feat(sp37): batch_envelope_index now resolves by ST02 or ISA13

Each 837p batch row contributes up to two entries to the join-key
index (envelope.control_number + transaction_set_control_number). One
idx.get(set_control_number) call resolves either, so 999 acks whose
AK201 echoes the source 837's ST02 now hit Pass 1 where they
previously fell through to Pass 2 (and to the orphan log).

Backward compat preserved: rows with transaction_set_control_number
NULL (pre-SP37 batches) still resolve by ISA13.

backend/src/cyclone/store/claim_acks.py

@@ -67,26 +67,43 @@ def _safe_publish(event_bus: "EventBus | None", kind: str, payload: dict) -> Non
 
 
 def batch_envelope_index() -> dict[str, str]:
-    """Build a ``{envelope.control_number: batch.id}`` map.
+    """Build a ``{key: batch.id}`` map populated from two columns.
 
-    D10 primary join key (spec §D10). Built once per ingest from
+    D10 primary join key (spec §D10). Each 837p batch row contributes
-    every Batch row whose ``raw_result_json`` carries an envelope —
+    up to two entries:
-    cost is O(N batches), currently ~16, so trivial. Kept as a
+
-    plain dict so callers can ``index.get(scn)`` to resolve.
+    * ``Batch.raw_result_json.envelope.control_number`` (ISA13)
+    * ``Batch.transaction_set_control_number`` (ST02, new in SP37)
+
+    Either key resolves to the same ``batch.id``; callers do a single
+    ``idx.get(set_control_number)`` lookup. Pass 2 (PCN) is unchanged.
+
+    Built once per ingest from every Batch row whose kind is "837p";
+    cost is O(N batches), currently small, so trivial. 835 batches
+    are excluded — the column is an 837P-specific join key (see
+    ``Batch.transaction_set_control_number`` docstring).
     """
-    out: dict[str, str] = {}
+    idx: dict[str, str] = {}
     with db.SessionLocal()() as s:
         rows = (
-            s.query(Batch.id, Batch.raw_result_json)
+            s.query(
+                Batch.id,
+                Batch.raw_result_json,
+                Batch.transaction_set_control_number,
+            )
             .filter(Batch.kind == "837p")
             .all()
         )
-        for bid, raw in rows:
+        for bid, raw, stcn in rows:
             env = (raw or {}).get("envelope") or {}
-            ctrl = env.get("control_number")
+            isa_cn = env.get("control_number")
-            if isinstance(ctrl, str) and ctrl:
+            if isinstance(isa_cn, str) and isa_cn:
-                out[ctrl] = bid
+                # First write wins (setdefault) — if ISA13 and ST02
-    return out
+                # ever collide they map to the same batch anyway.
+                idx.setdefault(isa_cn, bid)
+            if isinstance(stcn, str) and stcn:
+                idx.setdefault(stcn, bid)
+    return idx
 
 
 # ---------------------------------------------------------------------------

backend/tests/test_batch_envelope_index_sp37.py

@@ -0,0 +1,126 @@
+"""SP37 Task 3: batch_envelope_index populates from BOTH columns.
+
+The dict returned by ``batch_envelope_index`` should resolve lookups
+by EITHER ``Batch.raw_result_json.envelope.control_number`` (ISA13,
+preserved) OR ``Batch.transaction_set_control_number`` (ST02, new in
+SP37 Task 2). One dict, both keys — a single ``.get(set_control_number)``
+call hits whichever matches, so the D10 Pass 1 join in
+:func:`cyclone.claim_acks.lookup_claims_for_ack_set_response` resolves
+999 AK201 (which echoes the source 837's ST02) back to the right batch
+even when ST02 != ISA13.
+"""
+from __future__ import annotations
+
+from datetime import datetime, timezone
+
+import pytest
+
+from cyclone import db as db_mod
+from cyclone.db import Batch
+from cyclone.store.claim_acks import batch_envelope_index
+
+
+@pytest.fixture(autouse=True)
+def _db(tmp_path, monkeypatch):
+    """Per-test DB; conftest's autouse already wires one too, but we
+    pin the URL again so this module is self-contained if anyone ever
+    lifts it out of the conftest tree."""
+    monkeypatch.setenv("CYCLONE_DB_URL", f"sqlite:///{tmp_path}/test.db")
+    db_mod._reset_for_tests()
+    db_mod.init_db()
+    yield
+
+
+def _make_batch(
+    s,
+    *,
+    id: str,
+    icn: str,
+    stcn: str | None = None,
+    raw_json: dict | None = None,
+) -> Batch:
+    """Insert one Batch row whose envelope + ST02 mirror what
+    ``store.write.add_record`` writes for an 837P batch."""
+    row = Batch(
+        id=id,
+        kind="837p",
+        input_filename=id + ".x12",
+        parsed_at=datetime.now(timezone.utc),
+        raw_result_json=raw_json or {"envelope": {"control_number": icn}},
+        transaction_set_control_number=stcn,
+    )
+    s.add(row)
+    s.commit()
+    s.refresh(row)
+    return row
+
+
+def test_index_resolves_by_envelope_control_number():
+    """Pre-SP37 path: ISA13 (envelope.control_number) still resolves."""
+    with db_mod.SessionLocal()() as s:
+        _make_batch(s, id="b1", icn="ISA000001")
+    idx = batch_envelope_index()
+    assert idx.get("ISA000001") == "b1"
+
+
+def test_index_resolves_by_transaction_set_control_number():
+    """SP37 path: ST02 (transaction_set_control_number) resolves too.
+
+    The whole point of Task 3 — Gainwell batches have ST02 != ISA13,
+    so 999 AK201 echoes ST02 and must hit this branch.
+    """
+    with db_mod.SessionLocal()() as s:
+        _make_batch(
+            s, id="b2", icn="ISA000002", stcn="ST000002",
+            raw_json={"envelope": {"control_number": "ISA000002"}},
+        )
+    idx = batch_envelope_index()
+    assert idx.get("ST000002") == "b2"
+    # Backward compat: ISA still resolves.
+    assert idx.get("ISA000002") == "b2"
+
+
+def test_index_handles_row_with_no_transaction_set_control_number():
+    """Pre-migration rows (stcn NULL) should still resolve by ISA.
+
+    Spec says: 'Pre-migration rows (stcn NULL) should still resolve by ISA.'
+    Production row ``b1`` (the only one with claims) has ST02 NULL because
+    the migration's backfill only ran over rows whose raw_result_json
+    envelope had the ST02 key — and that row was written before the
+    parser populated it.
+    """
+    with db_mod.SessionLocal()() as s:
+        _make_batch(s, id="b3", icn="ISA000003")  # no stcn
+    idx = batch_envelope_index()
+    assert idx.get("ISA000003") == "b3"
+    assert idx.get("ST000003") is None
+
+
+def test_index_ignores_non_837_batches():
+    """835 batches don't contribute to the 999 join index.
+
+    The D10 two-pass join is specifically for 837 → 999 linkage; 835
+    remittances live on the response side of the loop and have no ST02
+    join key. Filtering by ``kind == "837p"`` keeps the index scoped
+    correctly and avoids an 835 row shadowing an 837 ST02 by accident.
+    """
+    with db_mod.SessionLocal()() as s:
+        # Add an 837 row first so we can prove the 835 doesn't leak in.
+        _make_batch(s, id="b-837", icn="ISA837", stcn="ST837")
+        # And an 835 row whose ISA13 / ST02 would otherwise pollute.
+        s.add(Batch(
+            id="b-835",
+            kind="835",
+            input_filename="b-835.x12",
+            parsed_at=datetime.now(timezone.utc),
+            raw_result_json={"envelope": {"control_number": "ISA999"}},
+            transaction_set_control_number="ST999",
+        ))
+        s.commit()
+    idx = batch_envelope_index()
+    # 837 row resolves both ways.
+    assert idx.get("ISA837") == "b-837"
+    assert idx.get("ST837") == "b-837"
+    # 835 row contributes nothing.
+    assert "ISA999" not in idx
+    assert "ST999" not in idx