Files
pezkuwi-subxt/substrate/frame/support/src/lib.rs
T
Kian Paimani eaf1bc5633 Introduce Polkadot-Sdk developer_hub (#2102)
This PR introduces the new crate `developer_hub` into the polkadot-sdk
repo. The vision for the developer-hub crate is detailed in [this
document](https://docs.google.com/document/d/1XLLkFNE8v8HLvZpI2rzsa8N2IN1FcKntc8q-Sc4xBAk/edit?usp=sharing).

<img width="1128" alt="Screenshot 2023-11-02 at 10 45 48"
src="https://github.com/paritytech/polkadot-sdk/assets/5588131/1e12b60f-fef5-42c4-8503-a3ba234077c3">


Other than adding the new crate, it also does the following: 

* Remove the `substrate` crate, as there is now a unique umbrella crate
for multiple things in `developer_hub::polkadot_sdk`.
* (backport candidate) A minor change to `frame-support` macros that
allows `T::RuntimeOrigin` to also be acceptable as the origin type.
* (backport candidate) A minor change to `frame-system` that allows us
to deposit events at genesis because now the real genesis config is
generated via wasm, and we can safely assume `cfg!(feature = "std")`
means only testing. related to #62.
* (backport candidate) Introduces a small `read_events_for_pallet` to
`frame_system` for easier event reading in tests.
* From https://github.com/paritytech/polkadot-sdk-docs/issues/31, it
takes action on improving the `pallet::call` docs.
* From https://github.com/paritytech/polkadot-sdk-docs/issues/31, it
takes action on improving the `UncheckedExtrinsic` docs.

## Way Forward

First, a version of this is deployed temporarily
[here](https://blog.kianenigma.nl/polkadot-sdk/developer_hub/index.html).
I will keep it up to date on a daily basis.

### This Pull Request

I see two ways forward: 

1. We acknowledge that everything in `developer-hub` is going to be WIP,
and merge this asap. We should not yet use links to this crate anywhere.
2. We make this be the feature branch, make PRs against this, and either
gradually backport it, or only merge to master once it is done.

I am personally in favor of option 1. If we stick to option 2, we need a
better way to deploy a staging version of this to gh-pages.

### Issue Tracking

The main issues related to the future of `developer_hub` are: 

- https://github.com/paritytech/polkadot-sdk-docs/issues/31
- https://github.com/paritytech/polkadot-sdk-docs/issues/4
- https://github.com/paritytech/polkadot-sdk-docs/issues/26 
- https://github.com/paritytech/polkadot-sdk-docs/issues/32
- https://github.com/paritytech/polkadot-sdk-docs/issues/36


### After This Pull Request

- [ ] create a redirect for
https://paritytech.github.io/polkadot-sdk/master/substrate/
- [x] analytics 
- [ ] link checker
- [ ] the matter of publishing, and how all of these relative links for
when we do, that is still an open question. There is section on this in
the landing page.
- [ ] updated https://paritytech.github.io/

---------

Co-authored-by: Liam Aharon <liam.aharon@hotmail.com>
Co-authored-by: Juan Girini <juangirini@gmail.com>
Co-authored-by: bader y <ibnbassem@gmail.com>
Co-authored-by: Sebastian Kunert <skunert49@gmail.com>
Co-authored-by: James Wilson <james@jsdw.me>
Co-authored-by: Michal Kucharczyk <1728078+michalkucharczyk@users.noreply.github.com>
2023-11-30 12:15:46 +01:00

2788 lines
105 KiB
Rust

// 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.
#[doc(hidden)]
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_inherents;
#[cfg(feature = "std")]
pub use sp_io::TestExternalities;
pub use sp_io::{self, hashing, 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, DispatchError, RuntimeDebug, StateVersion, TransactionOutcome,
};
#[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<T>` 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<u64>;
/// type OtherParameter: Get<u64>;
/// type StorageParameter: Get<u64>;
/// type StaticParameter: Get<u32>;
/// }
///
/// 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, F: FnOnce(&mut $type) -> 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<T: Config> {
/// 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<T: Config> {
/// 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<T: Config> {
/// 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<T: Config> {
/// 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<T: Config> {
/// c: T::C,
/// }
///
/// // Also works with enums, by specifying the default with #[default]:
/// #[derive(DefaultNoBound)]
/// enum Bar<T: Config> {
/// // 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 }]
} => {};
}
/// Do something hypothetically by rolling back any changes afterwards.
///
/// Returns the original result of the closure.
#[macro_export]
#[cfg(feature = "experimental")]
macro_rules! hypothetically {
( $e:expr ) => {
$crate::storage::transactional::with_transaction(|| -> $crate::__private::TransactionOutcome<Result<_, $crate::__private::DispatchError>> {
$crate::__private::TransactionOutcome::Rollback(Ok($e))
},
).expect("Always returning Ok; qed")
};
}
/// Assert something to be *hypothetically* `Ok`, without actually committing it.
///
/// Reverts any storage changes made by the closure.
#[macro_export]
#[cfg(feature = "experimental")]
macro_rules! hypothetically_ok {
($e:expr $(, $args:expr)* $(,)?) => {
$crate::assert_ok!($crate::hypothetically!($e) $(, $args)*);
};
}
#[doc(hidden)]
pub use serde::{Deserialize, Serialize};
#[doc(hidden)]
#[cfg(not(no_std))]
pub use macro_magic;
/// 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::{
defensive, defensive_assert,
dispatch::{DispatchClass, DispatchResult, DispatchResultWithPostInfo, Parameter, Pays},
ensure,
inherent::{InherentData, InherentIdentifier, ProvideInherent},
storage,
storage::{
bounded_btree_map::BoundedBTreeMap,
bounded_btree_set::BoundedBTreeSet,
bounded_vec::BoundedVec,
types::{
CountedStorageMap, CountedStorageNMap, Key as NMapKey, OptionQuery, ResultQuery,
StorageDoubleMap, StorageMap, StorageNMap, StorageValue, ValueQuery,
},
weak_bounded_vec::WeakBoundedVec,
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.
///
/// <div class="example-wrap" style="display:inline-block"><pre class="compile_fail"
/// style="white-space:normal;font:inherit;">
/// <strong>WARNING</strong>:
/// 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.
/// </pre></div>
///
/// # 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<T>(_);
/// ```
/// 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<T>`. 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<Event>` and `IsType<<Self as frame_system::Config>::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<u32>;
/// }
/// ```
///
/// Also see [`pallet::constant`](`frame_support::pallet_macros::constant`)
///
/// ## `pallet::disable_frame_system_supertrait_check`
/// <a name="disable_supertrait_check"></a>
///
/// 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<T>(_);
/// ```
/// 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
/// `<Pallet as Store>::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<T>(_);
/// ```
///
/// 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<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> $optional_where_clause {
/// ...
/// }
/// ```
/// I.e. a regular trait implementation with generic bound: `T: Config`, for the trait
/// `Hooks<BlockNumberFor<T>>` (they are defined in preludes), for the type `Pallet<T>` and
/// with an optional where clause.
///
/// If no `#[pallet::hooks]` exists, then the following default implementation is
/// automatically generated:
/// ```ignore
/// #[pallet::hooks]
/// impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {}
/// ```
///
/// 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<T: Config> Pallet<T> {
/// /// $some_doc
/// #[pallet::weight($ExpressionResultingInWeight)]
/// pub fn $fn_name(
/// origin: OriginFor<T>,
/// $some_arg: $some_type,
/// // or with compact attribute: #[pallet::compact] $some_arg: $some_type,
/// ...
/// ) -> DispatchResultWithPostInfo { // or `-> DispatchResult`
/// ...
/// }
/// ...
/// }
/// ```
/// I.e. a regular type implementation, with generic `T: Config`, on type `Pallet<T>`, with
/// an optional where clause.
///
/// ## `#[pallet::weight($expr)]`
///
/// Each dispatchable needs to define a weight with `#[pallet::weight($expr)]` attribute, the
/// first argument must be `origin: OriginFor<T>`.
///
/// 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<T: Config> Pallet<T> 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<T> {
/// /// $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::<Pallet<..>>()` and the name of the storage type. E.g. if runtime names
/// the pallet "MyExample" then the storage `type Foo<T> = ...` 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<T> =
/// CountedStorageaMap<...>` will store its counter at the prefix: `Twox128(b"MyExample") ++
/// Twox128(b"CounterForFoo")`.
///
/// E.g:
///
/// ```ignore
/// #[pallet::storage]
/// pub(super) type MyStorage<T> = StorageMap<Hasher = Blake2_128Concat, Key = u32, Value = u32>;
/// ```
///
/// 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<T> = StorageMap<Hasher = Blake2_128Concat, Key = u32, Value = u32>;
/// ```
///
/// or
///
/// ```ignore
/// #[pallet::storage]
/// #[pallet::getter(fn my_storage)]
/// pub(super) type MyStorage<T> = 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<T> = StorageValue<Value = u32>;
/// ```
///
/// 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<T, E>`, 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 { $expr }
/// ```
///
/// I.e.: a function definition with generics none or `T: Config` and a returned type.
///
/// E.g.:
///
/// ```ignore
/// #[pallet::type_value]
/// fn MyDefault<T: Config>() -> T::Balance { 3.into() }
/// ```
///
/// Also see [`pallet::type_value`](`frame_support::pallet_macros::type_value`)
///
/// # Genesis config: `#[pallet::genesis_config]` (optional)
///
/// The `#[pallet::genesis_config]` attribute allows you to define the genesis configuration
/// for the pallet.
///
/// Item is defined as either an enum or a struct. It needs to be public and implement the
/// trait [`BuildGenesisConfig`](`traits::BuildGenesisConfig`) with
/// [`#[pallet::genesis_build]`](#genesis-build-palletgenesis_build-optional). The type
/// generics are constrained to be either none, or `T` or `T: Config`.
///
/// E.g:
///
/// ```ignore
/// #[pallet::genesis_config]
/// pub struct GenesisConfig<T: Config> {
/// _myfield: BalanceOf<T>,
/// }
/// ```
///
/// Also see [`pallet::genesis_config`](`frame_support::pallet_macros::genesis_config`)
///
/// # Genesis build: `#[pallet::genesis_build]` (optional)
///
/// The `#[pallet::genesis_build]` attribute allows you to define how `genesis_configuration`
/// is built. This takes as input the `GenesisConfig` type (as `self`) and constructs the
/// pallet's initial state.
///
/// The impl must be defined as:
///
/// ```ignore
/// #[pallet::genesis_build]
/// impl<T: Config> GenesisBuild<T> for GenesisConfig<$maybe_generics> {
/// fn build(&self) { $expr }
/// }
/// ```
///
/// I.e. a trait implementation with generic `T: Config`, of trait `GenesisBuild<T>` on
/// type `GenesisConfig` with generics none or `T`.
///
/// E.g.:
///
/// ```ignore
/// #[pallet::genesis_build]
/// impl<T: Config> GenesisBuild<T> 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<T: Config> ProvideInherent for Pallet<T> {
/// // ... regular trait implementation
/// }
/// ```
///
/// I.e. a trait implementation with bound `T: Config`, of trait
/// [`ProvideInherent`](`pallet_prelude::ProvideInherent`) for type `Pallet<T>`, 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<T: Config> ValidateUnsigned for Pallet<T> {
/// // ... regular trait implementation
/// }
/// ```
///
/// I.e. a trait implementation with bound `T: Config`, of trait
/// [`ValidateUnsigned`](`pallet_prelude::ValidateUnsigned`) for type `Pallet<T>`, 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<T>(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, 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<I>`. 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<T: Config<I>, I: 'static>`, and types look like
/// `SomeType<T, I=()>` or `SomeType<T: Config<I>, 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<T> = <T as Config>::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<u32>;
/// type Balance: Parameter + MaxEncodedLen + From<u8>;
/// type RuntimeEvent: From<Event<Self>> + IsType<<Self as frame_system::Config>::RuntimeEvent>;
/// }
///
/// // Define some additional constant to put into the constant metadata.
/// #[pallet::extra_constants]
/// impl<T: Config> Pallet<T> {
/// /// 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<T>(_);
///
/// // Implement the pallet hooks.
/// #[pallet::hooks]
/// impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {
/// fn on_initialize(_n: BlockNumberFor<T>) -> 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<T: Config> Pallet<T> {
/// /// Doc comment put in metadata
/// #[pallet::weight(0)] // Defines weight for call (function parameters are in scope)
/// pub fn toto(
/// origin: OriginFor<T>,
/// #[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<T> {
/// /// 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<T: Config> {
/// /// doc comment put in metadata
/// // `<T as frame_system::Config>::AccountId` is not defined in metadata list, the last
/// // Thus the metadata is `<T as frame_system::Config>::AccountId`.
/// Proposed(<T as frame_system::Config>::AccountId),
/// /// doc
/// // here metadata will be `Balance` as define in metadata list
/// Spending(BalanceOf<T>),
/// // here metadata will be `Other` as define in metadata list
/// Something(u32),
/// }
///
/// // Define a struct which implements `frame_support::traits::Get<T::Balance>` (optional).
/// #[pallet::type_value]
/// pub(super) fn MyDefault<T: Config>() -> 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<T: Config> =
/// StorageValue<Value = T::Balance, QueryKind = ValueQuery, OnEmpty = MyDefault<T>>;
///
/// // Another storage declaration
/// #[pallet::storage]
/// #[pallet::getter(fn my_storage)]
/// #[pallet::storage_prefix = "SomeOtherName"]
/// pub(super) type MyStorage<T> =
/// StorageMap<Hasher = Blake2_128Concat, Key = u32, Value = u32>;
///
/// // 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<T: Config> {
/// _config: sp_std::marker::PhantomData<T>,
/// _myfield: u32,
/// }
///
/// // Declare genesis builder. (This is need only if GenesisConfig is declared)
/// #[pallet::genesis_build]
/// impl<T: Config> BuildGenesisConfig for GenesisConfig<T> {
/// 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<T>(PhantomData<T>);
///
/// // Declare a hold reason (this is optional).
/// //
/// // Creates a hold reason for this pallet that is aggregated by `construct_runtime`.
/// // A similar enum can be defined for `FreezeReason`, `LockId` or `SlashReason`.
/// #[pallet::composite_enum]
/// pub enum HoldReason {
/// SomeHoldReason
/// }
///
/// // Declare validate_unsigned implementation (this is optional).
/// #[pallet::validate_unsigned]
/// impl<T: Config> ValidateUnsigned for Pallet<T> {
/// type Call = Call<T>;
/// 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<T: Config> ProvideInherent for Pallet<T> {
/// type Call = Call<T>;
/// type Error = InherentError;
///
/// const INHERENT_IDENTIFIER: InherentIdentifier = INHERENT_IDENTIFIER;
///
/// fn create_inherent(_data: &InherentData) -> Option<Self::Call> {
/// 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<T, I = ()> = <T as Config<I>>::Balance;
///
/// #[pallet::config]
/// pub trait Config<I: 'static = ()>: frame_system::Config {
/// #[pallet::constant]
/// type MyGetParam: Get<u32>;
/// type Balance: Parameter + MaxEncodedLen + From<u8>;
/// type RuntimeEvent: From<Event<Self, I>> + IsType<<Self as frame_system::Config>::RuntimeEvent>;
/// }
///
/// #[pallet::extra_constants]
/// impl<T: Config<I>, I: 'static> Pallet<T, I> {
/// /// Some description
/// fn extra_constant_name() -> u128 { 4u128 }
/// }
///
/// #[pallet::pallet]
/// #[pallet::generate_store(pub(super) trait Store)]
/// pub struct Pallet<T, I = ()>(PhantomData<(T, I)>);
///
/// #[pallet::hooks]
/// impl<T: Config<I>, I: 'static> Hooks<BlockNumberFor<T>> for Pallet<T, I> {
/// }
///
/// #[pallet::call]
/// impl<T: Config<I>, I: 'static> Pallet<T, I> {
/// /// Doc comment put in metadata
/// #[pallet::weight(0)]
/// pub fn toto(origin: OriginFor<T>, #[pallet::compact] _foo: u32) -> DispatchResultWithPostInfo {
/// let _ = origin;
/// unimplemented!();
/// }
/// }
///
/// #[pallet::error]
/// pub enum Error<T, I = ()> {
/// /// doc comment put into metadata
/// InsufficientProposersBalance,
/// }
///
/// #[pallet::event]
/// #[pallet::generate_deposit(pub(super) fn deposit_event)]
/// pub enum Event<T: Config<I>, I: 'static = ()> {
/// /// doc comment put in metadata
/// Proposed(<T as frame_system::Config>::AccountId),
/// /// doc
/// Spending(BalanceOf<T, I>),
/// Something(u32),
/// }
///
/// #[pallet::type_value]
/// pub(super) fn MyDefault<T: Config<I>, I: 'static>() -> T::Balance { 3.into() }
///
/// #[pallet::storage]
/// pub(super) type MyStorageValue<T: Config<I>, I: 'static = ()> =
/// StorageValue<Value = T::Balance, QueryKind = ValueQuery, OnEmpty = MyDefault<T, I>>;
///
/// #[pallet::storage]
/// #[pallet::getter(fn my_storage)]
/// #[pallet::storage_prefix = "SomeOtherName"]
/// pub(super) type MyStorage<T, I = ()> =
/// StorageMap<Hasher = Blake2_128Concat, Key = u32, Value = u32>;
///
/// #[pallet::genesis_config]
/// #[derive(frame_support::DefaultNoBound)]
/// pub struct GenesisConfig<T: Config<I>, I: 'static = ()> {
/// _config: sp_std::marker::PhantomData<(T,I)>,
/// _myfield: u32,
/// }
///
/// #[pallet::genesis_build]
/// impl<T: Config<I>, I: 'static> BuildGenesisConfig for GenesisConfig<T, I> {
/// fn build(&self) {}
/// }
///
/// #[pallet::origin]
/// pub struct Origin<T, I = ()>(PhantomData<(T, I)>);
///
/// #[pallet::composite_enum]
/// pub enum HoldReason<I: 'static = ()> {
/// SomeHoldReason
/// }
///
/// #[pallet::validate_unsigned]
/// impl<T: Config<I>, I: 'static> ValidateUnsigned for Pallet<T, I> {
/// type Call = Call<T, I>;
/// fn validate_unsigned(
/// source: TransactionSource,
/// call: &Self::Call
/// ) -> TransactionValidity {
/// Err(TransactionValidityError::Invalid(InvalidTransaction::Call))
/// }
/// }
///
/// #[pallet::inherent]
/// impl<T: Config<I>, I: 'static> ProvideInherent for Pallet<T, I> {
/// type Call = Call<T, I>;
/// type Error = InherentError;
///
/// const INHERENT_IDENTIFIER: InherentIdentifier = INHERENT_IDENTIFIER;
///
/// fn create_inherent(_data: &InherentData) -> Option<Self::Call> {
/// 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
/// <PALLET_NAME> > 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<T>(_);
/// // pub struct Pallet<T, I = ()>(PhantomData<T>); // 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<<Self as frame_system::Config>::RuntimeEvent>` to `type
/// RuntimeEvent`
/// 7. **migrate decl_module**: write:
/// ```ignore
/// #[pallet::hooks]
/// impl<T: Config> Hooks for Pallet<T> {
/// }
/// ```
/// and write inside `on_initialize`, `on_finalize`, `on_runtime_upgrade`,
/// `offchain_worker`, and `integrity_test`.
///
/// then write:
/// ```ignore
/// #[pallet::call]
/// impl<T: Config> Pallet<T> {
/// }
/// ```
/// 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<T>`
/// - 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($vis
/// fn deposit_event)]`](#event-palletevent-optional) to generate `deposit_event`,
/// 8. **migrate error**: rewrite it with attribute
/// [`#[pallet::error]`](#error-palleterror-optional).
/// 9. **migrate storage**: `decl_storage` provide an upgrade template (see 3.). All storages,
/// genesis config, genesis build and default implementation of genesis config can be taken
/// from it directly.
///
/// Otherwise here is the manual process:
///
/// first migrate the genesis logic. write:
/// ```ignore
/// #[pallet::genesis_config]
/// struct GenesisConfig {
/// // fields of add_extra_genesis
/// }
/// impl Default for GenesisConfig {
/// // type default or default provided for fields
/// }
/// #[pallet::genesis_build]
/// impl<T: Config> GenesisBuild<T> for GenesisConfig {
/// // for instantiable pallet:
/// // `impl<T: Config, I: 'static> GenesisBuild<T, I> for GenesisConfig {
/// fn build() {
/// // The add_extra_genesis build logic
/// }
/// }
/// ```
/// for each storage, if it contains `config(..)` then add fields, and make it default to
/// the value in `= ..;` or the type default if none, if it contains no build then also add
/// the logic to build the value. for each storage if it contains `build(..)` then add the
/// logic to `genesis_build`.
///
/// NOTE: within `decl_storage`: the individual config is executed first, followed by the
/// build and finally the `add_extra_genesis` build.
///
/// Once this is done you can migrate storages individually, a few notes:
/// - for private storage use `pub(crate) type ` or `pub(super) type` or nothing,
/// - for storages with `get(fn ..)` use [`#[pallet::getter(fn
/// ...)]`](#palletgetterfn-my_getter_fn_name-optional)
/// - for storages with value being `Option<$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<T> = 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::{
composite_enum, config, disable_frame_system_supertrait_check, error, event,
extra_constants, feeless_if, generate_deposit, generate_store, getter, hooks,
import_section, inherent, no_default, no_default_bounds, origin, pallet_section,
storage_prefix, storage_version, type_value, unbounded, validate_unsigned, weight,
whitelist_storage,
};
/// Allows a pallet to declare a set of functions as a *dispatchable extrinsic*. In
/// slightly simplified terms, this macro declares the set of "transactions" of a pallet.
///
/// > The exact definition of **extrinsic** can be found in
/// > [`sp_runtime::generic::UncheckedExtrinsic`].
///
/// A **dispatchable** is a common term in FRAME, referring to process of constructing a
/// function, and dispatching it with the correct inputs. This is commonly used with
/// extrinsics, for example "an extrinsic has been dispatched". See
/// [`sp_runtime::traits::Dispatchable`] and [`crate::traits::UnfilteredDispatchable`].
///
/// ## Call Enum
///
/// The macro is called `call` (rather than `#[pallet::extrinsics]`) because of the
/// generation of a `enum Call`. This enum contains only the encoding of the function
/// arguments of the dispatchable, alongside the information needed to route it to the
/// correct function.
///
/// ```
/// #[frame_support::pallet(dev_mode)]
/// pub mod custom_pallet {
/// # use frame_support::pallet_prelude::*;
/// # use frame_system::pallet_prelude::*;
/// # #[pallet::config]
/// # pub trait Config: frame_system::Config {}
/// # #[pallet::pallet]
/// # pub struct Pallet<T>(_);
/// # use frame_support::traits::BuildGenesisConfig;
/// #[pallet::call]
/// impl<T: Config> Pallet<T> {
/// pub fn some_dispatchable(_origin: OriginFor<T>, _input: u32) -> DispatchResult {
/// Ok(())
/// }
/// pub fn other(_origin: OriginFor<T>, _input: u64) -> DispatchResult {
/// Ok(())
/// }
/// }
///
/// // generates something like:
/// // enum Call<T: Config> {
/// // some_dispatchable { input: u32 }
/// // other { input: u64 }
/// // }
/// }
///
/// fn main() {
/// # use frame_support::{derive_impl, construct_runtime};
/// # use frame_support::__private::codec::Encode;
/// # use frame_support::__private::TestExternalities;
/// # use frame_support::traits::UnfilteredDispatchable;
/// # impl custom_pallet::Config for Runtime {}
/// # #[derive_impl(frame_system::config_preludes::TestDefaultConfig as frame_system::DefaultConfig)]
/// # impl frame_system::Config for Runtime {
/// # type Block = frame_system::mocking::MockBlock<Self>;
/// # }
/// construct_runtime! {
/// pub struct Runtime {
/// System: frame_system,
/// Custom: custom_pallet
/// }
/// }
///
/// # TestExternalities::new_empty().execute_with(|| {
/// let origin: RuntimeOrigin = frame_system::RawOrigin::Signed(10).into();
/// // calling into a dispatchable from within the runtime is simply a function call.
/// let _ = custom_pallet::Pallet::<Runtime>::some_dispatchable(origin.clone(), 10);
///
/// // calling into a dispatchable from the outer world involves constructing the bytes of
/// let call = custom_pallet::Call::<Runtime>::some_dispatchable { input: 10 };
/// let _ = call.clone().dispatch_bypass_filter(origin);
///
/// // the routing of a dispatchable is simply done through encoding of the `Call` enum,
/// // which is the index of the variant, followed by the arguments.
/// assert_eq!(call.encode(), vec![0u8, 10, 0, 0, 0]);
///
/// // notice how in the encoding of the second function, the first byte is different and
/// // referring to the second variant of `enum Call`.
/// let call = custom_pallet::Call::<Runtime>::other { input: 10 };
/// assert_eq!(call.encode(), vec![1u8, 10, 0, 0, 0, 0, 0, 0, 0]);
/// # });
/// }
/// ```
///
/// Further properties of dispatchable functions are as follows:
///
/// - Unless if annotated by `dev_mode`, it must contain [`weight`] to denote the
/// pre-dispatch weight consumed.
/// - The dispatchable must declare its index via [`call_index`], which can override the
/// position of a function in `enum Call`.
/// - The first argument is always an `OriginFor` (or `T::RuntimeOrigin`).
/// - The return type is always [`crate::dispatch::DispatchResult`] (or
/// [`crate::dispatch::DispatchResultWithPostInfo`]).
///
/// **WARNING**: modifying dispatchables, changing their order (i.e. using [`call_index`]),
/// removing some, etc., must be done with care. This will change the encoding of the , and
/// the call can be stored on-chain (e.g. in `pallet-scheduler`). Thus, migration might be
/// needed. This is why the use of `call_index` is mandatory by default in FRAME.
///
/// ## Default Behavior
///
/// If no `#[pallet::call]` exists, then a default implementation corresponding to the
/// following code is automatically generated:
///
/// ```ignore
/// #[pallet::call]
/// impl<T: Config> Pallet<T> {}
/// ```
pub use frame_support_procedural::call;
/// Enforce the index of a variant in the generated `enum Call`. See [`call`] for more
/// information.
///
/// 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.
pub use frame_support_procedural::call_index;
/// Declares the arguments of a [`call`] function to be encoded using
/// [`codec::Compact`]. This will results in smaller extrinsic encoding.
///
/// A common example of `compact` is for numeric values that are often times far far away
/// from their theoretical maximum. For example, in the context of a crypto-currency, the
/// balance of an individual account is oftentimes way less than what the numeric type
/// allows. In all such cases, using `compact` is sensible.
///
/// ```
/// #[frame_support::pallet(dev_mode)]
/// pub mod custom_pallet {
/// # use frame_support::pallet_prelude::*;
/// # use frame_system::pallet_prelude::*;
/// # #[pallet::config]
/// # pub trait Config: frame_system::Config {}
/// # #[pallet::pallet]
/// # pub struct Pallet<T>(_);
/// # use frame_support::traits::BuildGenesisConfig;
/// #[pallet::call]
/// impl<T: Config> Pallet<T> {
/// pub fn some_dispatchable(_origin: OriginFor<T>, #[pallet::compact] _input: u32) -> DispatchResult {
/// Ok(())
/// }
/// }
/// }
pub use frame_support_procedural::compact;
/// 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<T>(_);
/// # use frame_support::traits::BuildGenesisConfig;
/// #[pallet::genesis_config]
/// #[derive(frame_support::DefaultNoBound)]
/// pub struct GenesisConfig<T: Config> {
/// foo: Vec<T::AccountId>
/// }
///
/// #[pallet::genesis_build]
/// impl<T: Config> BuildGenesisConfig for GenesisConfig<T> {
/// fn build(&self) {
/// // use &self to access fields.
/// let foo = &self.foo;
/// todo!()
/// }
/// }
/// }
/// ```
///
/// ## Former Usage
///
/// Prior to <https://github.com/paritytech/substrate/pull/14306>, 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<T>(_);
/// # use frame_support::traits::GenesisBuild;
/// #[pallet::genesis_config]
/// #[derive(frame_support::DefaultNoBound)]
/// pub struct GenesisConfig<T: Config> {
/// foo: Vec<T::AccountId>
/// }
///
/// #[pallet::genesis_build]
/// impl<T: Config> GenesisBuild<T> for GenesisConfig<T> {
/// fn build(&self) {
/// todo!()
/// }
/// }
/// }
/// ```
pub use frame_support_procedural::genesis_build;
/// The `#[pallet::constant]` attribute can be used to add an associated type trait bounded
/// by [`Get`](frame_support::pallet_prelude::Get) from [`pallet::config`](`macro@config`)
/// into metadata.
///
/// ## Example
///
/// ```
/// #[frame_support::pallet]
/// mod pallet {
/// use frame_support::pallet_prelude::*;
/// # #[pallet::pallet]
/// # pub struct Pallet<T>(_);
/// #[pallet::config]
/// pub trait Config: frame_system::Config {
/// /// This is like a normal `Get` trait, but it will be added into metadata.
/// #[pallet::constant]
/// type Foo: Get<u32>;
/// }
/// }
/// ```
pub use frame_support_procedural::constant;
/// Declares a type alias as a storage item. Storage items are pointers to data stored
/// on-chain (the *blockchain state*), under a specific key. The exact key is dependent on
/// the type of the storage.
///
/// > From the perspective of this pallet, the entire blockchain state is abstracted behind
/// > a key-value api, namely [`sp_io::storage`].
///
/// ## Storage Types
///
/// The following storage types are supported by the `#[storage]` macro. For specific
/// information about each storage type, refer to the documentation of the respective type.
///
/// * [`StorageValue`](crate::storage::types::StorageValue)
/// * [`StorageMap`](crate::storage::types::StorageMap)
/// * [`CountedStorageMap`](crate::storage::types::CountedStorageMap)
/// * [`StorageDoubleMap`](crate::storage::types::StorageDoubleMap)
/// * [`StorageNMap`](crate::storage::types::StorageNMap)
/// * [`CountedStorageNMap`](crate::storage::types::CountedStorageNMap)
///
/// ## Storage Type Usage
///
/// The following details are relevant to all of the aforementioned storage types.
/// Depending on the exact storage type, it may require the following generic parameters:
///
/// * [`Prefix`](#prefixes) - Used to give the storage item a unique key in the underlying
/// storage.
/// * `Key` - Type of the keys used to store the values,
/// * `Value` - Type of the value being stored,
/// * [`Hasher`](#hashers) - Used to ensure the keys of a map are uniformly distributed,
/// * [`QueryKind`](#querykind) - Used to configure how to handle queries to the underlying
/// storage,
/// * `OnEmpty` - Used to handle missing values when querying the underlying storage,
/// * `MaxValues` - _not currently used_.
///
/// Each `Key` type requires its own designated `Hasher` declaration, so that
/// [`StorageDoubleMap`](frame_support::storage::types::StorageDoubleMap) needs two of
/// each, and [`StorageNMap`](frame_support::storage::types::StorageNMap) needs `N` such
/// pairs. Since [`StorageValue`](frame_support::storage::types::StorageValue) only stores
/// a single element, no configuration of hashers is needed.
///
/// ### Syntax
///
/// Two general syntaxes are supported, as demonstrated below:
///
/// 1. Named type parameters, e.g., `type Foo<T> = StorageValue<Value = u32>`.
/// 2. Positional type parameters, e.g., `type Foo<T> = StorageValue<_, u32>`.
///
/// In both instances, declaring the generic parameter `<T>` is mandatory. Optionally, it
/// can also be explicitly declared as `<T: Config>`. In the compiled code, `T` will
/// automatically include the trait bound `Config`.
///
/// Note that in positional syntax, the first generic type parameter must be `_`.
///
/// #### Example
///
/// ```
/// #[frame_support::pallet]
/// mod pallet {
/// # use frame_support::pallet_prelude::*;
/// # #[pallet::config]
/// # pub trait Config: frame_system::Config {}
/// # #[pallet::pallet]
/// # pub struct Pallet<T>(_);
/// /// Positional syntax, without bounding `T`.
/// #[pallet::storage]
/// pub type Foo<T> = StorageValue<_, u32>;
///
/// /// Positional syntax, with bounding `T`.
/// #[pallet::storage]
/// pub type Bar<T: Config> = StorageValue<_, u32>;
///
/// /// Named syntax.
/// #[pallet::storage]
/// pub type Baz<T> = StorageMap<Hasher = Blake2_128Concat, Key = u32, Value = u32>;
/// }
/// ```
///
/// ### QueryKind
///
/// Every storage type mentioned above has a generic type called
/// [`QueryKind`](frame_support::storage::types::QueryKindTrait) that determines its
/// "query" type. This refers to the kind of value returned when querying the storage, for
/// instance, through a `::get()` method.
///
/// There are three types of queries:
///
/// 1. [`OptionQuery`](frame_support::storage::types::OptionQuery): The default query type.
/// It returns `Some(V)` if the value is present, or `None` if it isn't, where `V` is
/// the value type.
/// 2. [`ValueQuery`](frame_support::storage::types::ValueQuery): Returns the value itself
/// if present; otherwise, it returns `Default::default()`. This behavior can be
/// adjusted with the `OnEmpty` generic parameter, which defaults to `OnEmpty =
/// GetDefault`.
/// 3. [`ResultQuery`](frame_support::storage::types::ResultQuery): Returns `Result<V, E>`,
/// where `V` is the value type.
///
/// See [`QueryKind`](frame_support::storage::types::QueryKindTrait) for further examples.
///
/// ### Optimized Appending
///
/// All storage items — such as
/// [`StorageValue`](frame_support::storage::types::StorageValue),
/// [`StorageMap`](frame_support::storage::types::StorageMap), and their variants—offer an
/// `::append()` method optimized for collections. Using this method avoids the
/// inefficiency of decoding and re-encoding entire collections when adding items. For
/// instance, consider the storage declaration `type MyVal<T> = StorageValue<_, Vec<u8>,
/// ValueQuery>`. With `MyVal` storing a large list of bytes, `::append()` lets you
/// directly add bytes to the end in storage without processing the full list. Depending on
/// the storage type, additional key specifications may be needed.
///
/// #### Example
#[doc = docify::embed!("src/lib.rs", example_storage_value_append)]
/// Similarly, there also exists a `::try_append()` method, which can be used when handling
/// types where an append operation might fail, such as a
/// [`BoundedVec`](frame_support::BoundedVec).
///
/// #### Example
#[doc = docify::embed!("src/lib.rs", example_storage_value_try_append)]
/// ### Optimized Length Decoding
///
/// All storage items — such as
/// [`StorageValue`](frame_support::storage::types::StorageValue),
/// [`StorageMap`](frame_support::storage::types::StorageMap), and their counterparts —
/// incorporate the `::decode_len()` method. This method allows for efficient retrieval of
/// a collection's length without the necessity of decoding the entire dataset.
/// #### Example
#[doc = docify::embed!("src/lib.rs", example_storage_value_decode_len)]
/// ### Hashers
///
/// For all storage types, except
/// [`StorageValue`](frame_support::storage::types::StorageValue), a set of hashers needs
/// to be specified. The choice of hashers is crucial, especially in production chains. The
/// purpose of storage hashers in maps is to ensure the keys of a map are
/// uniformly distributed. An unbalanced map/trie can lead to inefficient performance.
///
/// In general, hashers are categorized as either cryptographically secure or not. The
/// former is slower than the latter. `Blake2` and `Twox` serve as examples of each,
/// respectively.
///
/// As a rule of thumb:
///
/// 1. If the map keys are not controlled by end users, or are cryptographically secure by
/// definition (e.g., `AccountId`), then the use of cryptographically secure hashers is NOT
/// required.
/// 2. If the map keys are controllable by the end users, cryptographically secure hashers
/// should be used.
///
/// For more information, look at the types that implement
/// [`frame_support::StorageHasher`](frame_support::StorageHasher).
///
/// Lastly, it's recommended for hashers with "concat" to have reversible hashes. Refer to
/// the implementors section of
/// [`hash::ReversibleStorageHasher`](frame_support::hash::ReversibleStorageHasher).
///
/// ### Prefixes
///
/// Internally, every storage type generates a "prefix". This prefix serves as the initial
/// segment of the key utilized to store values in the on-chain state (i.e., the final key
/// used in [`sp_io::storage`](sp_io::storage)). For all storage types, the following rule
/// applies:
///
/// > The storage prefix begins with `twox128(pallet_prefix) ++ twox128(STORAGE_PREFIX)`,
/// > where
/// > `pallet_prefix` is the name assigned to the pallet instance in
/// > [`frame_support::construct_runtime`](frame_support::construct_runtime), and
/// > `STORAGE_PREFIX` is the name of the `type` aliased to a particular storage type, such
/// > as
/// > `Foo` in `type Foo<T> = StorageValue<..>`.
///
/// For [`StorageValue`](frame_support::storage::types::StorageValue), no additional key is
/// required. For map types, the prefix is extended with one or more keys defined by the
/// map.
///
/// #### Example
#[doc = docify::embed!("src/lib.rs", example_storage_value_map_prefixes)]
/// ## Related Macros
///
/// The following attribute macros can be used in conjunction with the `#[storage]` macro:
///
/// * [`macro@getter`]: Creates a custom getter function.
/// * [`macro@storage_prefix`]: Overrides the default prefix of the storage item.
/// * [`macro@unbounded`]: Declares the storage item as unbounded.
///
/// #### Example
/// ```
/// #[frame_support::pallet]
/// mod pallet {
/// # use frame_support::pallet_prelude::*;
/// # #[pallet::config]
/// # pub trait Config: frame_system::Config {}
/// # #[pallet::pallet]
/// # pub struct Pallet<T>(_);
/// /// A kitchen-sink StorageValue, with all possible additional attributes.
/// #[pallet::storage]
/// #[pallet::getter(fn foo)]
/// #[pallet::storage_prefix = "OtherFoo"]
/// #[pallet::unbounded]
/// pub type Foo<T> = StorageValue<_, u32, ValueQuery>;
/// }
/// ```
pub use frame_support_procedural::storage;
}
#[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;
#[cfg(test)]
mod test {
// use super::*;
use crate::{
hash::*,
storage::types::{StorageMap, StorageValue, ValueQuery},
traits::{ConstU32, StorageInstance},
BoundedVec,
};
use sp_io::{hashing::twox_128, TestExternalities};
struct Prefix;
impl StorageInstance for Prefix {
fn pallet_prefix() -> &'static str {
"test"
}
const STORAGE_PREFIX: &'static str = "foo";
}
struct Prefix1;
impl StorageInstance for Prefix1 {
fn pallet_prefix() -> &'static str {
"test"
}
const STORAGE_PREFIX: &'static str = "MyVal";
}
struct Prefix2;
impl StorageInstance for Prefix2 {
fn pallet_prefix() -> &'static str {
"test"
}
const STORAGE_PREFIX: &'static str = "MyMap";
}
#[docify::export]
#[test]
pub fn example_storage_value_try_append() {
type MyVal = StorageValue<Prefix, BoundedVec<u8, ConstU32<10>>, ValueQuery>;
TestExternalities::default().execute_with(|| {
MyVal::set(BoundedVec::try_from(vec![42, 43]).unwrap());
assert_eq!(MyVal::get(), vec![42, 43]);
// Try to append a single u32 to BoundedVec stored in `MyVal`
assert_ok!(MyVal::try_append(40));
assert_eq!(MyVal::get(), vec![42, 43, 40]);
});
}
#[docify::export]
#[test]
pub fn example_storage_value_append() {
type MyVal = StorageValue<Prefix, Vec<u8>, ValueQuery>;
TestExternalities::default().execute_with(|| {
MyVal::set(vec![42, 43]);
assert_eq!(MyVal::get(), vec![42, 43]);
// Append a single u32 to Vec stored in `MyVal`
MyVal::append(40);
assert_eq!(MyVal::get(), vec![42, 43, 40]);
});
}
#[docify::export]
#[test]
pub fn example_storage_value_decode_len() {
type MyVal = StorageValue<Prefix, BoundedVec<u8, ConstU32<10>>, ValueQuery>;
TestExternalities::default().execute_with(|| {
MyVal::set(BoundedVec::try_from(vec![42, 43]).unwrap());
assert_eq!(MyVal::decode_len().unwrap(), 2);
});
}
#[docify::export]
#[test]
pub fn example_storage_value_map_prefixes() {
type MyVal = StorageValue<Prefix1, u32, ValueQuery>;
type MyMap = StorageMap<Prefix2, Blake2_128Concat, u16, u32, ValueQuery>;
TestExternalities::default().execute_with(|| {
// This example assumes `pallet_prefix` to be "test"
// Get storage key for `MyVal` StorageValue
assert_eq!(
MyVal::hashed_key().to_vec(),
[twox_128(b"test"), twox_128(b"MyVal")].concat()
);
// Get storage key for `MyMap` StorageMap and `key` = 1
let mut k: Vec<u8> = vec![];
k.extend(&twox_128(b"test"));
k.extend(&twox_128(b"MyMap"));
k.extend(&1u16.blake2_128_concat());
assert_eq!(MyMap::hashed_key_for(1).to_vec(), k);
});
}
}