fix(learn): example rows drop another profile's null features when written and read

Static-profile feature records carry the nine plane-only features (agree.*,
ms.*, verify.*) as null in x; after cb85542 the 937 live example rows loaded,
but the renderer's validate_x refused every one of them ("features outside the
static allow-list"), so no program could prepare a prompt (found while probing
exp-002 model-free). profile_x drops a null feature outside the row's profile
and keeps a valued one, so a real leak still fails. Test added.

Co-Authored-By: Claude Fable 5.1 <[email protected]>
Claude-Session: https://claude.ai/code/session_01EmM1j46qgKMh3zqD1QMwEo

src/openultrasast/learn/examples.py

@@ -40,6 +40,16 @@ from typing import Any
 from ..plane.memory import MemoryStore, repo_key, row_id
 from .excerpt import EXAMPLE, Bounds, delta_diff, excerpt, function_bounds, identities_of
 from .labels import Label, Sources
+from .schema import features_for
+
+
+def profile_x(x: Mapping[str, Any], profile: str) -> dict[str, Any]:
+    """``x`` without another profile's features stored as null: a static feature record carries the plane-only
+    features (``agree.*``, ``ms.*``, ``verify.*``) as null, and :func:`.schema.validate_x` refuses a name outside
+    the profile's allow-list whatever its value. A foreign feature with a value stays, so the refusal still fires."""
+    known = {spec.name for spec in features_for(profile)}
+    return {k: v for k, v in x.items() if v is not None or k in known}
+
 
 EXAMPLE_KIND = "example"
 RUN = "learn-memory"
@@ -208,7 +218,8 @@ def build_examples(
                 "frameworks": list(label["frameworks"]) if label.get("frameworks") is not None else None, "unit": unit,
                 "direction": label.get("direction"), "pin_role": label.get("pin_role", "vulnerable"),
                 "weight": float(label.get("weight", 1.0)), "license": (license_of(label) if license_of else "") or "",
-                "x": dict(record["x"]), "instruments": {k: dict(v) for k, v in record["instruments"].items() if v is not None},
+                "x": profile_x(record["x"], profile),
+                "instruments": {k: dict(v) for k, v in record["instruments"].items() if v is not None},
                 "roles": list(roles_of(label)) if roles_of else [], "excerpt_sha": shown.sha, "label_set_digest": digest,
             }
         )  # fmt: skip
@@ -238,13 +249,14 @@ class Example:
     license: str = ""
 
     @classmethod
-    # An instrument that is not part of the row's profile may be stored as null (feature records carry every
-    # instrument name); it is not a table and is skipped, both when a row is written and when it is read.
+    # An instrument or a feature that is not part of the row's profile may be stored as null (feature records carry
+    # every instrument and feature name); both are skipped when a row is written and when it is read.
     def from_row(cls, row: Mapping[str, Any]) -> Example:
+        profile = str(row.get("profile") or "static")
         return cls(
             id=str(row["id"]), group=str(row.get("group") or ""), source=str(row["source"]), frameworks=tuple(row.get("frameworks") or ()),
             family=str(row["family"]), label=int(row["label"]), language=str(row.get("language") or "other"),
-            profile=str(row.get("profile") or "static"), unit=str(row.get("unit") or "pin"), x=dict(row["x"]),
+            profile=profile, unit=str(row.get("unit") or "pin"), x=profile_x(row["x"], profile),
             instruments={k: dict(v) for k, v in row["instruments"].items() if v is not None}, roles=tuple(row.get("roles") or ()),
             excerpt_sha=str(row["excerpt_sha"]), license=str(row.get("license") or ""),
         )  # fmt: skip

tests/test_learn_examples.py

@@ -229,3 +229,27 @@ def test_null_instruments_are_skipped_when_reading_and_writing() -> None:
     }  # fmt: skip
     example = Example.from_row(row)
     assert set(example.instruments) == {"language"}
+
+
+def test_null_foreign_features_are_skipped_but_a_valued_one_stays() -> None:
+    """Every live static example row (937 on 2026-10-02) carried the nine plane-only features as null in ``x``; the
+    renderer's ``validate_x`` refused them all. A foreign feature with a value is a leak and must still reach it."""
+    from openultrasast.learn.examples import Example, profile_x
+    from openultrasast.learn.schema import features_for
+
+    static = {spec.name for spec in features_for("static")}
+    plane_only = sorted({spec.name for spec in features_for("plane")} - static)
+    kept = sorted(static)[0]  # a static feature stored as null (its instrument failed) is kept for validate_x
+    assert "verify.votes" in plane_only
+    x: dict[str, object] = {name: None for name in plane_only}
+    x[kept] = None
+    assert profile_x(x, "static") == {kept: None}
+    assert profile_x({**x, "verify.votes": 3}, "static") == {kept: None, "verify.votes": 3}
+    row = {
+        "id": "x", "kind": "example", "repo": "o/r", "pin": "p", "run": "learn-memory", "task": "build", "population": "pairs",
+        "split": "train", "image": "host", "candidate": "a.py::f", "family": "injection", "language": "python",
+        "profile": "static", "label": 1, "source": "pairs", "group": "o/r", "frameworks": None, "unit": "pin",
+        "direction": None, "pin_role": "vulnerable", "weight": 1.0, "license": "MIT", "x": x,
+        "instruments": {"language": {"state": "ran"}, "verify": None}, "roles": [], "excerpt_sha": "0" * 64, "label_set_digest": "1" * 64,
+    }  # fmt: skip
+    assert set(Example.from_row(row).x) == {kept}