From 409 warnings down to 52 warnings.

By closing unclosed database connections.

Refs #2614

datasette/utils/__init__.py

@@ -681,13 +681,18 @@ def detect_fts_sql(table):
 
 
 def detect_json1(conn=None):
+    close_conn = False
     if conn is None:
         conn = sqlite3.connect(":memory:")
+        close_conn = True
     try:
         conn.execute("SELECT json('{}')")
         return True
     except Exception:
         return False
+    finally:
+        if close_conn:
+            conn.close()
 
 
 def table_columns(conn, table):

datasette/utils/sqlite.py

@@ -20,15 +20,16 @@ def sqlite_version():
 
 
 def _sqlite_version():
-    return tuple(
-        map(
-            int,
-            sqlite3.connect(":memory:")
-            .execute("select sqlite_version()")
-            .fetchone()[0]
-            .split("."),
+    conn = sqlite3.connect(":memory:")
+    try:
+        return tuple(
+            map(
+                int,
+                conn.execute("select sqlite_version()").fetchone()[0].split("."),
+            )
         )
-    )
+    finally:
+        conn.close()
 
 
 def supports_table_xinfo():