Introduce #[pallet::call_index] attribute to dispatchables (#11381)

* Introduce #[pallet::call_index] attribute to dispatchables

* cargo fmt

* Add more docs and prevent duplicates of call indices

* Add UI test for conflicting call indices

* cargo fmt

Co-authored-by: parity-processbot <>

substrate/frame/support/test/tests/pallet_ui/call_conflicting_indices.rs

@@ -0,0 +1,24 @@
+#[frame_support::pallet]
+mod pallet {
+	use frame_support::pallet_prelude::DispatchResultWithPostInfo;
+
+	#[pallet::config]
+	pub trait Config: frame_system::Config {}
+
+	#[pallet::pallet]
+	pub struct Pallet<T>(core::marker::PhantomData<T>);
+
+	#[pallet::call]
+	impl<T: Config> Pallet<T> {
+		#[pallet::weight(0)]
+		#[pallet::call_index(10)]
+		pub fn foo(origin: OriginFor<T>) -> DispatchResultWithPostInfo {}
+
+		#[pallet::weight(0)]
+		#[pallet::call_index(10)]
+		pub fn bar(origin: OriginFor<T>) -> DispatchResultWithPostInfo {}
+	}
+}
+
+fn main() {
+}

substrate/frame/support/test/tests/pallet_ui/call_conflicting_indices.stderr

@@ -0,0 +1,11 @@
+error: Call indices are conflicting: Both functions foo and bar are at index 10
+  --> tests/pallet_ui/call_conflicting_indices.rs:15:10
+   |
+15 |         pub fn foo(origin: OriginFor<T>) -> DispatchResultWithPostInfo {}
+   |                ^^^
+
+error: Call indices are conflicting: Both functions foo and bar are at index 10
+  --> tests/pallet_ui/call_conflicting_indices.rs:19:10
+   |
+19 |         pub fn bar(origin: OriginFor<T>) -> DispatchResultWithPostInfo {}
+   |                ^^^

substrate/frame/support/test/tests/pallet_ui/call_invalid_attr.rs

@@ -0,0 +1,20 @@
+#[frame_support::pallet]
+mod pallet {
+	use frame_support::pallet_prelude::DispatchResultWithPostInfo;
+	use frame_system::pallet_prelude::OriginFor;
+
+	#[pallet::config]
+	pub trait Config: frame_system::Config {}
+
+	#[pallet::pallet]
+	pub struct Pallet<T>(core::marker::PhantomData<T>);
+
+	#[pallet::call]
+	impl<T: Config> Pallet<T> {
+		#[pallet::weird_attr]
+		pub fn foo(origin: OriginFor<T>) -> DispatchResultWithPostInfo {}
+	}
+}
+
+fn main() {
+}

substrate/frame/support/test/tests/pallet_ui/call_invalid_attr.stderr

@@ -0,0 +1,5 @@
+error: expected `weight` or `call_index`
+  --> tests/pallet_ui/call_invalid_attr.rs:14:13
+   |
+14 |         #[pallet::weird_attr]
+   |                   ^^^^^^^^^^

substrate/frame/support/test/tests/pallet_ui/call_invalid_index.rs

@@ -0,0 +1,21 @@
+#[frame_support::pallet]
+mod pallet {
+	use frame_support::pallet_prelude::DispatchResultWithPostInfo;
+	use frame_system::pallet_prelude::OriginFor;
+
+	#[pallet::config]
+	pub trait Config: frame_system::Config {}
+
+	#[pallet::pallet]
+	pub struct Pallet<T>(core::marker::PhantomData<T>);
+
+	#[pallet::call]
+	impl<T: Config> Pallet<T> {
+		#[pallet::weight(0)]
+		#[pallet::call_index(256)]
+		pub fn foo(origin: OriginFor<T>) -> DispatchResultWithPostInfo {}
+	}
+}
+
+fn main() {
+}

substrate/frame/support/test/tests/pallet_ui/call_invalid_index.stderr

@@ -0,0 +1,5 @@
+error: number too large to fit in target type
+  --> tests/pallet_ui/call_invalid_index.rs:15:24
+   |
+15 |         #[pallet::call_index(256)]
+   |                              ^^^

substrate/frame/support/test/tests/pallet_ui/call_multiple_call_index.rs

@@ -0,0 +1,22 @@
+#[frame_support::pallet]
+mod pallet {
+	use frame_support::pallet_prelude::DispatchResultWithPostInfo;
+	use frame_system::pallet_prelude::OriginFor;
+
+	#[pallet::config]
+	pub trait Config: frame_system::Config {}
+
+	#[pallet::pallet]
+	pub struct Pallet<T>(core::marker::PhantomData<T>);
+
+	#[pallet::call]
+	impl<T: Config> Pallet<T> {
+		#[pallet::weight(0)]
+		#[pallet::call_index(1)]
+		#[pallet::call_index(2)]
+		pub fn foo(origin: OriginFor<T>) -> DispatchResultWithPostInfo {}
+	}
+}
+
+fn main() {
+}

substrate/frame/support/test/tests/pallet_ui/call_multiple_call_index.stderr

@@ -0,0 +1,5 @@
+error: Invalid pallet::call, too many call_index attributes given
+  --> tests/pallet_ui/call_multiple_call_index.rs:17:7
+   |
+17 |         pub fn foo(origin: OriginFor<T>) -> DispatchResultWithPostInfo {}
+   |             ^^