gh-96052: codeop: fix handling compiler warnings in incomplete input (GH-96132)

Previously codeop.compile_command() emitted compiler warnings (SyntaxWarning or
DeprecationWarning) and raised a SyntaxError for incomplete input containing
a potentially incorrect code. Now it always returns None for incomplete input
without emitting any warnings.
(cherry picked from commit 426d72e7ddb0af5cf851914ac75127186dd1ff04)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/Lib/test/test_codeop.py b/Lib/test/test_codeop.py
index 17376c7ed7..133096d25a 100644
--- a/Lib/test/test_codeop.py
+++ b/Lib/test/test_codeop.py
@@ -321,6 +321,26 @@ class CodeopTests(unittest.TestCase):
             warnings.simplefilter('error', SyntaxWarning)
             compile_command('1 is 1', symbol='exec')
 
+        # Check DeprecationWarning treated as an SyntaxError
+        with warnings.catch_warnings(), self.assertRaises(SyntaxError):
+            warnings.simplefilter('error', DeprecationWarning)
+            compile_command(r"'\e'", symbol='exec')
+
+    def test_incomplete_warning(self):
+        with warnings.catch_warnings(record=True) as w:
+            warnings.simplefilter('always')
+            self.assertIncomplete("'\\e' + (")
+        self.assertEqual(w, [])
+
+    def test_invalid_warning(self):
+        with warnings.catch_warnings(record=True) as w:
+            warnings.simplefilter('always')
+            self.assertInvalid("'\\e' 1")
+        self.assertEqual(len(w), 1)
+        self.assertEqual(w[0].category, DeprecationWarning)
+        self.assertRegex(str(w[0].message), 'invalid escape sequence')
+        self.assertEqual(w[0].filename, '<input>')
+
 
 if __name__ == "__main__":
     unittest.main()