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

Lib/sqlite3/_completer.py

@@ -11,6 +11,11 @@
 _completion_matches = []
 
 
+def _quote_schema(schema):
+    # Quote an SQLite identifier, doubling embedded double quotes.
+    return '"' + schema.replace('"', '""') + '"'
+
+
 def _complete(con, text, state):
     global _completion_matches
 
@@ -32,7 +37,7 @@ def _complete(con, text, state):
             # escape '_' which can appear in attached database names
             select_clauses = (
                 f"""\
-                SELECT name || ' ' FROM \"{schema}\".sqlite_master
+                SELECT name || ' ' FROM {_quote_schema(schema)}.sqlite_master
                 WHERE name LIKE REPLACE(:text, '_', '^_') || '%' ESCAPE '^'"""
                 for schema in schemata
             )
@@ -46,8 +51,8 @@ def _complete(con, text, state):
             try:
                 select_clauses = (
                     f"""\
-                    SELECT pti.name || ' ' FROM "{schema}".sqlite_master AS sm
-                    JOIN pragma_table_xinfo(sm.name,'{schema}') AS pti
+                    SELECT pti.name || ' ' FROM {_quote_schema(schema)}.sqlite_master AS sm
+                    JOIN pragma_table_xinfo(sm.name,{_quote_schema(schema)}) AS pti
                     WHERE sm.type='table' AND
                     pti.name LIKE REPLACE(:text, '_', '^_') || '%' ESCAPE '^'"""
                     for schema in schemata

Lib/test/test_sqlite3/test_completer.py

@@ -0,0 +1,19 @@
+import sqlite3
+import unittest
+from sqlite3 import _completer
+
+
+class CompleterTests(unittest.TestCase):
+    def test_schema_with_double_quote(self):
+        con = sqlite3.connect(':memory:')
+        self.addCleanup(con.close)
+        con.execute('ATTACH DATABASE \':memory:\' AS \'weird"name\'')
+        matches = []
+        state = 0
+        while True:
+            match = _completer._complete(con, 'a', state)
+            if match is None:
+                break
+            matches.append(match)
+            state += 1
+        self.assertTrue(matches)

Misc/NEWS.d/next/Library/2026-09-26-12-34-38.gh-issue-158215.AbCdEf.rst

@@ -0,0 +1,2 @@
+Fix :mod:`sqlite3` completer to handle attached database names
+containing a double quote. Patch by Tony Leung.