ktlint: `0.45.0` backwards incompatibility: `KtLint.Params#userData` gets ignored, unclear migration path + more feedback

Initially reported on Kotlin slack: https://kotlinlang.slack.com/archives/CKS3XG0LS/p1647897839331439 but I was asked to create issue here.

Expected Behavior

0.45.0 is backward compatible with 0.44.0, or has clear migration path

Observed Behavior

I’ll copy-paste what I wrote on Slack:

1. Can someone share what’s the future of userData map, does it only change its purpose, or will it be removed completely at some point? The code I was upgrading had been passing indent_size and disabled_rules within userData map. The migration path for indent_size seemed to be hidden but I was able to identify DefaultEditorConfigProperties.indentSizeProperty which looked legitimate and worked in my case, but I couldn’t find a replacement for disabled_rules. The fact ExperimentalParams still takes userData suggests that’s still the “recommended” option, am I wrong here? What’s the proper way to pass rules that I expect to be disabled?
2. It seems like there is a behavior change introduced in 0.45.0, where values passed as userData using the now deprecated lint method are ignored. Maybe I misread the release notes, but they had vibe you strongly advise to migrate now, because later it will be more difficult, but in overall 0.45.0 is still backwards compatible. If breaking the compatibility was intended, then I’ll share my personal opinion: I think it would be better for api consumers if you removed the method already in this release so api consumers would get a compile-time error, instead of runtime one (or bug reports from end users 😛). If breaking the compatibility wasn’t intended, then FYI it did, at least the case described above 😛 And just for context: I attempted to bump ktlint in Gradle Plugin, so I might be missing something here, as the release notes weren’t 100% clear for me (for example: I’ve never seen ASTNode.getEditorConfigValue(editorConfigProperty) or EDITOR_CONFIG_USER_DATA_KEY mentioned there 😬 )
3. I noticed isUnitTestContext = true gets passed when calling any of KtLint#lint methods. It doesn’t break anything, but looks suspicious, so I thought it might be worth pointing out, especially when seeing todos like this 👇 AFAIU both ktlint-gradle and kotlinter-gradle use lint and format in regular usage, not in tests soo… 👀

Feel free to split them into 3 separate issues if it’s more convenient for you 😃

Steps to Reproduce

Run KtLint.lint(KtLint.Params(userData = mapOf("indent_size" to "5"), ...)) on a file with respective indentation and observe the lint reporting failures.

Your Environment

• Version of ktlint used: 0.45.1
• Relevant parts of the .editorconfig settings: none
• Name and version (or code for custom task) of integration used (Gradle plugin, Maven plugin, command line, custom Gradle task): I tried to upgrade kotlinter-gradle and the tests failed: https://github.com/jeremymailen/kotlinter-gradle/pull/243/files I had to switch to the ExperimentalParams class which introduced even more confusion - hence all the questions above
• Version of Gradle used (if applicable): it’s not
• Operating System and version: macos-latest, windows-latest