fix(context): preserve images with duplicate basenames

harness2/core/context.py

@@ -247,9 +247,9 @@ def _write_rollout(dest: Path, r: RunView, adapter, trunc: int, names_only: bool
 
     d = dest / "deliverables" / r.label
     d.mkdir(parents=True, exist_ok=True)
-    for img in _images(adapter, r.run_dir)[:8]:
+    for index, img in enumerate(_images(adapter, r.run_dir)[:8], 1):
         try:
-            t = d / "images" / Path(img).name
+            t = d / "images" / f"{index}-{Path(img).name}"
             t.parent.mkdir(parents=True, exist_ok=True)
             shutil.copy2(img, t)
         except OSError:

tests/test_context_images.py

@@ -0,0 +1,91 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Image evidence survives copying from a JobBench rollout into its context."""
+
+import struct
+import tempfile
+import unittest
+import zlib
+from pathlib import Path
+from unittest.mock import patch
+
+from harness2 import config
+from harness2.benchmarks.jobbench import JobBenchAdapter
+from harness2.core import context
+from harness2.core.spec import RunView
+
+
+def png(red: int) -> bytes:
+    def chunk(kind, data):
+        checksum = zlib.crc32(kind + data)
+        return struct.pack(">I", len(data)) + kind + data + struct.pack(">I", checksum)
+
+    return (
+        b"\x89PNG\r\n\x1a\n"
+        + chunk(b"IHDR", struct.pack(">2I5B", 1, 1, 8, 2, 0, 0, 0))
+        + chunk(b"IDAT", zlib.compress(bytes([0, red, 0, 0])))
+        + chunk(b"IEND", b"")
+    )
+
+
+class ContextImagesTests(unittest.TestCase):
+    def setUp(self):
+        temporary = tempfile.TemporaryDirectory()
+        self.addCleanup(temporary.cleanup)
+        self.root = Path(temporary.name)
+        self.task_id = "analysts/task1"
+        dependencies = self.root / "dependencies"
+        location = patch.object(config, "DEPENDENCIES", dependencies)
+        location.start()
+        self.addCleanup(location.stop)
+        task = dependencies / "job-bench-eval/dataset/main" / self.task_id / "task_folder"
+        task.mkdir(parents=True)
+        (task / "TASK_INSTRUCTIONS.txt").write_text("Prepare quarterly charts.", encoding="utf-8")
+        self.adapter = JobBenchAdapter(store_root=self.root / "store")
+        self.run = self.root / "store" / self.task_id / "model_output/agg1"
+        self.run.mkdir(parents=True)
+
+    def check_images(self, names):
+        originals = []
+        for index, name in enumerate(names, 1):
+            image = self.run / name
+            image.parent.mkdir(parents=True, exist_ok=True)
+            data = png(index)
+            image.write_bytes(data)
+            originals.append(data)
+        self.assertEqual(len(self.adapter.deliverable_images(self.run)), len(names))
+        evidence = context.build(
+            self.root / "context",
+            self.adapter,
+            self.task_id,
+            [RunView("agg1", "run1", self.run, True, True)],
+        )
+        images = evidence.root / "deliverables/agg1/images"
+        copied = [image.read_bytes() for image in images.iterdir()]
+        self.assertCountEqual(copied, originals)
+        self.assertEqual(len(copied), len(names))
+
+    def test_same_basename_images_are_preserved(self):
+        self.check_images(["Q1/chart.png", "Q2/chart.png"])
+
+    def test_distinct_basename_images_are_preserved(self):
+        self.check_images(["Q1/chart.png", "Q2/other.png"])
+
+    def test_numbered_source_names_do_not_collide(self):
+        self.check_images(["Q1/chart.png", "Q2/1-chart.png", "Q3/chart.png"])
+
+
+if __name__ == "__main__":
+    unittest.main()