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kotlinlang

Does Kotlin provide a way to easily *diff* two objects, recursively?

```foo.bar.baz.x // 5
val copy = foo
foo.bar.baz.x = 7

diff(copy, foo) // { field: .bar.baz.x, before: 5, after: 7 }```

AFAIK not. It isn’t a very trivial problem. For a previous project I rolled my own. But I guess that with some compiler plugin magic a lot is possible. With reflection you can also get pretty far.


In which form would you expect this to happen? What type would `diff` return?
If you want to diff for debug purposes or in a textual form in general, you could consider serializing to JSON and diffing the JSON as text (there are libraries for this AFAIK)

For instance this one might help with the text diff: <https://github.com/GitLiveApp/kotlin-diff-utils|https://github.com/GitLiveApp/kotlin-diff-utils>

That "copy" only copied the reference so there won't actually be a diff.