bpo-44859: Improve error handling in sqlite3 and and raise more accurate exceptions. (GH-27654)

* MemoryError is now raised instead of sqlite3.Warning when
  memory is not enough for encoding a statement to UTF-8
  in Connection.__call__() and Cursor.execute().
* UnicodEncodeError is now raised instead of sqlite3.Warning when
  the statement contains surrogate characters
  in Connection.__call__() and Cursor.execute().
* TypeError is now raised instead of ValueError for non-string
  script argument in Cursor.executescript().
* ValueError is now raised for script containing the null
  character instead of truncating it in Cursor.executescript().
* Correctly handle exceptions raised when getting boolean value
  of the result of the progress handler.
* Add many tests covering different corner cases.

Co-authored-by: Erlend Egeberg Aasland <erlend.aasland@innova.no>

1 files changed, 30 insertions, 3 deletions

diff --git a/Lib/sqlite3/test/dbapi.py b/Lib/sqlite3/test/dbapi.py
index 408f9945f2c..5d7e5bba05b 100644
--- a/Lib/sqlite3/test/dbapi.py
+++ b/Lib/sqlite3/test/dbapi.py
@@ -26,7 +26,7 @@ import sys
 import threading
 import unittest
 
-from test.support import check_disallow_instantiation, threading_helper
+from test.support import check_disallow_instantiation, threading_helper, bigmemtest
 from test.support.os_helper import TESTFN, unlink
 
 
@@ -758,9 +758,35 @@ class ExtensionTests(unittest.TestCase):
     def test_cursor_executescript_as_bytes(self):
         con = sqlite.connect(":memory:")
         cur = con.cursor()
-        with self.assertRaises(ValueError) as cm:
+        with self.assertRaises(TypeError):
             cur.executescript(b"create table test(foo); insert into test(foo) values (5);")
-        self.assertEqual(str(cm.exception), 'script argument must be unicode.')
+
+    def test_cursor_executescript_with_null_characters(self):
+        con = sqlite.connect(":memory:")
+        cur = con.cursor()
+        with self.assertRaises(ValueError):
+            cur.executescript("""
+                create table a(i);\0
+                insert into a(i) values (5);
+                """)
+
+    def test_cursor_executescript_with_surrogates(self):
+        con = sqlite.connect(":memory:")
+        cur = con.cursor()
+        with self.assertRaises(UnicodeEncodeError):
+            cur.executescript("""
+                create table a(s);
+                insert into a(s) values ('\ud8ff');
+                """)
+
+    @unittest.skipUnless(sys.maxsize > 2**32, 'requires 64bit platform')
+    @bigmemtest(size=2**31, memuse=3, dry_run=False)
+    def test_cursor_executescript_too_large_script(self, maxsize):
+        con = sqlite.connect(":memory:")
+        cur = con.cursor()
+        for size in 2**31-1, 2**31:
+            with self.assertRaises(sqlite.DataError):
+                cur.executescript("create table a(s);".ljust(size))
 
     def test_connection_execute(self):
         con = sqlite.connect(":memory:")
@@ -969,6 +995,7 @@ def suite():
         CursorTests,
         ExtensionTests,
         ModuleTests,
+        OpenTests,
         SqliteOnConflictTests,
         ThreadTests,
         UninitialisedConnectionTests,