Fix for #36387, User Preferences "Addons" panel bogs down the whole interface.

The addons panel draw function calls addon_utils.modules() which in turn retrieves a list of fake modules from the script paths every time. This can become costly when network paths are included for
addons. Solution is to put the scanning process into a dedicated "refresh" function and disable it in frequently called draw and filter functions, i.e. in these cases the cached addons_fake_modules list
will be used instead.

Note that this may lead to invalid addon lists if script paths are changed (which is not working 100% without restart anyway according to Campbell). For this there is now a "Refresh" operator button in
the addons preferences. If necessary and feasible such forced refreshes can be added later too.

1 files changed, 17 insertions, 4 deletions

diff --git a/release/scripts/startup/bl_operators/wm.py b/release/scripts/startup/bl_operators/wm.py
index 5095bfdd9d2..c575b6dfdaf 100644
--- a/release/scripts/startup/bl_operators/wm.py
+++ b/release/scripts/startup/bl_operators/wm.py
@@ -1693,6 +1693,19 @@ class WM_OT_theme_install(Operator):
         return {'RUNNING_MODAL'}
 
 
+class WM_OT_addon_refresh(Operator):
+    "Scan addon directories for new modules"
+    bl_idname = "wm.addon_refresh"
+    bl_label = "Refresh"
+
+    def execute(self, context):
+        import addon_utils
+        
+        addon_utils.modules_refresh()
+        
+        return {'FINISHED'}
+
+
 class WM_OT_addon_install(Operator):
     "Install an addon"
     bl_idname = "wm.addon_install"
@@ -1782,7 +1795,7 @@ class WM_OT_addon_install(Operator):
         del pyfile_dir
         # done checking for exceptional case
 
-        addons_old = {mod.__name__ for mod in addon_utils.modules(addon_utils.addons_fake_modules)}
+        addons_old = {mod.__name__ for mod in addon_utils.modules()}
 
         #check to see if the file is in compressed format (.zip)
         if zipfile.is_zipfile(pyfile):
@@ -1825,7 +1838,7 @@ class WM_OT_addon_install(Operator):
                 traceback.print_exc()
                 return {'CANCELLED'}
 
-        addons_new = {mod.__name__ for mod in addon_utils.modules(addon_utils.addons_fake_modules)} - addons_old
+        addons_new = {mod.__name__ for mod in addon_utils.modules()} - addons_old
         addons_new.discard("modules")
 
         # disable any addons we may have enabled previously and removed.
@@ -1835,7 +1848,7 @@ class WM_OT_addon_install(Operator):
 
         # possible the zip contains multiple addons, we could disallow this
         # but for now just use the first
-        for mod in addon_utils.modules(addon_utils.addons_fake_modules):
+        for mod in addon_utils.modules(refresh=False):
             if mod.__name__ in addons_new:
                 info = addon_utils.module_bl_info(mod)
 
@@ -1875,7 +1888,7 @@ class WM_OT_addon_remove(Operator):
         import os
         import addon_utils
 
-        for mod in addon_utils.modules(addon_utils.addons_fake_modules):
+        for mod in addon_utils.modules():
             if mod.__name__ == module:
                 filepath = mod.__file__
                 if os.path.exists(filepath):