CP-SAT returns two copies of the same solution

[jeremydover]

What version of OR-Tools and what language are you using?
Version: 9.10.4067
Language: Python

Which solver are you using (e.g. CP-SAT, Routing Solver, GLOP, BOP, Gurobi)
CP-SAT

What operating system (Linux, Windows, ...) and version?
Windows 10

What did you do?
Steps to reproduce the behavior:

1. Execute attached code.
   bug-report.txt

What did you expect to see
The code should have produced a single solution.

What did you see instead?
The code produces two copies of the same solution. All model variables in the solution are identical.

[lperron]

are you sure all the variables you have created are equal ? Or only the one you display.
It is easy to have a dandling Boolean variable that can be equally true or false for the same assignment of the primary variables.

[jeremydover]

I'm definitely aware of the dangling Boolean issue, and I am sure I looked for it, but will look again this evening. I am fairly confident that I'm displaying all variables that are created, but again I will double check.

[lperron]

even the ones created in __varBitmap ?

To make sure, compare len(model.proto.variables) and len(self.allVars)

[jeremydover]

D'oh! Confirmed this is a bug on my part...found the logic error. Sorry for misplacing blame!