Issue #27897: Fixed possible crash in sqlite3.Connection.create_collation()

if pass invalid string-like object as a name.  Patch by Xiang Zhang.

Lib/sqlite3/test/hooks.py

@@ -25,6 +25,11 @@ import unittest
 import sqlite3 as sqlite
 
 class CollationTests(unittest.TestCase):
+    def CheckCreateCollationNotString(self):
+        con = sqlite.connect(":memory:")
+        with self.assertRaises(TypeError):
+            con.create_collation(None, lambda x, y: (x > y) - (x < y))
+
     def CheckCreateCollationNotCallable(self):
         con = sqlite.connect(":memory:")
         with self.assertRaises(TypeError) as cm:
@@ -36,6 +41,23 @@ class CollationTests(unittest.TestCase):
         with self.assertRaises(sqlite.ProgrammingError):
             con.create_collation("collä", lambda x, y: (x > y) - (x < y))
 
+    def CheckCreateCollationBadUpper(self):
+        class BadUpperStr(str):
+            def upper(self):
+                return None
+        con = sqlite.connect(":memory:")
+        mycoll = lambda x, y: -((x > y) - (x < y))
+        con.create_collation(BadUpperStr("mycoll"), mycoll)
+        result = con.execute("""
+            select x from (
+            select 'a' as x
+            union
+            select 'b' as x
+            ) order by x collate mycoll
+            """).fetchall()
+        self.assertEqual(result[0][0], 'b')
+        self.assertEqual(result[1][0], 'a')
+
     @unittest.skipIf(sqlite.sqlite_version_info < (3, 2, 1),
                      'old SQLite versions crash on this test')
     def CheckCollationIsUsed(self):