gh-93883: elide traceback indicators when possible

Elide traceback column indicators when the entire line of the frame is implicated. This reduces traceback length and draws even more attention to the remaining (very relevant) indicators. Example: ``` Traceback (most recent call last): File "query.py", line 99, in <module> bar() File "query.py", line 66, in bar foo() File "query.py", line 37, in foo magic_arithmetic('foo') File "query.py", line 18, in magic_arithmetic return add_counts(x) / 25 ^^^^^^^^^^^^^ File "query.py", line 24, in add_counts return 25 + query_user(user1) + query_user(user2) ^^^^^^^^^^^^^^^^^ File "query.py", line 32, in query_user return 1 + query_count(db, response['a']['b']['c']['user'], retry=True) ~~~~~~~~~~~~~~~~~~^^^^^ TypeError: 'NoneType' object is not subscriptable ``` WORK IN PROGRESS TODO: * C traceback implementation * update documentation
python · pablogsal · Jul 11, 2022 · Jun 19, 2022 · Jun 19, 2022 · Jun 23, 2022
commit bd99c329e714a5207b731e1dedc5a36bca0e6dd7
diff --git a/Lib/test/test_doctest.py b/Lib/test/test_doctest.py
@@ -2876,10 +2876,8 @@ def test_unicode(): """
        Traceback (most recent call last):
          File ...
            exec(compile(example.source, filename, "single",
-            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
          File "<doctest foo-bär@baz[0]>", line 1, in <module>
            raise Exception('clé')
-            ^^^^^^^^^^^^^^^^^^^^^^
        Exception: clé
    TestResults(failed=1, attempted=1)
    """