immutable | Declare methods as immutable , somewhat like Java | Functional Programming library

i face the same problem, i think Spark 3.2 is the problem itself

switched to Spark 3.1.2, it works fine

Is there a way to work around this issue without imposing additional constraints on map key and value types?

It doesn't appear doable in safe Rust, at least not with reasonable algorithmic complexity. (See Aiden4's answer for a solution that does it by re-building the whole map.)

But if you're allowed to use unsafe, and if you're determined enough that you want to delve into it, this code could do it:

You can't make Python classes fully immutable. You can however imitate it:

Yes, this is a copy, since without & it's moving and moving i32 is copying it since it implements the Copy trait (moreover, you cannot move out of an index, so this must be a copy).

Edit: As suggested by @prog-fh in the comment, if you use a non-Copy type the compiler will tell you that:

In this case, the pending intent for the geofence needs to use FLAG_MUTABLE while the notification pending intent needs to use FLAG_IMMUTABLE. Unfortunately, they have not updated the documentation or the codelabs example for targeting Android 12 yet. Here's how I modified the codelabs geofence example to work.

First, update gradle to target SDK31.

In HuntMainActivity, change the geofencePendingIntent to:

If I understand the Raku docs correctly, the elements of Arrays are always containerized, i.e. Scalars.

That's almost correct, but not quite – Array initialization (i.e., with [1, 2]) containerizes the values, but that doesn't mean that elements are always containerized. For example, you can explicitly bind a value to a position in an array.

Or, as you've discovered, you can wind up with a non-containerized value when creating an Array in an unusual way. Let's take a look at what deepmap is doing here:

Just assign via binding to wrapped value, like

Somehow, answering the questions parts in the opposite order felt more natural to me. :-)

Second, does auto-flattening allow any behavior that would be impossible if the left hand side were non-flattening?

It's relatively common to want to assign the first (or first few) items of a list into scalars and have the rest placed into an array. List assignment descending into iterables on the left is what makes this work:

Coming off @raiphs comment, I have figured out a quick and dirty fix that uses the fact that I know the .say method works to produce the unadorned value of the Object...

... OO programming purists, please look away now.