Create a script to aid with migrating from v1.x to v2.0

[laurenyu]

To go along with the breaking changes proposed in #1459, we should provide a script that makes it easier to update one's code. For example, TensorFlow did this for upgrading to TF 2.0 (source).

[Olamyy]

Hi @laurenyu , would love to contribute to this feature. Are external contributors allowed in the migration? If yes, how can I help?

[laurenyu]

@Olamyy yes! I've just posted a PR (#1492) to start laying some ground work. Take a look, comment with suggestions for refactoring, renaming, etc.

after that, I think the next steps would include:

• setting up some tests
• class(es) for reading source files and feeding the code into the ASTTransformer class, and dumping the results into a new file
• the CLI interface (see TensorFlow's for an example)
• configuration for vending the CLI tool
• some of the other options that TF's script has, such as handling directories, printing a report of the changes, etc.

anything of the above jump out as something you'd like to pick up?

[Olamyy]

I went through the ASTTransformer PR and it seems fine to me.
I want to try and move on to setting up tests.
Should these tests be ASTTransformer related or general v2 migration tests?

[laurenyu]

@Olamyy just for the ASTTransformer and code related to this migration script

edit: since I've merged some more code, just wanted to clarify - we're looking for some unit tests for testing the stuff in tools/compatibility/v2 that can also be run from buildspec-unittests.yml. You don't have to fill in tests for everything that's been merged this week, though - I can definitely help out with that :)

[laurenyu]

@Olamyy have you had a chance to try working on things here?