python3.7 installation failing - so why?

[Chris Angelico]

On Sat, Feb 23, 2019 at 2:51 PM Frank Miles <pedicularis at mail.com> wrote:
>
> I have a Debian/Linux machine that I just upgraded to the newer "testing"
> distribution.  I'd done that earlier to another machine and all went
> well.  With the latest machine, python2 is OK but python3 can barely run
> at all.  For example:
>
> $ python3
> Python 3.7.2+ (default, Feb  2 2019, 14:31:48)
> [GCC 8.2.0] on linux
> Type "help", "copyright", "credits" or "license" for more information.
> >>> help()
> Traceback (most recent call last):
>   File "<stdin>", line 1, in <module>
>   File "/usr/lib/python3.7/_sitebuiltins.py", line 102, in __call__
>     import pydoc
>   File "/usr/lib/python3.7/pydoc.py", line 66, in <module>
>     import inspect
>   File "/usr/lib/python3.7/inspect.py", line 40, in <module>
>     import linecache
>   File "/usr/lib/python3.7/linecache.py", line 11, in <module>
>     import tokenize
>   File "/usr/lib/python3.7/tokenize.py", line 33, in <module>
>     import re
>   File "/usr/lib/python3.7/re.py", line 143, in <module>
>     class RegexFlag(enum.IntFlag):
> AttributeError: module 'enum' has no attribute 'IntFlag'
> >>>
>
> Question: how can I determine what has gone wrong?

Hmm. I'd start with:

$ which python3
$ dpkg -S `which python3`

and from inside Python:
>>> import sys; sys.path
>>> import enum; enum.__file__

My best guess at the moment is that your "enum" package is actually a
compatibility shim for earlier Python versions, less functional than
the one provided by Python 3.7. You may need to *uninstall* a shim
package. But I could well be wrong, and maybe there'd be a clue in
your paths.

ChrisA