• pip install future # http://python-future.org/futurize_cheatsheet.html
• Why fork (not clone): https://stackoverflow.com/questions/6286571/are-git-forks-actually-git-clones
  • If you do not have write access to the repo then you must fork (not clone) the repo (upstream) into a repo (origin) in your own GitHub account. You then make changes and commits to a repo (local) on your computer and push those changes from local to origin. Then you can create a pull request to suggest that changes move from origin to upstream.
• Syncing with upstream: https://docs.python.org/devguide/gitbootcamp.html#syncing-with-upstream

1. Using the GitHub web ui, visit the repo to be processed and click "fork" in the upper right (not clone).
2. $ git clone https://github.com/<your GitHub username>/<repo name>
3. $ cd <repo name>
4. $ git remote add upstream https://github.com/<repo username>/<repo name>
5. $ git checkout -b modernize-python2-code
6. $ python2 -m flake8 . --count --select=E901,E999,F821,F822,F823 --show-source --statistics
7. $ futurize --stage1 -x libfuturize.fixes.fix_absolute_import -w .
   • Or $ futurize -f libfuturize.fixes.fix_print_with_import -w .
8. $ python3 -m flake8 . --count --select=E901,E999,F821,F822,F823 --show-source --statistics
9. $ git commit -am "Modernize Python 2 code to get ready for Python 3"
10. $ git push --force origin modernize-python2-code
11. $ open https://github.com/<repo username>/<repo name> Refreshes GitHub web ui and you should have a Pull Request to submit back to upstream.

There are two problems with automating this process. Neither git CLI nor github3.py support:

1. creating a fork
2. creating a pull request (See: https://github.com/cclauss/git-push-inside-travis)

New proposal:

1. Using the GitHub web ui, the user visits the repo to be processed and clicks "fork" in the upper right (not clone).
2. User runs itinerant_futurizer.py locally and when asked provide their GitHub password.
3. At the end of processing, a web browser is opened to the futurize-stage-1 branch of the origin repo.
4. User can create a pull request to suggest that changes move from origin to upstream.

Under this proposal, itinerant_futurizer.py does:

1. Ask user for their GitHub password
2. Get the last repo created and ask user to verify this is the repo that they want to process
3. Verify that branch futurize-stage-1 does not yet exist on origin. If it does then bail.
4. If .travis.yml exists in that repo then rename it to was.travis.yml
5. travis enable -r user/repo # https://github.com/travis-ci/travis.rb#enable
6. Push our .travis.yml into repo to kick off futurize stage 1
7. Remove our .travis.yml and restore was.travis.yml if present
8. Open webbrowser to branch futurize-stage-1 on origin

Our .travis.yml does:

1. git checkout -b futurize-stage-1
2. pip install future
3. futurize --stage1 --nofix=libfuturize.fixes.fix_absolute_import -w .
4. git commit --all -m "Modernize Python 2 code to get ready for Python 3"
5. git push --set-upstream origin futurize-stage-1
6. rm .travis.yml
7. mv was.travis.yml .travis.yml

ArduPilot/ardupilot#6954 (comment)

Zap trailing whitespace: sed -i 's/ +$//' **/*.py