port buildgen to py3

[GoingTharn]

Problem

Porting buildgen to py3. Needs references to str and object.

Solution

added builtins import for str and object

[GoingTharn]

cc @Eric-Arellano

[stuhood]

Hey, this will need a rebase to master. Sorry for the trouble!

[mateor]

thanks John! Feel free to add me to the reviewer lists. I am in the middle of moving but I will continue to swing by and look at patches once a day or so.

[Eric-Arellano]

The BUILD file is missing the dependency for “3rdparty/python:future”. Stu, you may want to revert this commit if or manually add that line before doing the release.

I’m surprised the tests are passing on this and that we don’t get an import error.

This slipped through because our script was only smart enough to add the line in certain cases. We updated our script so that it will always add the line when necessary, so going forward this shouldn’t happen.

[jsirois]

@Eric-Arellano ths is why tests pass:

$ ./pants depmap --tree --minimal contrib/buildgen/tests/python/pants_test/contrib/buildgen:build_file_manipulator | head
--internal-contrib.buildgen.tests.python.pants_test.contrib.buildgen.build_file_manipulator
  |--internal-contrib.buildgen.src.python.pants.contrib.buildgen.build_file_manipulator
  |  |--internal-src.python.pants.build_graph.build_graph
  |  |  |--internal-3rdparty.python.six
  |  |  |--internal-3rdparty.python.twitter.commons.twitter.common.collections
  |  |  |--internal-src.python.pants.base.build_environment
  |  |  |  |--internal-3rdparty.python.future
  |  |  |  |--internal-src.python.pants.version
  |  |  |  |  |--internal-3rdparty.python.packaging
  |  |  |  |  |--internal-src.python.pants.version-resource

[Eric-Arellano]

Ah that makes more sense, thanks John.

We still probably to explicitly add to the BUILD file in case this assumption breaks for whatever reason, right?

We can submit a separate PR patching this if we don’t want to revert this merge.

[jsirois]

Yes, definitely. This is a bug to be fixed. No need to revert though and a new PR would be perfect.