From 3e66c7869424563b2373498381124a5b65772f96 Mon Sep 17 00:00:00 2001
From: Jens <jens@localhost>
Date: Thu, 30 Jul 2026 01:27:05 +0200
Subject: [PATCH] Harden regional dataset split validation

---
 scripts/build_regional_yolo_dataset.py    | 43 +++++++++++++++++++----
 tests/test_build_regional_yolo_dataset.py | 12 +++++++
 2 files changed, 49 insertions(+), 6 deletions(-)

diff --git a/scripts/build_regional_yolo_dataset.py b/scripts/build_regional_yolo_dataset.py
index cd1a5fb6..c1bd5298 100644
--- a/scripts/build_regional_yolo_dataset.py
+++ b/scripts/build_regional_yolo_dataset.py
@@ -46,11 +46,17 @@ def build(
         if sample is None:
             unknown.append(tile["sample_slug"])
             continue
-        split = str(tile.get("split") or sample.get("split") or "")
-        if split in PROTECTED_SPLITS:
+        tile_split = str(tile.get("split") or "")
+        manifest_split = str(sample.get("split") or "")
+        if tile_split in PROTECTED_SPLITS or manifest_split in PROTECTED_SPLITS:
             protected.append(tile["sample_slug"])
             continue
-        if sample.get("region") == region and split in {"train", "val"}:
+        if tile_split != manifest_split:
+            raise ValueError(
+                f"tile/manifest split mismatch for {tile['sample_slug']}: "
+                f"{tile_split!r} != {manifest_split!r}"
+            )
+        if sample.get("region") == region and tile_split in {"train", "val"}:
             selected.append((tile, sample))
     if unknown:
         raise ValueError(f"summary references unknown samples: {sorted(set(unknown))}")
@@ -98,6 +104,31 @@ def build(
     return train, val, evidence
 
 
+def select_paths(
+    summary: dict[str, Any], manifest: dict[str, Any], region: str
+) -> tuple[list[str], list[str]]:
+    """Backward-compatible unweighted regional selection API."""
+    samples = {item["sample_slug"]: item for item in manifest["samples"]}
+    compatible_summary = {
+        **summary,
+        "tiles": [
+            tile
+            for tile in summary["tiles"]
+            if tile["sample_slug"] in samples
+            and samples[tile["sample_slug"]].get("split") in {"train", "val"}
+        ],
+    }
+    train, val, _evidence = build(
+        summary=compatible_summary,
+        manifest=manifest,
+        region=region,
+        priority_contexts=set(),
+        priority_repeat=1,
+        negative_repeat=1,
+    )
+    return sorted(train), sorted(val)
+
+
 def main() -> int:
     parser = argparse.ArgumentParser()
     parser.add_argument("--summary", type=Path, required=True)
@@ -139,9 +170,9 @@ def main() -> int:
         "validation_sha256": sha256(val_path),
         "dataset_yaml": str(yaml_path),
     })
-    (args.output_dir / "regional-dataset-evidence.json").write_text(
-        json.dumps(evidence, indent=2), encoding="utf-8"
-    )
+    encoded_evidence = json.dumps(evidence, indent=2)
+    (args.output_dir / "regional-dataset-evidence.json").write_text(encoded_evidence, encoding="utf-8")
+    (args.output_dir / "regional-dataset.json").write_text(encoded_evidence, encoding="utf-8")
     print(json.dumps(evidence, indent=2))
     return 0
 
diff --git a/tests/test_build_regional_yolo_dataset.py b/tests/test_build_regional_yolo_dataset.py
index 9443e3a3..82d03ca5 100644
--- a/tests/test_build_regional_yolo_dataset.py
+++ b/tests/test_build_regional_yolo_dataset.py
@@ -45,3 +45,15 @@ def test_regional_dataset_rejects_protected_tiles() -> None:
             summary=summary, manifest=manifest, region="flanders",
             priority_contexts=set(), priority_repeat=1, negative_repeat=1,
         )
+
+
+def test_regional_dataset_rejects_manifest_protection_hidden_by_tile_split() -> None:
+    manifest = {"samples": [
+        {"sample_slug": "f-cal", "region": "flanders", "split": "calibration", "context": "ribbon"},
+    ]}
+    summary = {"tiles": [{"sample_slug": "f-cal", "split": "train", "image_path": "/cal.png"}]}
+    with pytest.raises(ValueError, match="protected"):
+        module.build(
+            summary=summary, manifest=manifest, region="flanders",
+            priority_contexts=set(), priority_repeat=1, negative_repeat=1,
+        )