Fix #6307. Warning: critical bug where saving a file broke undo state.

Previously, changing props.ifc_file had an update hook to reload
information about the IFC model. But this isn't always correct because
there are two situations:

 1. The ifc_file path changed because you saved the file for the first
time or saved as, and this is merely recording a new saved path of the
existing file object.
 2. The ifc_file path changed because the user manually changed it or
selected a new file. This could reference an entirely new file object.
This is dangerous because we can't trust anything anymore, including our
undo history.

So the new default situation is that there is no magic hook. If you
change props.ifc_file, that's all it changes ... just a path stored in
Blender with not much significance.

If the user runs select_ifc_file to explicitly relink the file, it now
explicitly purges in that situation and clears the undo history.

Basically now behaviour is explicit, not using magic hooks.

src/bonsai/bonsai/bim/handler.py

@@ -24,17 +24,15 @@ import ifcopenshell.util.unit
 import ifcopenshell.api.owner.settings
 import bonsai.bim
 import bonsai.tool as tool
-import bonsai.core.owner as core_owner
 from bpy.app.handlers import persistent
 from bonsai.bim.ifc import IfcStore
-from bonsai.bim.module.owner.prop import get_user_person, get_user_organisation
 from bonsai.bim.module.model.data import AuthoringData
 from bonsai.bim.module.aggregate.decorator import AggregateDecorator
 from bonsai.bim.module.georeference.decorator import GeoreferenceDecorator
 from bonsai.bim.module.model.decorator import WallAxisDecorator, SlabDirectionDecorator
 from bonsai.bim.module.nest.decorator import NestDecorator
 from mathutils import Vector
-from math import cos, degrees
+from math import cos
 from typing import Union, Callable
 
 

src/bonsai/bonsai/bim/ifc.py

@@ -33,7 +33,7 @@ import bonsai.bim.handler
 import bonsai.tool as tool
 from pathlib import Path
 from bonsai.tool.brick import BrickStore
-from typing import Set, Union, Optional, TypedDict, Callable, NotRequired, cast
+from typing import Set, Union, Optional, TypedDict, Callable, NotRequired
 
 
 IFC_CONNECTED_TYPE = Union[bpy.types.Material, bpy.types.Object]
@@ -106,10 +106,7 @@ class IfcStore:
     def get_file():
         if IfcStore.file is None:
             props = tool.Blender.get_bim_props()
-            IfcStore.path = props.ifc_file
-            # Interpret relative paths as relative to .blend file.
-            if IfcStore.path and not os.path.isabs(IfcStore.path):
-                IfcStore.path = os.path.abspath(os.path.join(bpy.path.abspath("//"), IfcStore.path))
+            IfcStore.set_path(props.ifc_file)
             if IfcStore.path:
                 try:
                     IfcStore.load_file(IfcStore.path)
@@ -117,6 +114,13 @@ class IfcStore:
                     print(f"Failed to load file {IfcStore.path}. Error details: {e}")
         return IfcStore.file
 
+    @staticmethod
+    def set_path(value):
+        IfcStore.path = value
+        # Interpret relative paths as relative to .blend file.
+        if IfcStore.path and not os.path.isabs(IfcStore.path):
+            IfcStore.path = os.path.abspath(os.path.join(bpy.path.abspath("//"), IfcStore.path))
+
     @staticmethod
     def get_cache():
         if IfcStore.cache is None and IfcStore.path:

src/bonsai/bonsai/bim/module/project/operator.py

@@ -985,8 +985,7 @@ class LoadProject(bpy.types.Operator, IFCFileSelector):
             if not self.is_advanced and not self.should_start_fresh_session:
                 bpy.ops.bim.convert_to_blender()
 
-            bim_props = tool.Blender.get_bim_props()
-            bim_props.ifc_file = filepath
+            tool.Ifc.set_path(filepath)
             if not tool.Ifc.get():
                 self.report(
                     {"ERROR"},
@@ -1650,7 +1649,7 @@ class ExportIFC(bpy.types.Operator):
             output_file = os.path.relpath(output_file, bpy.path.abspath("//"))
         bim_props = tool.Blender.get_bim_props()
         if bim_props.ifc_file != output_file and extension not in ("ifczip", "ifcjson"):
-            bim_props.ifc_file = output_file
+            tool.Ifc.set_path(output_file)
         save_blend_file = bool(bpy.data.is_saved and bpy.data.is_dirty and bpy.data.filepath)
         if save_blend_file:
             bpy.ops.wm.save_mainfile(filepath=bpy.data.filepath)

src/bonsai/bonsai/bim/operator.py

@@ -30,6 +30,7 @@ import webbrowser
 import ifcopenshell
 import bonsai.bim
 import bonsai.tool as tool
+import bonsai.bim.handler
 from bonsai.bim import import_ifc
 from bonsai.bim.prop import StrProperty
 from bonsai.bim.ui import IFCFileSelector
@@ -222,6 +223,8 @@ class SelectIfcFile(bpy.types.Operator, IFCFileSelector):
         if self.is_existing_ifc_file():
             props = tool.Blender.get_bim_props()
             props.ifc_file = self.get_filepath()
+            bonsai.bim.handler.loadIfcStore(bpy.context.scene)
+            tool.Blender.clear_undo_history()
         return {"FINISHED"}
 
     def invoke(self, context, event):

src/bonsai/bonsai/bim/prop.py

@@ -137,12 +137,6 @@ def update_cache_dir(self: "BIMProperties", context: bpy.types.Context) -> None:
     bonsai.bim.schema.ifc.cache_dir = bim_props.cache_dir
 
 
-def update_ifc_file(self: "BIMProperties", context: bpy.types.Context) -> None:
-    bim_props = tool.Blender.get_bim_props()
-    if bim_props.ifc_file:
-        bonsai.bim.handler.loadIfcStore(context.scene)
-
-
 def update_section_color(self: "BIMProperties", context: bpy.types.Context) -> None:
     section_node_group = bpy.data.node_groups.get("Section Override")
     if section_node_group is None:
@@ -506,7 +500,7 @@ class BIMProperties(PropertyGroup):
     )
     has_blend_warning: BoolProperty(name="Has Blend Warning", default=False)
     pset_dir: StringProperty(default=os.path.join("psets") + os.path.sep, name="Default Psets Directory")
-    ifc_file: StringProperty(name="IFC File", update=update_ifc_file)
+    ifc_file: StringProperty(name="IFC File")
     last_transaction: StringProperty(name="Last Transaction")
     should_section_selected_objects: BoolProperty(name="Section Selected Objects", default=False)
     section_plane_colour: FloatVectorProperty(

src/bonsai/bonsai/tool/blender.py

@@ -1616,3 +1616,16 @@ class Blender(bonsai.core.tool.Blender):
         if 0 <= index < len(collection):
             return collection[index]
         return None
+
+    @classmethod
+    def clear_undo_history(cls) -> None:
+        """Clears the Blender history, Bonsai history, and IfcOpenShell history"""
+        old_undo_steps = bpy.context.preferences.edit.undo_steps
+        bpy.context.preferences.edit.undo_steps = 2
+        for i in range(3):
+            bpy.ops.ed.undo_push(message="Undo history cleared")
+        bpy.context.preferences.edit.undo_steps = old_undo_steps
+        tool.Ifc.clear_history()
+        old_history_size = tool.Ifc.get().history_size
+        tool.Ifc.get().set_history_size(0)
+        tool.Ifc.get().set_history_size(old_history_size)

src/bonsai/bonsai/tool/ifc.py

@@ -56,6 +56,12 @@ class Ifc(bonsai.core.tool.Ifc):
     def get(cls) -> ifcopenshell.file:
         return IfcStore.get_file()
 
+    @classmethod
+    def set_path(cls, value: str) -> None:
+        bim_props = tool.Blender.get_bim_props()
+        bim_props.ifc_file = value
+        IfcStore.set_path(value)
+
     @classmethod
     def get_path(cls) -> str:
         """Get absolute filepath to the IFC file, return empty string if file is not saved."""
@@ -66,6 +72,12 @@ class Ifc(bonsai.core.tool.Ifc):
         if IfcStore.get_file():
             return IfcStore.get_file().schema
 
+    @classmethod
+    def clear_history(cls) -> None:
+        IfcStore.last_transaction = ""
+        IfcStore.history = []
+        IfcStore.future = []
+
     @classmethod
     def is_edited(cls, obj: bpy.types.Object, *, ignore_scale: bool = False) -> bool:
         return (not ignore_scale and tool.Geometry.is_scaled(obj)) or obj in IfcStore.edited_objs