fix: restore stage-based Alpha check classification

backend/migrations/versions/0019_check_stages.py

@@ -0,0 +1,91 @@
+"""Restore stage-based check classification, preserving raw platform snapshots."""
+
+from datetime import datetime, timezone
+
+import sqlalchemy as sa
+from alembic import op
+
+revision = "0019"
+down_revision = "0018"
+branch_labels = None
+depends_on = None
+
+
+def timestamp(value):
+    """Read historical timestamps; missing or invalid evidence cannot prove a /check."""
+    try:
+        value = datetime.fromisoformat(value) if isinstance(value, str) else value
+        return value.replace(tzinfo=timezone.utc) if value.tzinfo is None else value
+    except (ValueError, TypeError, AttributeError):
+        return None
+
+
+def classify(checks, checked, legacy):
+    """Frozen migration rules; legacy means the pre-0019 correlation-presence rule."""
+    checks = checks if isinstance(checks, list) else []
+    checks = [c for c in checks if not (isinstance(c, dict) and c.get("name") == "REGULAR_SUBMISSION")]
+    valid = [c for c in checks if isinstance(c, dict)]
+    results = [c.get("result") for c in valid]
+    if not legacy:
+        results = [v.upper() if isinstance(v, str) else None for v in results]
+    failures = sum(v == "FAIL" for v in results)
+    if failures:
+        return "FAIL_1" if failures == 1 else "FAIL_2"
+    allowed = ("PASS",) if legacy else ("PASS", "PENDING", "WARNING")
+    if not checks or len(valid) != len(checks) or any(v not in allowed for v in results):
+        return "PENDING"
+    passed = any(c.get("name") == "PROD_CORRELATION" for c in valid) if legacy else checked
+    return "PASS" if passed else "PRE_CHECK"
+
+
+def reclassify(legacy=False):
+    """Recompute in batches; only a check checkpoint newer than the sync proves its stage.
+
+    A prior PASS is not evidence because the old rule inferred it from a check name.
+    A subsequent sync replaces the snapshot and is classified as pre-check again.
+    """
+    alphas = sa.table("alphas", sa.column("id", sa.String()), sa.column("checks", sa.JSON()),
+                      sa.column("synced_at", sa.DateTime(timezone=True)), sa.column("check_type", sa.String()))
+    jobs = sa.table("sync_jobs", sa.column("kind", sa.String()), sa.column("payload", sa.JSON()),
+                    sa.column("checkpoint", sa.JSON()))
+    connection = op.get_bind()
+    last_id = None
+    while True:
+        query = sa.select(alphas.c.id, alphas.c.checks, alphas.c.synced_at).order_by(alphas.c.id).limit(500)
+        if last_id is not None:
+            query = query.where(alphas.c.id > last_id)
+        rows = connection.execute(query).mappings().all()
+        if not rows:
+            break
+        checked_at = {}
+        if not legacy:
+            observations = connection.execute(sa.select(jobs.c.checkpoint).where(
+                jobs.c.kind == "submission_check",
+                jobs.c.payload["alpha_ids"][0].as_string().in_([r["id"] for r in rows]),
+            )).scalars()
+            for checkpoint in observations:
+                if not isinstance(checkpoint, dict) or checkpoint.get("phase") != "checked":
+                    continue
+                alpha_id = checkpoint.get("alpha_id")
+                observed = timestamp(checkpoint.get("checked_at"))
+                if isinstance(alpha_id, str) and observed and (
+                    alpha_id not in checked_at or observed > checked_at[alpha_id]
+                ):
+                    checked_at[alpha_id] = observed
+        updates = []
+        for row in rows:
+            synced = timestamp(row["synced_at"])
+            observed = checked_at.get(row["id"])
+            updates.append({"snapshot_id": row["id"], "classification": classify(
+                row["checks"], bool(synced and observed and observed > synced), legacy)})
+        connection.execute(alphas.update().where(alphas.c.id == sa.bindparam("snapshot_id"))
+                           .values(check_type=sa.bindparam("classification")), updates)
+        last_id = rows[-1]["id"]
+
+
+def upgrade():
+    reclassify()
+
+
+def downgrade():
+    reclassify(legacy=True)