traceback bug with closures

[sqlalchemy-bot]

Migrated issue, originally created by Michael Bayer (@zzzeek)

When it lists the backtrace, like:

 ('/home/wacky/build/Vigilia/env/lib/python2.6/site-packages/pylons/controllers/core.py',
  105,
  '_inspect_call',
  'result = self._perform_call(func, args)'),
 ('/home/wacky/build/Vigilia/env/lib/python2.6/site-packages/pylons/controllers/core.py',
  57,
  '_perform_call',
  'return func(**args)'),
 ('<string>', 2, 'edit_album', None),
 ('/home/wacky/build/Vigilia/vigilia/lib/base.py',
  88,
  'wrapper',
  'return func(self, *args, **kwargs)'),


notice the <string>, 'edit_album', and None object.  This None object is the cause. It should be converted to string, or Mako should know how to deal with it.

We get a None there when the function is a closure, or a returned function that dynamically generated, which is the case with most decorators.

The solution is a two-liner:

diff -r 6cf6461d778243d8a8986c658eb2246e5939bdce mako/exceptions.py
--- a/mako/exceptions.py	Tue Apr 13 10:07:04 2010 -0400
+++ b/mako/exceptions.py	Sat Apr 17 16:28:52 2010 -0400
@@ -152,6 +152,8 @@
         rawrecords = traceback.extract_tb(trcback)
         new_trcback = []
         for filename, lineno, function, line in rawrecords:
+            if not line:
+                line = ''
             try:
                 (line_map, template_lines) = mods[filename]
             except KeyError:
}}

[sqlalchemy-bot]

Michael Bayer (@zzzeek) wrote:

we suspect this is the bug:

    def test_format_closures(self):
        try:
            exec "def foo():"\
                 "    raise RuntimeError('test')"\
                 in locals()
            foo()
        except:
            html_error = exceptions.html_error_template().render()
            print html_error

[sqlalchemy-bot]

Michael Bayer (@zzzeek) wrote:

the fix + test is in 68c7229 . reopen if further issues

[sqlalchemy-bot]

Changes by Michael Bayer (@zzzeek):

• changed status to closed

[sqlalchemy-bot]

Anonymous wrote:

Here's a demo Pylons application (create -t pylons) with Pylons 1.0b1

http://f.abourget.net/dump/makobug2-0.1dev.tar.gz

it does crash.. and shows what's required to make it crash, just go to http://localhost:5000/bug/index