Merge branch 'staging' into 'master'

Hotfix: Database migration caused data loss.

See merge request s3lph/matemat!47

matemat/db/wrapper.py

@@ -62,14 +62,8 @@ class DatabaseWrapper(object):
         return DatabaseTransaction(self._sqlite_db, exclusive)
 
     def _setup(self) -> None:
-        # Enable foreign key enforcement
-        cursor = self._sqlite_db.cursor()
-        cursor.execute('PRAGMA foreign_keys = 1')
-
         # Create or update schemas if necessary
         with self.transaction() as c:
-            # Defer foreign key enforcement in the setup transaction
-            c.execute('PRAGMA defer_foreign_keys = 1')
             version: int = self._user_version
             if version < 1:
                 # Don't use executescript, as it issues a COMMIT first
@@ -81,6 +75,10 @@ class DatabaseWrapper(object):
                 raise RuntimeError('Database schema is newer than supported by this version of Matemat.')
             self._user_version = self.SCHEMA_VERSION
 
+        # Enable foreign key enforcement
+        cursor = self._sqlite_db.cursor()
+        cursor.execute('PRAGMA foreign_keys = 1')
+
     def _upgrade(self, from_version: int, to_version: int) -> None:
         with self.transaction() as c:
             # Note to future s3lph: If there are further migrations, also consider upgrades like 1 -> 3