Fix T68014: Add-on's override Python built-in modules

Append addon paths to the sys.path to avoid name
collisions with system modules.

1 files changed, 12 insertions, 6 deletions

diff --git a/release/scripts/modules/bpy/utils/__init__.py b/release/scripts/modules/bpy/utils/__init__.py
index b39099158c6..04aaa7bd69d 100644
--- a/release/scripts/modules/bpy/utils/__init__.py
+++ b/release/scripts/modules/bpy/utils/__init__.py
@@ -119,11 +119,17 @@ def _test_import(module_name, loaded_modules):
     return mod
 
 
-def _sys_path_ensure(path):
-    if path not in _sys.path:  # reloading would add twice
+# Reloading would add twice.
+def _sys_path_ensure_prepend(path):
+    if path not in _sys.path:
         _sys.path.insert(0, path)
 
 
+def _sys_path_ensure_append(path):
+    if path not in _sys.path:
+        _sys.path.append(path)
+
+
 def modules_from_path(path, loaded_modules):
     """
     Load all modules in a path and return them as a list.
@@ -253,7 +259,7 @@ def load_scripts(reload_scripts=False, refresh_scripts=False):
             for path_subdir in _script_module_dirs:
                 path = _os.path.join(base_path, path_subdir)
                 if _os.path.isdir(path):
-                    _sys_path_ensure(path)
+                    _sys_path_ensure_prepend(path)
 
                     # Only add to 'sys.modules' unless this is 'startup'.
                     if path_subdir == "startup":
@@ -385,13 +391,13 @@ def refresh_script_paths():
         for path_subdir in _script_module_dirs:
             path = _os.path.join(base_path, path_subdir)
             if _os.path.isdir(path):
-                _sys_path_ensure(path)
+                _sys_path_ensure_prepend(path)
 
     for path in _addon_utils.paths():
-        _sys_path_ensure(path)
+        _sys_path_ensure_append(path)
         path = _os.path.join(path, "modules")
         if _os.path.isdir(path):
-            _sys_path_ensure(path)
+            _sys_path_ensure_append(path)
 
 
 def app_template_paths(subdir=None):