Auto-incremental CollectionId (#11796)

* autoincrementing CollectionId

* fix

* benchmarking fix

* fmt

* fix

* update before checking

* fmt

* fix

* fmt

* commit

* tests & fix

* fix

* commit

* docs

* safe math

* unexpose function

* benchmark

* fmt

* better naming

* fix?

* merge fixes

* fmt

* ".git/.scripts/bench-bot.sh" pallet dev pallet_uniques

* wrong weight

* Update frame/uniques/src/lib.rs

Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Update frame/uniques/src/lib.rs

Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* using substrate trait instead of num-traits

* remove unnecessary trait

* emit NextCollectionIdIncremented in do_create_collection

* fix in benchmarks

* check for event & group import

* docs

Co-authored-by: Sergej Sakač <sergejsakac@Sergejs-MacBook-Air.local>
Co-authored-by: command-bot <>
Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

substrate/frame/uniques/src/functions.rs

@@ -88,7 +88,12 @@ impl<T: Config<I>, I: 'static> Pallet<T, I> {
 			},
 		);
 
+		let next_id = collection.saturating_add(1u32.into());
+
 		CollectionAccount::<T, I>::insert(&owner, &collection, ());
+		NextCollectionId::<T, I>::set(next_id);
+
+		Self::deposit_event(Event::NextCollectionIdIncremented { next_id });
 		Self::deposit_event(event);
 		Ok(())
 	}
@@ -208,6 +213,16 @@ impl<T: Config<I>, I: 'static> Pallet<T, I> {
 		Ok(())
 	}
 
+	#[cfg(any(test, feature = "runtime-benchmarks"))]
+	pub fn set_next_id(count: u32) {
+		NextCollectionId::<T, I>::set(count.into());
+	}
+
+	#[cfg(test)]
+	pub fn get_next_id() -> T::CollectionId {
+		NextCollectionId::<T, I>::get()
+	}
+
 	pub fn do_set_price(
 		collection: T::CollectionId,
 		item: T::ItemId,