sqlite3: _completer raises OperationalError when an attached database name contains a double quote

[Tony123-tech]

In Lib/sqlite3/_completer.py, the schema name from PRAGMA database_list
is interpolated directly into an SQL string:

SELECT name || ' ' FROM \"{schema}\".sqlite_master

If a user attaches a database whose name contains a double quote, the
resulting SQL is invalid and _complete() raises OperationalError instead
of returning completion matches.

Reproduction:

import sqlite3
from sqlite3 import _completer
con = sqlite3.connect(':memory:')
con.execute('ATTACH DATABASE \':memory:\' AS \'weird"name\'')
_completer._complete(con, 'a', 0)

Output:

OperationalError unrecognized token: "".sqlite_master
                WHERE name LIKE REPLACE(:text, '_', '^_') || '%' ESCAPE '^'"

The same problem exists in the column-completion query:

JOIN pragma_table_xinfo(sm.name,'{schema}') AS pti

Suggested fix: quote the schema name as an SQL identifier, replacing
embedded double quotes with two double quotes.

Discovered while reviewing the module with an AI assistant.

Linked PRs

• gh-158215: Fix sqlite3 completer for schema names with a double quote #158216