Merge branch 'ifcgit-features' into v0.8.0

src/bonsai/bonsai/bim/module/ifcgit/__init__.py

@@ -34,8 +34,10 @@ classes = (
     operator.Fetch,
     operator.Merge,
     operator.ObjectLog,
+    operator.SelectConflictEntity,
     operator.Push,
     operator.RefreshGit,
+    operator.RenameBranch,
     operator.SwitchRevision,
     operator.InstallGit,
     operator.RunGitDiff,

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

@@ -202,7 +202,7 @@ class DeleteTag(bpy.types.Operator):
 class RefreshGit(bpy.types.Operator):
     """Refresh revision list"""
 
-    bl_label = ""
+    bl_label = "Refresh"
     bl_idname = "ifcgit.refresh"
     bl_options = {"REGISTER"}
 
@@ -225,7 +225,7 @@ class RefreshGit(bpy.types.Operator):
 class DisplayRevision(bpy.types.Operator):
     """Colourise objects by selected revision"""
 
-    bl_label = ""
+    bl_label = "Colourise Revision"
     bl_idname = "ifcgit.display_revision"
     bl_options = {"REGISTER"}
 
@@ -260,7 +260,7 @@ class DisplayUncommitted(bpy.types.Operator):
 class SwitchRevision(bpy.types.Operator):
     """Switches the repository to the selected revision and reloads the IFC file"""
 
-    bl_label = ""
+    bl_label = "Switch Revision"
     bl_idname = "ifcgit.switch_revision"
     bl_options = {"REGISTER"}
 
@@ -278,7 +278,7 @@ class SwitchRevision(bpy.types.Operator):
 
 
 class Merge(bpy.types.Operator):
-    """Merges the selected branch into working branch"""
+    """Merges the selected branch into working branch.\nCtrl+click to preview without merging"""
 
     bl_label = "Merge this branch"
     bl_idname = "ifcgit.merge"
@@ -292,8 +292,14 @@ class Merge(bpy.types.Operator):
             return True
         return False
 
-    def execute(self, context):
+    def invoke(self, context, event):
+        if event.ctrl:
+            core.dry_run_merge(tool.IfcGit, tool.Ifc, self)
+            refresh()
+            return {"FINISHED"}
+        return self.execute(context)
 
+    def execute(self, context):
         if core.merge_branch(tool.IfcGit, tool.Ifc, self) is not False:
             refresh()
             return {"FINISHED"}
@@ -301,6 +307,69 @@ class Merge(bpy.types.Operator):
             return {"CANCELLED"}
 
 
+class SelectConflictEntity(bpy.types.Operator):
+    """Select the conflicting entity in the viewport"""
+
+    bl_label = "Select Conflict Entity"
+    bl_idname = "ifcgit.select_conflict_entity"
+    bl_options = {"REGISTER"}
+
+    step_id: bpy.props.IntProperty()  # pyright: ignore[reportRedeclaration]
+
+    if TYPE_CHECKING:
+        step_id: int
+
+    def execute(self, context):
+        model = tool.Ifc.get()
+        if not model:
+            return {"CANCELLED"}
+
+        try:
+            entity = model.by_id(self.step_id)
+        except Exception:
+            self.report({"WARNING"}, f"Entity #{self.step_id} not found (may have been deleted locally)")
+            return {"CANCELLED"}
+
+        obj = tool.Ifc.get_object(entity)
+        if obj is None:
+            # Walk inverse references up to 5 hops to find nearest entity with a Blender object
+            visited = {entity.id()}
+            queue = [entity]
+            for _ in range(5):
+                next_queue = []
+                for ent in queue:
+                    for inv in model.get_inverse(ent):
+                        if inv.id() in visited:
+                            continue
+                        visited.add(inv.id())
+                        obj = tool.Ifc.get_object(inv)
+                        if obj is not None:
+                            break
+                        next_queue.append(inv)
+                    if obj is not None:
+                        break
+                if obj is not None:
+                    break
+                queue = next_queue
+
+        if obj is None:
+            self.report({"INFO"}, f"No viewport representation found for #{self.step_id} ({entity.is_a()})")
+            return {"CANCELLED"}
+
+        bpy.ops.object.select_all(action="DESELECT")
+        obj.select_set(True)
+        context.view_layer.objects.active = obj
+        for area in context.screen.areas:
+            if area.type == "VIEW_3D":
+                region = next((r for r in area.regions if r.type == "WINDOW"), None)
+                if region:
+                    with context.temp_override(area=area, region=region):
+                        bpy.ops.view3d.view_selected()
+                break
+
+        return {"FINISHED"}
+
+
 class Push(bpy.types.Operator):
     """Pushes the working branch to selected remote"""
 
@@ -469,3 +538,37 @@ class RunGitDiff(bpy.types.Operator):
     def execute(self, context):
         core.run_git_diff(tool.IfcGit, self, self.save_to_temp)
         return {"FINISHED"}
+
+
+class RenameBranch(bpy.types.Operator):
+    """Rename the current branch"""
+
+    bl_label = "Rename Branch"
+    bl_idname = "ifcgit.rename_branch"
+    bl_options = {"REGISTER"}
+
+    new_name: bpy.props.StringProperty(name="New name")  # pyright: ignore[reportRedeclaration]
+
+    if TYPE_CHECKING:
+        new_name: str
+
+    @classmethod
+    def poll(cls, context):
+        IfcGitData.make_sure_is_loaded()
+        if not IfcGitData.data["repo"]:
+            return False
+        if IfcGitData.data["is_detached"]:
+            return False
+        if IfcGitData.data["is_dirty"]:
+            return False
+        return True
+
+    def invoke(self, context, event):
+        self.new_name = IfcGitData.data["active_branch_name"]
+        return context.window_manager.invoke_props_dialog(self)
+
+    def execute(self, context):
+        repo = IfcGitData.data["repo"]
+        core.rename_branch(tool.IfcGit, repo, self.new_name)
+        refresh()
+        return {"FINISHED"}

src/bonsai/bonsai/bim/module/ifcgit/prop.py

@@ -139,6 +139,11 @@ class IfcGitProperties(PropertyGroup):
         ],
         update=update_revlist,
     )
+    merge_conflicts: StringProperty(
+        name="Merge Conflicts",
+        description="JSON report from last failed merge attempt",
+        default="",
+    )
 
     if TYPE_CHECKING:
         ifcgit_commits: bpy.types.bpy_prop_collection_idprop[IfcGitListItem]
@@ -153,3 +158,4 @@ class IfcGitProperties(PropertyGroup):
         display_branch: str
         select_remote: str
         ifcgit_filter: Literal["all", "tagged", "relevant"]
+        merge_conflicts: str

src/bonsai/bonsai/bim/module/ifcgit/ui.py

@@ -112,15 +112,13 @@ class IFCGIT_PT_panel(bpy.types.Panel):
             row.label(text="Working branch: Detached HEAD")
         else:
             row.label(text="Working branch: " + IfcGitData.data["active_branch_name"])
+            row.operator("ifcgit.rename_branch", icon="GREASEPENCIL", text="")
 
-        grouped = layout.row()
+        row = layout.row()
-        column = grouped.column()
-        row = column.row()
         row.prop(props, "display_branch", text="Browse branch")
         row.prop(props, "ifcgit_filter", text="Filter revisions")
 
-        row = column.row()
+        layout.template_list(
-        row.template_list(
             "COMMIT_UL_List",
             "The_List",
             props,
@@ -128,20 +126,64 @@ class IFCGIT_PT_panel(bpy.types.Panel):
             props,
             "commit_index",
         )
-        column = grouped.column()
+
-        row = column.row()
+        row = layout.row(align=True)
         row.operator("ifcgit.refresh", icon="FILE_REFRESH")
-
         if not is_dirty:
-
-            row = column.row()
             row.operator("ifcgit.display_revision", icon="SELECT_DIFFERENCE")
-
-            row = column.row()
             row.operator("ifcgit.switch_revision", icon="CURRENT_FILE")
+            row.operator("ifcgit.merge", icon="SYSTEM")
 
-            row = column.row()
+        conflicts = tool.IfcGit.get_merge_conflicts()
-            row.operator("ifcgit.merge", icon="EXPERIMENTAL", text="")
+        if conflicts is not None:
+            box = layout.box()
+            box.alert = True
+            row = box.row()
+            row.label(
+                text=f"Merge failed \u2014 {len(conflicts)} conflict(s)",
+                icon="ERROR",
+            )
+            for conflict in conflicts:
+                col = box.column(align=True)
+                conflict_type = conflict.get("type", "")
+                entity_id = conflict.get("entity_id", "?")
+                local_id = conflict.get("original_local_id")
+
+                if conflict_type == "attribute_conflict":
+                    entity_class = conflict.get("entity_class", "Entity")
+                    attr_idx = conflict.get("attribute_index", "?")
+                    desc = f"#{entity_id} {entity_class}: attribute {attr_idx} conflict"
+                elif conflict_type == "entity_deleted_and_modified":
+                    entity_class = conflict.get("entity_class", "Entity")
+                    desc = f"#{entity_id} {entity_class}: " + conflict.get("message", "deleted/modified conflict")
+                elif conflict_type == "class_changed":
+                    desc = (
+                        f"#{entity_id}: class changed "
+                        + conflict.get("base_class", "?")
+                        + " \u2192 "
+                        + conflict.get("modified_class", "?")
+                    )
+                elif conflict_type == "required_entity_deleted":
+                    desc = f"#{entity_id}: " + conflict.get("message", "required entity deleted")
+                else:
+                    desc = f"#{entity_id}: {conflict_type}"
+
+                row = col.row(align=True)
+                row.label(text=desc)
+                if local_id:
+                    op = row.operator(
+                        "ifcgit.select_conflict_entity",
+                        text="",
+                        icon="RESTRICT_SELECT_OFF",
+                    )
+                    op.step_id = local_id
+
+                if conflict_type == "attribute_conflict":
+                    sub = col.column(align=True)
+                    sub.scale_y = 0.75
+                    sub.label(text=f"  Base:   {conflict.get('base_value', '')}")
+                    sub.label(text=f"  Local:  {conflict.get('local_value', '')}")
+                    sub.label(text=f"  Remote: {conflict.get('remote_value', '')}")
 
         if not props.ifcgit_commits:
             return

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

@@ -19,6 +19,7 @@
 from __future__ import annotations
 
 import os
+import shutil
 from typing import TYPE_CHECKING
 
 import bpy
@@ -384,6 +385,18 @@ class BIM_PT_new_project_wizard(Panel):
         row = self.layout.row()
         row.operator("bim.create_project")
 
+        if shutil.which("git"):
+            git_props = context.scene.IfcGitProperties
+            box = self.layout.box()
+            row = box.row()
+            row.label(text="Clone a remote Git repository")
+            row = box.row()
+            row.prop(git_props, "remote_url")
+            row = box.row()
+            row.prop(git_props, "local_folder")
+            row = box.row()
+            row.operator("ifcgit.clone_repo", icon="IMPORT")
+
 
 class BIM_PT_project_library(Panel):
     bl_label = "Project Library"

src/bonsai/bonsai/core/ifcgit.py

@@ -87,6 +87,10 @@ def delete_remote(ifcgit: type[tool.IfcGit], repo: git.Repo, remote_name: str) -
     ifcgit.delete_remote(repo, remote_name)
 
 
+def rename_branch(ifcgit: type[tool.IfcGit], repo: git.Repo, new_name: str) -> None:
+    ifcgit.rename_branch(repo, new_name)
+
+
 def push(ifcgit: type[tool.IfcGit], repo: git.Repo, remote_name: str, operator: bpy.types.Operator) -> None:
     error_message = ifcgit.push(repo, remote_name, ifcgit.get_active_branch_name())
     if error_message:
@@ -94,6 +98,7 @@ def push(ifcgit: type[tool.IfcGit], repo: git.Repo, remote_name: str, operator:
 
 
 def refresh_revision_list(ifcgit: type[tool.IfcGit], ifc: type[tool.Ifc]) -> None:
+    ifcgit.clear_merge_conflicts()
     if ifcgit.repo_has_commits():
         ifcgit.refresh_revision_list(ifc.get_path())
 
@@ -143,19 +148,60 @@ def merge_branch(ifcgit: type[tool.IfcGit], ifc: type[tool.Ifc], operator: bpy.t
         operator.report({"ERROR"}, "Unknown IFC Merge failure")
         return False
     elif merge_result == "conflict":
-        error = ifcgit.git_mergetool(mergetool)
+        conflicts = ifcgit.git_mergetool(mergetool, path_ifc)
-        if error:
+        if conflicts is not None:
             ifcgit.git_merge_abort()
-            operator.report({"ERROR"}, "IFC Merge failed:" + error)
+            ifcgit.store_merge_conflicts(conflicts)
+            operator.report({"WARNING"}, "Merge failed — see the conflict report in the panel below")
             return False
         ifcgit.commit_merge(path_ifc)
 
+    ifcgit.clear_merge_conflicts()
     ifcgit.set_display_branch()
+    ifcgit.git_checkout(path_ifc)
     ifcgit.load_project(path_ifc)
     ifcgit.refresh_revision_list(path_ifc)
     ifcgit.decolourise()
 
 
+def dry_run_merge(ifcgit: type[tool.IfcGit], ifc: type[tool.Ifc], operator: bpy.types.Operator) -> None:
+    path_ifc = ifc.get_path()
+    ifcgit.config_ifcmerge()
+
+    branch_name = ifcgit.get_selected_branch()
+    if branch_name is None:
+        return
+
+    mergetool = ifcgit.get_merge_tool(branch_name)
+    merge_result = ifcgit.git_merge_no_commit(branch_name)
+
+    if merge_result == "error":
+        try:
+            ifcgit.git_merge_abort()
+        except Exception:
+            pass
+        operator.report({"ERROR"}, "Unknown IFC Merge failure")
+        return
+
+    if merge_result == "conflict":
+        conflicts = ifcgit.git_mergetool(mergetool, path_ifc)
+        ifcgit.git_merge_abort()
+        if conflicts is not None:
+            ifcgit.store_merge_conflicts(conflicts)
+            operator.report({"WARNING"}, "Merge preview: conflicts found — see the panel below")
+        else:
+            ifcgit.clear_merge_conflicts()
+            operator.report({"INFO"}, "Merge preview: no conflicts")
+    else:
+        # Clean merge or already up to date — abort the pending merge state if any
+        try:
+            ifcgit.git_merge_abort()
+        except Exception:
+            pass
+        ifcgit.clear_merge_conflicts()
+        operator.report({"INFO"}, "Merge preview: no conflicts")
+
+
 def entity_log(ifcgit: type[tool.IfcGit], ifc: type[tool.Ifc], step_id: int, operator: bpy.types.Operator) -> None:
     path_ifc = ifc.get_path()
     log_text = ifcgit.entity_log(path_ifc, step_id)

src/bonsai/bonsai/core/tool.py

@@ -559,7 +559,11 @@ class IfcGit:
     def get_selected_branch(cls): pass
     def git_merge(cls, branch_name): pass
     def git_merge_abort(cls): pass
-    def git_mergetool(cls, mergetool): pass
+    def git_merge_no_commit(cls, branch_name): pass
+    def git_mergetool(cls, mergetool, path_ifc): pass
+    def store_merge_conflicts(cls, conflicts): pass
+    def clear_merge_conflicts(cls): pass
+    def get_merge_conflicts(cls): pass
     def set_display_branch(cls): pass
     def get_active_branch_name(cls): pass
     def get_ifcgit_props(cls): pass

src/bonsai/bonsai/tool/ifcgit.py

@@ -18,6 +18,7 @@
 
 from __future__ import annotations
 
+import json
 import logging
 import os
 import re
@@ -155,6 +156,10 @@ class IfcGit:
         if tag_name in repo.tags:
             repo.delete_tag(tag_name)
 
+    @classmethod
+    def rename_branch(cls, repo: git.Repo, new_name: str) -> None:
+        repo.active_branch.rename(new_name)
+
     @classmethod
     def add_remote(cls, repo: git.Repo, remote_name: str, remote_url: str) -> None:
         repo.create_remote(name=remote_name, url=remote_url)
@@ -278,6 +283,10 @@ class IfcGit:
         bpy.data.orphans_purge(do_recursive=True)  # ty:ignore[unknown-argument]
 
         from bonsai.bim.module.root.data import IfcClassData
+        from bonsai.bim.module.model.data import AuthoringData
+        import bonsai.bim.handler
+
+        AuthoringData.type_thumbnails = {}
 
         IfcClassData.is_loaded = False
 
@@ -285,10 +294,11 @@ class IfcGit:
         settings.should_setup_viewport_camera = False
         ifc_importer = import_ifc.IfcImporter(settings)
         ifc_importer.execute()
-        tool.Project.load_project_pset_templates()
         tool.Project.load_default_thumbnails()
         tool.Project.set_default_context()
         tool.Project.set_default_modeling_dimensions()
+        tool.Root.reload_grid_decorator()
+        bonsai.bim.handler.refresh_ui_data()
         bpy.ops.object.select_all(action="DESELECT")
 
     @classmethod
@@ -388,20 +398,43 @@ class IfcGit:
         model = tool.Ifc.get()
         modified_step_ids = {"modified": set()}
 
-        for step_id in step_ids["modified"] | step_ids["added"]:
+        def collect(entity, depth=0):
-            try:
+            if depth > 2:
-                entity = model.by_id(step_id)
+                return
-            except:
+            if entity.is_a("IfcProduct"):
-                continue
+                modified_step_ids["modified"].add(entity.id())
-            if entity.is_a("IfcProductDefinitionShape"):
+            elif entity.is_a("IfcProductDefinitionShape"):
                 for product in entity.ShapeOfProduct:
                     modified_step_ids["modified"].add(product.id())
             elif entity.is_a("IfcObjectPlacement"):
                 for product in entity.PlacesObject:
                     modified_step_ids["modified"].add(product.id())
-            elif entity.is_a("IfcTypeProduct") and entity.Types:
+            elif entity.is_a("IfcTypeProduct"):
-                for related_object in entity.Types[0].RelatedObjects:
+                for rel in entity.Types:
-                    modified_step_ids["modified"].add(related_object.id())
+                    for obj in rel.RelatedObjects:
+                        modified_step_ids["modified"].add(obj.id())
+            elif entity.is_a("IfcShapeRepresentation"):
+                for prod_rep in entity.OfProductRepresentation:
+                    for product in prod_rep.ShapeOfProduct:
+                        modified_step_ids["modified"].add(product.id())
+            elif entity.is_a("IfcRepresentationItem"):
+                for referencing in model.get_inverse(entity):
+                    if referencing.is_a("IfcShapeRepresentation"):
+                        collect(referencing, depth + 1)
+            elif entity.is_a("IfcPropertySet"):
+                for rel in entity.DefinesOccurrence:
+                    for obj in rel.RelatedObjects:
+                        modified_step_ids["modified"].add(obj.id())
+            elif entity.is_a("IfcProperty"):
+                for pset in entity.PartOfPset:
+                    collect(pset, depth + 1)
+
+        for step_id in step_ids["modified"] | step_ids["added"]:
+            try:
+                entity = model.by_id(step_id)
+            except:
+                continue
+            collect(entity)
 
         return modified_step_ids
 
@@ -453,11 +486,28 @@ class IfcGit:
         if item.hexsha in lookup:
             for branch in lookup[item.hexsha]:
                 if branch.name == props.display_branch:
+                    if isinstance(branch, git.RemoteReference):
+                        # Checking out a remote branch tip goes to detached HEAD.
+                        # Pre-fill the new branch name field with the local equivalent
+                        # so the user isn't blocked from committing without a hint.
+                        local_name = branch.remote_head
+                        props.new_branch_name = cls._unique_branch_name(repo, local_name)
                     branch.checkout()
                     return
         # NOTE this is calling the git binary in a subprocess
         repo.git.checkout(item.hexsha)
 
+    @classmethod
+    def _unique_branch_name(cls, repo: git.Repo, name: str) -> str:
+        """Return name if unused, otherwise name-2, name-3, etc."""
+        existing = {h.name for h in repo.heads}
+        if name not in existing:
+            return name
+        i = 2
+        while f"{name}-{i}" in existing:
+            i += 1
+        return f"{name}-{i}"
+
     @classmethod
     def delete_collection(cls, blender_collection: bpy.types.Collection) -> None:
         for obj in blender_collection.objects:
@@ -468,14 +518,24 @@ class IfcGit:
     def config_ifcmerge(cls) -> None:
         config_reader = IfcGitRepo.repo.config_reader()
         section = 'mergetool "ifcmerge"'
+        new_cmd = "ifcmerge $BASE $LOCAL $REMOTE $MERGED > $MERGED.ifcmerge"
         if not config_reader.has_section(section):
             with IfcGitRepo.repo.config_writer() as config_writer:
-                config_writer.set_value(section, "cmd", "ifcmerge $BASE $LOCAL $REMOTE $MERGED")
+                config_writer.set_value(section, "cmd", new_cmd)
+                config_writer.set_value(section, "trustExitCode", True)
+        elif config_reader.get_value(section, "cmd") != new_cmd:
+            with IfcGitRepo.repo.config_writer() as config_writer:
+                config_writer.set_value(section, "cmd", new_cmd)
                 config_writer.set_value(section, "trustExitCode", True)
         section = 'mergetool "ifcmerge-forward"'
+        new_cmd = "ifcmerge --prioritise-local $BASE $LOCAL $REMOTE $MERGED > $MERGED.ifcmerge"
         if not config_reader.has_section(section):
             with IfcGitRepo.repo.config_writer() as config_writer:
-                config_writer.set_value(section, "cmd", "ifcmerge $BASE $REMOTE $LOCAL $MERGED")
+                config_writer.set_value(section, "cmd", new_cmd)
+                config_writer.set_value(section, "trustExitCode", True)
+        elif config_reader.get_value(section, "cmd") != new_cmd:
+            with IfcGitRepo.repo.config_writer() as config_writer:
+                config_writer.set_value(section, "cmd", new_cmd)
                 config_writer.set_value(section, "trustExitCode", True)
 
     @classmethod
@@ -539,14 +599,62 @@ class IfcGit:
             return "error"
 
     @classmethod
-    def git_mergetool(cls, mergetool: str) -> Union[str, None]:
+    def git_merge_no_commit(cls, branch_name: str) -> Union[str, None]:
-        """Run ifcmerge tool. Returns None on success, error message string on failure."""
+        """Attempt a git merge without committing (always leaves a merge state to abort).
+        Returns None on clean merge, 'conflict' on conflict, or 'error' on unknown failure."""
         repo = IfcGitRepo.repo
+        branch = repo.branches[branch_name]
+        try:
+            repo.git.merge(branch, no_commit=True, no_ff=True)
+            return None
+        except git.exc.GitCommandError:
+            return "conflict"
+        except git.exc.GitError:
+            return "error"
+
+    @classmethod
+    def git_mergetool(cls, mergetool: str, path_ifc: str) -> Union[list, None]:
+        """Run ifcmerge tool. Returns None on success, list of conflict dicts on failure."""
+        repo = IfcGitRepo.repo
+        report_path = path_ifc + ".ifcmerge"
         try:
             repo.git.mergetool(tool=mergetool)
+        except git.exc.GitCommandError:
+            pass
+
+        conflicts = None
+        if os.path.exists(report_path):
+            try:
+                with open(report_path) as f:
+                    content = f.read().strip()
+                if content:
+                    data = json.loads(content)
+                    conflicts = data.get("conflicts", [])
+            except (json.JSONDecodeError, OSError):
+                pass
+            try:
+                os.remove(report_path)
+            except OSError:
+                pass
+        return conflicts
+
+    @classmethod
+    def store_merge_conflicts(cls, conflicts: list) -> None:
+        cls.get_ifcgit_props().merge_conflicts = json.dumps(conflicts)
+
+    @classmethod
+    def clear_merge_conflicts(cls) -> None:
+        cls.get_ifcgit_props().merge_conflicts = ""
+
+    @classmethod
+    def get_merge_conflicts(cls) -> Union[list, None]:
+        raw = cls.get_ifcgit_props().merge_conflicts
+        if not raw:
+            return None
+        try:
+            return json.loads(raw)
+        except json.JSONDecodeError:
             return None
-        except git.exc.GitCommandError as exc:
-            return re.sub("(  stdout: '|')", "", exc.stdout)
 
     @classmethod
     def git_merge_abort(cls) -> None:

src/bonsai/test/core/test_ifcgit.py

@@ -132,12 +132,14 @@ class TestPush:
 
 class TestRefreshRevisionList:
     def test_refreshes_when_repo_has_heads(self, ifcgit, ifc):
+        ifcgit.clear_merge_conflicts().should_be_called()
         ifcgit.repo_has_commits().should_be_called().will_return(True)
         ifc.get_path().should_be_called().will_return("path/to/model.ifc")
         ifcgit.refresh_revision_list("path/to/model.ifc").should_be_called()
         subject.refresh_revision_list(ifcgit, ifc)
 
     def test_skips_when_repo_has_no_heads(self, ifcgit, ifc):
+        ifcgit.clear_merge_conflicts().should_be_called()
         ifcgit.repo_has_commits().should_be_called().will_return(False)
         subject.refresh_revision_list(ifcgit, ifc)
         # nothing else should be called — Prophecy will verify
@@ -194,7 +196,9 @@ class TestMergeBranch:
         ifcgit.get_selected_branch().should_be_called().will_return("feature")
         ifcgit.get_merge_tool("feature").should_be_called().will_return("ifcmerge-forward")
         ifcgit.git_merge("feature").should_be_called().will_return(None)
+        ifcgit.clear_merge_conflicts().should_be_called()
         ifcgit.set_display_branch().should_be_called()
+        ifcgit.git_checkout("path/to/model.ifc").should_be_called()
         ifcgit.load_project("path/to/model.ifc").should_be_called()
         ifcgit.refresh_revision_list("path/to/model.ifc").should_be_called()
         ifcgit.decolourise().should_be_called()
@@ -206,25 +210,29 @@ class TestMergeBranch:
         ifcgit.get_selected_branch().should_be_called().will_return("feature")
         ifcgit.get_merge_tool("feature").should_be_called().will_return("ifcmerge-forward")
         ifcgit.git_merge("feature").should_be_called().will_return("conflict")
-        ifcgit.git_mergetool("ifcmerge-forward").should_be_called().will_return(None)
+        ifcgit.git_mergetool("ifcmerge-forward", "path/to/model.ifc").should_be_called().will_return(None)
         ifcgit.commit_merge("path/to/model.ifc").should_be_called()
+        ifcgit.clear_merge_conflicts().should_be_called()
         ifcgit.set_display_branch().should_be_called()
+        ifcgit.git_checkout("path/to/model.ifc").should_be_called()
         ifcgit.load_project("path/to/model.ifc").should_be_called()
         ifcgit.refresh_revision_list("path/to/model.ifc").should_be_called()
         ifcgit.decolourise().should_be_called()
         subject.merge_branch(ifcgit, ifc, operator=None)
 
     def test_conflict_mergetool_failure(self, ifcgit, ifc):
+        conflicts = [{"type": "attribute_conflict", "entity_id": 42}]
         ifc.get_path().should_be_called().will_return("path/to/model.ifc")
         ifcgit.config_ifcmerge().should_be_called()
         ifcgit.get_selected_branch().should_be_called().will_return("feature")
         ifcgit.get_merge_tool("feature").should_be_called().will_return("ifcmerge-forward")
         ifcgit.git_merge("feature").should_be_called().will_return("conflict")
-        ifcgit.git_mergetool("ifcmerge-forward").should_be_called().will_return("merge error")
+        ifcgit.git_mergetool("ifcmerge-forward", "path/to/model.ifc").should_be_called().will_return(conflicts)
         ifcgit.git_merge_abort().should_be_called()
+        ifcgit.store_merge_conflicts(conflicts).should_be_called()
         op = MockOperator()
         subject.merge_branch(ifcgit, ifc, op)
-        assert op.reports == [({"ERROR"}, "IFC Merge failed:merge error")]
+        assert op.reports == [({"WARNING"}, "Merge failed — see the conflict report in the panel below")]
 
     def test_unknown_merge_error(self, ifcgit, ifc):
         ifc.get_path().should_be_called().will_return("path/to/model.ifc")
@@ -237,6 +245,53 @@ class TestMergeBranch:
         assert op.reports == [({"ERROR"}, "Unknown IFC Merge failure")]
 
 
+class TestDryRunMerge:
+    def test_no_branch_at_selected_commit(self, ifcgit, ifc):
+        ifc.get_path().should_be_called().will_return("path/to/model.ifc")
+        ifcgit.config_ifcmerge().should_be_called()
+        ifcgit.get_selected_branch().should_be_called().will_return(None)
+        subject.dry_run_merge(ifcgit, ifc, operator=None)
+
+    def test_clean_merge_preview(self, ifcgit, ifc):
+        ifc.get_path().should_be_called().will_return("path/to/model.ifc")
+        ifcgit.config_ifcmerge().should_be_called()
+        ifcgit.get_selected_branch().should_be_called().will_return("feature")
+        ifcgit.get_merge_tool("feature").should_be_called().will_return("ifcmerge-forward")
+        ifcgit.git_merge_no_commit("feature").should_be_called().will_return(None)
+        ifcgit.git_merge_abort().should_be_called()
+        ifcgit.clear_merge_conflicts().should_be_called()
+        op = MockOperator()
+        subject.dry_run_merge(ifcgit, ifc, op)
+        assert op.reports == [({"INFO"}, "Merge preview: no conflicts")]
+
+    def test_conflict_preview_shows_report(self, ifcgit, ifc):
+        conflicts = [{"type": "attribute_conflict", "entity_id": 42}]
+        ifc.get_path().should_be_called().will_return("path/to/model.ifc")
+        ifcgit.config_ifcmerge().should_be_called()
+        ifcgit.get_selected_branch().should_be_called().will_return("feature")
+        ifcgit.get_merge_tool("feature").should_be_called().will_return("ifcmerge-forward")
+        ifcgit.git_merge_no_commit("feature").should_be_called().will_return("conflict")
+        ifcgit.git_mergetool("ifcmerge-forward", "path/to/model.ifc").should_be_called().will_return(conflicts)
+        ifcgit.git_merge_abort().should_be_called()
+        ifcgit.store_merge_conflicts(conflicts).should_be_called()
+        op = MockOperator()
+        subject.dry_run_merge(ifcgit, ifc, op)
+        assert op.reports == [({"WARNING"}, "Merge preview: conflicts found — see the panel below")]
+
+    def test_conflict_preview_mergetool_succeeds(self, ifcgit, ifc):
+        ifc.get_path().should_be_called().will_return("path/to/model.ifc")
+        ifcgit.config_ifcmerge().should_be_called()
+        ifcgit.get_selected_branch().should_be_called().will_return("feature")
+        ifcgit.get_merge_tool("feature").should_be_called().will_return("ifcmerge-forward")
+        ifcgit.git_merge_no_commit("feature").should_be_called().will_return("conflict")
+        ifcgit.git_mergetool("ifcmerge-forward", "path/to/model.ifc").should_be_called().will_return(None)
+        ifcgit.git_merge_abort().should_be_called()
+        ifcgit.clear_merge_conflicts().should_be_called()
+        op = MockOperator()
+        subject.dry_run_merge(ifcgit, ifc, op)
+        assert op.reports == [({"INFO"}, "Merge preview: no conflicts")]
+
+
 class TestEntityLog:
     def test_run(self, ifcgit, ifc):
         ifc.get_path().should_be_called().will_return("path/to/model.ifc")

src/bonsai/test/tool/test_ifcgit.py

@@ -454,3 +454,128 @@ class TestIfcDiffIds(NewFile):
             result = IfcGit.ifc_diff_ids(repo, sha_a, sha_b, ifc_path)
             assert 1 in result["modified"]
             assert 2 in result["modified"]
+
+
+# ---------------------------------------------------------------------------
+# Merge conflict report — store / clear / get
+# ---------------------------------------------------------------------------
+
+
+class TestStoreClearGetMergeConflicts(NewFile):
+    def test_round_trip(self):
+        conflicts = [{"type": "attribute_conflict", "entity_id": 42}]
+        IfcGit.store_merge_conflicts(conflicts)
+        result = IfcGit.get_merge_conflicts()
+        assert result == conflicts
+
+    def test_get_returns_none_when_empty(self):
+        IfcGit.clear_merge_conflicts()
+        assert IfcGit.get_merge_conflicts() is None
+
+    def test_clear_removes_stored_conflicts(self):
+        IfcGit.store_merge_conflicts([{"type": "class_changed"}])
+        IfcGit.clear_merge_conflicts()
+        assert IfcGit.get_merge_conflicts() is None
+
+    def test_get_returns_none_on_corrupt_json(self):
+        import bpy
+
+        bpy.context.scene.IfcGitProperties.merge_conflicts = "not valid json {"
+        assert IfcGit.get_merge_conflicts() is None
+
+
+# ---------------------------------------------------------------------------
+# git_mergetool — report file reading
+# ---------------------------------------------------------------------------
+
+
+class TestGitMergetool:
+    @requires_git
+    def test_returns_none_when_report_file_absent(self):
+        import unittest.mock as mock
+
+        with tempfile.TemporaryDirectory() as tmpdir:
+            ifc_path = os.path.join(tmpdir, "model.ifc")
+            mock_repo = mock.MagicMock()
+            IfcGitRepo.repo = mock_repo
+            result = IfcGit.git_mergetool("ifcmerge", ifc_path)
+            assert result is None
+            IfcGitRepo.repo = None
+
+    @requires_git
+    def test_returns_none_when_report_file_empty(self):
+        import unittest.mock as mock
+
+        with tempfile.TemporaryDirectory() as tmpdir:
+            ifc_path = os.path.join(tmpdir, "model.ifc")
+            report_path = ifc_path + ".ifcmerge"
+            open(report_path, "w").close()
+            mock_repo = mock.MagicMock()
+            IfcGitRepo.repo = mock_repo
+            result = IfcGit.git_mergetool("ifcmerge", ifc_path)
+            assert result is None
+            assert not os.path.exists(report_path)
+            IfcGitRepo.repo = None
+
+    @requires_git
+    def test_parses_conflict_report_and_deletes_file(self):
+        import json
+        import unittest.mock as mock
+
+        with tempfile.TemporaryDirectory() as tmpdir:
+            ifc_path = os.path.join(tmpdir, "model.ifc")
+            report_path = ifc_path + ".ifcmerge"
+            conflicts = [{"type": "attribute_conflict", "entity_id": 5}]
+            with open(report_path, "w") as f:
+                json.dump({"status": "failed", "conflicts": conflicts}, f)
+            mock_repo = mock.MagicMock()
+            mock_repo.git.mergetool.side_effect = git.exc.GitCommandError("mergetool", 1)
+            IfcGitRepo.repo = mock_repo
+            result = IfcGit.git_mergetool("ifcmerge", ifc_path)
+            assert result == conflicts
+            assert not os.path.exists(report_path)
+            IfcGitRepo.repo = None
+
+
+# ---------------------------------------------------------------------------
+# config_ifcmerge — cmd format and update
+# ---------------------------------------------------------------------------
+
+
+class TestConfigIfcmerge:
+    @requires_git
+    def test_writes_redirect_cmd_on_first_call(self):
+        with tempfile.TemporaryDirectory() as tmpdir:
+            repo = _make_repo(tmpdir)
+            IfcGitRepo.repo = repo
+            IfcGit.config_ifcmerge()
+            reader = repo.config_reader()
+            cmd = reader.get_value('mergetool "ifcmerge"', "cmd")
+            assert "> $MERGED.ifcmerge" in cmd
+            IfcGitRepo.repo = None
+
+    @requires_git
+    def test_updates_cmd_missing_redirect(self):
+        with tempfile.TemporaryDirectory() as tmpdir:
+            repo = _make_repo(tmpdir)
+            IfcGitRepo.repo = repo
+            with repo.config_writer() as w:
+                w.set_value('mergetool "ifcmerge"', "cmd", "ifcmerge $BASE $LOCAL $REMOTE $MERGED")
+                w.set_value('mergetool "ifcmerge"', "trustExitCode", True)
+            IfcGit.config_ifcmerge()
+            reader = repo.config_reader()
+            cmd = reader.get_value('mergetool "ifcmerge"', "cmd")
+            assert "> $MERGED.ifcmerge" in cmd
+            IfcGitRepo.repo = None
+
+    @requires_git
+    def test_forward_tool_writes_redirect_cmd(self):
+        with tempfile.TemporaryDirectory() as tmpdir:
+            repo = _make_repo(tmpdir)
+            IfcGitRepo.repo = repo
+            IfcGit.config_ifcmerge()
+            reader = repo.config_reader()
+            cmd = reader.get_value('mergetool "ifcmerge-forward"', "cmd")
+            assert "--prioritise-local" in cmd
+            assert "> $MERGED.ifcmerge" in cmd
+            IfcGitRepo.repo = None