[pypy-issue] Issue #2755: dbm.open() expects a str for filename, throws TypeError if passed a unicode filename (pypy/pypy)

[Josh Friend]

New issue 2755: dbm.open() expects a str for filename, throws TypeError if passed a unicode filename
https://bitbucket.org/pypy/pypy/issues/2755/dbmopen-expects-a-str-for-filename-throws

Josh Friend:

https://bitbucket.org/pypy/pypy/src/3f6eaa010fce78cc7973bdc1dfdb95970f08fed2/lib_pypy/_dbm.py?at=release-pypy3.5-v5.10.1&fileviewer=file-view-default#_dbm.py-170

I ran into this when [using celery v4 with pypy2-5.8.0](https://github.com/celery/celery/issues/4533). Celery tries to access the `celerybeat-schedule` file using a unicode filename, which is rejected by pypy's implementation of `dbm` because `isinstance(u'something', str)` is false in python2. Unicode filenames are accepted by the `dbm` module in CPython.