Set up tooling to run decaffeinate on popular open source projects

decaffeinate has now gotten stable enough that it can run on some open source projects (e.g. hubot and autoprefixer) with no errors, and in some cases it’s possible to then run all of the tests and have them all pass. It would be cool to have a collection of these projects, especially to use them as a stress test to spot regressions and work through the long tail of rare correctness issues.

Here’s roughly what I have in mind:

• Make a new project, maybe decaffeinate-examples. It will effectively be a collection of scripts to run decaffeinate on various existing codebases, but it won’t actually contain all of those codebases.
• Create a generic system for describing everything about a repo to automatically run decaffeinate and all tests. For example:
  • A config file with things like the clone URL for the repo.
  • A bulk-decaffeinate.config.js file with the proper options and excluded files.
  • Common config files that should be added, like .babelrc and maybe .eslintrc.
  • A patch to the codebase that changes the build system to use babel (if necessary).
  • A script to run all tests and report the result.
• For each supported project, make a directory in the decaffeinate-examples repo with the right config files, patch, etc.
• For each project, the tool can then clone the repo, do npm install, put the config files in place, apply the patch, run bulk-decaffeinate, run all tests, and report the result. I guess ideally it would also handle any cases where decaffeinate can’t handle everything yet, and will report what files can be converted and what tests pass.
• Potentially we could have a github org with JS forks of all of these projects, and automatically run the latest decaffeinate on the latest code every week to make sure everything still works.

[eventualbuddha]

Thus is great! Made my day. 😊

[alangpierce]

CI is set up and there’s a table on the README. There are a few additional improvements that could be made, but it’s probably safe to call this task done, and a task has been filed for each individual repo to get it working fully.