Add URLEqualHashCode Recipe

[JLLeitschuh]

Based upon, but not completely fixing this: https://errorprone.info/bugpattern/URLEqualsHashCode

Signed-off-by: Jonathan Leitschuh Jonathan.Leitschuh@gmail.com

What's changed?

Adds a recipe URLEqualsHashCode.

What's your motivation?

I was curious about trying out the new template recipe generation. This seemed like a fun way to try it out.

Anything in particular you'd like reviewers to focus on?

Are there any use cases/tests that I likely missed?

Anyone you would like to review specifically?

Have you considered any alternatives or workarounds?

Thought about writing the recipe not using the template engine, but this seemed like a good use case.

Also, the reason I'm using URI#toString to create a URI, instead of URL#toURI is because URL#toURI throws a checked exception

Any additional context

Checklist

• I've added unit tests to cover both positive and negative cases
• I've read and applied the recipe conventions and best practices
• I've used the IntelliJ IDEA auto-formatter on affected files

[knutwannheden]

Interesting. I suppose there are also legitimate uses (like file URLs). Otherwise any HashSet or HashMap would also be problematic. In this case the URLs are known to be for files: https://github.com/jetty/jetty.project/blob/5d9679adf861bc589fdb213758a88f16436f6286/jetty-webapp/src/main/java/org/eclipse/jetty/webapp/MetaInfConfiguration.java#L660

[JLLeitschuh]

Interesting insight. Not sure if there's a great way to detect that. In general, this could be an optionally applied recipe.

Dealing with collections could be super complicated, especially when the collection is returned/escapes the scope of the method.

[JLLeitschuh]

Is this good to merge?

[knutwannheden]

I think we should add some Markdown formatting here. Also, I don't think the errorprone tag is very useful. Does Errorprone have a check of this type?

[JLLeitschuh]

https://errorprone.info/bugpattern/URLEqualsHashCode

I'll add the markdown formatting. Good point. 😄