Add a rule to flag places where `ifBlank` and `ifEmpty` can be used

[BraisGabin]

Kotlin provides the functions ifBlank and ifEmpty so we should flag the points where this functions could be used. Example:

if (api.name.isBlank()) "John" else api.name
can be replaced to:
api.name.ifBlank { "John" }

The same for ifEmpty.

Context

https://twitter.com/kotlin/status/1277897234043097090

[schalkms]

This would go into the style ruleset in my point of view.

[adwsingh]

If no one is working on this, would like to take a stab at it. :)

[schalkms]

Thanks @MehWhatever for the help! We really appreciate your help.
It's all yours. 🙂

[adwsingh]

Do we also want to handle things like,

if (x.isBlank()) {
       return "A"
} else {
      return x
}

Though by opening that door, it would also make sense to catch these,

if (x.isBlank()) {
       return "A"
} 
return x

Which seems to be slightly tricky to catch.

On another note do we have a style rule for this,

if(something){
   return x
}
else {
   return y
}

to return if(something) x else y

[schalkms]

I think it's better to start simple and improve in subsequent PRs.

[BraisGabin]

if (x.isBlank()) {
       return "A"
} 
return x

I think that this case can be generalized and create a new rule for it. I think that the desired code here should be:

return if (x.isBlank()) {
       "A"
} else {
       x
}

I mean. a rule that detects an if that ends with a return and followed by that a return that could be changed by an else. Do you agree? But I think that we need a different issue to track this.

On another note do we have a style rule for this,

if(something){
   return x
}
else {
   return y
}

This should be handled by formatting. This is implemented by ktlint already.

[BraisGabin]

@MehWhatever I'm unassigning you from this issue. If you are still interested in this issue you can open the PR anyway :)