fix(tracing): snapshot mutable evolution trace payloads

openevolve/evolution_trace.py

@@ -8,6 +8,7 @@
 import json
 import logging
 import time
+from copy import deepcopy
 from dataclasses import asdict, dataclass
 from pathlib import Path
 from typing import Any, Dict, List, Optional, Union
@@ -164,12 +165,12 @@ def log_trace(
                 timestamp=time.time(),
                 parent_id=parent_program.id,
                 child_id=child_program.id,
-                parent_metrics=parent_program.metrics,
-                child_metrics=child_program.metrics,
+                parent_metrics=deepcopy(parent_program.metrics),
+                child_metrics=deepcopy(child_program.metrics),
                 island_id=island_id,
                 generation=child_program.generation,
-                artifacts=artifacts,
-                metadata=metadata,
+                artifacts=deepcopy(artifacts),
+                metadata=deepcopy(metadata),
             )
 
             # Optionally include code
@@ -179,12 +180,16 @@ def log_trace(
 
             # Changes descriptions (large-codebase mode)
             if self.include_changes_description:
-                trace.parent_changes_description = getattr(parent_program, "changes_description", None)
-                trace.child_changes_description = getattr(child_program, "changes_description", None)
+                trace.parent_changes_description = getattr(
+                    parent_program, "changes_description", None
+                )
+                trace.child_changes_description = getattr(
+                    child_program, "changes_description", None
+                )
 
             # Optionally include prompts
             if self.include_prompts:
-                trace.prompt = prompt
+                trace.prompt = deepcopy(prompt)
                 trace.llm_response = llm_response
 
             # Calculate improvement
@@ -294,7 +299,9 @@ def close(self):
                     "created_at": time.time(),
                     "include_code": self.include_code,
                     "include_prompts": self.include_prompts,
-                    "include_changes_description": getattr(self, "include_changes_description", True),
+                    "include_changes_description": getattr(
+                        self, "include_changes_description", True
+                    ),
                 }
                 export_traces(all_traces, self.output_path, format="hdf5", metadata=metadata)
 

tests/test_evolution_trace_snapshots.py

@@ -0,0 +1,88 @@
+"""Regression tests for evolution traces recorded from reused mutable payloads."""
+
+import json
+import tempfile
+import unittest
+from pathlib import Path
+
+from openevolve.database import Program
+from openevolve.evolution_trace import EvolutionTracer
+
+
+class TestEvolutionTraceSnapshots(unittest.TestCase):
+    def test_reused_program_metrics_preserve_each_transition(self):
+        for format, buffer_size in (("jsonl", 1), ("jsonl", 10), ("json", 1), ("json", 10)):
+            with (
+                self.subTest(format=format, buffer_size=buffer_size),
+                tempfile.TemporaryDirectory() as directory,
+            ):
+                path = Path(directory) / f"trace.{format}"
+                parent = Program(id="parent", code="pass", metrics={"combined_score": 1.0})
+                child = Program(id="child", code="pass", metrics={"combined_score": 3.0})
+                with EvolutionTracer(str(path), format=format, buffer_size=buffer_size) as tracer:
+                    tracer.log_trace(1, parent, child)
+                    parent.metrics["combined_score"] = 10.0
+                    child.metrics["combined_score"] = 30.0
+                    tracer.log_trace(2, parent, child)
+                    parent.metrics.clear()
+                    child.metrics["combined_score"] = 100.0
+
+                if format == "jsonl":
+                    traces = [json.loads(line) for line in path.read_text().splitlines()]
+                else:
+                    traces = json.loads(path.read_text())["traces"]
+                self.assertEqual(len(traces), 2)
+                for trace, parent_score, child_score in zip(traces, (1.0, 10.0), (3.0, 30.0)):
+                    self.assertEqual(trace["parent_metrics"], {"combined_score": parent_score})
+                    self.assertEqual(trace["child_metrics"], {"combined_score": child_score})
+                    self.assertEqual(
+                        trace["improvement_delta"], {"combined_score": child_score - parent_score}
+                    )
+                self.assertEqual(
+                    tracer.get_statistics()["total_improvement"], {"combined_score": 22.0}
+                )
+
+    def test_prompt_artifacts_and_metadata_are_deep_snapshots(self):
+        with tempfile.TemporaryDirectory() as directory:
+            path = Path(directory) / "trace.jsonl"
+            parent = Program(id="parent", code="pass")
+            child = Program(id="child", code="pass")
+            prompt = {"system": "original"}
+            artifacts = {"evaluation": {"messages": ["original"]}}
+            metadata = {"worker": {"attempts": [1]}}
+            with EvolutionTracer(str(path), buffer_size=10) as tracer:
+                tracer.log_trace(
+                    1, parent, child, prompt=prompt, artifacts=artifacts, metadata=metadata
+                )
+                prompt["system"] = "changed"
+                artifacts["evaluation"]["messages"].append("changed")
+                metadata["worker"]["attempts"].append(2)
+                tracer.log_trace(
+                    2, parent, child, prompt=prompt, artifacts=artifacts, metadata=metadata
+                )
+                prompt.clear()
+                artifacts.clear()
+                metadata.clear()
+
+            first, second = [json.loads(line) for line in path.read_text().splitlines()]
+            self.assertEqual(first["prompt"], {"system": "original"})
+            self.assertEqual(first["artifacts"], {"evaluation": {"messages": ["original"]}})
+            self.assertEqual(first["metadata"], {"worker": {"attempts": [1]}})
+            self.assertEqual(second["prompt"], {"system": "changed"})
+            self.assertEqual(
+                second["artifacts"], {"evaluation": {"messages": ["original", "changed"]}}
+            )
+            self.assertEqual(second["metadata"], {"worker": {"attempts": [1, 2]}})
+
+    def test_excluded_prompts_stay_out_of_trace(self):
+        with tempfile.TemporaryDirectory() as directory:
+            path = Path(directory) / "trace.jsonl"
+            parent = Program(id="parent", code="pass")
+            child = Program(id="child", code="pass")
+            with EvolutionTracer(str(path), include_prompts=False) as tracer:
+                tracer.log_trace(
+                    1, parent, child, prompt={"system": "private"}, llm_response="private"
+                )
+            trace = json.loads(path.read_text())
+            self.assertNotIn("prompt", trace)
+            self.assertNotIn("llm_response", trace)