'CMAEvolutionStrategy' object has no attribute 'integer_mutations' when using bounds on parameters

[jagerber48]

I'm hitting this error when I run this simple optimization

import nevergrad as ng

params_dict = {}
params_dict['param_1'] = ng.p.Scalar(lower=-0.1, upper=0.1)
params_dict['param_2'] = ng.p.Scalar(lower=-0.1, upper=0.1)
params_dict['param_3'] = ng.p.Scalar(lower=-0.1, upper=0.1)
param_space = ng.p.Dict(**params_dict)

budget = 150

optimizer = ng.optimizers.CMA(parametrization=param_space, budget=budget)

cost_func = lambda x: sum(map(float, x.values()))

for step in range(optimizer.budget):
    print(step)
    candidate = optimizer.ask()
    value = cost_func(candidate.value)
    optimizer.tell(candidate, value)

After a few iterations, I get the error

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
Cell In[30], line 19
     17 candidate = optimizer.ask()
     18 value = cost_func(candidate.value)
---> 19 optimizer.tell(candidate, value)

File [...\Lib\site-packages\nevergrad\optimization\base.py:426](http://localhost:8888/lab/tree/.../Lib/site-packages/nevergrad/optimization/base.py#line=425), in Optimizer.tell(self, candidate, loss, constraint_violation, penalty_style)
    423     self._update_archive_and_bests(candidate, loss)
    425 if candidate.uid in self._asked:
--> 426     self._internal_tell_candidate(candidate, loss)
    427     self._asked.remove(candidate.uid)
    428 else:

File [...\Lib\site-packages\nevergrad\optimization\optimizerlib.py:965](http://localhost:8888/lab/tree/.../Lib/site-packages/nevergrad/optimization/optimizerlib.py#line=964), in ChoiceBase._internal_tell_candidate(self, candidate, loss)
    964 def _internal_tell_candidate(self, candidate: p.Parameter, loss: tp.FloatLoss) -> None:
--> 965     self.optim.tell(candidate, loss)

File [...\Lib\site-packages\nevergrad\optimization\base.py:426](http://localhost:8888/lab/tree/.../Lib/site-packages/nevergrad/optimization/base.py#line=425), in Optimizer.tell(self, candidate, loss, constraint_violation, penalty_style)
    423     self._update_archive_and_bests(candidate, loss)
    425 if candidate.uid in self._asked:
--> 426     self._internal_tell_candidate(candidate, loss)
    427     self._asked.remove(candidate.uid)
    428 else:

File [...\Lib\site-packages\nevergrad\optimization\optimizerlib.py:817](http://localhost:8888/lab/tree/.../Lib/site-packages/nevergrad/optimization/optimizerlib.py#line=816), in _CMA._internal_tell_candidate(self, candidate, loss)
    815 args = (listy, listx) if self._config.fcmaes else (listx, listy)
    816 try:
--> 817     self.es.tell(*args)
    818 except (RuntimeError, AssertionError):
    819     pass

File [...\Lib\site-packages\cma\evolution_strategy.py:2272](http://localhost:8888/lab/tree/.../Lib/site-packages/cma/evolution_strategy.py#line=2271), in CMAEvolutionStrategy.tell(self, solutions, function_values, check_points, copy)
   2270 # sort pop for practicability, now pop != self.pop, which is unsorted
   2271 pop = np.asarray(pop)[fit.idx]  # array is used for weighted recombination
-> 2272 injected_solutions_indices = self._clean_injected_solutions_archive(pop)
   2274 # prepend best-ever solution to population, in case
   2275 # note that pop and fit.fit do not agree anymore in this case
   2276 prepended_solutions = 0

File [...\Lib\site-packages\cma\evolution_strategy.py:2659](http://localhost:8888/lab/tree/.../Lib/site-packages/cma/evolution_strategy.py#line=2658), in CMAEvolutionStrategy._clean_injected_solutions_archive(self, pop)
   2657 for k, s in list(self._injected_solutions_archive.items()):
   2658     if s['iteration'] < self.countiter - 2:
-> 2659         if self.integer_mutations.is_none:  # integer_mutations removes some bad solutions
   2660             # warn unless TPA injections were messed up by integer centering
   2661             if (not isinstance(self.adapt_sigma, CMAAdaptSigmaTPA)
   2662                     # self.integer_centering and
   2663                     # self.integer_centering is not _pass and
   2664                 # or not isinstance(self.integer_centering, IntegerCentering)
   2665                 or s['index'] > 1):
   2666                 warnings.warn("""orphanated injected solution %s
   2667                     This could be a bug in the calling order/logics or due to
   2668                     a too small popsize used in `ask()` or when only using
   (...)   2671                     ``warnings.simplefilter("ignore", cma.evolution_strategy.InjectionWarning)``
   2672                     """ % str(s), InjectionWarning)

AttributeError: 'CMAEvolutionStrategy' object has no attribute 'integer_mutations'

The issue is caused by the lower and upper bounds on the parameters. If I remove the bounds I don't hit this error. Is this known/expected behavior that is documented somewhere? e.g. that I shouldn't use bounds on the CMA model?