Find out if Mesh Operator (bpy.ops.mesh...) was cancelled or not via python I am using bpy.ops.mesh.extrude_region_move to extrude a selected region along their averaged normal. I don't set the value-component of TRANSFORM_OT_translate, so the operator is modal. The return-value of the operator is not {'CANCELLED'} or {'FINISHED'} it's {'RUNNING_MODAL'}.
The user can accept the extrusion with enter or cancel it via esc (normal behaviour of that operator). 

My blender-addon needs to know if the user has accepted a extrusion or if it was cancelled (The addon stores the face-ids of a selected region. If the user now extrudes the face ids are recreated. Therefore I need to update the stored face-ids. But I need to know 'when').

Any ideas how I can find out if the extrude_region_move was cancelled/not cancelled?

Thanks!
This looks at the TRANSFORM_OT_translate.value Vector as shown in the 'INFO' reports.  If the operator was cancelled it returns (0, 0, 0) else has a length.

import bpy

wm = bpy.context.window_manager

print("TESTing Extrude Op")
for op in wm.operators:
    if op.bl_idname == 'MESH_OT_extrude_region_move':  #name == 'Extrude Region and Move'
        print(op.name, "Found")
        v = op.macros['TRANSFORM_OT_translate'].properties.value
        if v.length:
            print("operator used")
        else:
            print("operator canceled")