commit 2eca5b465f7404cc8484457b7966f828f434ec20
author Serhiy Storchaka <storchaka@gmail.com> Fri Jun 16 16:29:42 2017 +0300
committer ericvsmith <ericvsmith@users.noreply.github.com> Fri Jun 16 09:29:42 2017 -0400
tree 24eb2215c217bd8669b0f5da5e098f3ebf0cd3be
parent a0ccc54e6dffacf9e7c06f2a3e9056d2d35d21eb

[3.6] bpo-30682: Removed a too-strict assertion that failed for certain f-strings. (GH-2232) (#2242)

This caused a segfault on eval("f'\\\n'") and eval("f'\\\r'") in debug build..
(cherry picked from commit 11e97f2f80bf65cc828c127eafc95229df35d403)

Python/ast.c

diff --git a/Python/ast.c b/Python/ast.c
index c61ca4b..8d53736 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -4887,6 +4887,8 @@
             /* 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 {
@@ -4896,8 +4898,6 @@
                 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. */