Add-ons: remove temporary disabling of use_global_undo

This can cause bugs where if the operator throws an exception, undo is not
properly enabled again. There have been maybe a dozen Blender bug reports
related to this. This could get worse now that we are autosaving preferences.

Some add-ons guard against this, but turning off undo should not be needed in
the first place. If the operator is set to do an undo push, any operators it
calls will automatically not do any undo pushes.

If this fail in some cases, it should be reported as a bug in Blender. I could
not find issues or a performance impact testing a few add-ons though.

Differential Revision: https://developer.blender.org/D4908

1 files changed, 16 insertions, 20 deletions

diff --git a/mesh_looptools.py b/mesh_looptools.py
index 2b11465f..87c23383 100644
--- a/mesh_looptools.py
+++ b/mesh_looptools.py
@@ -747,8 +747,6 @@ def get_parallel_loops(bm_mod, loops):
 
 # gather initial data
 def initialise():
-    global_undo = bpy.context.preferences.edit.use_global_undo
-    bpy.context.preferences.edit.use_global_undo = False
     object = bpy.context.active_object
     if 'MIRROR' in [mod.type for mod in object.modifiers if mod.show_viewport]:
         # ensure that selection is synced for the derived mesh
@@ -760,7 +758,7 @@ def initialise():
     bm.edges.ensure_lookup_table()
     bm.faces.ensure_lookup_table()
 
-    return(global_undo, object, bm)
+    return(object, bm)
 
 
 # move the vertices to their new locations
@@ -830,14 +828,12 @@ def settings_write(self):
 
 
 # clean up and set settings back to original state
-def terminate(global_undo):
+def terminate():
     # update editmesh cached data
     obj = bpy.context.active_object
     if obj.mode == 'EDIT':
         bmesh.update_edit_mesh(obj.data, loop_triangles=True, destructive=True)
 
-    bpy.context.preferences.edit.use_global_undo = global_undo
-
 
 # ########################################
 # ##### Bridge functions #################
@@ -3301,7 +3297,7 @@ class Bridge(Operator):
 
     def execute(self, context):
         # initialise
-        global_undo, object, bm = initialise()
+        object, bm = initialise()
         edge_faces, edgekey_to_edge, old_selected_faces, smooth = \
             bridge_initialise(bm, self.interpolation)
         settings_write(self)
@@ -3375,7 +3371,7 @@ class Bridge(Operator):
             bpy.ops.mesh.normals_make_consistent()
 
         # cleaning up
-        terminate(global_undo)
+        terminate()
 
         return{'FINISHED'}
 
@@ -3484,7 +3480,7 @@ class Circle(Operator):
 
     def execute(self, context):
         # initialise
-        global_undo, object, bm = initialise()
+        object, bm = initialise()
         settings_write(self)
         # check cache to see if we can save time
         cached, single_loops, loops, derived, mapping = cache_read("Circle",
@@ -3548,7 +3544,7 @@ class Circle(Operator):
         # cleaning up
         if derived:
             bm_mod.free()
-        terminate(global_undo)
+        terminate()
 
         return{'FINISHED'}
 
@@ -3648,7 +3644,7 @@ class Curve(Operator):
 
     def execute(self, context):
         # initialise
-        global_undo, object, bm = initialise()
+        object, bm = initialise()
         settings_write(self)
         # check cache to see if we can save time
         cached, single_loops, loops, derived, mapping = cache_read("Curve",
@@ -3692,7 +3688,7 @@ class Curve(Operator):
         # cleaning up
         if derived:
             bm_mod.free()
-        terminate(global_undo)
+        terminate()
 
         return{'FINISHED'}
 
@@ -3780,7 +3776,7 @@ class Flatten(Operator):
 
     def execute(self, context):
         # initialise
-        global_undo, object, bm = initialise()
+        object, bm = initialise()
         settings_write(self)
         # check cache to see if we can save time
         cached, single_loops, loops, derived, mapping = cache_read("Flatten",
@@ -3814,7 +3810,7 @@ class Flatten(Operator):
         move_verts(object, bm, False, move, lock, self.influence)
 
         # cleaning up
-        terminate(global_undo)
+        terminate()
 
         return{'FINISHED'}
 
@@ -3989,7 +3985,7 @@ class GStretch(Operator):
 
     def execute(self, context):
         # initialise
-        global_undo, object, bm = initialise()
+        object, bm = initialise()
         settings_write(self)
 
         # check cache to see if we can save time
@@ -4093,7 +4089,7 @@ class GStretch(Operator):
         # cleaning up
         if derived:
             bm_mod.free()
-        terminate(global_undo)
+        terminate()
 
         return{'FINISHED'}
 
@@ -4157,7 +4153,7 @@ class Relax(Operator):
 
     def execute(self, context):
         # initialise
-        global_undo, object, bm = initialise()
+        object, bm = initialise()
         settings_write(self)
         # check cache to see if we can save time
         cached, single_loops, loops, derived, mapping = cache_read("Relax",
@@ -4191,7 +4187,7 @@ class Relax(Operator):
         # cleaning up
         if derived:
             bm_mod.free()
-        terminate(global_undo)
+        terminate()
 
         return{'FINISHED'}
 
@@ -4279,7 +4275,7 @@ class Space(Operator):
 
     def execute(self, context):
         # initialise
-        global_undo, object, bm = initialise()
+        object, bm = initialise()
         settings_write(self)
         # check cache to see if we can save time
         cached, single_loops, loops, derived, mapping = cache_read("Space",
@@ -4317,7 +4313,7 @@ class Space(Operator):
         # cleaning up
         if derived:
             bm_mod.free()
-        terminate(global_undo)
+        terminate()
 
         return{'FINISHED'}