Use immutable data structures

[6543]

well there are third-partys ...

https://github.com/benbjohnson/immutable
https://github.com/fishy/go-immutable
...
but if they work for us, i dont know. as we have to de-/serialize from/to json inbetween

but it would bring us 1. performance and 2. more savety to alter not to be altered data

[6543]

e.g. #3135 (comment)

[lafriks]

Why do we need them?

[6543]

1. performance
2. type savety
3. security

[lafriks]

More context would probably be needed but...

1. Immutable will have additional cost (performance/memory usage will degrade as it makes copies of lists/maps)
2. We already have type safety except only in some cases but I don't think in these cases immutable will help anyway.