Re-apply the non-BISAC nonfiction reset a release later (PP-5129)

startup_tasks/2026_10_02_reapply_non_bisac_nonfiction_reset.py

@@ -0,0 +1,38 @@
+"""Re-apply the non-BISAC nonfiction reset now that no old code is running.
+
+Startup task ``2026_09_14_reclassify_non_bisac_nonfiction_subjects`` repaired
+these subjects a release ago, but its reset was exposed to any old code still
+live: hosting-playbook's ``helpers/migrate.yml`` recycles the web containers
+after the migrate step, and does not govern Fargate deployments at all. Old
+code reaching ``Subject.assign_to_genre`` consumes the reset and re-stamps
+``checked=True`` with the same wrong value; see that task's docstring for the
+detail. A release later nothing old is running anywhere, so the same reset is
+safe to apply again.
+
+It recomputes which subjects the classifier disagrees with rather than
+replaying a stored list, so if the first repair took this is a no-op.
+Re-scoring is left to the nightly ``classify_unchecked_subjects``; the release
+N task chained it only because it was racing old code.
+
+This mirrors the null-audience repair, where ``2026_06_17`` re-ran what
+``2026_05_12`` had dispatched a release earlier.
+
+TODO: Remove the whole repair once this has run on all deployments (PP-5129):
+this task, the release N startup task, ``reset_non_bisac_nonfiction_subjects``
+with its script and bin wrapper, and
+``BISACClassifier.contradicts_stored_fiction``, whose only non-test caller is
+that task."""
+
+from __future__ import annotations
+
+import logging
+
+from celery.canvas import Signature
+from sqlalchemy.orm import Session
+
+from palace.manager.celery.tasks.work import reset_non_bisac_nonfiction_subjects
+from palace.manager.service.container import Services
+
+
+def run(services: Services, session: Session, log: logging.Logger) -> Signature | None:
+    return reset_non_bisac_nonfiction_subjects.s()

tests/manager/scripts/test_startup.py

@@ -15,7 +15,9 @@
 
 from palace.util.datetime_helpers import utc_now
 
+from palace.manager.celery.tasks.work import reset_non_bisac_nonfiction_subjects
 from palace.manager.scripts.startup import (
+    STARTUP_TASKS_DIR,
     _slugify,
     create_startup_task,
     discover_startup_tasks,
@@ -94,6 +96,42 @@ def test_discover_nonexistent_directory(
         assert result == {}
         assert "does not exist" in caplog.text
 
+    def test_discover_shipped_startup_tasks(self) -> None:
+        """Every task we actually ship imports and exposes a usable run().
+
+        The other tests here point discovery at `tmp_path`, so nothing else
+        imports `startup_tasks/` -- a task that fails to load would ship green.
+        Discovery logs and skips a module it cannot import, so compare against
+        the files on disk rather than just checking what came back.
+        """
+        expected = {
+            path.stem
+            for path in STARTUP_TASKS_DIR.glob("*.py")
+            if not path.stem.startswith("_")
+        }
+
+        result = discover_startup_tasks(STARTUP_TASKS_DIR)
+
+        assert expected, f"No startup tasks found in {STARTUP_TASKS_DIR}."
+        assert set(result) == expected
+        assert all(callable(run) for run in result.values())
+
+    def test_reapply_non_bisac_nonfiction_reset(self) -> None:
+        """The re-apply task queues the reset, and only the reset.
+
+        Unlike the release N task it deliberately does not chain the re-score.
+
+        TODO: Remove with the rest of the repair (PP-5129).
+        """
+        run = discover_startup_tasks(STARTUP_TASKS_DIR)[
+            "2026_10_02_reapply_non_bisac_nonfiction_reset"
+        ]
+
+        signature = run(MagicMock(), MagicMock(), logging.getLogger())
+
+        assert isinstance(signature, Signature)
+        assert signature.task == reset_non_bisac_nonfiction_subjects.name
+
 
 class RunStartupTasksFixture:
     def __init__(self, mock_discover_startup_tasks) -> None: