Recover external git repo changes, fixes #5311

IfcGit didn't cope gracefully when commits and/or repositories vanished
unexpectedly

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

@@ -154,15 +154,17 @@ class IfcGitData:
     @classmethod
     def commit(cls):
         props = bpy.context.scene.IfcGitProperties
-        if len(props.ifcgit_commits) > 0:
+        if cls.repo() and len(props.ifcgit_commits) > 0:
             item = props.ifcgit_commits[props.commit_index]
-            if cls.repo():
+            try:
                 return cls.repo().commit(rev=item.hexsha)
+            except ValueError:
+                return
 
     @classmethod
     def current_revision(cls):
         props = bpy.context.scene.IfcGitProperties
-        if len(props.ifcgit_commits) > 0:
+        if cls.repo() and cls.repo().head.is_valid() and len(props.ifcgit_commits) > 0:
             return tool.IfcGitRepo.repo.commit()
 
     @classmethod

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

@@ -1,5 +1,7 @@
 import bpy
 import time
+import os
+
 from bonsai.bim.module.ifcgit.data import IfcGitData
 
 
@@ -32,7 +34,7 @@ class IFCGIT_PT_panel(bpy.types.Panel):
 
         row = layout.row()
         if path_ifc:
-            if IfcGitData.data["repo"]:
+            if IfcGitData.data["repo"] and os.path.exists(IfcGitData.data["repo"].git_dir):
                 name_ifc = IfcGitData.data["name_ifc"]
                 row.label(text=IfcGitData.data["working_dir"], icon="SYSTEM")
                 if name_ifc in IfcGitData.data["untracked_files"]:
@@ -44,6 +46,7 @@ class IFCGIT_PT_panel(bpy.types.Panel):
                 else:
                     row.label(text=name_ifc, icon="FILE")
             else:
+                IfcGitData.load()
                 row.operator(
                     "ifcgit.createrepo",
                     text="Create '" + IfcGitData.data["dir_name"] + "' repository",
@@ -193,7 +196,10 @@ class COMMIT_UL_List(bpy.types.UIList):
 
         # TODO Figure how this "item" can be acesse in "data.py"
         # so it's possible to move the ".commit"
-        commit = IfcGitData.data["repo"].commit(rev=item.hexsha)
+        try:
+            commit = IfcGitData.data["repo"].commit(rev=item.hexsha)
+        except ValueError:
+            return
 
         lookup = IfcGitData.data["branches_by_hexsha"]
         refs = ""

src/bonsai/bonsai/tool/ifcgit.py

@@ -79,7 +79,7 @@ class IfcGit:
         else:
             return None
 
-        if IfcGitRepo.repo is not None and IfcGitRepo.repo.working_dir == path_dir:
+        if IfcGitRepo.repo is not None and os.path.exists(IfcGitRepo.repo.git_dir) and IfcGitRepo.repo.working_dir == path_dir:
             return IfcGitRepo.repo
 
         try:
@@ -88,9 +88,11 @@ class IfcGit:
             parentdir_path = os.path.abspath(os.path.join(path_dir, os.pardir))
             if parentdir_path == path_dir:
                 # root folder
+                IfcGitRepo.repo = None
                 return None
             return cls.repo_from_path(parentdir_path)
         except git.exc.NoSuchPathError:
+            IfcGitRepo.repo = None
             return None
         if repo:
             IfcGitRepo.repo = repo