// This file is part of Substrate. // Copyright (C) Parity Technologies (UK) Ltd. // SPDX-License-Identifier: Apache-2.0 // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. //! Support code for the runtime. //! //! ## Note on Tuple Traits //! //! Many of the traits defined in [`traits`] have auto-implementations on tuples as well. Usually, //! the tuple is a function of number of pallets in the runtime. By default, the traits are //! implemented for tuples of up to 64 items. // // If you have more pallets in your runtime, or for any other reason need more, enabled `tuples-96` // or the `tuples-128` complication flag. Note that these features *will increase* the compilation // of this crate. #![cfg_attr(not(feature = "std"), no_std)] /// Export ourself as `frame_support` to make tests happy. extern crate self as frame_support; /// Private exports that are being used by macros. /// /// The exports are not stable and should not be relied on. #[doc(hidden)] pub mod __private { pub use codec; pub use frame_metadata as metadata; pub use log; pub use paste; pub use scale_info; pub use serde; pub use sp_core::{OpaqueMetadata, Void}; pub use sp_core_hashing_proc_macro; pub use sp_io::{self, storage::root as storage_root}; pub use sp_metadata_ir as metadata_ir; #[cfg(feature = "std")] pub use sp_runtime::{bounded_btree_map, bounded_vec}; pub use sp_runtime::{traits::Dispatchable, RuntimeDebug, StateVersion}; #[cfg(feature = "std")] pub use sp_state_machine::BasicExternalities; pub use sp_std; pub use sp_tracing; pub use tt_call::*; } #[macro_use] pub mod dispatch; pub mod crypto; pub mod dispatch_context; mod hash; pub mod inherent; pub mod instances; pub mod migrations; pub mod storage; #[cfg(test)] mod tests; pub mod traits; pub mod weights; #[doc(hidden)] pub mod unsigned { #[doc(hidden)] pub use crate::sp_runtime::traits::ValidateUnsigned; #[doc(hidden)] pub use crate::sp_runtime::transaction_validity::{ TransactionSource, TransactionValidity, TransactionValidityError, UnknownTransaction, }; } #[cfg(any(feature = "std", feature = "runtime-benchmarks", feature = "try-runtime", test))] pub use self::storage::storage_noop_guard::StorageNoopGuard; pub use self::{ dispatch::{Callable, Parameter}, hash::{ Blake2_128, Blake2_128Concat, Blake2_256, Hashable, Identity, ReversibleStorageHasher, StorageHasher, Twox128, Twox256, Twox64Concat, }, storage::{ bounded_btree_map::BoundedBTreeMap, bounded_btree_set::BoundedBTreeSet, bounded_vec::{BoundedSlice, BoundedVec}, migration, weak_bounded_vec::WeakBoundedVec, IterableStorageDoubleMap, IterableStorageMap, IterableStorageNMap, StorageDoubleMap, StorageMap, StorageNMap, StoragePrefixedMap, StorageValue, }, }; pub use sp_runtime::{ self, print, traits::Printable, ConsensusEngineId, MAX_MODULE_ERROR_ENCODED_SIZE, }; use codec::{Decode, Encode}; use scale_info::TypeInfo; use sp_runtime::TypeId; /// A unified log target for support operations. pub const LOG_TARGET: &str = "runtime::frame-support"; /// A type that cannot be instantiated. #[derive(Encode, Decode, Debug, PartialEq, Eq, Clone, TypeInfo)] pub enum Never {} /// A pallet identifier. These are per pallet and should be stored in a registry somewhere. #[derive(Clone, Copy, Eq, PartialEq, Encode, Decode, TypeInfo)] pub struct PalletId(pub [u8; 8]); impl TypeId for PalletId { const TYPE_ID: [u8; 4] = *b"modl"; } /// Generate a [`#[pallet::storage]`](pallet_macros::storage) alias outside of a pallet. /// /// This storage alias works similarly to the [`#[pallet::storage]`](pallet_macros::storage) /// attribute macro. It supports [`StorageValue`](storage::types::StorageValue), /// [`StorageMap`](storage::types::StorageMap), /// [`StorageDoubleMap`](storage::types::StorageDoubleMap) and /// [`StorageNMap`](storage::types::StorageNMap). The main difference to the normal /// [`#[pallet::storage]`](pallet_macros::storage) is the flexibility around declaring the /// storage prefix to use. The storage prefix determines where to find the value in the /// storage. [`#[pallet::storage]`](pallet_macros::storage) uses the name of the pallet as /// declared in [`construct_runtime!`]. /// /// The flexibility around declaring the storage prefix makes this macro very useful for /// writing migrations etc. /// /// # Examples /// /// There are different ways to declare the `prefix` to use. The `prefix` type can either be /// declared explicetly by passing it to the macro as an attribute or by letting the macro /// guess on what the `prefix` type is. The `prefix` is always passed as the first generic /// argument to the type declaration. When using [`#[pallet::storage]`](pallet_macros::storage) /// this first generic argument is always `_`. Besides declaring the `prefix`, the rest of the /// type declaration works as with [`#[pallet::storage]`](pallet_macros::storage). /// /// 1. Use the `verbatim` prefix type. This prefix type uses the given identifier as the /// `prefix`: #[doc = docify::embed!("src/tests/storage_alias.rs", verbatim_attribute)] /// /// 2. Use the `pallet_name` prefix type. This prefix type uses the name of the pallet as /// configured in [`construct_runtime!`] as the `prefix`: #[doc = docify::embed!("src/tests/storage_alias.rs", pallet_name_attribute)] /// It requires that the given prefix type implements /// [`PalletInfoAccess`](traits::PalletInfoAccess) (which is always the case for FRAME pallet /// structs). In the example above, `Pallet` is the prefix type. /// /// 3. Use the `dynamic` prefix type. This prefix type calls [`Get::get()`](traits::Get::get) /// to get the `prefix`: #[doc = docify::embed!("src/tests/storage_alias.rs", dynamic_attribute)] /// It requires that the given prefix type implements [`Get<'static str>`](traits::Get). /// /// 4. Let the macro "guess" what kind of prefix type to use. This only supports verbatim or /// pallet name. The macro uses the presence of generic arguments to the prefix type as an /// indication that it should use the pallet name as the `prefix`: #[doc = docify::embed!("src/tests/storage_alias.rs", storage_alias_guess)] pub use frame_support_procedural::storage_alias; pub use frame_support_procedural::derive_impl; /// Create new implementations of the [`Get`](crate::traits::Get) trait. /// /// The so-called parameter type can be created in four different ways: /// /// - Using `const` to create a parameter type that provides a `const` getter. It is required that /// the `value` is const. /// /// - Declare the parameter type without `const` to have more freedom when creating the value. /// /// - Using `storage` to create a storage parameter type. This type is special as it tries to load /// the value from the storage under a fixed key. If the value could not be found in the storage, /// the given default value will be returned. It is required that the value implements /// [`Encode`](codec::Encode) and [`Decode`](codec::Decode). The key for looking up the value in /// the storage is built using the following formula: /// /// `twox_128(":" ++ NAME ++ ":")` where `NAME` is the name that is passed as type name. /// /// - Using `static` to create a static parameter type. Its value is being provided by a static /// variable with the equivalent name in `UPPER_SNAKE_CASE`. An additional `set` function is /// provided in this case to alter the static variable. **This is intended for testing ONLY and is /// ONLY available when `std` is enabled.** /// /// # Examples /// /// ``` /// # use frame_support::traits::Get; /// # use frame_support::parameter_types; /// // This function cannot be used in a const context. /// fn non_const_expression() -> u64 { 99 } /// /// const FIXED_VALUE: u64 = 10; /// parameter_types! { /// pub const Argument: u64 = 42 + FIXED_VALUE; /// /// Visibility of the type is optional /// OtherArgument: u64 = non_const_expression(); /// pub storage StorageArgument: u64 = 5; /// pub static StaticArgument: u32 = 7; /// } /// /// trait Config { /// type Parameter: Get; /// type OtherParameter: Get; /// type StorageParameter: Get; /// type StaticParameter: Get; /// } /// /// struct Runtime; /// impl Config for Runtime { /// type Parameter = Argument; /// type OtherParameter = OtherArgument; /// type StorageParameter = StorageArgument; /// type StaticParameter = StaticArgument; /// } /// /// // In testing, `StaticArgument` can be altered later: `StaticArgument::set(8)`. /// ``` /// /// # Invalid example: /// /// ```compile_fail /// # use frame_support::traits::Get; /// # use frame_support::parameter_types; /// // This function cannot be used in a const context. /// fn non_const_expression() -> u64 { 99 } /// /// parameter_types! { /// pub const Argument: u64 = non_const_expression(); /// } /// ``` #[macro_export] macro_rules! parameter_types { ( $( #[ $attr:meta ] )* $vis:vis const $name:ident $(< $($ty_params:ident),* >)?: $type:ty = $value:expr; $( $rest:tt )* ) => ( $( #[ $attr ] )* $vis struct $name $( < $($ty_params),* >( $($crate::__private::sp_std::marker::PhantomData<$ty_params>),* ) )?; $crate::parameter_types!(IMPL_CONST $name , $type , $value $( $(, $ty_params)* )?); $crate::parameter_types!( $( $rest )* ); ); ( $( #[ $attr:meta ] )* $vis:vis $name:ident $(< $($ty_params:ident),* >)?: $type:ty = $value:expr; $( $rest:tt )* ) => ( $( #[ $attr ] )* $vis struct $name $( < $($ty_params),* >( $($crate::__private::sp_std::marker::PhantomData<$ty_params>),* ) )?; $crate::parameter_types!(IMPL $name, $type, $value $( $(, $ty_params)* )?); $crate::parameter_types!( $( $rest )* ); ); ( $( #[ $attr:meta ] )* $vis:vis storage $name:ident $(< $($ty_params:ident),* >)?: $type:ty = $value:expr; $( $rest:tt )* ) => ( $( #[ $attr ] )* $vis struct $name $( < $($ty_params),* >( $($crate::__private::sp_std::marker::PhantomData<$ty_params>),* ) )?; $crate::parameter_types!(IMPL_STORAGE $name, $type, $value $( $(, $ty_params)* )?); $crate::parameter_types!( $( $rest )* ); ); () => (); (IMPL_CONST $name:ident, $type:ty, $value:expr $(, $ty_params:ident)*) => { impl< $($ty_params),* > $name< $($ty_params),* > { /// Returns the value of this parameter type. pub const fn get() -> $type { $value } } impl<_I: From<$type> $(, $ty_params)*> $crate::traits::Get<_I> for $name< $($ty_params),* > { fn get() -> _I { _I::from(Self::get()) } } impl< $($ty_params),* > $crate::traits::TypedGet for $name< $($ty_params),* > { type Type = $type; fn get() -> $type { Self::get() } } }; (IMPL $name:ident, $type:ty, $value:expr $(, $ty_params:ident)*) => { impl< $($ty_params),* > $name< $($ty_params),* > { /// Returns the value of this parameter type. pub fn get() -> $type { $value } } impl<_I: From<$type>, $(, $ty_params)*> $crate::traits::Get<_I> for $name< $($ty_params),* > { fn get() -> _I { _I::from(Self::get()) } } impl< $($ty_params),* > $crate::traits::TypedGet for $name< $($ty_params),* > { type Type = $type; fn get() -> $type { Self::get() } } }; (IMPL_STORAGE $name:ident, $type:ty, $value:expr $(, $ty_params:ident)*) => { #[allow(unused)] impl< $($ty_params),* > $name< $($ty_params),* > { /// Returns the key for this parameter type. pub fn key() -> [u8; 16] { $crate::__private::sp_core_hashing_proc_macro::twox_128!(b":", $name, b":") } /// Set the value of this parameter type in the storage. /// /// This needs to be executed in an externalities provided environment. pub fn set(value: &$type) { $crate::storage::unhashed::put(&Self::key(), value); } /// Returns the value of this parameter type. /// /// This needs to be executed in an externalities provided environment. #[allow(unused)] pub fn get() -> $type { $crate::storage::unhashed::get(&Self::key()).unwrap_or_else(|| $value) } } impl<_I: From<$type> $(, $ty_params)*> $crate::traits::Get<_I> for $name< $($ty_params),* > { fn get() -> _I { _I::from(Self::get()) } } impl< $($ty_params),* > $crate::traits::TypedGet for $name< $($ty_params),* > { type Type = $type; fn get() -> $type { Self::get() } } }; ( $( #[ $attr:meta ] )* $vis:vis static $name:ident: $type:ty = $value:expr; $( $rest:tt )* ) => ( $crate::parameter_types_impl_thread_local!( $( #[ $attr ] )* $vis static $name: $type = $value; ); $crate::parameter_types!( $( $rest )* ); ); } #[cfg(not(feature = "std"))] #[macro_export] macro_rules! parameter_types_impl_thread_local { ( $( $any:tt )* ) => { compile_error!("static parameter types is only available in std and for testing."); }; } #[cfg(feature = "std")] #[macro_export] macro_rules! parameter_types_impl_thread_local { ( $( $( #[ $attr:meta ] )* $vis:vis static $name:ident: $type:ty = $value:expr; )* ) => { $crate::parameter_types_impl_thread_local!( IMPL_THREAD_LOCAL $( $vis, $name, $type, $value, )* ); $crate::__private::paste::item! { $crate::parameter_types!( $( $( #[ $attr ] )* $vis $name: $type = [<$name:snake:upper>].with(|v| v.borrow().clone()); )* ); $( impl $name { /// Set the internal value. pub fn set(t: $type) { [<$name:snake:upper>].with(|v| *v.borrow_mut() = t); } /// Mutate the internal value in place. #[allow(unused)] pub fn mutate R>(mutate: F) -> R{ let mut current = Self::get(); let result = mutate(&mut current); Self::set(current); result } /// Get current value and replace with initial value of the parameter type. #[allow(unused)] pub fn take() -> $type { let current = Self::get(); Self::set($value); current } } )* } }; (IMPL_THREAD_LOCAL $( $vis:vis, $name:ident, $type:ty, $value:expr, )* ) => { $crate::__private::paste::item! { thread_local! { $( pub static [<$name:snake:upper>]: std::cell::RefCell<$type> = std::cell::RefCell::new($value); )* } } }; } /// Macro for easily creating a new implementation of both the `Get` and `Contains` traits. Use /// exactly as with `parameter_types`, only the type must be `Ord`. #[macro_export] macro_rules! ord_parameter_types { ( $( #[ $attr:meta ] )* $vis:vis const $name:ident: $type:ty = $value:expr; $( $rest:tt )* ) => ( $( #[ $attr ] )* $vis struct $name; $crate::parameter_types!{IMPL $name , $type , $value} $crate::ord_parameter_types!{IMPL $name , $type , $value} $crate::ord_parameter_types!{ $( $rest )* } ); () => (); (IMPL $name:ident , $type:ty , $value:expr) => { impl $crate::traits::SortedMembers<$type> for $name { fn contains(t: &$type) -> bool { &$value == t } fn sorted_members() -> $crate::__private::sp_std::prelude::Vec<$type> { vec![$value] } fn count() -> usize { 1 } #[cfg(feature = "runtime-benchmarks")] fn add(_: &$type) {} } impl $crate::traits::Contains<$type> for $name { fn contains(t: &$type) -> bool { &$value == t } } } } /// Print out a formatted message. /// /// # Example /// /// ``` /// frame_support::runtime_print!("my value is {}", 3); /// ``` #[macro_export] macro_rules! runtime_print { ($($arg:tt)+) => { { use core::fmt::Write; let mut w = $crate::__private::sp_std::Writer::default(); let _ = core::write!(&mut w, $($arg)+); $crate::__private::sp_io::misc::print_utf8(&w.inner()) } } } /// Print out the debuggable type. pub fn debug(data: &impl sp_std::fmt::Debug) { runtime_print!("{:?}", data); } #[doc(inline)] pub use frame_support_procedural::{ construct_runtime, match_and_insert, transactional, PalletError, RuntimeDebugNoBound, }; #[doc(hidden)] pub use frame_support_procedural::{__create_tt_macro, __generate_dummy_part_checker}; /// Derive [`Clone`] but do not bound any generic. /// /// This is useful for type generic over runtime: /// ``` /// # use frame_support::CloneNoBound; /// trait Config { /// type C: Clone; /// } /// /// // Foo implements [`Clone`] because `C` bounds [`Clone`]. /// // Otherwise compilation will fail with an output telling `c` doesn't implement [`Clone`]. /// #[derive(CloneNoBound)] /// struct Foo { /// c: T::C, /// } /// ``` pub use frame_support_procedural::CloneNoBound; /// Derive [`Eq`] but do not bound any generic. /// /// This is useful for type generic over runtime: /// ``` /// # use frame_support::{EqNoBound, PartialEqNoBound}; /// trait Config { /// type C: Eq; /// } /// /// // Foo implements [`Eq`] because `C` bounds [`Eq`]. /// // Otherwise compilation will fail with an output telling `c` doesn't implement [`Eq`]. /// #[derive(PartialEqNoBound, EqNoBound)] /// struct Foo { /// c: T::C, /// } /// ``` pub use frame_support_procedural::EqNoBound; /// Derive [`PartialEq`] but do not bound any generic. /// /// This is useful for type generic over runtime: /// ``` /// # use frame_support::PartialEqNoBound; /// trait Config { /// type C: PartialEq; /// } /// /// // Foo implements [`PartialEq`] because `C` bounds [`PartialEq`]. /// // Otherwise compilation will fail with an output telling `c` doesn't implement [`PartialEq`]. /// #[derive(PartialEqNoBound)] /// struct Foo { /// c: T::C, /// } /// ``` pub use frame_support_procedural::PartialEqNoBound; /// Derive [`Debug`] but do not bound any generic. /// /// This is useful for type generic over runtime: /// ``` /// # use frame_support::DebugNoBound; /// # use core::fmt::Debug; /// trait Config { /// type C: Debug; /// } /// /// // Foo implements [`Debug`] because `C` bounds [`Debug`]. /// // Otherwise compilation will fail with an output telling `c` doesn't implement [`Debug`]. /// #[derive(DebugNoBound)] /// struct Foo { /// c: T::C, /// } /// ``` pub use frame_support_procedural::DebugNoBound; /// Derive [`Default`] but do not bound any generic. /// /// This is useful for type generic over runtime: /// ``` /// # use frame_support::DefaultNoBound; /// # use core::default::Default; /// trait Config { /// type C: Default; /// } /// /// // Foo implements [`Default`] because `C` bounds [`Default`]. /// // Otherwise compilation will fail with an output telling `c` doesn't implement [`Default`]. /// #[derive(DefaultNoBound)] /// struct Foo { /// c: T::C, /// } /// /// // Also works with enums, by specifying the default with #[default]: /// #[derive(DefaultNoBound)] /// enum Bar { /// // Bar will implement Default as long as all of the types within Baz also implement default. /// #[default] /// Baz(T::C), /// Quxx, /// } /// ``` pub use frame_support_procedural::DefaultNoBound; /// Assert the annotated function is executed within a storage transaction. /// /// The assertion is enabled for native execution and when `debug_assertions` are enabled. /// /// # Example /// /// ``` /// # use frame_support::{ /// # require_transactional, transactional, dispatch::DispatchResult /// # }; /// /// #[require_transactional] /// fn update_all(value: u32) -> DispatchResult { /// // Update multiple storages. /// // Return `Err` to indicate should revert. /// Ok(()) /// } /// /// #[transactional] /// fn safe_update(value: u32) -> DispatchResult { /// // This is safe /// update_all(value) /// } /// /// fn unsafe_update(value: u32) -> DispatchResult { /// // this may panic if unsafe_update is not called within a storage transaction /// update_all(value) /// } /// ``` pub use frame_support_procedural::require_transactional; /// Convert the current crate version into a [`CrateVersion`](crate::traits::CrateVersion). /// /// It uses the `CARGO_PKG_VERSION_MAJOR`, `CARGO_PKG_VERSION_MINOR` and /// `CARGO_PKG_VERSION_PATCH` environment variables to fetch the crate version. /// This means that the [`CrateVersion`](crate::traits::CrateVersion) /// object will correspond to the version of the crate the macro is called in! /// /// # Example /// /// ``` /// # use frame_support::{traits::CrateVersion, crate_to_crate_version}; /// const Version: CrateVersion = crate_to_crate_version!(); /// ``` pub use frame_support_procedural::crate_to_crate_version; /// Return Err of the expression: `return Err($expression);`. /// /// Used as `fail!(expression)`. #[macro_export] macro_rules! fail { ( $y:expr ) => {{ return Err($y.into()) }}; } /// Evaluate `$x:expr` and if not true return `Err($y:expr)`. /// /// Used as `ensure!(expression_to_ensure, expression_to_return_on_false)`. #[macro_export] macro_rules! ensure { ( $x:expr, $y:expr $(,)? ) => {{ if !$x { $crate::fail!($y); } }}; } /// Evaluate an expression, assert it returns an expected `Err` value and that /// runtime storage has not been mutated (i.e. expression is a no-operation). /// /// Used as `assert_noop(expression_to_assert, expected_error_expression)`. #[macro_export] macro_rules! assert_noop { ( $x:expr, $y:expr $(,)? ) => { let h = $crate::__private::storage_root($crate::__private::StateVersion::V1); $crate::assert_err!($x, $y); assert_eq!( h, $crate::__private::storage_root($crate::__private::StateVersion::V1), "storage has been mutated" ); }; } /// Evaluate any expression and assert that runtime storage has not been mutated /// (i.e. expression is a storage no-operation). /// /// Used as `assert_storage_noop(expression_to_assert)`. #[macro_export] macro_rules! assert_storage_noop { ( $x:expr ) => { let h = $crate::__private::storage_root($crate::__private::StateVersion::V1); $x; assert_eq!(h, $crate::__private::storage_root($crate::__private::StateVersion::V1)); }; } /// Assert an expression returns an error specified. /// /// Used as `assert_err!(expression_to_assert, expected_error_expression)` #[macro_export] macro_rules! assert_err { ( $x:expr , $y:expr $(,)? ) => { assert_eq!($x, Err($y.into())); }; } /// Assert an expression returns an error specified. /// /// This can be used on `DispatchResultWithPostInfo` when the post info should /// be ignored. #[macro_export] macro_rules! assert_err_ignore_postinfo { ( $x:expr , $y:expr $(,)? ) => { $crate::assert_err!($x.map(|_| ()).map_err(|e| e.error), $y); }; } /// Assert an expression returns error with the given weight. #[macro_export] macro_rules! assert_err_with_weight { ($call:expr, $err:expr, $weight:expr $(,)? ) => { if let Err(dispatch_err_with_post) = $call { $crate::assert_err!($call.map(|_| ()).map_err(|e| e.error), $err); assert_eq!(dispatch_err_with_post.post_info.actual_weight, $weight); } else { panic!("expected Err(_), got Ok(_).") } }; } /// Panic if an expression doesn't evaluate to `Ok`. /// /// Used as `assert_ok!(expression_to_assert, expected_ok_expression)`, /// or `assert_ok!(expression_to_assert)` which would assert against `Ok(())`. #[macro_export] macro_rules! assert_ok { ( $x:expr $(,)? ) => { let is = $x; match is { Ok(_) => (), _ => assert!(false, "Expected Ok(_). Got {:#?}", is), } }; ( $x:expr, $y:expr $(,)? ) => { assert_eq!($x, Ok($y)); }; } /// Assert that the maximum encoding size does not exceed the value defined in /// [`MAX_MODULE_ERROR_ENCODED_SIZE`] during compilation. /// /// This macro is intended to be used in conjunction with `tt_call!`. #[macro_export] macro_rules! assert_error_encoded_size { { path = [{ $($path:ident)::+ }] runtime = [{ $runtime:ident }] assert_message = [{ $assert_message:literal }] error = [{ $error:ident }] } => { const _: () = assert!( < $($path::)+$error<$runtime> as $crate::traits::PalletError >::MAX_ENCODED_SIZE <= $crate::MAX_MODULE_ERROR_ENCODED_SIZE, $assert_message ); }; { path = [{ $($path:ident)::+ }] runtime = [{ $runtime:ident }] assert_message = [{ $assert_message:literal }] } => {}; } #[doc(hidden)] pub use serde::{Deserialize, Serialize}; #[doc(hidden)] #[cfg(not(no_std))] pub use macro_magic; /// Private module re-exporting items used by frame support macros. #[doc(hidden)] pub mod _private { pub use sp_inherents; } /// Prelude to be used for pallet testing, for ease of use. #[cfg(feature = "std")] pub mod testing_prelude { pub use super::{ assert_err, assert_err_ignore_postinfo, assert_err_with_weight, assert_error_encoded_size, assert_noop, assert_ok, assert_storage_noop, parameter_types, traits::Get, }; pub use sp_arithmetic::assert_eq_error_rate; pub use sp_runtime::{bounded_btree_map, bounded_vec}; } /// Prelude to be used alongside pallet macro, for ease of use. pub mod pallet_prelude { pub use crate::{ dispatch::{DispatchClass, DispatchResult, DispatchResultWithPostInfo, Parameter, Pays}, ensure, inherent::{InherentData, InherentIdentifier, ProvideInherent}, storage, storage::{ bounded_vec::BoundedVec, types::{ CountedStorageMap, CountedStorageNMap, Key as NMapKey, OptionQuery, ResultQuery, StorageDoubleMap, StorageMap, StorageNMap, StorageValue, ValueQuery, }, StorageList, }, traits::{ BuildGenesisConfig, ConstU32, EnsureOrigin, Get, GetDefault, GetStorageVersion, Hooks, IsType, PalletInfoAccess, StorageInfoTrait, StorageVersion, TypedGet, }, Blake2_128, Blake2_128Concat, Blake2_256, CloneNoBound, DebugNoBound, EqNoBound, Identity, PartialEqNoBound, RuntimeDebugNoBound, Twox128, Twox256, Twox64Concat, }; pub use codec::{Decode, Encode, MaxEncodedLen}; pub use frame_support::pallet_macros::*; /// The optional attribute `#[inject_runtime_type]` can be attached to `RuntimeCall`, /// `RuntimeEvent`, `RuntimeOrigin` or `PalletInfo` in an impl statement that has /// `#[register_default_impl]` attached to indicate that this item is generated by /// `construct_runtime`. /// /// Attaching this attribute to such an item ensures that the combined impl generated via /// [`#[derive_impl(..)]`](`macro@super::derive_impl`) will use the correct type /// auto-generated by `construct_runtime!`. #[doc = docify::embed!("src/tests/inject_runtime_type.rs", derive_impl_works_with_runtime_type_injection)] /// /// However, if `no_aggregated_types` is specified while using /// `[`#[derive_impl(..)]`](`macro@super::derive_impl`)`, then these items are attached /// verbatim to the combined impl. #[doc = docify::embed!("src/tests/inject_runtime_type.rs", derive_impl_works_with_no_aggregated_types)] pub use frame_support_procedural::inject_runtime_type; pub use frame_support_procedural::register_default_impl; pub use scale_info::TypeInfo; pub use sp_inherents::MakeFatalError; pub use sp_runtime::{ traits::{MaybeSerializeDeserialize, Member, ValidateUnsigned}, transaction_validity::{ InvalidTransaction, TransactionLongevity, TransactionPriority, TransactionSource, TransactionTag, TransactionValidity, TransactionValidityError, UnknownTransaction, ValidTransaction, }, DispatchError, RuntimeDebug, MAX_MODULE_ERROR_ENCODED_SIZE, }; pub use sp_std::marker::PhantomData; pub use sp_weights::Weight; } /// The `pallet` attribute macro defines a pallet that can be used with /// [`construct_runtime!`]. It must be attached to a module named `pallet` as follows: /// /// ```ignore /// #[pallet] /// pub mod pallet { /// ... /// } /// ``` /// /// Note that various types can be automatically imported using /// [`frame_support::pallet_prelude`] and `frame_system::pallet_prelude`: /// /// ```ignore /// #[pallet] /// pub mod pallet { /// use frame_support::pallet_prelude::*; /// use frame_system::pallet_prelude::*; /// ... /// } /// ``` /// /// # pallet::* Attributes /// /// The `pallet` macro will parse any items within your `pallet` module that are annotated with /// `#[pallet::*]` attributes. Some of these attributes are mandatory and some are optional, /// and they can attach to different types of items within your pallet depending on the /// attribute in question. The full list of `#[pallet::*]` attributes is shown below in the /// order in which they are mentioned in this document: /// /// * [`pallet::pallet`](#pallet-struct-placeholder-palletpallet-mandatory) /// * [`pallet::config`](#config-trait-palletconfig-mandatory) /// * [`pallet::constant`](#palletconstant) /// * [`pallet::disable_frame_system_supertrait_check`](#disable_supertrait_check) /// * [`pallet::generate_store($vis trait Store)`](#palletgenerate_storevis-trait-store) /// * [`pallet::storage_version`](#palletstorage_version) /// * [`pallet::hooks`](#hooks-pallethooks-optional) /// * [`pallet::call`](#call-palletcall-optional) /// * [`pallet::weight($expr)`](#palletweightexpr) /// * [`pallet::compact`](#palletcompact-some_arg-some_type) /// * [`pallet::call_index($idx)`](#palletcall_indexidx) /// * [`pallet::extra_constants`](#extra-constants-palletextra_constants-optional) /// * [`pallet::error`](#error-palleterror-optional) /// * [`pallet::event`](#event-palletevent-optional) /// * [`pallet::generate_deposit($visibility fn /// deposit_event)`](#palletgenerate_depositvisibility-fn-deposit_event) /// * [`pallet::storage`](#storage-palletstorage-optional) /// * [`pallet::getter(fn $my_getter_fn_name)`](#palletgetterfn-my_getter_fn_name-optional) /// * [`pallet::storage_prefix = "SomeName"`](#palletstorage_prefix--somename-optional) /// * [`pallet::unbounded`](#palletunbounded-optional) /// * [`pallet::whitelist_storage`](#palletwhitelist_storage-optional) /// * [`cfg(..)`](#cfg-for-storage) (on storage items) /// * [`pallet::type_value`](#type-value-pallettype_value-optional) /// * [`pallet::genesis_config`](#genesis-config-palletgenesis_config-optional) /// * [`pallet::genesis_build`](#genesis-build-palletgenesis_build-optional) /// * [`pallet::inherent`](#inherent-palletinherent-optional) /// * [`pallet::validate_unsigned`](#validate-unsigned-palletvalidate_unsigned-optional) /// * [`pallet::origin`](#origin-palletorigin-optional) /// * [`pallet::composite_enum`](#composite-enum-palletcomposite_enum-optional) /// /// Note that at compile-time, the `#[pallet]` macro will analyze and expand all of these /// attributes, ultimately removing their AST nodes before they can be parsed as real /// attribute macro calls. This means that technically we do not need attribute macro /// definitions for any of these attributes, however, for consistency and discoverability /// reasons, we still maintain stub attribute macro definitions for all of these attributes in /// the [`pallet_macros`] module which is automatically included in all pallets as part of the /// pallet prelude. The actual "work" for all of these attribute macros can be found in the /// macro expansion for `#[pallet]`. /// /// Also note that in this document, pallet attributes are explained using the syntax of /// non-instantiable pallets. For an example of an instantiable pallet, see [this /// example](#example-of-an-instantiable-pallet). /// /// # Dev Mode (`#[pallet(dev_mode)]`) /// /// Specifying the argument `dev_mode` on the `#[pallet]` or `#[frame_support::pallet]` /// attribute attached to your pallet module will allow you to enable dev mode for a pallet. /// The aim of dev mode is to loosen some of the restrictions and requirements placed on /// production pallets for easy tinkering and development. Dev mode pallets should not be used /// in production. Enabling dev mode has the following effects: /// /// * Weights no longer need to be specified on every `#[pallet::call]` declaration. By /// default, dev mode pallets will assume a weight of zero (`0`) if a weight is not /// specified. This is equivalent to specifying `#[weight(0)]` on all calls that do not /// specify a weight. /// * Call indices no longer need to be specified on every `#[pallet::call]` declaration. By /// default, dev mode pallets will assume a call index based on the order of the call. /// * All storages are marked as unbounded, meaning you do not need to implement /// `MaxEncodedLen` on storage types. This is equivalent to specifying `#[pallet::unbounded]` /// on all storage type definitions. /// * Storage hashers no longer need to be specified and can be replaced by `_`. In dev mode, /// these will be replaced by `Blake2_128Concat`. In case of explicit key-binding, `Hasher` /// can simply be ignored when in `dev_mode`. /// /// Note that the `dev_mode` argument can only be supplied to the `#[pallet]` or /// `#[frame_support::pallet]` attribute macro that encloses your pallet module. This argument /// cannot be specified anywhere else, including but not limited to the `#[pallet::pallet]` /// attribute macro. /// ///
/// WARNING:
/// You should not deploy or use dev mode pallets in production. Doing so can break your chain
/// and therefore should never be done. Once you are done tinkering, you should remove the
/// 'dev_mode' argument from your #[pallet] declaration and fix any compile errors before
/// attempting to use your pallet in a production scenario.
/// 
/// /// # Pallet struct placeholder: `#[pallet::pallet]` (mandatory) /// /// The pallet struct placeholder `#[pallet::pallet]` is mandatory and allows you to specify /// pallet information. /// /// The struct must be defined as follows: /// ```ignore /// #[pallet::pallet] /// pub struct Pallet(_); /// ``` /// I.e. a regular struct definition named `Pallet`, with generic T and no where clause. /// /// ## Macro expansion: /// /// The macro adds this attribute to the struct definition: /// ```ignore /// #[derive( /// frame_support::CloneNoBound, /// frame_support::EqNoBound, /// frame_support::PartialEqNoBound, /// frame_support::RuntimeDebugNoBound, /// )] /// ``` /// and replaces the type `_` with `PhantomData`. It also implements on the pallet: /// * [`GetStorageVersion`](`traits::GetStorageVersion`) /// * [`OnGenesis`](`traits::OnGenesis`): contains some logic to write the pallet version into /// storage. /// * `PalletErrorTypeInfo`: provides the type information for the pallet error, if defined. /// /// It declares `type Module` type alias for `Pallet`, used by `construct_runtime`. /// /// It implements [`PalletInfoAccess`](`traits::PalletInfoAccess') on `Pallet` to ease access /// to pallet information given by [`frame_support::traits::PalletInfo`]. (The implementation /// uses the associated type `frame_system::Config::PalletInfo`). /// /// It implements [`StorageInfoTrait`](`traits::StorageInfoTrait`) on `Pallet` which give /// information about all storages. /// /// If the attribute `generate_store` is set then the macro creates the trait `Store` and /// implements it on `Pallet`. /// /// If the attribute `set_storage_max_encoded_len` is set then the macro calls /// [`StorageInfoTrait`](`traits::StorageInfoTrait`) for each storage in the implementation of /// [`StorageInfoTrait`](`traits::StorageInfoTrait`) for the pallet. Otherwise it implements /// [`StorageInfoTrait`](`traits::StorageInfoTrait`) for the pallet using the /// [`PartialStorageInfoTrait`](`traits::PartialStorageInfoTrait`) implementation of storages. /// /// # Config trait: `#[pallet::config]` (mandatory) /// /// The mandatory attribute `#[pallet::config]` defines the configurable options for the /// pallet. /// /// Item must be defined as: /// /// ```ignore /// #[pallet::config] /// pub trait Config: frame_system::Config + $optionally_some_other_supertraits /// $optional_where_clause /// { /// ... /// } /// ``` /// /// I.e. a regular trait definition named `Config`, with the supertrait /// `frame_system::pallet::Config`, and optionally other supertraits and a where clause. /// (Specifying other supertraits here is known as [tight /// coupling](https://docs.substrate.io/reference/how-to-guides/pallet-design/use-tight-coupling/)) /// /// The associated type `RuntimeEvent` is reserved. If defined, it must have the bounds /// `From` and `IsType<::RuntimeEvent>`. /// /// [`pallet::event`](`frame_support::pallet_macros::event`) must be present if `RuntimeEvent` /// exists as a config item in your `#[pallet::config]`. /// /// Also see [`pallet::config`](`frame_support::pallet_macros::config`) /// /// ## `pallet::constant` /// /// The `#[pallet::constant]` attribute can be used to add an associated type trait bounded by /// [`Get`](crate::traits::Get) from [`pallet::config`](#palletconfig) into metadata, e.g.: /// /// ```ignore /// #[pallet::config] /// pub trait Config: frame_system::Config { /// #[pallet::constant] /// type Foo: Get; /// } /// ``` /// /// Also see [`pallet::constant`](`frame_support::pallet_macros::constant`) /// /// ## `pallet::disable_frame_system_supertrait_check` /// /// /// To bypass the `frame_system::Config` supertrait check, use the attribute /// `pallet::disable_frame_system_supertrait_check`, e.g.: /// /// ```ignore /// #[pallet::config] /// #[pallet::disable_frame_system_supertrait_check] /// pub trait Config: pallet_timestamp::Config {} /// ``` /// /// NOTE: Bypassing the `frame_system::Config` supertrait check is typically desirable when you /// want to write an alternative to the `frame_system` pallet. /// /// Also see /// [`pallet::disable_frame_system_supertrait_check`](`frame_support::pallet_macros::disable_frame_system_supertrait_check`) /// /// ## Macro expansion: /// /// The macro expands pallet constant metadata with the information given by /// `#[pallet::constant]`. /// /// # `pallet::generate_store($vis trait Store)` /// /// To generate a `Store` trait associating all storages, annotate your `Pallet` struct with /// the attribute `#[pallet::generate_store($vis trait Store)]`, e.g.: /// /// ```ignore /// #[pallet::pallet] /// #[pallet::generate_store(pub(super) trait Store)] /// pub struct Pallet(_); /// ``` /// More precisely, the `Store` trait contains an associated type for each storage. It is /// implemented for `Pallet` allowing access to the storage from pallet struct. /// /// Thus when defining a storage named `Foo`, it can later be accessed from `Pallet` using /// `::Foo`. /// /// NOTE: this attribute is only valid when applied _directly_ to your `Pallet` struct /// definition. /// /// Also see [`pallet::generate_store`](`frame_support::pallet_macros::generate_store`). /// /// # `pallet::storage_version` /// /// Because the [`pallet::pallet`](#pallet-struct-placeholder-palletpallet-mandatory) macro /// implements [`traits::GetStorageVersion`], the current storage version needs to be /// communicated to the macro. This can be done by using the `pallet::storage_version` /// attribute: /// /// ```ignore /// const STORAGE_VERSION: StorageVersion = StorageVersion::new(5); /// /// #[pallet::pallet] /// #[pallet::storage_version(STORAGE_VERSION)] /// pub struct Pallet(_); /// ``` /// /// If not present, the current storage version is set to the default value. /// /// Also see [`pallet::storage_version`](`frame_support::pallet_macros::storage_version`) /// /// # Hooks: `#[pallet::hooks]` (optional) /// /// The `pallet::hooks` attribute allows you to specify a `Hooks` implementation for `Pallet` /// that specifies pallet-specific logic. /// /// The item the attribute attaches to must be defined as follows: /// ```ignore /// #[pallet::hooks] /// impl Hooks> for Pallet $optional_where_clause { /// ... /// } /// ``` /// I.e. a regular trait implementation with generic bound: `T: Config`, for the trait /// `Hooks>` (they are defined in preludes), for the type `Pallet` and /// with an optional where clause. /// /// If no `#[pallet::hooks]` exists, then the following default implementation is /// automatically generated: /// ```ignore /// #[pallet::hooks] /// impl Hooks> for Pallet {} /// ``` /// /// Also see [`pallet::hooks`](`frame_support::pallet_macros::hooks`) /// /// # Call: `#[pallet::call]` (optional) /// /// Implementation of pallet dispatchables. /// /// Item must be defined as: /// ```ignore /// #[pallet::call] /// impl Pallet { /// /// $some_doc /// #[pallet::weight($ExpressionResultingInWeight)] /// pub fn $fn_name( /// origin: OriginFor, /// $some_arg: $some_type, /// // or with compact attribute: #[pallet::compact] $some_arg: $some_type, /// ... /// ) -> DispatchResultWithPostInfo { // or `-> DispatchResult` /// ... /// } /// ... /// } /// ``` /// I.e. a regular type implementation, with generic `T: Config`, on type `Pallet`, with /// an optional where clause. /// /// ## `#[pallet::weight($expr)]` /// /// Each dispatchable needs to define a weight with `#[pallet::weight($expr)]` attribute, the /// first argument must be `origin: OriginFor`. /// /// Also see [`pallet::weight`](`frame_support::pallet_macros::weight`) /// /// ### `#[pallet::compact] $some_arg: $some_type` /// /// Compact encoding for arguments can be achieved via `#[pallet::compact]`. The function must /// return a `DispatchResultWithPostInfo` or `DispatchResult`. /// /// Also see [`pallet::compact`](`frame_support::pallet_macros::compact`) /// /// ## `#[pallet::call_index($idx)]` /// /// Each dispatchable may also be annotated with the `#[pallet::call_index($idx)]` attribute, /// which explicitly defines the codec index for the dispatchable function in the `Call` enum. /// /// All call indexes start from 0, until it encounters a dispatchable function with a defined /// call index. The dispatchable function that lexically follows the function with a defined /// call index will have that call index, but incremented by 1, e.g. if there are 3 /// dispatchable functions `fn foo`, `fn bar` and `fn qux` in that order, and only `fn bar` /// has a call index of 10, then `fn qux` will have an index of 11, instead of 1. /// /// **WARNING**: modifying dispatchables, changing their order, removing some, etc., must be /// done with care. Indeed this will change the outer runtime call type (which is an enum with /// one variant per pallet), this outer runtime call can be stored on-chain (e.g. in /// `pallet-scheduler`). Thus migration might be needed. To mitigate against some of this, the /// `#[pallet::call_index($idx)]` attribute can be used to fix the order of the dispatchable so /// that the `Call` enum encoding does not change after modification. As a general rule of /// thumb, it is therefore adventageous to always add new calls to the end so you can maintain /// the existing order of calls. /// /// Also see [`pallet::call_index`](`frame_support::pallet_macros::call_index`) /// /// # Extra constants: `#[pallet::extra_constants]` (optional) /// /// Allows you to define some extra constants to be added into constant metadata. /// /// Item must be defined as: /// /// ```ignore /// #[pallet::extra_constants] /// impl Pallet where $optional_where_clause { /// /// $some_doc /// $vis fn $fn_name() -> $some_return_type { /// ... /// } /// ... /// } /// ``` /// I.e. a regular rust `impl` block with some optional where clause and functions with 0 args, /// 0 generics, and some return type. /// /// ## Macro expansion /// /// The macro add some extra constants to pallet constant metadata. /// /// Also see: [`pallet::extra_constants`](`frame_support::pallet_macros::extra_constants`) /// /// # Error: `#[pallet::error]` (optional) /// /// The `#[pallet::error]` attribute allows you to define an error enum that will be returned /// from the dispatchable when an error occurs. The information for this error type is then /// stored in metadata. /// /// Item must be defined as: /// /// ```ignore /// #[pallet::error] /// pub enum Error { /// /// $some_optional_doc /// $SomeFieldLessVariant, /// /// $some_more_optional_doc /// $SomeVariantWithOneField(FieldType), /// ... /// } /// ``` /// I.e. a regular enum named `Error`, with generic `T` and fieldless or multiple-field /// variants. /// /// Any field type in the enum variants must implement [`scale_info::TypeInfo`] in order to be /// properly used in the metadata, and its encoded size should be as small as possible, /// preferably 1 byte in size in order to reduce storage size. The error enum itself has an /// absolute maximum encoded size specified by [`MAX_MODULE_ERROR_ENCODED_SIZE`]. /// /// (1 byte can still be 256 different errors. The more specific the error, the easier it is to /// diagnose problems and give a better experience to the user. Don't skimp on having lots of /// individual error conditions.) /// /// Field types in enum variants must also implement [`PalletError`](traits::PalletError), /// otherwise the pallet will fail to compile. Rust primitive types have already implemented /// the [`PalletError`](traits::PalletError) trait along with some commonly used stdlib types /// such as [`Option`] and /// [`PhantomData`](`frame_support::__private::sp_std::marker::PhantomData`), and hence in most /// use cases, a manual implementation is not necessary and is discouraged. /// /// The generic `T` must not bound anything and a `where` clause is not allowed. That said, /// bounds and/or a where clause should not needed for any use-case. /// /// Also see: [`pallet::error`](`frame_support::pallet_macros::error`) /// /// # Event: `#[pallet::event]` (optional) /// /// Allows you to define pallet events. Pallet events are stored under the `system` / `events` /// key when the block is applied (and then replaced when the next block writes it's events). /// /// The Event enum must be defined as follows: /// /// ```ignore /// #[pallet::event] /// #[pallet::generate_deposit($visibility fn deposit_event)] // Optional /// pub enum Event<$some_generic> $optional_where_clause { /// /// Some doc /// $SomeName($SomeType, $YetanotherType, ...), /// ... /// } /// ``` /// /// I.e. an enum (with named or unnamed fields variant), named `Event`, with generic: none or /// `T` or `T: Config`, and optional w here clause. /// /// Each field must implement [`Clone`], [`Eq`], [`PartialEq`], [`Encode`], [`Decode`], and /// [`Debug`] (on std only). For ease of use, bound by the trait /// [`Member`](`frame_support::pallet_prelude::Member`), available in /// frame_support::pallet_prelude. /// /// Also see [`pallet::event`](`frame_support::pallet_macros::event`) /// /// ## `#[pallet::generate_deposit($visibility fn deposit_event)]` /// /// The attribute `#[pallet::generate_deposit($visibility fn deposit_event)]` generates a /// helper function on `Pallet` that handles deposit events. /// /// NOTE: For instantiable pallets, the event must be generic over `T` and `I`. /// /// Also see [`pallet::generate_deposit`](`frame_support::pallet_macros::generate_deposit`) /// /// # Storage: `#[pallet::storage]` (optional) /// /// The `#[pallet::storage]` attribute lets you define some abstract storage inside of runtime /// storage and also set its metadata. This attribute can be used multiple times. /// /// Item should be defined as: /// /// ```ignore /// #[pallet::storage] /// #[pallet::getter(fn $getter_name)] // optional /// $vis type $StorageName<$some_generic> $optional_where_clause /// = $StorageType<$generic_name = $some_generics, $other_name = $some_other, ...>; /// ``` /// /// or with unnamed generic: /// /// ```ignore /// #[pallet::storage] /// #[pallet::getter(fn $getter_name)] // optional /// $vis type $StorageName<$some_generic> $optional_where_clause /// = $StorageType<_, $some_generics, ...>; /// ``` /// /// I.e. it must be a type alias, with generics: `T` or `T: Config`. The aliased type must be /// one of [`StorageValue`](`pallet_prelude::StorageValue`), /// [`StorageMap`](`pallet_prelude::StorageMap`) or /// [`StorageDoubleMap`](`pallet_prelude::StorageDoubleMap`). The generic arguments of the /// storage type can be given in two manners: named and unnamed. For named generic arguments, /// the name for each argument should match the name defined for it on the storage struct: /// * [`StorageValue`](`pallet_prelude::StorageValue`) expects `Value` and optionally /// `QueryKind` and `OnEmpty`, /// * [`StorageMap`](`pallet_prelude::StorageMap`) expects `Hasher`, `Key`, `Value` and /// optionally `QueryKind` and `OnEmpty`, /// * [`CountedStorageMap`](`pallet_prelude::CountedStorageMap`) expects `Hasher`, `Key`, /// `Value` and optionally `QueryKind` and `OnEmpty`, /// * [`StorageDoubleMap`](`pallet_prelude::StorageDoubleMap`) expects `Hasher1`, `Key1`, /// `Hasher2`, `Key2`, `Value` and optionally `QueryKind` and `OnEmpty`. /// /// For unnamed generic arguments: Their first generic must be `_` as it is replaced by the /// macro and other generic must declared as a normal generic type declaration. /// /// The `Prefix` generic written by the macro is generated using /// `PalletInfo::name::>()` and the name of the storage type. E.g. if runtime names /// the pallet "MyExample" then the storage `type Foo = ...` should use the prefix: /// `Twox128(b"MyExample") ++ Twox128(b"Foo")`. /// /// For the [`CountedStorageMap`](`pallet_prelude::CountedStorageMap`) variant, the `Prefix` /// also implements /// [`CountedStorageMapInstance`](`frame_support::storage::types::CountedStorageMapInstance`). /// It also associates a [`CounterPrefix`](`pallet_prelude::CounterPrefix'), which is /// implemented the same as above, but the storage prefix is prepend with `"CounterFor"`. E.g. /// if runtime names the pallet "MyExample" then the storage `type Foo = /// CountedStorageaMap<...>` will store its counter at the prefix: `Twox128(b"MyExample") ++ /// Twox128(b"CounterForFoo")`. /// /// E.g: /// /// ```ignore /// #[pallet::storage] /// pub(super) type MyStorage = StorageMap; /// ``` /// /// In this case the final prefix used by the map is `Twox128(b"MyExample") ++ /// Twox128(b"OtherName")`. /// /// Also see [`pallet::storage`](`frame_support::pallet_macros::storage`) /// /// ## `#[pallet::getter(fn $my_getter_fn_name)]` (optional) /// /// The optional attribute `#[pallet::getter(fn $my_getter_fn_name)]` allows you to define a /// getter function on `Pallet`. /// /// Also see [`pallet::getter`](`frame_support::pallet_macros::getter`) /// /// ## `#[pallet::storage_prefix = "SomeName"]` (optional) /// /// The optional attribute `#[pallet::storage_prefix = "SomeName"]` allows you to define the /// storage prefix to use, see how `Prefix` generic is implemented above. This is helpful if /// you wish to rename the storage field but don't want to perform a migration. /// /// E.g: /// /// ```ignore /// #[pallet::storage] /// #[pallet::storage_prefix = "foo"] /// #[pallet::getter(fn my_storage)] /// pub(super) type MyStorage = StorageMap; /// ``` /// /// or /// /// ```ignore /// #[pallet::storage] /// #[pallet::getter(fn my_storage)] /// pub(super) type MyStorage = StorageMap<_, Blake2_128Concat, u32, u32>; /// ``` /// /// Also see [`pallet::storage_prefix`](`frame_support::pallet_macros::storage_prefix`) /// /// ## `#[pallet::unbounded]` (optional) /// /// The optional attribute `#[pallet::unbounded]` declares the storage as unbounded. When /// implementating the storage info (when `#[pallet::generate_storage_info]` is specified on /// the pallet struct placeholder), the size of the storage will be declared as unbounded. This /// can be useful for storage which can never go into PoV (Proof of Validity). /// /// Also see [`pallet::unbounded`](`frame_support::pallet_macros::unbounded`) /// /// ## `#[pallet::whitelist_storage]` (optional) /// /// The optional attribute `#[pallet::whitelist_storage]` will declare the storage as /// whitelisted from benchmarking. /// /// See /// [`pallet::whitelist_storage`](frame_support::pallet_macros::whitelist_storage) /// for more info. /// /// ## `#[cfg(..)]` (for storage) /// The optional attributes `#[cfg(..)]` allow conditional compilation for the storage. /// /// E.g: /// /// ```ignore /// #[cfg(feature = "my-feature")] /// #[pallet::storage] /// pub(super) type MyStorage = StorageValue; /// ``` /// /// All the `cfg` attributes are automatically copied to the items generated for the storage, /// i.e. the getter, storage prefix, and the metadata element etc. /// /// Any type placed as the `QueryKind` parameter must implement /// [`frame_support::storage::types::QueryKindTrait`]. There are 3 implementations of this /// trait by default: /// /// 1. [`OptionQuery`](`frame_support::storage::types::OptionQuery`), the default `QueryKind` /// used when this type parameter is omitted. Specifying this as the `QueryKind` would cause /// storage map APIs that return a `QueryKind` to instead return an [`Option`], returning /// `Some` when a value does exist under a specified storage key, and `None` otherwise. /// 2. [`ValueQuery`](`frame_support::storage::types::ValueQuery`) causes storage map APIs that /// return a `QueryKind` to instead return the value type. In cases where a value does not /// exist under a specified storage key, the `OnEmpty` type parameter on `QueryKindTrait` is /// used to return an appropriate value. /// 3. [`ResultQuery`](`frame_support::storage::types::ResultQuery`) causes storage map APIs /// that return a `QueryKind` to instead return a `Result`, with `T` being the value /// type and `E` being the pallet error type specified by the `#[pallet::error]` attribute. /// In cases where a value does not exist under a specified storage key, an `Err` with the /// specified pallet error variant is returned. /// /// NOTE: If the `QueryKind` generic parameter is still generic at this stage or is using some /// type alias then the generation of the getter might fail. In this case the getter can be /// implemented manually. /// /// NOTE: The generic `Hasher` must implement the [`StorageHasher`] trait (or the type is not /// usable at all). We use [`StorageHasher::METADATA`] for the metadata of the hasher of the /// storage item. Thus generic hasher is supported. /// /// ## Macro expansion /// /// For each storage item the macro generates a struct named /// `_GeneratedPrefixForStorage$NameOfStorage`, and implements /// [`StorageInstance`](traits::StorageInstance) on it using the pallet and storage name. It /// then uses it as the first generic of the aliased type. For /// [`CountedStorageMap`](`pallet_prelude::CountedStorageMap`), /// [`CountedStorageMapInstance`](`frame_support::storage::types::CountedStorageMapInstance`) /// is implemented, and another similar struct is generated. /// /// For a named generic, the macro will reorder the generics, and remove the names. /// /// The macro implements the function `storage_metadata` on the `Pallet` implementing the /// metadata for all storage items based on their kind: /// * for a storage value, the type of the value is copied into the metadata /// * for a storage map, the type of the values and the key's type is copied into the metadata /// * for a storage double map, the type of the values, and the types of `key1` and `key2` are /// copied into the metadata. /// /// # Type value: `#[pallet::type_value]` (optional) /// /// The `#[pallet::type_value]` attribute lets you define a struct implementing the /// [`Get`](crate::traits::Get) trait to ease use of storage types. This attribute is meant to /// be used alongside [`#[pallet::storage]`](#storage-palletstorage-optional) to define a /// storage's default value. This attribute can be used multiple times. /// /// Item must be defined as: /// /// ```ignore /// #[pallet::type_value] /// fn $MyDefaultName<$some_generic>() -> $default_type $optional_where_clause { $expr } /// ``` /// /// I.e.: a function definition with generics none or `T: Config` and a returned type. /// /// E.g.: /// /// ```ignore /// #[pallet::type_value] /// fn MyDefault() -> T::Balance { 3.into() } /// ``` /// /// Also see [`pallet::type_value`](`frame_support::pallet_macros::type_value`) /// /// # Genesis config: `#[pallet::genesis_config]` (optional) /// /// The `#[pallet::genesis_config]` attribute allows you to define the genesis configuration /// for the pallet. /// /// Item is defined as either an enum or a struct. It needs to be public and implement the /// trait [`BuildGenesisConfig`](`traits::BuildGenesisConfig`) with /// [`#[pallet::genesis_build]`](#genesis-build-palletgenesis_build-optional). The type /// generics are constrained to be either none, or `T` or `T: Config`. /// /// E.g: /// /// ```ignore /// #[pallet::genesis_config] /// pub struct GenesisConfig { /// _myfield: BalanceOf, /// } /// ``` /// /// Also see [`pallet::genesis_config`](`frame_support::pallet_macros::genesis_config`) /// /// # Genesis build: `#[pallet::genesis_build]` (optional) /// /// The `#[pallet::genesis_build]` attribute allows you to define how `genesis_configuration` /// is built. This takes as input the `GenesisConfig` type (as `self`) and constructs the /// pallet's initial state. /// /// The impl must be defined as: /// /// ```ignore /// #[pallet::genesis_build] /// impl GenesisBuild for GenesisConfig<$maybe_generics> { /// fn build(&self) { $expr } /// } /// ``` /// /// I.e. a trait implementation with generic `T: Config`, of trait `GenesisBuild` on /// type `GenesisConfig` with generics none or `T`. /// /// E.g.: /// /// ```ignore /// #[pallet::genesis_build] /// impl GenesisBuild for GenesisConfig { /// fn build(&self) {} /// } /// ``` /// /// Also see [`pallet::genesis_build`](`frame_support::pallet_macros::genesis_build`) /// /// # Inherent: `#[pallet::inherent]` (optional) /// /// The `#[pallet::inherent]` attribute allows the pallet to provide some /// [inherent](https://docs.substrate.io/fundamentals/transaction-types/#inherent-transactions). /// An inherent is some piece of data that is inserted by a block authoring node at block /// creation time and can either be accepted or rejected by validators based on whether the /// data falls within an acceptable range. /// /// The most common inherent is the `timestamp` that is inserted into every block. Since there /// is no way to validate timestamps, validators simply check that the timestamp reported by /// the block authoring node falls within an acceptable range. /// /// Item must be defined as: /// /// ```ignore /// #[pallet::inherent] /// impl ProvideInherent for Pallet { /// // ... regular trait implementation /// } /// ``` /// /// I.e. a trait implementation with bound `T: Config`, of trait /// [`ProvideInherent`](`pallet_prelude::ProvideInherent`) for type `Pallet`, and some /// optional where clause. /// /// Also see [`pallet::inherent`](`frame_support::pallet_macros::inherent`) /// /// # Validate unsigned: `#[pallet::validate_unsigned]` (optional) /// /// The `#[pallet::validate_unsigned]` attribute allows the pallet to validate some unsigned /// transaction: /// /// Item must be defined as: /// /// ```ignore /// #[pallet::validate_unsigned] /// impl ValidateUnsigned for Pallet { /// // ... regular trait implementation /// } /// ``` /// /// I.e. a trait implementation with bound `T: Config`, of trait /// [`ValidateUnsigned`](`pallet_prelude::ValidateUnsigned`) for type `Pallet`, and some /// optional where clause. /// /// NOTE: There is also the [`sp_runtime::traits::SignedExtension`] trait that can be used to /// add some specific logic for transaction validation. /// /// Also see [`pallet::validate_unsigned`](`frame_support::pallet_macros::validate_unsigned`) /// /// # Origin: `#[pallet::origin]` (optional) /// /// The `#[pallet::origin]` attribute allows you to define some origin for the pallet. /// /// Item must be either a type alias, an enum, or a struct. It needs to be public. /// /// E.g.: /// /// ```ignore /// #[pallet::origin] /// pub struct Origin(PhantomData<(T)>); /// ``` /// /// **WARNING**: modifying origin changes the outer runtime origin. This outer runtime origin /// can be stored on-chain (e.g. in `pallet-scheduler`), thus any change must be done with care /// as it might require some migration. /// /// NOTE: for instantiable pallets, the origin must be generic over `T` and `I`. /// /// Also see [`pallet::origin`](`frame_support::pallet_macros::origin`) /// /// # Composite enum `#[pallet::composite_enum]` (optional) /// /// The `#[pallet::composite_enum]` attribute allows you to define an enum on the pallet which /// will then instruct `construct_runtime` to amalgamate all similarly-named enums from other /// pallets into an aggregate enum. This is similar in principle with how the aggregate enum is /// generated for `#[pallet::event]` or `#[pallet::error]`. /// /// The item tagged with `#[pallet::composite_enum]` MUST be an enum declaration, and can ONLY /// be the following identifiers: `FreezeReason`, `HoldReason`, `LockId` or `SlashReason`. /// Custom identifiers are not supported. /// /// NOTE: For ease of usage, when no `#[derive]` attributes are detected, the /// `#[pallet::composite_enum]` attribute will automatically derive the following traits for /// the enum: /// /// ```ignore /// Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Encode, Decode, MaxEncodedLen, TypeInfo, /// RuntimeDebug /// ``` /// /// The inverse is also true: if there are any #[derive] attributes present for the enum, then /// the attribute will not automatically derive any of the traits described above. /// /// # General notes on instantiable pallets /// /// An instantiable pallet is one where Config is generic, i.e. `Config`. This allows /// runtime to implement multiple instances of the pallet, by using different types for the /// generic. This is the sole purpose of the generic `I`, but because /// [`PalletInfo`](`traits::PalletInfo`) requires the `Pallet` placeholder to be static, it is /// important to bound by `'static` whenever [`PalletInfo`](`traits::PalletInfo`) can be used. /// Additionally, in order to make an instantiable pallet usable as a regular pallet without an /// instance, it is important to bound by `= ()` on every type. /// /// Thus impl bound looks like `impl, I: 'static>`, and types look like /// `SomeType` or `SomeType, I: 'static = ()>`. /// /// # Example of a non-instantiable pallet /// /// ``` /// pub use pallet::*; // reexport in crate namespace for `construct_runtime!` /// /// #[frame_support::pallet] /// // NOTE: The name of the pallet is provided by `construct_runtime` and is used as /// // the unique identifier for the pallet's storage. It is not defined in the pallet itself. /// pub mod pallet { /// use frame_support::pallet_prelude::*; // Import various types used in the pallet definition /// use frame_system::pallet_prelude::*; // Import some system helper types. /// /// type BalanceOf = ::Balance; /// /// // Define the generic parameter of the pallet /// // The macro parses `#[pallet::constant]` attributes and uses them to generate metadata /// // for the pallet's constants. /// #[pallet::config] /// pub trait Config: frame_system::Config { /// #[pallet::constant] // put the constant in metadata /// type MyGetParam: Get; /// type Balance: Parameter + MaxEncodedLen + From; /// type RuntimeEvent: From> + IsType<::RuntimeEvent>; /// } /// /// // Define some additional constant to put into the constant metadata. /// #[pallet::extra_constants] /// impl Pallet { /// /// Some description /// fn exra_constant_name() -> u128 { 4u128 } /// } /// /// // Define the pallet struct placeholder, various pallet function are implemented on it. /// #[pallet::pallet] /// #[pallet::generate_store(pub(super) trait Store)] /// pub struct Pallet(_); /// /// // Implement the pallet hooks. /// #[pallet::hooks] /// impl Hooks> for Pallet { /// fn on_initialize(_n: BlockNumberFor) -> Weight { /// unimplemented!(); /// } /// /// // can implement also: on_finalize, on_runtime_upgrade, offchain_worker, ... /// // see `Hooks` trait /// } /// /// // Declare Call struct and implement dispatchables. /// // /// // WARNING: Each parameter used in functions must implement: Clone, Debug, Eq, PartialEq, /// // Codec. /// // /// // The macro parses `#[pallet::compact]` attributes on function arguments and implements /// // the `Call` encoding/decoding accordingly. /// #[pallet::call] /// impl Pallet { /// /// Doc comment put in metadata /// #[pallet::weight(0)] // Defines weight for call (function parameters are in scope) /// pub fn toto( /// origin: OriginFor, /// #[pallet::compact] _foo: u32, /// ) -> DispatchResultWithPostInfo { /// let _ = origin; /// unimplemented!(); /// } /// } /// /// // Declare the pallet `Error` enum (this is optional). /// // The macro generates error metadata using the doc comment on each variant. /// #[pallet::error] /// pub enum Error { /// /// doc comment put into metadata /// InsufficientProposersBalance, /// } /// /// // Declare pallet Event enum (this is optional). /// // /// // WARNING: Each type used in variants must implement: Clone, Debug, Eq, PartialEq, Codec. /// // /// // The macro generates event metadata, and derive Clone, Debug, Eq, PartialEq and Codec /// #[pallet::event] /// // Generate a funciton on Pallet to deposit an event. /// #[pallet::generate_deposit(pub(super) fn deposit_event)] /// pub enum Event { /// /// doc comment put in metadata /// // `::AccountId` is not defined in metadata list, the last /// // Thus the metadata is `::AccountId`. /// Proposed(::AccountId), /// /// doc /// // here metadata will be `Balance` as define in metadata list /// Spending(BalanceOf), /// // here metadata will be `Other` as define in metadata list /// Something(u32), /// } /// /// // Define a struct which implements `frame_support::traits::Get` (optional). /// #[pallet::type_value] /// pub(super) fn MyDefault() -> T::Balance { 3.into() } /// /// // Declare a storage item. Any amount of storage items can be declared (optional). /// // /// // Is expected either `StorageValue`, `StorageMap` or `StorageDoubleMap`. /// // The macro generates the prefix type and replaces the first generic `_`. /// // /// // The macro expands the metadata for the storage item with the type used: /// // * for a storage value the type of the value is copied into the metadata /// // * for a storage map the type of the values and the type of the key is copied into the metadata /// // * for a storage double map the types of the values and keys are copied into the /// // metadata. /// // /// // NOTE: The generic `Hasher` must implement the `StorageHasher` trait (or the type is not /// // usable at all). We use [`StorageHasher::METADATA`] for the metadata of the hasher of the /// // storage item. Thus generic hasher is supported. /// #[pallet::storage] /// pub(super) type MyStorageValue = /// StorageValue>; /// /// // Another storage declaration /// #[pallet::storage] /// #[pallet::getter(fn my_storage)] /// #[pallet::storage_prefix = "SomeOtherName"] /// pub(super) type MyStorage = /// StorageMap; /// /// // Declare the genesis config (optional). /// // /// // The macro accepts either a struct or an enum; it checks that generics are consistent. /// // /// // Type must implement the `Default` trait. /// #[pallet::genesis_config] /// #[derive(frame_support::DefaultNoBound)] /// pub struct GenesisConfig { /// _config: sp_std::marker::PhantomData, /// _myfield: u32, /// } /// /// // Declare genesis builder. (This is need only if GenesisConfig is declared) /// #[pallet::genesis_build] /// impl BuildGenesisConfig for GenesisConfig { /// fn build(&self) {} /// } /// /// // Declare a pallet origin (this is optional). /// // /// // The macro accept type alias or struct or enum, it checks generics are consistent. /// #[pallet::origin] /// pub struct Origin(PhantomData); /// /// // Declare validate_unsigned implementation (this is optional). /// #[pallet::validate_unsigned] /// impl ValidateUnsigned for Pallet { /// type Call = Call; /// fn validate_unsigned( /// source: TransactionSource, /// call: &Self::Call /// ) -> TransactionValidity { /// Err(TransactionValidityError::Invalid(InvalidTransaction::Call)) /// } /// } /// /// // Declare inherent provider for pallet (this is optional). /// #[pallet::inherent] /// impl ProvideInherent for Pallet { /// type Call = Call; /// type Error = InherentError; /// /// const INHERENT_IDENTIFIER: InherentIdentifier = INHERENT_IDENTIFIER; /// /// fn create_inherent(_data: &InherentData) -> Option { /// unimplemented!(); /// } /// /// fn is_inherent(_call: &Self::Call) -> bool { /// unimplemented!(); /// } /// } /// /// // Regular rust code needed for implementing ProvideInherent trait /// /// #[derive(codec::Encode, sp_runtime::RuntimeDebug)] /// #[cfg_attr(feature = "std", derive(codec::Decode))] /// pub enum InherentError { /// } /// /// impl sp_inherents::IsFatalError for InherentError { /// fn is_fatal_error(&self) -> bool { /// unimplemented!(); /// } /// } /// /// pub const INHERENT_IDENTIFIER: sp_inherents::InherentIdentifier = *b"testpall"; /// } /// ``` /// /// # Example of an instantiable pallet /// /// ``` /// pub use pallet::*; /// /// #[frame_support::pallet] /// pub mod pallet { /// use frame_support::pallet_prelude::*; /// use frame_system::pallet_prelude::*; /// /// type BalanceOf = >::Balance; /// /// #[pallet::config] /// pub trait Config: frame_system::Config { /// #[pallet::constant] /// type MyGetParam: Get; /// type Balance: Parameter + MaxEncodedLen + From; /// type RuntimeEvent: From> + IsType<::RuntimeEvent>; /// } /// /// #[pallet::extra_constants] /// impl, I: 'static> Pallet { /// /// Some description /// fn extra_constant_name() -> u128 { 4u128 } /// } /// /// #[pallet::pallet] /// #[pallet::generate_store(pub(super) trait Store)] /// pub struct Pallet(PhantomData<(T, I)>); /// /// #[pallet::hooks] /// impl, I: 'static> Hooks> for Pallet { /// } /// /// #[pallet::call] /// impl, I: 'static> Pallet { /// /// Doc comment put in metadata /// #[pallet::weight(0)] /// pub fn toto(origin: OriginFor, #[pallet::compact] _foo: u32) -> DispatchResultWithPostInfo { /// let _ = origin; /// unimplemented!(); /// } /// } /// /// #[pallet::error] /// pub enum Error { /// /// doc comment put into metadata /// InsufficientProposersBalance, /// } /// /// #[pallet::event] /// #[pallet::generate_deposit(pub(super) fn deposit_event)] /// pub enum Event, I: 'static = ()> { /// /// doc comment put in metadata /// Proposed(::AccountId), /// /// doc /// Spending(BalanceOf), /// Something(u32), /// } /// /// #[pallet::type_value] /// pub(super) fn MyDefault, I: 'static>() -> T::Balance { 3.into() } /// /// #[pallet::storage] /// pub(super) type MyStorageValue, I: 'static = ()> = /// StorageValue>; /// /// #[pallet::storage] /// #[pallet::getter(fn my_storage)] /// #[pallet::storage_prefix = "SomeOtherName"] /// pub(super) type MyStorage = /// StorageMap; /// /// #[pallet::genesis_config] /// #[derive(frame_support::DefaultNoBound)] /// pub struct GenesisConfig, I: 'static = ()> { /// _config: sp_std::marker::PhantomData<(T,I)>, /// _myfield: u32, /// } /// /// #[pallet::genesis_build] /// impl, I: 'static> BuildGenesisConfig for GenesisConfig { /// fn build(&self) {} /// } /// /// #[pallet::origin] /// pub struct Origin(PhantomData<(T, I)>); /// /// #[pallet::validate_unsigned] /// impl, I: 'static> ValidateUnsigned for Pallet { /// type Call = Call; /// fn validate_unsigned( /// source: TransactionSource, /// call: &Self::Call /// ) -> TransactionValidity { /// Err(TransactionValidityError::Invalid(InvalidTransaction::Call)) /// } /// } /// /// #[pallet::inherent] /// impl, I: 'static> ProvideInherent for Pallet { /// type Call = Call; /// type Error = InherentError; /// /// const INHERENT_IDENTIFIER: InherentIdentifier = INHERENT_IDENTIFIER; /// /// fn create_inherent(_data: &InherentData) -> Option { /// unimplemented!(); /// } /// /// fn is_inherent(_call: &Self::Call) -> bool { /// unimplemented!(); /// } /// } /// /// // Regular rust code needed for implementing ProvideInherent trait /// /// #[derive(codec::Encode, sp_runtime::RuntimeDebug)] /// #[cfg_attr(feature = "std", derive(codec::Decode))] /// pub enum InherentError { /// } /// /// impl sp_inherents::IsFatalError for InherentError { /// fn is_fatal_error(&self) -> bool { /// unimplemented!(); /// } /// } /// /// pub const INHERENT_IDENTIFIER: sp_inherents::InherentIdentifier = *b"testpall"; /// } /// ``` /// /// # Upgrade guidelines /// /// 1. Export the metadata of the pallet for later checks /// - run your node with the pallet active /// - query the metadata using the `state_getMetadata` RPC and curl, or use `subsee -p /// > meta.json` /// 2. Generate the template upgrade for the pallet provided by `decl_storage` with the /// environment variable `PRINT_PALLET_UPGRADE`: `PRINT_PALLET_UPGRADE=1 cargo check -p /// my_pallet`. This template can be used as it contains all information for storages, /// genesis config and genesis build. /// 3. Reorganize the pallet to have the trait `Config`, `decl_*` macros, /// [`ValidateUnsigned`](`pallet_prelude::ValidateUnsigned`), /// [`ProvideInherent`](`pallet_prelude::ProvideInherent`), and Origin` all together in one /// file. Suggested order: /// * `Config`, /// * `decl_module`, /// * `decl_event`, /// * `decl_error`, /// * `decl_storage`, /// * `origin`, /// * `validate_unsigned`, /// * `provide_inherent`, so far it should compile and all be correct. /// 4. start writing the new pallet module /// ```ignore /// pub use pallet::*; /// /// #[frame_support::pallet] /// pub mod pallet { /// use frame_support::pallet_prelude::*; /// use frame_system::pallet_prelude::*; /// use super::*; /// /// #[pallet::pallet] /// #[pallet::generate_store($visibility_of_trait_store trait Store)] /// // NOTE: if the visibility of trait store is private but you want to make it available /// // in super, then use `pub(super)` or `pub(crate)` to make it available in crate. /// pub struct Pallet(_); /// // pub struct Pallet(PhantomData); // for instantiable pallet /// } /// ``` /// 5. **migrate Config**: move trait into the module with /// * all const in `decl_module` to [`#[pallet::constant]`](#palletconstant) /// * add the bound `IsType<::RuntimeEvent>` to `type /// RuntimeEvent` /// 7. **migrate decl_module**: write: /// ```ignore /// #[pallet::hooks] /// impl Hooks for Pallet { /// } /// ``` /// and write inside `on_initialize`, `on_finalize`, `on_runtime_upgrade`, /// `offchain_worker`, and `integrity_test`. /// /// then write: /// ```ignore /// #[pallet::call] /// impl Pallet { /// } /// ``` /// and write inside all the calls in `decl_module` with a few changes in the signature: /// - origin must now be written completely, e.g. `origin: OriginFor` /// - result type must be `DispatchResultWithPostInfo`, you need to write it and also you /// might need to put `Ok(().into())` at the end or the function. /// - `#[compact]` must now be written /// [`#[pallet::compact]`](#palletcompact-some_arg-some_type) /// - `#[weight = ..]` must now be written [`#[pallet::weight(..)]`](#palletweightexpr) /// /// 7. **migrate event**: rewrite as a simple enum with the attribute /// [`#[pallet::event]`](#event-palletevent-optional), use [`#[pallet::generate_deposit($vis /// fn deposit_event)]`](#event-palletevent-optional) to generate `deposit_event`, /// 8. **migrate error**: rewrite it with attribute /// [`#[pallet::error]`](#error-palleterror-optional). /// 9. **migrate storage**: `decl_storage` provide an upgrade template (see 3.). All storages, /// genesis config, genesis build and default implementation of genesis config can be taken /// from it directly. /// /// Otherwise here is the manual process: /// /// first migrate the genesis logic. write: /// ```ignore /// #[pallet::genesis_config] /// struct GenesisConfig { /// // fields of add_extra_genesis /// } /// impl Default for GenesisConfig { /// // type default or default provided for fields /// } /// #[pallet::genesis_build] /// impl GenesisBuild for GenesisConfig { /// // for instantiable pallet: /// // `impl GenesisBuild for GenesisConfig { /// fn build() { /// // The add_extra_genesis build logic /// } /// } /// ``` /// for each storage, if it contains `config(..)` then add fields, and make it default to /// the value in `= ..;` or the type default if none, if it contains no build then also add /// the logic to build the value. for each storage if it contains `build(..)` then add the /// logic to `genesis_build`. /// /// NOTE: within `decl_storage`: the individual config is executed first, followed by the /// build and finally the `add_extra_genesis` build. /// /// Once this is done you can migrate storages individually, a few notes: /// - for private storage use `pub(crate) type ` or `pub(super) type` or nothing, /// - for storages with `get(fn ..)` use [`#[pallet::getter(fn /// ...)]`](#palletgetterfn-my_getter_fn_name-optional) /// - for storages with value being `Option<$something>` make generic `Value` being /// `$something` and generic `QueryKind` being `OptionQuery` (note: this is default). /// Otherwise make `Value` the complete value type and `QueryKind` being `ValueQuery`. /// - for storages with default value: `= $expr;` provide some specific `OnEmpty` generic. /// To do so use of `#[pallet::type_value]` to generate the wanted struct to put. /// example: `MyStorage: u32 = 3u32` would be written: /// /// ```ignore /// #[pallet::type_value] fn MyStorageOnEmpty() -> u32 { 3u32 } /// #[pallet::storage] /// pub(super) type MyStorage = StorageValue<_, u32, ValueQuery, MyStorageOnEmpty>; /// ``` /// /// NOTE: `decl_storage` also generates the functions `assimilate_storage` and /// `build_storage` directly on `GenesisConfig`, and these are sometimes used in tests. /// In order not to break they can be implemented manually, one can implement those /// functions by calling the `GenesisBuild` implementation. /// 10. **migrate origin**: move the origin to the pallet module to be under a /// [`#[pallet::origin]`](#origin-palletorigin-optional) attribute /// 11. **migrate validate_unsigned**: move the /// [`ValidateUnsigned`](`pallet_prelude::ValidateUnsigned`) implementation to the pallet /// module under a /// [`#[pallet::validate_unsigned]`](#validate-unsigned-palletvalidate_unsigned-optional) /// attribute /// 12. **migrate provide_inherent**: move the /// [`ProvideInherent`](`pallet_prelude::ProvideInherent`) implementation to the pallet /// module under a [`#[pallet::inherent]`](#inherent-palletinherent-optional) attribute /// 13. rename the usage of `Module` to `Pallet` inside the crate. /// 14. migration is done, now double check the migration with the checking migration /// guidelines shown below. /// /// # Checking upgrade guidelines: /// /// * compare metadata. Use [subsee](https://github.com/ascjones/subsee) to fetch the metadata /// and do a diff of the resulting json before and after migration. This checks for: /// * call, names, signature, docs /// * event names, docs /// * error names, docs /// * storage names, hasher, prefixes, default value /// * error, error, constant /// * manually check that: /// * `Origin` was moved inside the macro under /// [`#[pallet::origin]`](#origin-palletorigin-optional) if it exists /// * [`ValidateUnsigned`](`pallet_prelude::ValidateUnsigned`) was moved inside the macro /// under /// [`#[pallet::validate_unsigned)]`](#validate-unsigned-palletvalidate_unsigned-optional) /// if it exists /// * [`ProvideInherent`](`pallet_prelude::ProvideInherent`) was moved inside the macro /// under [`#[pallet::inherent)]`](#inherent-palletinherent-optional) if it exists /// * `on_initialize` / `on_finalize` / `on_runtime_upgrade` / `offchain_worker` were moved /// to the `Hooks` implementation /// * storages with `config(..)` were converted to `GenesisConfig` field, and their default /// is `= $expr;` if the storage has a default value /// * storages with `build($expr)` or `config(..)` were built in `GenesisBuild::build` /// * `add_extra_genesis` fields were converted to `GenesisConfig` field with their correct /// default if specified /// * `add_extra_genesis` build was written into `GenesisBuild::build` /// * storage items defined with [`pallet`] use the name of the pallet provided by /// [`traits::PalletInfo::name`] as `pallet_prefix` (in `decl_storage`, storage items used /// the `pallet_prefix` given as input of `decl_storage` with the syntax `as Example`). Thus /// a runtime using the pallet must be careful with this change. To handle this change: /// * either ensure that the name of the pallet given to `construct_runtime!` is the same /// as the name the pallet was giving to `decl_storage`, /// * or do a storage migration from the old prefix used to the new prefix used. /// /// NOTE: The prefixes used by storage items are in metadata. Thus, ensuring the metadata /// hasn't changed ensures that the `pallet_prefix`s used by the storage items haven't changed. /// /// # Notes when macro fails to show proper error message spans: /// /// Rustc loses span for some macro input. Some tips to fix it: /// * do not use inner attribute: /// ```ignore /// #[pallet] /// pub mod pallet { /// //! This inner attribute will make span fail /// .. /// } /// ``` /// * use the newest nightly possible. pub use frame_support_procedural::pallet; /// Contains macro stubs for all of the pallet:: macros pub mod pallet_macros { pub use frame_support_procedural::{ call_index, compact, composite_enum, config, constant, disable_frame_system_supertrait_check, error, event, extra_constants, generate_deposit, generate_store, getter, hooks, import_section, inherent, no_default, no_default_bounds, origin, pallet_section, storage, storage_prefix, storage_version, type_value, unbounded, validate_unsigned, weight, whitelist_storage, }; /// Allows you to define the genesis configuration for the pallet. /// /// Item is defined as either an enum or a struct. It needs to be public and implement the /// trait [`frame_support::traits::BuildGenesisConfig`]. /// /// See [`genesis_build`] for an example. pub use frame_support_procedural::genesis_config; /// Allows you to define how the state of your pallet at genesis is built. This /// takes as input the `GenesisConfig` type (as `self`) and constructs the pallet's initial /// state. /// /// The fields of the `GenesisConfig` can in turn be populated by the chain-spec. /// /// ## Example: /// /// ``` /// #[frame_support::pallet] /// pub mod pallet { /// # #[pallet::config] /// # pub trait Config: frame_system::Config {} /// # #[pallet::pallet] /// # pub struct Pallet(_); /// # use frame_support::traits::BuildGenesisConfig; /// #[pallet::genesis_config] /// #[derive(frame_support::DefaultNoBound)] /// pub struct GenesisConfig { /// foo: Vec /// } /// /// #[pallet::genesis_build] /// impl BuildGenesisConfig for GenesisConfig { /// fn build(&self) { /// // use &self to access fields. /// let foo = &self.foo; /// todo!() /// } /// } /// } /// ``` /// /// ## Former Usage /// /// Prior to , the following syntax was used. /// This is deprecated and will soon be removed. /// /// ``` /// #[frame_support::pallet] /// pub mod pallet { /// # #[pallet::config] /// # pub trait Config: frame_system::Config {} /// # #[pallet::pallet] /// # pub struct Pallet(_); /// # use frame_support::traits::GenesisBuild; /// #[pallet::genesis_config] /// #[derive(frame_support::DefaultNoBound)] /// pub struct GenesisConfig { /// foo: Vec /// } /// /// #[pallet::genesis_build] /// impl GenesisBuild for GenesisConfig { /// fn build(&self) { /// todo!() /// } /// } /// } /// ``` pub use frame_support_procedural::genesis_build; } #[deprecated(note = "Will be removed after July 2023; Use `sp_runtime::traits` directly instead.")] pub mod error { #[doc(hidden)] pub use sp_runtime::traits::{BadOrigin, LookupError}; } #[doc(inline)] pub use frame_support_procedural::register_default_impl; // Generate a macro that will enable/disable code based on `std` feature being active. sp_core::generate_feature_enabled_macro!(std_enabled, feature = "std", $); // Helper for implementing GenesisBuilder runtime API pub mod genesis_builder_helper;