[myhdl-list] Strange behaviour in traceSignals()

[David K. <dav...@in...>]

I am puzzled by traceSignals() generating 'Inconsistent hierarchy' 
messages with the following code, but not if badBehaviour is False.
Note that the print at line 32 gives the same structure in both cases, 
so its something I don't understand in the introspection.
I wanted to structure a collection of tests using a common library, and 
this (bad) behaviour gets in the way of a natural expression of reuse.

Example:

#!/usr/bin/python
# example of strange behaviour in traceSignals()
badBehaviour = True

from myhdl import *

def ClkDriver(clk, halfperiod=5):
     halfPeriod = delay(halfperiod)
     @always(halfPeriod)
     def driveClk():
         clk.next = 1 & ~clk
     return driveClk

def device_test(clk1, cd1):
     clk2 = Signal(0)
     cd2 = ClkDriver(clk2, halfperiod=3759) # in picoseconds to give 
7.5ns(133MHz) cycle
     if badBehaviour:
         return (cd2,)
     else:
         return cd1, cd2

def test():
     # make a clock generator
     clk1 = Signal(0)
     cd1 = ClkDriver(clk1, halfperiod=3759) # in picoseconds to give 
7.5ns(133MHz) cycle
     if badBehaviour:
         ret = (cd1,) + device_test(clk1, cd1)
     else:
         ret = device_test(clk1, cd1)
     print ret
     return ret

def process(timesteps):
     # wrap in a tracer for vcd output
     tr_out = traceSignals(test)
     # simulate
     sim = Simulation(tr_out)
     sim.run(timesteps)

if __name__ == '__main__':
     timesteps = 1000
     process(timesteps)

Dave Kitchen