Output unnamed variables

[chongkai]

Before this PR

Exception is thrown when there are unnamed variables in source code (issue: #1236).

The error is like, "com.palantir.javaformat.java.FormatterException: 217:106: error: expected token: '_'; generated instead".

The cases we have seen include:

• unnamed var in try-with blocks,
  try (var _ = abc) {}
• unnamed argument in lambda
  (a, _) -> {}

After this PR

The source code can be formatted properly when containing unnamed variables.

Possible downsides?

[palantirtech]

Thanks for your interest in palantir/palantir-java-format, @chongkai! Before we can accept your pull request, you need to sign our contributor license agreement - just visit https://cla.palantir.com/ and follow the instructions. Once you sign, I'll automatically update this pull request.

[changelog-app]

Generate changelog in changelog/@unreleased

Type (Select exactly one)

• Feature (Adding new functionality)
• Improvement (Improving existing functionality)
• Fix (Fixing an issue with existing functionality)
• Break (Creating a new major version by breaking public APIs)
• Deprecation (Removing functionality in a non-breaking way)
• Migration (Automatically moving data/functionality to a new system)

Description

Output unnamed variables

Check the box to generate changelog(s)

• Generate changelog entry

[olsavmic]

Hello, just wanted to check in — I’d really appreciate if we could move forward with this fix as it’s something I also need 🙏 Thanks a ton in advance! 💪✨

I see tests are missing, that could prolong the code-review process 🤔

[chongkai]

looks like I have missed the opportunity to add the change log entry when asked by the bot. How can I add one manually now?

PS, has anyone reviewed this PR?