I see that my team mates are using

lateinit var

for things that should be downloaded first. Is it good practice? (I don’t like it)

IMO lateinit var should only be used when there is a guarantee that variable will be initialized immediately (just not in the constructor)

Any good thoughts to explain it?

What happens if download fails? It throws that variable has not been initialised? That does not seem logical from the exception.

it just ignores logic that is there or tries redownload

Could you show the code? I don't understand why a lateinit var is needed if the logic is skipped on failure. Where is the variable accessed then? Or are there checks everywhere if the download succeeded?

My thumb of rule: if you got a case that you need

isInitialised

than you misuse lateinit and should use nullable instead

I wonder what's the use case that they added

isInitialised

for because like you said if you use it you should probably use nullable type instead.

Because it may be needed for some rare cases, for example for libraries that set lateinit, but most probably it’s not needef for common code

Thank you for comments, if it would be official Kotlin guides about usage of

lateinit var

then it would be great

My rule of thumb is like Andrey's. Only use lateinit if you don't control the object's lifecycle (eg Activity), a 3rd party library injects upon construction (eg Dagger) or a lateinit represents an expensive resources (still, prefer 'lazy' in this case). And I agree, it's a major codesmell when you need 'isInitialized'.