CONTRIBUTING.md

Contributing

Build

Sbt Projects

• scala-collection-compat project (in the root directory): implementation of the compatibility library ;
• In directory scalafix/ there is an independent build containing the implementation of the migration tool.

Migration tool

Several levels of contribution are possible!

Report a missing case

Create an issue tagged with the migration label. Embrace diffs to describe differences between the standard collections and the strawman:

- xs.toIterator
+ xs.iterator

Add a missing test case

Even better, instead of providing a diff, you can directly add it as a test case!

1. Fork this repository and create a separate branch;

2. Add a file in the scalafix/input/src/main/scala/fix/ directory with code that uses the standard collections:

class toIteratorVsIterator(xs: Iterable[Int]) {
  xs.toIterator
}

3. Add a corresponding file in the scalafix/output/src/main/scala/fix/ directory with the same code but using the strawman:

import strawman.collection.Iterable

class toIteratorVsIterator(xs: Iterable[Int]) {
  xs.iterator
}

4. Check that your code example compiles

   • run sbt from the scalafix/ directory and then run the following tasks ; input/compile ; output/compile;

5. Commit your changes, push your branch to your fork and create a pull request.

Then maybe someone will take over and implement your use case… or maybe you will (see next section)!

Implement a missing case

Even better, complete the migration tool implementation to support the missing case!

After you have added the missing case (see previous section), run the following sbt task (with sbt started from the scalafix/ directory) to run the migration tool on the input files and check whether the result matches the expected output files:

> tests/test

Fix the implementation of the rule (in the rules/src/main/scala/fix/Scalacollectioncompat_v0.scala file) until the tests are green. You can find more help about the scalafix API in its documentation.