The extra depsgraph relations that were added to prevent threading issues during evaluation (rB4c30dc343165) caused a considerable slowdown on complex scenes with many drivers (T77277, T78615). This commit improves this as follows. Only the following drivers are considered for execution serialisation: - Drivers on Array elements, and - Drivers on Boolean or Enum properties. Relations between drivers of the same arrays are added blindly, i.e. without checking for transitive or cyclic relations. This is possible as other relations will just target the `PROPERTIES_ENTRY` or `PROPERTIES_EXIT` nodes. Checking whether a driver is on an array is first done by checking `array_index > 0`, and then falling back to resolving the RNA path to an RNA property and inspecting that. The code also avoids circular dependencies when there are multiple drivers on the same property. This not something that is expected to happen (both the UI and the Python API prevent duplicate drivers), it did happen in a file (F8669945, example file of T78615) and it is easy to deal with here. Reviewers: sergey Subscribers: mont29 Comment update