fix: fail closed on incomplete 2024 political TIGER manifest

docs/research/2026-10-05-district-data-source-verification.md

@@ -62,8 +62,12 @@ Census states that the 2024 vintage contains the 119th Congressional District
 and 2024 state-legislative plans and that legal boundaries/names are as of
 2024-01-01. The official directory members use
 `tl_2024_<state FIPS>_cd119.zip`, `tl_2024_<state FIPS>_sldu.zip`, and
-`tl_2024_<state FIPS>_sldl.zip`. File sizes are publisher-listed and are
-re-probed by the normal `tiger-bulk-preview` capacity gate before transfer.
+`tl_2024_<state FIPS>_sldl.zip`. The publisher indexes contain **56 CD119
+archives, 52 SLDU archives, and 50 SLDL archives (158 total)**. These counts are
+now a fail-closed completeness contract for the frozen 2024 package: discovery
+still comes from Census, but a partial directory response cannot silently become
+an approved manifest. File sizes are publisher-listed and are re-probed by the
+normal `tiger-bulk-preview` capacity gate before transfer.
 
 The 2024 record layouts make the join contract explicit:
 

src/opendiscourse_research/ingestion/tiger_bulk.py

@@ -39,6 +39,14 @@
     ("SLDL", "sldl"),
 )
 
+# Verified against the frozen official TIGER2024 publisher indexes on
+# 2026-10-05. These are package completeness checks, not guessed jurisdiction
+# lists: discovery still reads the Census directory, but a partial response
+# may not silently become an approved manifest.
+_POLITICAL_EXPECTED_MEMBER_COUNTS = {
+    2024: {"cd119": 56, "sldu": 52, "sldl": 50},
+}
+
 
 def _zcta_layer(year: int) -> str:
     if year < _ZCTA_CUTOVER_YEAR:
@@ -98,6 +106,22 @@ def _national_core_artifacts(year: int) -> list[dict[str, Any]]:
     ]
 
 
+def _require_political_member_count(
+    year: int, kind: str, count: int, index_url: str
+) -> None:
+    """Fail closed when a reviewed frozen publisher index is incomplete."""
+    expected = _POLITICAL_EXPECTED_MEMBER_COUNTS.get(year, {}).get(kind)
+    if expected is None:
+        raise ValueError(
+            f"No reviewed TIGER member-count contract exists for {year} {kind}"
+        )
+    if count != expected:
+        raise ValueError(
+            f"Census {year} {kind} manifest at {index_url} returned {count} "
+            f"ZIP members; expected reviewed publisher count {expected}"
+        )
+
+
 def discover_political_tiger_artifacts(year: int) -> list[dict[str, Any]]:
     """Enumerate exactly the political ZIPs Census publishes for one reviewed vintage.
 
@@ -125,10 +149,9 @@ def discover_political_tiger_artifacts(year: int) -> list[dict[str, Any]]:
                 match = pattern.fullmatch(filename)
                 if match:
                     matches.append((url, filename, match.group("state")))
-            if not matches:
-                raise ValueError(
-                    f"Census published no {kind} ZIP members at {index_url}"
-                )
+            _require_political_member_count(
+                year, kind, len(matches), index_url
+            )
             for url, filename, state_fips in sorted(matches):
                 artifacts.append(
                     {

tests/test_census_bulk.py

@@ -30,6 +30,7 @@
 from opendiscourse_research.ingestion.pep_bulk import build_pep_bulk_plan
 from opendiscourse_research.ingestion.pep_load import _scope as pep_scope
 from opendiscourse_research.ingestion.tiger_bulk import (
+    _require_political_member_count,
     build_tiger_bulk_plan,
     tiger_layers,
 )
@@ -197,6 +198,21 @@ def test_tiger_plan_requires_exact_package(self) -> None:
         with self.assertRaisesRegex(ValueError, "exactly"):
             build_tiger_bulk_plan("test", [])
 
+    def test_tiger_political_manifest_count_fails_closed_when_partial(self) -> None:
+        _require_political_member_count(
+            2024,
+            "cd119",
+            56,
+            "https://www2.census.gov/geo/tiger/TIGER2024/CD/",
+        )
+        with self.assertRaisesRegex(ValueError, "expected reviewed publisher count 56"):
+            _require_political_member_count(
+                2024,
+                "cd119",
+                55,
+                "https://www2.census.gov/geo/tiger/TIGER2024/CD/",
+            )
+
     def test_tiger_political_plan_is_bounded_to_119th_and_2024_sld(self) -> None:
         artifacts = [
             {