[pypy-commit] pypy py3.5: Fix traceback.print_exception() when exc.offset == 0

[rlamy]

Author: Ronan Lamy <ronan.lamy at gmail.com>
Branch: py3.5
Changeset: r93117:e37a09d8450a
Date: 2017-11-21 18:38 +0000
http://bitbucket.org/pypy/pypy/changeset/e37a09d8450a/

Log:	Fix traceback.print_exception() when exc.offset == 0

diff --git a/lib-python/3/traceback.py b/lib-python/3/traceback.py
--- a/lib-python/3/traceback.py
+++ b/lib-python/3/traceback.py
@@ -544,8 +544,8 @@
             yield '    {}\n'.format(badline.strip())
             if offset is not None:
                 caretspace = badline.rstrip('\n')
-                offset = min(len(caretspace), offset) - 1
-                caretspace = caretspace[:offset].lstrip()
+                # bug in CPython: the case offset==0 is mishandled
+                caretspace = caretspace[:offset].lstrip()[:-1]
                 # non-space whitespace (likes tabs) must be kept for alignment
                 caretspace = ((c.isspace() and c or ' ') for c in caretspace)
                 yield '    {}^\n'.format(''.join(caretspace))