fix(tests): close leaked sqlite connections; gate ResourceWarning as error (refs #618)

zot Db.__init__ leak on schema-parity raise; test fixtures not closing
raw Db/create_db connections; cli comments _build_bib_helpers cache
connection never closed. Gate: error::ResourceWarning (coverage's own
sqlitedb warning ignored). Root causes tracemalloc-verified; most
per-test attributions in #618 were GC-timing misattribution across
xdist workers.

pyproject.toml

@@ -207,6 +207,10 @@ testpaths = ["tests"]
 markers = [
     "stub: marks tests that report stub vs implemented status (deselect with '-m \"not stub\"')",
 ]
+filterwarnings = [
+    "error::ResourceWarning",
+    "ignore::ResourceWarning:coverage.*",
+]
 
 [tool.coverage.run]
 # Required for reliable pytest-cov + pytest-xdist combining: each worker

src/cli/comments.py

@@ -50,15 +50,17 @@ def _build_bib_helpers(use_bib: bool, attach: bool):
 
     db = str(path("db.bib"))
     con = sqlite3.connect(db, check_same_thread=False)
-
-    cache: dict[str, tuple[str, str]] = {}
-    for row in con.execute(
-        "SELECT key, url, abstract FROM items "
-        "WHERE url LIKE 'https://www.regulations.gov/comment/%'"
-    ):
-        cid = (row[1] or "").rsplit("/", 1)[-1]
-        if cid:
-            cache[cid] = (row[0], row[2] or "")
+    try:
+        cache: dict[str, tuple[str, str]] = {}
+        for row in con.execute(
+            "SELECT key, url, abstract FROM items "
+            "WHERE url LIKE 'https://www.regulations.gov/comment/%'"
+        ):
+            cid = (row[1] or "").rsplit("/", 1)[-1]
+            if cid:
+                cache[cid] = (row[0], row[2] or "")
+    finally:
+        con.close()
 
     def body_lookup(comment_id: str) -> str:
         return cache.get(comment_id, ("", ""))[1]

src/zot/db.py

@@ -293,10 +293,14 @@ class Db:
     def __init__(self, path: str) -> None:
         self.path = path
         self.con = sqlite3.connect(path)
-        self.con.row_factory = sqlite3.Row
-        self.con.execute("PRAGMA journal_mode=WAL")
-        self.con.execute("PRAGMA foreign_keys=ON")
-        self._verify_schema_parity()
+        try:
+            self.con.row_factory = sqlite3.Row
+            self.con.execute("PRAGMA journal_mode=WAL")
+            self.con.execute("PRAGMA foreign_keys=ON")
+            self._verify_schema_parity()
+        except Exception:
+            self.con.close()
+            raise
 
     def _verify_schema_parity(self) -> None:
         """Fail fast if Zotero's live schema disagrees with our maps.

tests/zot/test_extract.py

@@ -182,6 +182,7 @@ def extractor(zotero_db) -> Extractor:
     ex = Extractor(db)
     yield ex
     ex.close()
+    db.close()
 
 
 class TestExtractorQuotes:

tests/zot/test_schema.py

@@ -35,26 +35,31 @@ class TestCreateDb:
         con = create_db()
         count = con.execute("SELECT count(*) FROM itemTypes").fetchone()[0]
         assert count == 40
+        con.close()
 
     def test_fields_seeded(self):
         con = create_db()
         count = con.execute("SELECT count(*) FROM fields").fetchone()[0]
         assert count == 123
+        con.close()
 
     def test_creator_types_seeded(self):
         con = create_db()
         count = con.execute("SELECT count(*) FROM creatorTypes").fetchone()[0]
         assert count == 37
+        con.close()
 
     def test_item_type_fields_seeded(self):
         con = create_db()
         count = con.execute("SELECT count(*) FROM itemTypeFields").fetchone()[0]
         assert count == 770
+        con.close()
 
     def test_base_field_mappings_seeded(self):
         con = create_db()
         count = con.execute("SELECT count(*) FROM baseFieldMappings").fetchone()[0]
         assert count == 72
+        con.close()
 
     def test_library_exists(self):
         con = create_db()