ARRAY_UNIQUE_IDENTICAL option

Hi internals There's an open bug report that array_unique doesn't work for enums: https://github.com/php/php-src/issues/9775 This comes down to the fact that array_unique internally sorts the array before iterating over it to remove duplicates, and that enums are intentionally incomparable. Foo::Bar < Foo::Baz // false Foo::Baz < Foo::Bar // false Unfortunately, this means that array_unique might coincidentally work fine if the array is already sorted, or gets correctly sorted by chance while breaking otherwise. To solve this, I propose adding an ARRAY_UNIQUE_IDENTICAL option that can be passed to array_uniques $flags which uses identical operator (===) semantics. Internally it uses a new hashmap that allows using arbitrary PHP values as keys to efficiently remove duplicates. This is slightly over-engineered for this use case. However, this data structure will be required for implementing ADTs to deduplicate instances with the same values. This hashmap is a heavily minimized version of the teds extensions StrictHashMap [1]. Time complexity of this function is O(n). With the exception of SORT_STRING (which uses PHPs existing hashmap in a very similar fashion and also has O(n)) it should scale better than the other sort options which are O(n log n). Here's a link to the implementation: https://github.com/php/php-src/pull/9882/files If there are no concerns or complaints I'd like to merge this into PHP 8.3. Otherwise I will create an RFC. Looking forward to your feedback. Ilija [1| https://github.com/TysonAndre/pecl-teds/blob/main/teds_stricthashmap.c