bpo-45249: Fix caret location when end_offset is set to 0 (GH-28855)

(cherry picked from commit fe0d9e22a52a10c4cbe52254b51f2d4e74d83568)

Co-authored-by: Pablo Galindo Salgado <Pablogsal@gmail.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/Lib/test/test_traceback.py b/Lib/test/test_traceback.py
index fabe5d01a9..ba03ce4629 100644
--- a/Lib/test/test_traceback.py
+++ b/Lib/test/test_traceback.py
@@ -51,6 +51,9 @@ class TracebackCases(unittest.TestCase):
     def syntax_error_bad_indentation2(self):
         compile(" print(2)", "?", "exec")
 
+    def tokenizer_error_with_caret_range(self):
+        compile("blech  (  ", "?", "exec")
+
     def test_caret(self):
         err = self.get_exception_format(self.syntax_error_with_caret,
                                         SyntaxError)
@@ -81,6 +84,13 @@ class TracebackCases(unittest.TestCase):
         self.assertEqual(err[1].find("y"), err[2].find("^"))  # in the right place
         self.assertEqual(err[2].count("^"), len("y for y in range(30)"))
 
+        err = self.get_exception_format(self.tokenizer_error_with_caret_range,
+                                        SyntaxError)
+        self.assertIn("^", err[2]) # third line has caret
+        self.assertEqual(err[2].count('\n'), 1)   # and no additional newline
+        self.assertEqual(err[1].find("("), err[2].find("^"))  # in the right place
+        self.assertEqual(err[2].count("^"), 1)
+
     def test_nocaret(self):
         exc = SyntaxError("error", ("x.py", 23, None, "bad syntax"))
         err = traceback.format_exception_only(SyntaxError, exc)