Better control for nested wildcard behavior with the distinct validation rule

[joelclermont]

I bumped into something I found a bit unintuitive with nested wildcards.

If we have a rule like this
'field.*.*' => ['distinct']

And data like this
'field' => [[1,2,3], [4,5,6], [1,4]]

I would have expected it to pass the validation rule because each array has internally distinct values. But because of how wildcard expansion works, it flattens those fields into a single array [1,2,3,4,5,6,1,4] for the distinct check, which fails validation.

This can be worked around in a few different ways. (I wrote this up more thoroughly here)

Additionally, I realize that some people might rely on this behavior, and changing it would be a backward compatibility break, but it still strikes me as potentially confusing. I did a very small informal poll among other Laravel devs, and they all assumed distinct would operate on each individual array of values, not a flattened set of values.

I'm not sure what a better solution is. I thought maybe a different character like field._.* to more explicitly define where you want wildcard expansion to limit flattening.

Am I alone in thinking this could be improved? Is there a better idea for how to explicitly define this?

[esetnik]

I ran into the same issue as @joelclermont and found the default wildcard expansion behavior to be quite surprising and unexpected. I agree that using something like field._.* would be a good way to prevent this behavior and essentially create a scoped set of validations to run on each array element at the depth of _.