Support enums in array_unique

[iluuu1994]

Fixes GH-9775

As suggested in #9775 (comment).

I'm a little concerned about performance regression. Also, I think this is observable in min/max. These functions always return something, so it might as well return something that is consistent.

[bwoebi]

I would change the two branches, given that the IS_OBJECT check will typically be consistently true or false, but result will be wildly unpredictable. The Bucket should be in L1 cache after the comparison.

[iluuu1994]

In that case we may just remove the result branch because once we've established an enum is involved it should always be uncomparable. Edit: Unless you mean type == IS_OBJECT && result == UNCOMPARABLE && class->ce_flags & ZEND_ACC_ENUM?

[bwoebi]

@iluuu1994 Sounds right.

But put the UNEXPECTED() around the IS_OBJECT comparison in particular, not the whole condition.

[iluuu1994]

Before merging, add a comment that this is added for array_unique. Otherwise this may seem cryptic.

[bwoebi]

Looks good to me.

[iluuu1994]

Ugh, this doesn't handle references... They are usually unwrapped in zend_compare. I will need to fix that.