Mako unable to import on Python 3.8

[amol-]

From TurboGears2 test suite:

  File "/home/travis/build/TurboGears/tg2/tg/renderers/mako.py", line 23, in <module>
    from mako.template import Template
  File "/home/travis/virtualenv/python3.8-dev/lib/python3.8/site-packages/mako/template.py", line 20, in <module>
    from mako import codegen
  File "/home/travis/virtualenv/python3.8-dev/lib/python3.8/site-packages/mako/codegen.py", line 13, in <module>
    from mako import ast
  File "/home/travis/virtualenv/python3.8-dev/lib/python3.8/site-packages/mako/ast.py", line 14, in <module>
    from mako import pyparser
  File "/home/travis/virtualenv/python3.8-dev/lib/python3.8/site-packages/mako/pyparser.py", line 17, in <module>
    from mako import _ast_util
  File "/home/travis/virtualenv/python3.8-dev/lib/python3.8/site-packages/mako/_ast_util.py", line 67, in <module>
    from _ast import Str
ImportError: cannot import name 'Str' from '_ast' (unknown location)

Seems that mako is relying on _ast.Str which got recently removed from Python3.8: python/cpython@3f22811#diff-4d3d72b905c99b789fe1a7af29bcd55dL8248 (See python/cpython#9445 )

[zzzeek]

oh because I removed all the "bad" "import *". haha, that sucks. now we have to add all the conditionals for those.

[sqla-tester]

Mike Bayer has proposed a fix for this issue in the master branch:

Remove all non-essential functions from _ast_util.py https://gerrit.sqlalchemy.org/1299

[praiskup]

just curious, is there ETA for releasing this? It seems to break python3.8 unit tests in travis

[zzzeek]

python 3.8 is still in beta so I generally don't release the same day as a fix though i was going to get to it