Windows 10, NVidia GTX970
Short description of error
I have a series of motion graphics templates that were created in earlier Blender versions. I know it worked fine in 2.74, and now with 2.79 drivers report invalid python expression. Expression is this:
where text_width is variable taking dimensions.x value from a text object. Driver is influencing dimensions.x of an object based on text object dimensions.x. Value is calculated and displayed correctly in debug info, but driver doesn't execute.
What I found out is that I can no longer set a driver for dimensions and that is most likely causing this issue.
Exact steps for others to reproduce the error
Based on a (as simple as possible) attached .blend file with minimum amount of steps
Just create two cubes in previous version of Blender (I used 2.74) and set a single driver on X dimension property on second one (Cube.001). go to driver setup in graph editor, and set default var variable to be single property dimension.x of first Cube object. Use simple expression as driver and just type in "var". Scaling Cube, makes Cube.001 scale too as long as autoexecute python scripts is enabled.
Load that into 2.79 and it doesn't work. With Cube.001 selected, go to graph editor where dimensions.x driver is clearly listeg, but it says it's "Invalid Python Expression".
Attached .blend is done in 2.74.