_subcontext = ifcopenshell.api.run("context.add_context", self.file, parent=file_context, context_type="Model", context_identifier="Body", target_view="MODEL_VIEW")
+        file_subcontext = ifcopenshell.api.run(
+            "context.add_context",
+            self.file,
+            parent=file_context,
+            context_type="Model",
+            context_identifier="Body",
+            target_view="MODEL_VIEW",
+        )
 
         library = ifcopenshell.api.run("project.create_file")
         ifcopenshell.api.run("root.create_entity", library, ifc_class="IfcProject")
         material = ifcopenshell.api.run("material.add_material", library, name="Material")
         style = ifcopenshell.api.run("style.add_style", library)
         context = ifcopenshell.api.run("context.add_context", library, context_type="Model")
-        subcontext = ifcopenshell.api.run("context.add_context", library, parent=context, context_type="Model", context_identifier="Body", target_view="MODEL_VIEW")
+        subcontext = ifcopenshell.api.run(
+            "context.add_context",
+            library,
+            parent=context,
+            context_type="Model",
+            context_identifier="Body",
+            target_view="MODEL_VIEW",
+        )
         ifcopenshell.api.run("style.assign_material_style", library, material=material, style=style, context=subcontext)
         ifcopenshell.api.run("project.append_asset", self.file, library=library, element=material)
         assert len(self.file.by_type("IfcMaterial")) == 1
@@ -227,6 +263,7 @@ class TestAppendAsset(test.bootstrap.IFC4):
         assert len(self.file.by_type("IfcGeometricRepresentationSubContext", include_subtypes=False)) == 1
         subcontext = self.file.by_type("IfcMaterial")[0].HasRepresentation[0].Representations[0].ContextOfItems
         assert subcontext == file_subcontext
+        # make sure it's still valid
         assert subcontext.ParentContext.WorldCoordinateSystem
 
     def test_append_a_material_with_a_representation_and_reuse_an_existing_context_by_a_new_subcontext(self):
@@ -238,8 +275,14 @@ class TestAppendAsset(test.bootstrap.IFC4):
         material = ifcopenshell.api.run("material.add_material", library, name="Material")
         style = ifcopenshell.api.run("style.add_style", library)
         context = ifcopenshell.api.run("context.add_context", library, context_type="Model")
-        subcontext = ifcopenshell.api.run("context.add_context", library, context_type="Model",
+        subcontext = ifcopenshell.api.run(
-                context_identifier="Body", target_view="MODEL_VIEW", parent=context)
+            "context.add_context",
+            library,
+            context_type="Model",
+            context_identifier="Body",
+            target_view="MODEL_VIEW",
+            parent=context,
+        )
         ifcopenshell.api.run("style.assign_material_style", library, material=material, style=style, context=subcontext)
         ifcopenshell.api.run("project.append_asset", self.file, library=library, element=material)
         assert len(self.file.by_type("IfcMaterial")) == 1