Make System Events Private from the Runtime (#9619)

* make events private

* "i know what i am doing"

* feedback

substrate/frame/system/src/lib.rs

@@ -612,9 +612,12 @@ pub mod pallet {
 	pub(super) type Digest<T: Config> = StorageValue<_, DigestOf<T>, ValueQuery>;
 
 	/// Events deposited for the current block.
+	///
+	/// NOTE: This storage item is explicitly unbounded since it is never intended to be read
+	/// from within the runtime.
 	#[pallet::storage]
-	#[pallet::getter(fn events)]
-	pub type Events<T: Config> = StorageValue<_, Vec<EventRecord<T::Event, T::Hash>>, ValueQuery>;
+	pub(super) type Events<T: Config> =
+		StorageValue<_, Vec<EventRecord<T::Event, T::Hash>>, ValueQuery>;
 
 	/// The number of events in the `Events<T>` list.
 	#[pallet::storage]
@@ -1448,6 +1451,24 @@ impl<T: Config> Pallet<T> {
 		})
 	}
 
+	/// Get the current events deposited by the runtime.
+	///
+	/// NOTE: This should only be used in tests. Reading events from the runtime can have a large
+	/// impact on the PoV size of a block. Users should use alternative and well bounded storage
+	/// items for any behavior like this.
+	#[cfg(any(feature = "std", feature = "runtime-benchmarks", test))]
+	pub fn events() -> Vec<EventRecord<T::Event, T::Hash>> {
+		Self::read_events_no_consensus()
+	}
+
+	/// Get the current events deposited by the runtime.
+	///
+	/// Should only be called if you know what you are doing and outside of the runtime block
+	/// execution else it can have a large impact on the PoV size of a block.
+	pub fn read_events_no_consensus() -> Vec<EventRecord<T::Event, T::Hash>> {
+		Events::<T>::get()
+	}
+
 	/// Set the block number to something in particular. Can be used as an alternative to
 	/// `initialize` for tests that don't need to bother with the other environment entries.
 	#[cfg(any(feature = "std", feature = "runtime-benchmarks", test))]