fix: add transaction guard to vacuum() method (fixes #479)

sqlite_utils/db.py

@@ -2024,8 +2024,15 @@ def index_foreign_keys(self) -> None:
                     existing_indexes.add(fk_columns)
 
     def vacuum(self) -> None:
-        "Run a SQLite ``VACUUM`` against the database."
-        self.execute("VACUUM;")
+        """
+        Run a SQLite ``VACUUM`` against the database.
+
+        :raises TransactionError: if called while a transaction is open - VACUUM
+          cannot run inside a transaction
+        """
+        self._ensure_no_open_transaction("vacuum()")
+        with self.ensure_autocommit_on():
+            self.execute("VACUUM;")
 
     def analyze(self, name: str | None = None) -> None:
         """

tests/test_atomic.py

@@ -1,6 +1,6 @@
 import pytest
 
-from sqlite_utils.db import Database, _iter_complete_sql_statements
+from sqlite_utils.db import Database, TransactionError, _iter_complete_sql_statements
 from sqlite_utils.utils import sqlite3
 
 
@@ -381,3 +381,18 @@ def test_atomic_preserves_error_from_insert_or_rollback(fresh_db):
     with pytest.raises(sqlite3.IntegrityError), fresh_db.atomic():
         fresh_db.execute("insert or rollback into t (id) values (1)")
     assert not fresh_db.conn.in_transaction
+
+
+def test_vacuum_raises_transaction_error_inside_atomic(fresh_db):
+    """Test that vacuum() raises TransactionError when called inside atomic()"""
+    fresh_db.table("t").insert({"id": 1}, pk="id")
+    with pytest.raises(TransactionError, match="vacuum\\(\\)"):
+        with fresh_db.atomic():
+            fresh_db.vacuum()
+
+
+def test_vacuum_works_outside_atomic(fresh_db):
+    """Test that vacuum() works when called outside a transaction"""
+    fresh_db.table("t").insert({"id": 1}, pk="id")
+    fresh_db.vacuum()
+    assert list(fresh_db.table("t").rows) == [{"id": 1}]