From 11e97f2f80bf65cc828c127eafc95229df35d403 Mon Sep 17 00:00:00 2001 From: ericvsmith Date: Fri, 16 Jun 2017 06:19:32 -0400 Subject: bpo-30682: Removed a too-strict assertion that failed for certain f-strings. (#2232) This caused a segfault on eval("f'\\\n'") and eval("f'\\\r'") in debug build. --- Lib/test/test_fstring.py | 6 ++++++ Misc/NEWS | 3 +++ Python/ast.c | 4 ++-- 3 files changed, 11 insertions(+), 2 deletions(-) diff --git a/Lib/test/test_fstring.py b/Lib/test/test_fstring.py index b398704..3d762b5 100644 --- a/Lib/test/test_fstring.py +++ b/Lib/test/test_fstring.py @@ -780,5 +780,11 @@ f'{a * x()}'""" self.assertEqual(f'{d["foo"]}', 'bar') self.assertEqual(f"{d['foo']}", 'bar') + def test_backslash_char(self): + # Check eval of a backslash followed by a control char. + # See bpo-30682: this used to raise an assert in pydebug mode. + self.assertEqual(eval('f"\\\n"'), '') + self.assertEqual(eval('f"\\\r"'), '') + if __name__ == '__main__': unittest.main() diff --git a/Misc/NEWS b/Misc/NEWS index 8daaeab..bdfe53b 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -10,6 +10,9 @@ What's New in Python 3.7.0 alpha 1? Core and Builtins ----------------- +- bpo-30682: Removed a too-strict assertion that failed for certain f-strings, + such as eval("f'\\\n'") and eval("f'\\\r'"). + - bpo-30501: The compiler now produces more optimal code for complex condition expressions in the "if", "while" and "assert" statement, the "if" expression, and generator expressions and comprehensions. diff --git a/Python/ast.c b/Python/ast.c index 7551b6f..becf0ad 100644 --- a/Python/ast.c +++ b/Python/ast.c @@ -4914,6 +4914,8 @@ FstringParser_ConcatFstring(FstringParser *state, const char **str, /* Do nothing. Just leave last_str alone (and possibly NULL). */ } else if (!state->last_str) { + /* Note that the literal can be zero length, if the + input string is "\\\n" or "\\\r", among others. */ state->last_str = literal; literal = NULL; } else { @@ -4923,8 +4925,6 @@ FstringParser_ConcatFstring(FstringParser *state, const char **str, return -1; literal = NULL; } - assert(!state->last_str || - PyUnicode_GET_LENGTH(state->last_str) != 0); /* We've dealt with the literal now. It can't be leaked on further errors. */ -- cgit v0.12