Remove dependency on use_2to3

[jaraco]

• Apply lib2to3 to the python code
• Restore Python 2 compatibility.
• Remove dependency on 2to3 and unpin Setuptools.

[jaraco]

Fixes #655 and Fixes #653 using a more permanent solution rather than a workaround.

I have not tested this code. Please test on Python 2 and 3 before releasing.

[hithwen]

When can we expect a release with this change?

[amukherjee28]

I am working on the new release.
Will make the release very soon with these changes.

Thanks

[ofek]

@amukherjee28 Hello! We have a big release on Monday, do you think this would be shipped by then?

[amukherjee28]

Yes will release it by Friday.

[amukherjee28]

Hi @jaraco

I was going through the changes suggested in the PR.

I have few question regarding the same.

The changes in the file ibm_db_dbi.py and testfunctions.py, is it in order to support the backward compatibility for PYTHON2.
I tested the change in setup.py with python3 (3.9) and other changes were not required. I did not test for python2 though.

Just going through the code made me realize that the other changes looks to be for python2 support.
Is my understanding correct here.

Thanks

[jaraco]

The changes in the file ibm_db_dbi.py and testfunctions.py, is it in order to support the backward compatibility for PYTHON2.

Yes. There are three commits. In the first, I run lib2to3 on the code, effectively achieving what would have happened during a build on Python 3 before. That converted the code to Python 3 only code.

In the next commit, I went back and manually restored support for Python 2 by reading through the previous change and restoring whatever expectation would have been present, but only for Python 2. This change was mainly to restore support for strings and ints having two forms on Python 2, but only one on Python 3. It's quite possible some of these changes aren't necessary in practice, but for safety, I applied them to be maximally compatible. If you no longer need support for Python 2, you can omit or revert that commit.

In the final commit, I clean up the lib2to3 during setup (the goal of this effort).

I'd recommend to test on Python 2, although I'm fairly confident in the changes and if the tests are passing on Python 3, I'd feel pretty good about Python 2, but you may wish to be prepared to make another release if Python 2 users somehow report unexpected problems.

[amukherjee28]

Hi @jaraco
Thanks for the confirmation.

One last confirmation with these changes do you thing we still need the pyproject.toml file ?

[jaraco]

With these changes , you don’t need the pyproject.toml file, although including it is good practice. The presence of the file will enable PEP 517 isolated builds and make the project more future-proof, rather than relying on legacy compatibility behaviors. Your call.

[ofek]

@amukherjee28 This sounds reasonable to me as well.

[amukherjee28]

With python3 the changes work fine. But with python2 there are issue when running test cases.
I have to look into the changes a bit more to understand the impact on both python3 and python2 else will have to release only with the first commit and ignoring the other two commits.

[jaraco]

The project isn’t stable after the first commit. It will still have 2to3 enabled and won’t run on python 2. If you wish to release a Python 3 only release, I could help prepare a PR that does that.

How important is it for this project to continue to support Python 2? If Python 2 users can rely only on preexisting releases, that’s the route I’d recommend (#669). If not, I’d suggest instead releasing a workaround to pin Setuptools until the issues with Python 2 in this PR can be worked out (#656).

[jaraco]

The changes in #656 should have been enough to prevent the issue for users using pip or another PEP 518-compatible builder, although I see in that PR that the fix seems not to have worked for some users. Note that without the MANIFEST.in change, the sdist that's produced for the release needs to be built using a late version of Setuptools (43 or later).

[amukherjee28]

Thanks a lot for the help @jaraco.
New version 3.1.0 released with the changes.

Support for the new setuptools working fine.