From 7803727e4a436c845163de85654721eaaabb10cf Mon Sep 17 00:00:00 2001
From: Liu Hao <169072815+lll-hhh@users.noreply.github.com>
Date: Thu, 29 Oct 2026 16:59:02 +0800
Subject: [PATCH] fix(map-elites): reject non-finite fitness and descriptors

---
 evoagentx/optimizers/map_elites_optimizer.py  | 11 ++-
 .../test_map_elites_finite_metrics.py         | 69 +++++++++++++++++++
 2 files changed, 78 insertions(+), 2 deletions(-)
 create mode 100644 tests/src/optimizers/test_map_elites_finite_metrics.py

diff --git a/evoagentx/optimizers/map_elites_optimizer.py b/evoagentx/optimizers/map_elites_optimizer.py
index f135733b..47653032 100644
--- a/evoagentx/optimizers/map_elites_optimizer.py
+++ b/evoagentx/optimizers/map_elites_optimizer.py
@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import copy
+import math
 import random
 from dataclasses import dataclass
 from typing import Any, Callable, Dict, List, Mapping, Optional, Tuple, Union
@@ -121,7 +122,10 @@ def _evaluate(self, output: Dict[str, Any]) -> Tuple[Metrics, float]:
         fitness = metrics[self.fitness_key]
         if not isinstance(fitness, (int, float)) or isinstance(fitness, bool):
             raise TypeError(f"fitness_key '{self.fitness_key}' must be numeric")
-        return metrics, float(fitness)
+        fitness = float(fitness)
+        if not math.isfinite(fitness):
+            raise ValueError(f"fitness_key '{self.fitness_key}' must be finite")
+        return metrics, fitness
 
     def _bins_for_dim(self, dim: str) -> int:
         if isinstance(self.feature_bins, int):
@@ -139,9 +143,12 @@ def _cell_from_metrics(self, metrics: Metrics) -> Tuple[int, ...]:
             value = metrics[dim]
             if not isinstance(value, (int, float)) or isinstance(value, bool):
                 raise TypeError(f"feature dimension '{dim}' must be numeric")
+            value = float(value)
+            if not math.isfinite(value):
+                raise ValueError(f"feature dimension '{dim}' must be finite")
             lo, hi = self.feature_ranges[dim]
             bins = max(1, self._bins_for_dim(dim))
-            coords.append(self._bin_index(float(value), lo, hi, bins))
+            coords.append(self._bin_index(value, lo, hi, bins))
         return tuple(coords)
 
     @staticmethod
diff --git a/tests/src/optimizers/test_map_elites_finite_metrics.py b/tests/src/optimizers/test_map_elites_finite_metrics.py
new file mode 100644
index 00000000..f3083c03
--- /dev/null
+++ b/tests/src/optimizers/test_map_elites_finite_metrics.py
@@ -0,0 +1,69 @@
+"""Exercise numeric validation through the actual MAP-Elites search loop."""
+
+import math
+
+import pytest
+
+from evoagentx.optimizers.engine.registry import ParamRegistry
+from evoagentx.optimizers.map_elites_optimizer import MapElitesOptimizer
+
+
+def make_optimizer(evaluator, *, scalar_result=False):
+    """Construct a deterministic search that requires no model or network."""
+    return MapElitesOptimizer(
+        registry=ParamRegistry(),
+        evaluator=evaluator,
+        search_space={},
+        feature_dimensions=[] if scalar_result else ["length"],
+        feature_ranges={} if scalar_result else {"length": (0.0, 2.0)},
+        n_iterations=2,
+        program=dict,
+    )
+
+
+@pytest.mark.parametrize("fitness", [float("nan"), float("inf"), float("-inf")])
+@pytest.mark.parametrize("scalar_result", [False, True])
+def test_nonfinite_fitness_is_rejected_before_archive_admission(fitness, scalar_result):
+    """Invalid fitness must not become an unbeatable elite or best candidate."""
+    result = fitness if scalar_result else {"score": fitness, "length": 1.0}
+    optimizer = make_optimizer(lambda output: result, scalar_result=scalar_result)
+
+    with pytest.raises(ValueError, match="fitness_key 'score' must be finite"):
+        optimizer.optimize()
+
+
+@pytest.mark.parametrize("value", [float("nan"), float("inf"), float("-inf")])
+def test_nonfinite_feature_is_rejected_before_binning(value):
+    """Infinite descriptors must not be silently clipped into boundary cells."""
+    optimizer = make_optimizer(lambda output: {"score": 1.0, "length": value})
+
+    with pytest.raises(ValueError, match="feature dimension 'length' must be finite"):
+        optimizer.optimize()
+
+
+@pytest.mark.parametrize("fitness", [-2.0, 0.0, 2.0])
+@pytest.mark.parametrize("length, cell", [(-1.0, (0,)), (0.0, (0,)), (1.0, (5,)), (2.0, (9,)), (3.0, (9,))])
+def test_finite_scores_and_clipped_descriptors_keep_their_behavior(fitness, length, cell):
+    """Signed fitness and finite out-of-range descriptors remain supported."""
+    optimizer = make_optimizer(lambda output: {"score": fitness, "length": length})
+
+    best_cfg, result = optimizer.optimize()
+
+    assert best_cfg == {}
+    assert result["best"].fitness == fitness
+    assert result["best"].cell == cell
+    assert list(result["archive"]) == [cell]
+    assert [row["accepted"] for row in result["history"]] == [True, False]
+    assert math.isfinite(result["best"].fitness)
+
+
+def test_later_finite_improvement_replaces_an_elite():
+    """Validation must preserve the optimizer's replacement and best tracking."""
+    scores = iter([-1.0, 1.0])
+    optimizer = make_optimizer(lambda output: {"score": next(scores), "length": 1.0})
+
+    _, result = optimizer.optimize()
+
+    assert [row["accepted"] for row in result["history"]] == [True, True]
+    assert result["best"].fitness == 1.0
+    assert result["archive"][(5,)].fitness == 1.0