frame_support/
lib.rs

1// This file is part of Substrate.
2
3// Copyright (C) Parity Technologies (UK) Ltd.
4// SPDX-License-Identifier: Apache-2.0
5
6// Licensed under the Apache License, Version 2.0 (the "License");
7// you may not use this file except in compliance with the License.
8// You may obtain a copy of the License at
9//
10// 	http://www.apache.org/licenses/LICENSE-2.0
11//
12// Unless required by applicable law or agreed to in writing, software
13// distributed under the License is distributed on an "AS IS" BASIS,
14// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15// See the License for the specific language governing permissions and
16// limitations under the License.
17
18//! Support code for the runtime.
19//!
20//! ## Note on Tuple Traits
21//!
22//! Many of the traits defined in [`traits`] have auto-implementations on tuples as well. Usually,
23//! the tuple is a function of number of pallets in the runtime. By default, the traits are
24//! implemented for tuples of up to 64 items.
25//
26// If you have more pallets in your runtime, or for any other reason need more, enabled `tuples-96`
27// or the `tuples-128` complication flag. Note that these features *will increase* the compilation
28// of this crate.
29
30#![cfg_attr(not(feature = "std"), no_std)]
31
32/// Export ourself as `frame_support` to make tests happy.
33#[doc(hidden)]
34extern crate self as frame_support;
35
36#[doc(hidden)]
37extern crate alloc;
38
39/// Private exports that are being used by macros.
40///
41/// The exports are not stable and should not be relied on.
42#[doc(hidden)]
43pub mod __private {
44	pub use alloc::{
45		boxed::Box,
46		fmt::Debug,
47		rc::Rc,
48		string::String,
49		vec,
50		vec::{IntoIter, Vec},
51	};
52	pub use codec;
53	pub use frame_metadata as metadata;
54	pub use log;
55	pub use paste;
56	pub use scale_info;
57	pub use serde;
58	pub use serde_json;
59	pub use sp_core::{Get, OpaqueMetadata, Void};
60	pub use sp_crypto_hashing_proc_macro;
61	pub use sp_inherents;
62	#[cfg(feature = "std")]
63	pub use sp_io::TestExternalities;
64	pub use sp_io::{self, hashing, storage::root as storage_root};
65	pub use sp_metadata_ir as metadata_ir;
66	#[cfg(feature = "std")]
67	pub use sp_runtime::{bounded_btree_map, bounded_vec};
68	pub use sp_runtime::{
69		traits::{AsSystemOriginSigner, AsTransactionAuthorizedOrigin, Dispatchable},
70		DispatchError, RuntimeDebug, StateVersion, TransactionOutcome,
71	};
72	#[cfg(feature = "std")]
73	pub use sp_state_machine::BasicExternalities;
74	pub use sp_std;
75	pub use sp_tracing;
76	pub use tt_call::*;
77}
78
79#[macro_use]
80pub mod dispatch;
81pub mod crypto;
82pub mod dispatch_context;
83mod hash;
84pub mod inherent;
85pub mod instances;
86pub mod migrations;
87pub mod storage;
88#[cfg(test)]
89mod tests;
90pub mod traits;
91pub mod view_functions;
92pub mod weights;
93#[doc(hidden)]
94pub mod unsigned {
95	#[doc(hidden)]
96	pub use crate::sp_runtime::traits::ValidateUnsigned;
97	#[doc(hidden)]
98	pub use crate::sp_runtime::transaction_validity::{
99		TransactionSource, TransactionValidity, TransactionValidityError, UnknownTransaction,
100	};
101}
102
103#[cfg(any(feature = "std", feature = "runtime-benchmarks", feature = "try-runtime", test))]
104pub use self::storage::storage_noop_guard::StorageNoopGuard;
105pub use self::{
106	dispatch::{Callable, Parameter},
107	hash::{
108		Blake2_128, Blake2_128Concat, Blake2_256, Hashable, Identity, ReversibleStorageHasher,
109		StorageHasher, Twox128, Twox256, Twox64Concat,
110	},
111	storage::{
112		bounded_btree_map::BoundedBTreeMap,
113		bounded_btree_set::BoundedBTreeSet,
114		bounded_vec::{BoundedSlice, BoundedVec},
115		migration,
116		weak_bounded_vec::WeakBoundedVec,
117		IterableStorageDoubleMap, IterableStorageMap, IterableStorageNMap, StorageDoubleMap,
118		StorageMap, StorageNMap, StoragePrefixedMap, StorageValue,
119	},
120};
121pub use sp_runtime::{
122	self, print, traits::Printable, ConsensusEngineId, MAX_MODULE_ERROR_ENCODED_SIZE,
123};
124
125use codec::{Decode, Encode};
126use scale_info::TypeInfo;
127use sp_runtime::TypeId;
128
129/// A unified log target for support operations.
130pub const LOG_TARGET: &str = "runtime::frame-support";
131
132/// A type that cannot be instantiated.
133#[derive(Encode, Decode, Debug, PartialEq, Eq, Clone, TypeInfo)]
134pub enum Never {}
135
136/// A pallet identifier. These are per pallet and should be stored in a registry somewhere.
137#[derive(Clone, Copy, Eq, PartialEq, Encode, Decode, TypeInfo)]
138pub struct PalletId(pub [u8; 8]);
139
140impl TypeId for PalletId {
141	const TYPE_ID: [u8; 4] = *b"modl";
142}
143
144/// Generate a [`#[pallet::storage]`](pallet_macros::storage) alias outside of a pallet.
145///
146/// This storage alias works similarly to the [`#[pallet::storage]`](pallet_macros::storage)
147/// attribute macro. It supports [`StorageValue`](storage::types::StorageValue),
148/// [`StorageMap`](storage::types::StorageMap),
149/// [`StorageDoubleMap`](storage::types::StorageDoubleMap) and
150/// [`StorageNMap`](storage::types::StorageNMap). The main difference to the normal
151/// [`#[pallet::storage]`](pallet_macros::storage) is the flexibility around declaring the
152/// storage prefix to use. The storage prefix determines where to find the value in the
153/// storage. [`#[pallet::storage]`](pallet_macros::storage) uses the name of the pallet as
154/// declared in [`construct_runtime!`].
155///
156/// The flexibility around declaring the storage prefix makes this macro very useful for
157/// writing migrations etc.
158///
159/// # Examples
160///
161/// There are different ways to declare the `prefix` to use. The `prefix` type can either be
162/// declared explicitly by passing it to the macro as an attribute or by letting the macro
163/// guess on what the `prefix` type is. The `prefix` is always passed as the first generic
164/// argument to the type declaration. When using [`#[pallet::storage]`](pallet_macros::storage)
165/// this first generic argument is always `_`. Besides declaring the `prefix`, the rest of the
166/// type declaration works as with [`#[pallet::storage]`](pallet_macros::storage).
167///
168/// 1. Use the `verbatim` prefix type. This prefix type uses the given identifier as the
169/// `prefix`:
170#[doc = docify::embed!("src/tests/storage_alias.rs", verbatim_attribute)]
171///
172/// 2. Use the `pallet_name` prefix type. This prefix type uses the name of the pallet as
173/// configured in    [`construct_runtime!`] as the `prefix`:
174#[doc = docify::embed!("src/tests/storage_alias.rs", pallet_name_attribute)]
175/// It requires that the given prefix type implements
176/// [`PalletInfoAccess`](traits::PalletInfoAccess) (which is always the case for FRAME pallet
177/// structs). In the example above, `Pallet<T>` is the prefix type.
178///
179/// 3. Use the `dynamic` prefix type. This prefix type calls [`Get::get()`](traits::Get::get)
180///    to get the `prefix`:
181#[doc = docify::embed!("src/tests/storage_alias.rs", dynamic_attribute)]
182/// It requires that the given prefix type implements [`Get<'static str>`](traits::Get).
183///
184/// 4. Let the macro "guess" what kind of prefix type to use. This only supports verbatim or
185///    pallet name. The macro uses the presence of generic arguments to the prefix type as an
186///    indication that it should use the pallet name as the `prefix`:
187#[doc = docify::embed!("src/tests/storage_alias.rs", storage_alias_guess)]
188pub use frame_support_procedural::storage_alias;
189
190pub use frame_support_procedural::derive_impl;
191
192/// Experimental macros for defining dynamic params that can be used in pallet configs.
193#[cfg(feature = "experimental")]
194pub mod dynamic_params {
195	pub use frame_support_procedural::{
196		dynamic_aggregated_params_internal, dynamic_pallet_params, dynamic_params,
197	};
198}
199
200/// Create new implementations of the [`Get`](crate::traits::Get) trait.
201///
202/// The so-called parameter type can be created in four different ways:
203///
204/// - Using `const` to create a parameter type that provides a `const` getter. It is required that
205///   the `value` is const.
206///
207/// - Declare the parameter type without `const` to have more freedom when creating the value.
208///
209/// - Using `storage` to create a storage parameter type. This type is special as it tries to load
210///   the value from the storage under a fixed key. If the value could not be found in the storage,
211///   the given default value will be returned. It is required that the value implements
212///   [`Encode`](codec::Encode) and [`Decode`](codec::Decode). The key for looking up the value in
213///   the storage is built using the following formula:
214///
215///   `twox_128(":" ++ NAME ++ ":")` where `NAME` is the name that is passed as type name.
216///
217/// - Using `static` to create a static parameter type. Its value is being provided by a static
218///   variable with the equivalent name in `UPPER_SNAKE_CASE`. An additional `set` function is
219///   provided in this case to alter the static variable. **This is intended for testing ONLY and is
220///   ONLY available when `std` is enabled.**
221///
222/// # Examples
223///
224/// ```
225/// # use frame_support::traits::Get;
226/// # use frame_support::parameter_types;
227/// // This function cannot be used in a const context.
228/// fn non_const_expression() -> u64 { 99 }
229///
230/// const FIXED_VALUE: u64 = 10;
231/// parameter_types! {
232///    pub const Argument: u64 = 42 + FIXED_VALUE;
233///    /// Visibility of the type is optional
234///    OtherArgument: u64 = non_const_expression();
235///    pub storage StorageArgument: u64 = 5;
236///    pub static StaticArgument: u32 = 7;
237/// }
238///
239/// trait Config {
240///    type Parameter: Get<u64>;
241///    type OtherParameter: Get<u64>;
242///    type StorageParameter: Get<u64>;
243///    type StaticParameter: Get<u32>;
244/// }
245///
246/// struct Runtime;
247/// impl Config for Runtime {
248///    type Parameter = Argument;
249///    type OtherParameter = OtherArgument;
250///    type StorageParameter = StorageArgument;
251///    type StaticParameter = StaticArgument;
252/// }
253///
254/// // In testing, `StaticArgument` can be altered later: `StaticArgument::set(8)`.
255/// ```
256///
257/// # Invalid example:
258///
259/// ```compile_fail
260/// # use frame_support::traits::Get;
261/// # use frame_support::parameter_types;
262/// // This function cannot be used in a const context.
263/// fn non_const_expression() -> u64 { 99 }
264///
265/// parameter_types! {
266///    pub const Argument: u64 = non_const_expression();
267/// }
268/// ```
269#[macro_export]
270macro_rules! parameter_types {
271	(
272		$( #[ $attr:meta ] )*
273		$vis:vis const $name:ident $(< $($ty_params:ident),* >)?: $type:ty = $value:expr;
274		$( $rest:tt )*
275	) => (
276		$( #[ $attr ] )*
277		$vis struct $name $(
278			< $($ty_params),* >( $(core::marker::PhantomData<$ty_params>),* )
279		)?;
280		$crate::parameter_types!(IMPL_CONST $name , $type , $value $( $(, $ty_params)* )?);
281		$crate::parameter_types!( $( $rest )* );
282	);
283	(
284		$( #[ $attr:meta ] )*
285		$vis:vis $name:ident $(< $($ty_params:ident),* >)?: $type:ty = $value:expr;
286		$( $rest:tt )*
287	) => (
288		$( #[ $attr ] )*
289		$vis struct $name $(
290			< $($ty_params),* >( $(core::marker::PhantomData<$ty_params>),* )
291		)?;
292		$crate::parameter_types!(IMPL $name, $type, $value $( $(, $ty_params)* )?);
293		$crate::parameter_types!( $( $rest )* );
294	);
295	(
296		$( #[ $attr:meta ] )*
297		$vis:vis storage $name:ident $(< $($ty_params:ident),* >)?: $type:ty = $value:expr;
298		$( $rest:tt )*
299	) => (
300		$( #[ $attr ] )*
301		$vis struct $name $(
302			< $($ty_params),* >( $(core::marker::PhantomData<$ty_params>),* )
303		)?;
304		$crate::parameter_types!(IMPL_STORAGE $name, $type, $value $( $(, $ty_params)* )?);
305		$crate::parameter_types!( $( $rest )* );
306	);
307	() => ();
308	(IMPL_CONST $name:ident, $type:ty, $value:expr $(, $ty_params:ident)*) => {
309		impl< $($ty_params),* > $name< $($ty_params),* > {
310			/// Returns the value of this parameter type.
311			pub const fn get() -> $type {
312				$value
313			}
314		}
315
316		impl<_I: From<$type> $(, $ty_params)*> $crate::traits::Get<_I> for $name< $($ty_params),* > {
317			fn get() -> _I {
318				_I::from(Self::get())
319			}
320		}
321
322		impl< $($ty_params),* > $crate::traits::TypedGet for $name< $($ty_params),* > {
323			type Type = $type;
324			fn get() -> $type {
325				Self::get()
326			}
327		}
328	};
329	(IMPL $name:ident, $type:ty, $value:expr $(, $ty_params:ident)*) => {
330		impl< $($ty_params),* > $name< $($ty_params),* > {
331			/// Returns the value of this parameter type.
332			pub fn get() -> $type {
333				$value
334			}
335		}
336
337		impl<_I: From<$type>, $(, $ty_params)*> $crate::traits::Get<_I> for $name< $($ty_params),* > {
338			fn get() -> _I {
339				_I::from(Self::get())
340			}
341		}
342
343		impl< $($ty_params),* > $crate::traits::TypedGet for $name< $($ty_params),* > {
344			type Type = $type;
345			fn get() -> $type {
346				Self::get()
347			}
348		}
349	};
350	(IMPL_STORAGE $name:ident, $type:ty, $value:expr $(, $ty_params:ident)*) => {
351		#[allow(unused)]
352		impl< $($ty_params),* > $name< $($ty_params),* > {
353			/// Returns the key for this parameter type.
354			pub fn key() -> [u8; 16] {
355				$crate::__private::sp_crypto_hashing_proc_macro::twox_128!(b":", $name, b":")
356			}
357
358			/// Set the value of this parameter type in the storage.
359			///
360			/// This needs to be executed in an externalities provided environment.
361			pub fn set(value: &$type) {
362				$crate::storage::unhashed::put(&Self::key(), value);
363			}
364
365			/// Returns the value of this parameter type.
366			///
367			/// This needs to be executed in an externalities provided environment.
368			#[allow(unused)]
369			pub fn get() -> $type {
370				$crate::storage::unhashed::get(&Self::key()).unwrap_or_else(|| $value)
371			}
372		}
373
374		impl<_I: From<$type> $(, $ty_params)*> $crate::traits::Get<_I> for $name< $($ty_params),* > {
375			fn get() -> _I {
376				_I::from(Self::get())
377			}
378		}
379
380		impl< $($ty_params),* > $crate::traits::TypedGet for $name< $($ty_params),* > {
381			type Type = $type;
382			fn get() -> $type {
383				Self::get()
384			}
385		}
386	};
387	(
388		$( #[ $attr:meta ] )*
389		$vis:vis static $name:ident: $type:ty = $value:expr;
390		$( $rest:tt )*
391	) => (
392		$crate::parameter_types_impl_thread_local!(
393			$( #[ $attr ] )*
394			$vis static $name: $type = $value;
395		);
396		$crate::parameter_types!( $( $rest )* );
397	);
398}
399
400#[cfg(not(feature = "std"))]
401#[macro_export]
402macro_rules! parameter_types_impl_thread_local {
403	( $( $any:tt )* ) => {
404		compile_error!("static parameter types is only available in std and for testing.");
405	};
406}
407
408#[cfg(feature = "std")]
409#[macro_export]
410macro_rules! parameter_types_impl_thread_local {
411	(
412		$(
413			$( #[ $attr:meta ] )*
414			$vis:vis static $name:ident: $type:ty = $value:expr;
415		)*
416	) => {
417		$crate::parameter_types_impl_thread_local!(
418			IMPL_THREAD_LOCAL $( $vis, $name, $type, $value, )*
419		);
420		$crate::__private::paste::item! {
421			$crate::parameter_types!(
422				$(
423					$( #[ $attr ] )*
424					$vis $name: $type = [<$name:snake:upper>].with(|v| v.borrow().clone());
425				)*
426			);
427			$(
428				impl $name {
429					/// Set the internal value.
430					pub fn set(t: $type) {
431						[<$name:snake:upper>].with(|v| *v.borrow_mut() = t);
432					}
433
434					/// Mutate the internal value in place.
435					#[allow(unused)]
436					pub fn mutate<R, F: FnOnce(&mut $type) -> R>(mutate: F) -> R{
437						let mut current = Self::get();
438						let result = mutate(&mut current);
439						Self::set(current);
440						result
441					}
442
443					/// Get current value and replace with initial value of the parameter type.
444					#[allow(unused)]
445					pub fn take() -> $type {
446						let current = Self::get();
447						Self::set($value);
448						current
449					}
450				}
451			)*
452		}
453	};
454	(IMPL_THREAD_LOCAL $( $vis:vis, $name:ident, $type:ty, $value:expr, )* ) => {
455		$crate::__private::paste::item! {
456			thread_local! {
457				$(
458					pub static [<$name:snake:upper>]: std::cell::RefCell<$type> =
459						std::cell::RefCell::new($value);
460				)*
461			}
462		}
463	};
464}
465
466/// Macro for easily creating a new implementation of both the `Get` and `Contains` traits. Use
467/// exactly as with `parameter_types`, only the type must be `Ord`.
468#[macro_export]
469macro_rules! ord_parameter_types {
470	(
471		$( #[ $attr:meta ] )*
472		$vis:vis const $name:ident: $type:ty = $value:expr;
473		$( $rest:tt )*
474	) => (
475		$( #[ $attr ] )*
476		$vis struct $name;
477		$crate::parameter_types!{IMPL $name , $type , $value}
478		$crate::ord_parameter_types!{IMPL $name , $type , $value}
479		$crate::ord_parameter_types!{ $( $rest )* }
480	);
481	() => ();
482	(IMPL $name:ident , $type:ty , $value:expr) => {
483		impl $crate::traits::SortedMembers<$type> for $name {
484			fn contains(t: &$type) -> bool { &$value == t }
485			fn sorted_members() -> $crate::__private::Vec<$type> { vec![$value] }
486			fn count() -> usize { 1 }
487			#[cfg(feature = "runtime-benchmarks")]
488			fn add(_: &$type) {}
489		}
490		impl $crate::traits::Contains<$type> for $name {
491			fn contains(t: &$type) -> bool { &$value == t }
492		}
493	}
494}
495
496/// Print out a formatted message.
497///
498/// # Example
499///
500/// ```
501/// frame_support::runtime_print!("my value is {}", 3);
502/// ```
503#[macro_export]
504macro_rules! runtime_print {
505	($($arg:tt)+) => {
506		{
507			use core::fmt::Write;
508			let mut msg = $crate::__private::String::default();
509			let _ = core::write!(&mut msg, $($arg)+);
510			$crate::__private::sp_io::misc::print_utf8(msg.as_bytes())
511		}
512	}
513}
514
515/// Print out the debuggable type.
516pub fn debug(data: &impl core::fmt::Debug) {
517	runtime_print!("{:?}", data);
518}
519
520#[doc(inline)]
521pub use frame_support_procedural::{
522	construct_runtime, match_and_insert, transactional, PalletError, RuntimeDebugNoBound,
523};
524
525pub use frame_support_procedural::runtime;
526
527#[doc(hidden)]
528pub use frame_support_procedural::{__create_tt_macro, __generate_dummy_part_checker};
529
530/// Derive [`Clone`] but do not bound any generic.
531///
532/// This is useful for type generic over runtime:
533/// ```
534/// # use frame_support::CloneNoBound;
535/// trait Config {
536/// 		type C: Clone;
537/// }
538///
539/// // Foo implements [`Clone`] because `C` bounds [`Clone`].
540/// // Otherwise compilation will fail with an output telling `c` doesn't implement [`Clone`].
541/// #[derive(CloneNoBound)]
542/// struct Foo<T: Config> {
543/// 		c: T::C,
544/// }
545/// ```
546pub use frame_support_procedural::CloneNoBound;
547
548/// Derive [`Eq`] but do not bound any generic.
549///
550/// This is useful for type generic over runtime:
551/// ```
552/// # use frame_support::{EqNoBound, PartialEqNoBound};
553/// trait Config {
554/// 		type C: Eq;
555/// }
556///
557/// // Foo implements [`Eq`] because `C` bounds [`Eq`].
558/// // Otherwise compilation will fail with an output telling `c` doesn't implement [`Eq`].
559/// #[derive(PartialEqNoBound, EqNoBound)]
560/// struct Foo<T: Config> {
561/// 		c: T::C,
562/// }
563/// ```
564pub use frame_support_procedural::EqNoBound;
565
566/// Derive [`PartialEq`] but do not bound any generic.
567///
568/// This is useful for type generic over runtime:
569/// ```
570/// # use frame_support::PartialEqNoBound;
571/// trait Config {
572/// 		type C: PartialEq;
573/// }
574///
575/// // Foo implements [`PartialEq`] because `C` bounds [`PartialEq`].
576/// // Otherwise compilation will fail with an output telling `c` doesn't implement [`PartialEq`].
577/// #[derive(PartialEqNoBound)]
578/// struct Foo<T: Config> {
579/// 		c: T::C,
580/// }
581/// ```
582pub use frame_support_procedural::PartialEqNoBound;
583
584/// Derive [`Ord`] but do not bound any generic.
585///
586/// This is useful for type generic over runtime:
587/// ```
588/// # use frame_support::{OrdNoBound, PartialOrdNoBound, EqNoBound, PartialEqNoBound};
589/// trait Config {
590/// 		type C: Ord;
591/// }
592///
593/// // Foo implements [`Ord`] because `C` bounds [`Ord`].
594/// // Otherwise compilation will fail with an output telling `c` doesn't implement [`Ord`].
595/// #[derive(EqNoBound, OrdNoBound, PartialEqNoBound, PartialOrdNoBound)]
596/// struct Foo<T: Config> {
597/// 		c: T::C,
598/// }
599/// ```
600pub use frame_support_procedural::OrdNoBound;
601
602/// Derive [`PartialOrd`] but do not bound any generic.
603///
604/// This is useful for type generic over runtime:
605/// ```
606/// # use frame_support::{OrdNoBound, PartialOrdNoBound, EqNoBound, PartialEqNoBound};
607/// trait Config {
608/// 		type C: PartialOrd;
609/// }
610///
611/// // Foo implements [`PartialOrd`] because `C` bounds [`PartialOrd`].
612/// // Otherwise compilation will fail with an output telling `c` doesn't implement [`PartialOrd`].
613/// #[derive(PartialOrdNoBound, PartialEqNoBound, EqNoBound)]
614/// struct Foo<T: Config> {
615/// 		c: T::C,
616/// }
617/// ```
618pub use frame_support_procedural::PartialOrdNoBound;
619
620/// Derive [`Debug`] but do not bound any generic.
621///
622/// This is useful for type generic over runtime:
623/// ```
624/// # use frame_support::DebugNoBound;
625/// # use core::fmt::Debug;
626/// trait Config {
627/// 		type C: Debug;
628/// }
629///
630/// // Foo implements [`Debug`] because `C` bounds [`Debug`].
631/// // Otherwise compilation will fail with an output telling `c` doesn't implement [`Debug`].
632/// #[derive(DebugNoBound)]
633/// struct Foo<T: Config> {
634/// 		c: T::C,
635/// }
636/// ```
637pub use frame_support_procedural::DebugNoBound;
638
639/// Derive [`Default`] but do not bound any generic.
640///
641/// This is useful for type generic over runtime:
642/// ```
643/// # use frame_support::DefaultNoBound;
644/// # use core::default::Default;
645/// trait Config {
646/// 	type C: Default;
647/// }
648///
649/// // Foo implements [`Default`] because `C` bounds [`Default`].
650/// // Otherwise compilation will fail with an output telling `c` doesn't implement [`Default`].
651/// #[derive(DefaultNoBound)]
652/// struct Foo<T: Config> {
653/// 	c: T::C,
654/// }
655///
656/// // Also works with enums, by specifying the default with #[default]:
657/// #[derive(DefaultNoBound)]
658/// enum Bar<T: Config> {
659/// 	// Bar will implement Default as long as all of the types within Baz also implement default.
660/// 	#[default]
661/// 	Baz(T::C),
662/// 	Quxx,
663/// }
664/// ```
665pub use frame_support_procedural::DefaultNoBound;
666
667/// Assert the annotated function is executed within a storage transaction.
668///
669/// The assertion is enabled for native execution and when `debug_assertions` are enabled.
670///
671/// # Example
672///
673/// ```
674/// # use frame_support::{
675/// # 	require_transactional, transactional, dispatch::DispatchResult
676/// # };
677///
678/// #[require_transactional]
679/// fn update_all(value: u32) -> DispatchResult {
680/// 	// Update multiple storages.
681/// 	// Return `Err` to indicate should revert.
682/// 	Ok(())
683/// }
684///
685/// #[transactional]
686/// fn safe_update(value: u32) -> DispatchResult {
687/// 	// This is safe
688/// 	update_all(value)
689/// }
690///
691/// fn unsafe_update(value: u32) -> DispatchResult {
692/// 	// this may panic if unsafe_update is not called within a storage transaction
693/// 	update_all(value)
694/// }
695/// ```
696pub use frame_support_procedural::require_transactional;
697
698/// Convert the current crate version into a [`CrateVersion`](crate::traits::CrateVersion).
699///
700/// It uses the `CARGO_PKG_VERSION_MAJOR`, `CARGO_PKG_VERSION_MINOR` and
701/// `CARGO_PKG_VERSION_PATCH` environment variables to fetch the crate version.
702/// This means that the [`CrateVersion`](crate::traits::CrateVersion)
703/// object will correspond to the version of the crate the macro is called in!
704///
705/// # Example
706///
707/// ```
708/// # use frame_support::{traits::CrateVersion, crate_to_crate_version};
709/// const Version: CrateVersion = crate_to_crate_version!();
710/// ```
711pub use frame_support_procedural::crate_to_crate_version;
712
713/// Return Err of the expression: `return Err($expression);`.
714///
715/// Used as `fail!(expression)`.
716#[macro_export]
717macro_rules! fail {
718	( $y:expr ) => {{
719		return Err($y.into());
720	}};
721}
722
723/// Evaluate `$x:expr` and if not true return `Err($y:expr)`.
724///
725/// Used as `ensure!(expression_to_ensure, expression_to_return_on_false)`.
726#[macro_export]
727macro_rules! ensure {
728	( $x:expr, $y:expr $(,)? ) => {{
729		if !$x {
730			$crate::fail!($y);
731		}
732	}};
733}
734
735/// Evaluate an expression, assert it returns an expected `Err` value and that
736/// runtime storage has not been mutated (i.e. expression is a no-operation).
737///
738/// Used as `assert_noop(expression_to_assert, expected_error_expression)`.
739#[macro_export]
740macro_rules! assert_noop {
741	(
742		$x:expr,
743		$y:expr $(,)?
744	) => {
745		let h = $crate::__private::storage_root($crate::__private::StateVersion::V1);
746		$crate::assert_err!($x, $y);
747		assert_eq!(
748			h,
749			$crate::__private::storage_root($crate::__private::StateVersion::V1),
750			"storage has been mutated"
751		);
752	};
753}
754
755/// Evaluate any expression and assert that runtime storage has not been mutated
756/// (i.e. expression is a storage no-operation).
757///
758/// Used as `assert_storage_noop(expression_to_assert)`.
759#[macro_export]
760macro_rules! assert_storage_noop {
761	(
762		$x:expr
763	) => {
764		let h = $crate::__private::storage_root($crate::__private::StateVersion::V1);
765		$x;
766		assert_eq!(h, $crate::__private::storage_root($crate::__private::StateVersion::V1));
767	};
768}
769
770/// Assert an expression returns an error specified.
771///
772/// Used as `assert_err!(expression_to_assert, expected_error_expression)`
773#[macro_export]
774macro_rules! assert_err {
775	( $x:expr , $y:expr $(,)? ) => {
776		assert_eq!($x, Err($y.into()));
777	};
778}
779
780/// Assert an expression returns an error specified.
781///
782/// This can be used on `DispatchResultWithPostInfo` when the post info should
783/// be ignored.
784#[macro_export]
785macro_rules! assert_err_ignore_postinfo {
786	( $x:expr , $y:expr $(,)? ) => {
787		$crate::assert_err!($x.map(|_| ()).map_err(|e| e.error), $y);
788	};
789}
790
791/// Assert an expression returns error with the given weight.
792#[macro_export]
793macro_rules! assert_err_with_weight {
794	($call:expr, $err:expr, $weight:expr $(,)? ) => {
795		if let Err(dispatch_err_with_post) = $call {
796			$crate::assert_err!($call.map(|_| ()).map_err(|e| e.error), $err);
797			assert_eq!(dispatch_err_with_post.post_info.actual_weight, $weight);
798		} else {
799			::core::panic!("expected Err(_), got Ok(_).")
800		}
801	};
802}
803
804/// Panic if an expression doesn't evaluate to `Ok`.
805///
806/// Used as `assert_ok!(expression_to_assert, expected_ok_expression)`,
807/// or `assert_ok!(expression_to_assert)` which would assert against `Ok(())`.
808#[macro_export]
809macro_rules! assert_ok {
810	( $x:expr $(,)? ) => {
811		let is = $x;
812		match is {
813			Ok(_) => (),
814			_ => assert!(false, "Expected Ok(_). Got {:#?}", is),
815		}
816	};
817	( $x:expr, $y:expr $(,)? ) => {
818		assert_eq!($x, Ok($y));
819	};
820}
821
822/// Assert that the maximum encoding size does not exceed the value defined in
823/// [`MAX_MODULE_ERROR_ENCODED_SIZE`] during compilation.
824///
825/// This macro is intended to be used in conjunction with `tt_call!`.
826#[macro_export]
827macro_rules! assert_error_encoded_size {
828	{
829		path = [{ $($path:ident)::+ }]
830		runtime = [{ $runtime:ident }]
831		assert_message = [{ $assert_message:literal }]
832		error = [{ $error:ident }]
833	} => {
834		const _: () = assert!(
835			<
836				$($path::)+$error<$runtime> as $crate::traits::PalletError
837			>::MAX_ENCODED_SIZE <= $crate::MAX_MODULE_ERROR_ENCODED_SIZE,
838			$assert_message
839		);
840	};
841	{
842		path = [{ $($path:ident)::+ }]
843		runtime = [{ $runtime:ident }]
844		assert_message = [{ $assert_message:literal }]
845	} => {};
846}
847
848/// Do something hypothetically by rolling back any changes afterwards.
849///
850/// Returns the original result of the closure.
851#[macro_export]
852#[cfg(feature = "experimental")]
853macro_rules! hypothetically {
854	( $e:expr ) => {
855		$crate::storage::transactional::with_transaction(|| -> $crate::__private::TransactionOutcome<Result<_, $crate::__private::DispatchError>> {
856			$crate::__private::TransactionOutcome::Rollback(Ok($e))
857		},
858		).expect("Always returning Ok; qed")
859	};
860}
861
862/// Assert something to be *hypothetically* `Ok`, without actually committing it.
863///
864/// Reverts any storage changes made by the closure.
865#[macro_export]
866#[cfg(feature = "experimental")]
867macro_rules! hypothetically_ok {
868	($e:expr $(, $args:expr)* $(,)?) => {
869		$crate::assert_ok!($crate::hypothetically!($e) $(, $args)*);
870	};
871}
872
873#[doc(hidden)]
874pub use serde::{Deserialize, Serialize};
875
876#[doc(hidden)]
877pub use macro_magic;
878
879/// Prelude to be used for pallet testing, for ease of use.
880#[cfg(feature = "std")]
881pub mod testing_prelude {
882	pub use super::{
883		assert_err, assert_err_ignore_postinfo, assert_err_with_weight, assert_error_encoded_size,
884		assert_noop, assert_ok, assert_storage_noop, parameter_types, traits::Get,
885	};
886	pub use sp_arithmetic::assert_eq_error_rate;
887	pub use sp_runtime::{bounded_btree_map, bounded_vec};
888}
889
890/// Prelude to be used alongside pallet macro, for ease of use.
891pub mod pallet_prelude {
892	pub use crate::{
893		defensive, defensive_assert,
894		dispatch::{DispatchClass, DispatchResult, DispatchResultWithPostInfo, Parameter, Pays},
895		ensure,
896		inherent::{InherentData, InherentIdentifier, ProvideInherent},
897		storage,
898		storage::{
899			bounded_btree_map::BoundedBTreeMap,
900			bounded_btree_set::BoundedBTreeSet,
901			bounded_vec::BoundedVec,
902			types::{
903				CountedStorageMap, CountedStorageNMap, Key as NMapKey, OptionQuery, ResultQuery,
904				StorageDoubleMap, StorageMap, StorageNMap, StorageValue, ValueQuery,
905			},
906			weak_bounded_vec::WeakBoundedVec,
907			StorageList,
908		},
909		traits::{
910			BuildGenesisConfig, ConstU32, ConstUint, EnsureOrigin, Get, GetDefault,
911			GetStorageVersion, Hooks, IsType, OriginTrait, PalletInfoAccess, StorageInfoTrait,
912			StorageVersion, Task, TypedGet,
913		},
914		Blake2_128, Blake2_128Concat, Blake2_256, CloneNoBound, DebugNoBound, EqNoBound, Identity,
915		PartialEqNoBound, RuntimeDebugNoBound, Twox128, Twox256, Twox64Concat,
916	};
917	pub use codec::{Decode, DecodeWithMemTracking, Encode, MaxEncodedLen};
918	pub use core::marker::PhantomData;
919	pub use frame_support::pallet_macros::*;
920	pub use frame_support_procedural::{inject_runtime_type, register_default_impl};
921	pub use scale_info::TypeInfo;
922	pub use sp_inherents::MakeFatalError;
923	pub use sp_runtime::{
924		traits::{
925			CheckedAdd, CheckedConversion, CheckedDiv, CheckedMul, CheckedShl, CheckedShr,
926			CheckedSub, MaybeSerializeDeserialize, Member, One, ValidateUnsigned, Zero,
927		},
928		transaction_validity::{
929			InvalidTransaction, TransactionLongevity, TransactionPriority, TransactionSource,
930			TransactionTag, TransactionValidity, TransactionValidityError, UnknownTransaction,
931			ValidTransaction,
932		},
933		DispatchError, RuntimeDebug, MAX_MODULE_ERROR_ENCODED_SIZE,
934	};
935	pub use sp_weights::Weight;
936}
937
938/// The pallet macro has 2 purposes:
939///
940/// * [For declaring a pallet as a rust module](#1---pallet-module-declaration)
941/// * [For declaring the `struct` placeholder of a
942///   pallet](#2---pallet-struct-placeholder-declaration)
943///
944/// # 1 - Pallet module declaration
945///
946/// The module to declare a pallet is organized as follows:
947/// ```
948/// #[frame_support::pallet]    // <- the macro
949/// mod pallet {
950/// 	#[pallet::pallet]
951/// 	pub struct Pallet<T>(_);
952///
953/// 	#[pallet::config]
954/// 	pub trait Config: frame_system::Config {}
955///
956/// 	#[pallet::call]
957/// 	impl<T: Config> Pallet<T> {
958/// 	}
959///
960/// 	/* ... */
961/// }
962/// ```
963///
964/// The documentation for each individual part can be found at [frame_support::pallet_macros]
965///
966/// ## Dev Mode (`#[pallet(dev_mode)]`)
967///
968/// Syntax:
969///
970/// ```
971/// #[frame_support::pallet(dev_mode)]
972/// mod pallet {
973/// # 	 #[pallet::pallet]
974/// # 	 pub struct Pallet<T>(_);
975/// # 	 #[pallet::config]
976/// # 	 pub trait Config: frame_system::Config {}
977/// 	/* ... */
978/// }
979/// ```
980///
981/// Specifying the argument `dev_mode` will allow you to enable dev mode for a pallet. The
982/// aim of dev mode is to loosen some of the restrictions and requirements placed on
983/// production pallets for easy tinkering and development. Dev mode pallets should not be
984/// used in production. Enabling dev mode has the following effects:
985///
986/// * Weights no longer need to be specified on every `#[pallet::call]` declaration. By
987///   default, dev mode pallets will assume a weight of zero (`0`) if a weight is not
988///   specified. This is equivalent to specifying `#[weight(0)]` on all calls that do not
989///   specify a weight.
990/// * Call indices no longer need to be specified on every `#[pallet::call]` declaration. By
991///   default, dev mode pallets will assume a call index based on the order of the call.
992/// * All storages are marked as unbounded, meaning you do not need to implement
993///   [`MaxEncodedLen`](frame_support::pallet_prelude::MaxEncodedLen) on storage types. This is
994///   equivalent to specifying `#[pallet::unbounded]` on all storage type definitions.
995/// * Storage hashers no longer need to be specified and can be replaced by `_`. In dev mode,
996///   these will be replaced by `Blake2_128Concat`. In case of explicit key-binding, `Hasher`
997///   can simply be ignored when in `dev_mode`.
998///
999/// Note that the `dev_mode` argument can only be supplied to the `#[pallet]` or
1000/// `#[frame_support::pallet]` attribute macro that encloses your pallet module. This
1001/// argument cannot be specified anywhere else, including but not limited to the
1002/// `#[pallet::pallet]` attribute macro.
1003///
1004/// <div class="example-wrap" style="display:inline-block"><pre class="compile_fail"
1005/// style="white-space:normal;font:inherit;">
1006/// <strong>WARNING</strong>:
1007/// You should never deploy or use dev mode pallets in production. Doing so can break your
1008/// chain. Once you are done tinkering, you should
1009/// remove the 'dev_mode' argument from your #[pallet] declaration and fix any compile
1010/// errors before attempting to use your pallet in a production scenario.
1011/// </pre></div>
1012///
1013/// # 2 - Pallet struct placeholder declaration
1014///
1015/// The pallet struct placeholder `#[pallet::pallet]` is mandatory and allows you to
1016/// specify pallet information.
1017///
1018/// The struct must be defined as follows:
1019/// ```
1020/// #[frame_support::pallet]
1021/// mod pallet {
1022/// 	#[pallet::pallet]         // <- the macro
1023/// 	pub struct Pallet<T>(_);  // <- the struct definition
1024///
1025/// 	#[pallet::config]
1026/// 	pub trait Config: frame_system::Config {}
1027/// }
1028/// ```
1029//
1030/// I.e. a regular struct definition named `Pallet`, with generic T and no where clause.
1031///
1032/// ## Macro expansion:
1033///
1034/// The macro adds this attribute to the Pallet struct definition:
1035/// ```ignore
1036/// #[derive(
1037/// 	frame_support::CloneNoBound,
1038/// 	frame_support::EqNoBound,
1039/// 	frame_support::PartialEqNoBound,
1040/// 	frame_support::RuntimeDebugNoBound,
1041/// )]
1042/// ```
1043/// and replaces the type `_` with `PhantomData<T>`.
1044///
1045/// It also implements on the pallet:
1046///
1047/// * [`GetStorageVersion`](frame_support::traits::GetStorageVersion)
1048/// * [`OnGenesis`](frame_support::traits::OnGenesis): contains some logic to write the pallet
1049///   version into storage.
1050/// * [`PalletInfoAccess`](frame_support::traits::PalletInfoAccess) to ease access to pallet
1051///   information given by [`frame_support::traits::PalletInfo`]. (The implementation uses the
1052///   associated type [`frame_support::traits::PalletInfo`]).
1053/// * [`StorageInfoTrait`](frame_support::traits::StorageInfoTrait) to give information about
1054///   storages.
1055///
1056/// If the attribute `set_storage_max_encoded_len` is set then the macro calls
1057/// [`StorageInfoTrait`](frame_support::traits::StorageInfoTrait) for each storage in the
1058/// implementation of [`StorageInfoTrait`](frame_support::traits::StorageInfoTrait) for the
1059/// pallet. Otherwise, it implements
1060/// [`StorageInfoTrait`](frame_support::traits::StorageInfoTrait) for the pallet using the
1061/// [`PartialStorageInfoTrait`](frame_support::traits::PartialStorageInfoTrait)
1062/// implementation of storages.
1063///
1064/// ## Note on deprecation.
1065///
1066/// - Usage of `deprecated` attribute will propagate deprecation information to the pallet
1067///   metadata.
1068/// - For general usage examples of `deprecated` attribute please refer to <https://doc.rust-lang.org/nightly/reference/attributes/diagnostics.html#the-deprecated-attribute>
1069pub use frame_support_procedural::pallet;
1070
1071/// Contains macro stubs for all of the `pallet::` macros
1072pub mod pallet_macros {
1073	/// Declare the storage as whitelisted from benchmarking.
1074	///
1075	/// Doing so will exclude reads of that value's storage key from counting towards weight
1076	/// calculations during benchmarking.
1077	///
1078	/// This attribute should only be attached to storages that are known to be
1079	/// read/used in every block. This will result in a more accurate benchmarking weight.
1080	///
1081	/// ### Example
1082	/// ```
1083	/// #[frame_support::pallet]
1084	/// mod pallet {
1085	/// # 	use frame_support::pallet_prelude::*;
1086	/// #
1087	/// 	#[pallet::pallet]
1088	/// 	pub struct Pallet<T>(_);
1089	///
1090	/// 	#[pallet::storage]
1091	/// 	#[pallet::whitelist_storage]
1092	/// 	pub type MyStorage<T> = StorageValue<_, u32>;
1093	/// #
1094	/// # 	#[pallet::config]
1095	/// # 	pub trait Config: frame_system::Config {}
1096	/// }
1097	/// ```
1098	pub use frame_support_procedural::whitelist_storage;
1099
1100	/// Allows specifying the weight of a call.
1101	///
1102	/// Each dispatchable needs to define a weight.
1103	/// This attribute allows to define a weight using the expression:
1104	/// `#[pallet::weight($expr)]` Note that argument of the call are available inside the
1105	/// expression.
1106	///
1107	/// If not defined explicitly, the weight can be implicitly inferred from the weight info
1108	/// defined in the attribute `pallet::call`: `#[pallet::call(weight = $WeightInfo)]`.
1109	/// Or it can be simply ignored when the pallet is in `dev_mode`.
1110	///
1111	/// ## Example
1112	///
1113	/// ```
1114	/// #[frame_support::pallet]
1115	/// mod pallet {
1116	///  	use frame_support::pallet_prelude::*;
1117	///  	use frame_system::pallet_prelude::*;
1118	///
1119	/// 	#[pallet::pallet]
1120	/// 	pub struct Pallet<T>(_);
1121	///
1122	///  	#[pallet::config]
1123	///  	pub trait Config: frame_system::Config {
1124	///         /// Type for specifying dispatchable weights.
1125	///         type WeightInfo: WeightInfo;
1126	///     }
1127	///
1128	/// 	#[pallet::call(weight = <T as Config>::WeightInfo)]
1129	/// 	impl<T: Config> Pallet<T> {
1130	/// 		// Explicit weight definition
1131	/// 		#[pallet::weight(<T as Config>::WeightInfo::do_something())]
1132	/// 		#[pallet::call_index(0)]
1133	/// 		pub fn do_something(
1134	/// 			origin: OriginFor<T>,
1135	/// 			foo: u32,
1136	/// 		) -> DispatchResult {
1137	/// 			Ok(())
1138	/// 		}
1139	///
1140	///             // Implicit weight definition, the macro looks up to the weight info defined in
1141	///             // `#[pallet::call(weight = $WeightInfo)]` attribute. Then use
1142	///             // `$WeightInfo::do_something_else` as the weight function.
1143	///             #[pallet::call_index(1)]
1144	///             pub fn do_something_else(
1145	///                 origin: OriginFor<T>,
1146	///                 bar: u64,
1147	///             ) -> DispatchResult {
1148	///                 Ok(())
1149	///             }
1150	///     }
1151	///
1152	///     /// The `WeightInfo` trait defines weight functions for dispatchable calls.
1153	///     pub trait WeightInfo {
1154	///         fn do_something() -> Weight;
1155	///         fn do_something_else() -> Weight;
1156	///     }
1157	/// }
1158	/// ```
1159	pub use frame_support_procedural::weight;
1160
1161	/// Allows whitelisting a storage item from decoding during try-runtime checks.
1162	///
1163	/// The optional attribute `#[pallet::disable_try_decode_storage]` will declare the
1164	/// storage as whitelisted from decoding during try-runtime checks. This should only be
1165	/// attached to transient storage which cannot be migrated during runtime upgrades.
1166	///
1167	/// ### Example
1168	/// ```
1169	/// #[frame_support::pallet]
1170	/// mod pallet {
1171	/// # 	use frame_support::pallet_prelude::*;
1172	/// #
1173	/// 	#[pallet::pallet]
1174	/// 	pub struct Pallet<T>(_);
1175	///
1176	/// 	#[pallet::storage]
1177	/// 	#[pallet::disable_try_decode_storage]
1178	/// 	pub type MyStorage<T> = StorageValue<_, u32>;
1179	/// #
1180	/// # 	#[pallet::config]
1181	/// # 	pub trait Config: frame_system::Config {}
1182	/// }
1183	/// ```
1184	pub use frame_support_procedural::disable_try_decode_storage;
1185
1186	/// Declares a storage as unbounded in potential size.
1187	///
1188	/// When implementing the storage info (when `#[pallet::generate_storage_info]` is
1189	/// specified on the pallet struct placeholder), the size of the storage will be declared
1190	/// as unbounded. This can be useful for storage which can never go into PoV (Proof of
1191	/// Validity).
1192	///
1193	/// ## Example
1194	///
1195	/// ```
1196	/// #[frame_support::pallet]
1197	/// mod pallet {
1198	/// # 	use frame_support::pallet_prelude::*;
1199	/// #
1200	/// 	#[pallet::pallet]
1201	/// 	pub struct Pallet<T>(_);
1202	///
1203	/// 	#[pallet::storage]
1204	/// 	#[pallet::unbounded]
1205	/// 	pub type MyStorage<T> = StorageValue<_, u32>;
1206	/// #
1207	/// # 	#[pallet::config]
1208	/// # 	pub trait Config: frame_system::Config {}
1209	/// }
1210	/// ```
1211	pub use frame_support_procedural::unbounded;
1212
1213	/// Defines what storage prefix to use for a storage item when building the trie.
1214	///
1215	/// This is helpful if you wish to rename the storage field but don't want to perform a
1216	/// migration.
1217	///
1218	/// ## Example
1219	///
1220	/// ```
1221	/// #[frame_support::pallet]
1222	/// mod pallet {
1223	/// # 	use frame_support::pallet_prelude::*;
1224	/// #
1225	/// 	#[pallet::pallet]
1226	/// 	pub struct Pallet<T>(_);
1227	///
1228	/// 	#[pallet::storage]
1229	/// 	#[pallet::storage_prefix = "foo"]
1230	/// 	pub type MyStorage<T> = StorageValue<_, u32>;
1231	/// #
1232	/// # 	#[pallet::config]
1233	/// # 	pub trait Config: frame_system::Config {}
1234	/// }
1235	/// ```
1236	pub use frame_support_procedural::storage_prefix;
1237
1238	/// Ensures the generated `DefaultConfig` will not have any bounds for
1239	/// that trait item.
1240	///
1241	/// Attaching this attribute to a trait item ensures that the generated trait
1242	/// `DefaultConfig` will not have any bounds for this trait item.
1243	///
1244	/// As an example, if you have a trait item `type AccountId: SomeTrait;` in your `Config`
1245	/// trait, the generated `DefaultConfig` will only have `type AccountId;` with no trait
1246	/// bound.
1247	pub use frame_support_procedural::no_default_bounds;
1248
1249	/// Ensures the trait item will not be used as a default with the
1250	/// `#[derive_impl(..)]` attribute macro.
1251	///
1252	/// The optional attribute `#[pallet::no_default]` can be attached to trait items within a
1253	/// `Config` trait impl that has [`#[pallet::config(with_default)]`](`config`)
1254	/// attached.
1255	pub use frame_support_procedural::no_default;
1256
1257	/// Declares a module as importable into a pallet via
1258	/// [`#[import_section]`](`import_section`).
1259	///
1260	/// Note that sections are imported by their module name/ident, and should be referred to
1261	/// by their _full path_ from the perspective of the target pallet. Do not attempt to make
1262	/// use of `use` statements to bring pallet sections into scope, as this will not work
1263	/// (unless you do so as part of a wildcard import, in which case it will work).
1264	///
1265	/// ## Naming Logistics
1266	///
1267	/// Also note that because of how `#[pallet_section]` works, pallet section names must be
1268	/// globally unique _within the crate in which they are defined_. For more information on
1269	/// why this must be the case, see macro_magic's
1270	/// [`#[export_tokens]`](https://docs.rs/macro_magic/latest/macro_magic/attr.export_tokens.html) macro.
1271	///
1272	/// Optionally, you may provide an argument to `#[pallet_section]` such as
1273	/// `#[pallet_section(some_ident)]`, in the event that there is another pallet section in
1274	/// same crate with the same ident/name. The ident you specify can then be used instead of
1275	/// the module's ident name when you go to import it via
1276	/// [`#[import_section]`](`import_section`).
1277	pub use frame_support_procedural::pallet_section;
1278
1279	/// The `#[pallet::inherent]` attribute allows the pallet to provide
1280	/// [inherents](https://docs.substrate.io/fundamentals/transaction-types/#inherent-transactions).
1281	///
1282	/// An inherent is some piece of data that is inserted by a block authoring node at block
1283	/// creation time and can either be accepted or rejected by validators based on whether the
1284	/// data falls within an acceptable range.
1285	///
1286	/// The most common inherent is the `timestamp` that is inserted into every block. Since
1287	/// there is no way to validate timestamps, validators simply check that the timestamp
1288	/// reported by the block authoring node falls within an acceptable range.
1289	///
1290	/// Example usage:
1291	///
1292	/// ```
1293	/// #[frame_support::pallet]
1294	/// mod pallet {
1295	/// # 	use frame_support::pallet_prelude::*;
1296	/// # 	use frame_support::inherent::IsFatalError;
1297	/// # 	use sp_timestamp::InherentError;
1298	/// # 	use core::result;
1299	/// #
1300	/// 	// Example inherent identifier
1301	/// 	pub const INHERENT_IDENTIFIER: InherentIdentifier = *b"timstap0";
1302	///
1303	/// 	#[pallet::pallet]
1304	/// 	pub struct Pallet<T>(_);
1305	///
1306	/// 	#[pallet::inherent]
1307	/// 	impl<T: Config> ProvideInherent for Pallet<T> {
1308	/// 		type Call = Call<T>;
1309	/// 		type Error = InherentError;
1310	/// 		const INHERENT_IDENTIFIER: InherentIdentifier = INHERENT_IDENTIFIER;
1311	///
1312	/// 		fn create_inherent(data: &InherentData) -> Option<Self::Call> {
1313	/// 			unimplemented!()
1314	/// 		}
1315	///
1316	/// 		fn check_inherent(
1317	/// 			call: &Self::Call,
1318	/// 			data: &InherentData,
1319	/// 		) -> result::Result<(), Self::Error> {
1320	/// 			unimplemented!()
1321	/// 		}
1322	///
1323	/// 		fn is_inherent(call: &Self::Call) -> bool {
1324	/// 			unimplemented!()
1325	/// 		}
1326	/// 	}
1327	/// #
1328	/// # 	#[pallet::config]
1329	/// # 	pub trait Config: frame_system::Config {}
1330	/// }
1331	/// ```
1332	///
1333	/// I.e. a trait implementation with bound `T: Config`, of trait `ProvideInherent` for type
1334	/// `Pallet<T>`, and some optional where clause.
1335	///
1336	/// ## Macro expansion
1337	///
1338	/// The macro currently makes no use of this information, but it might use this information
1339	/// in the future to give information directly to `construct_runtime`.
1340	pub use frame_support_procedural::inherent;
1341
1342	/// Splits a pallet declaration into multiple parts.
1343	///
1344	/// An attribute macro that can be attached to a module declaration. Doing so will
1345	/// import the contents of the specified external pallet section that is defined
1346	/// elsewhere using [`#[pallet_section]`](`pallet_section`).
1347	///
1348	/// ## Example
1349	/// ```
1350	/// # use frame_support::pallet_macros::pallet_section;
1351	/// # use frame_support::pallet_macros::import_section;
1352	/// #
1353	/// /// A [`pallet_section`] that defines the events for a pallet.
1354	/// /// This can later be imported into the pallet using [`import_section`].
1355	/// #[pallet_section]
1356	/// mod events {
1357	/// 	#[pallet::event]
1358	/// 	#[pallet::generate_deposit(pub(super) fn deposit_event)]
1359	/// 	pub enum Event<T: Config> {
1360	/// 		/// Event documentation should end with an array that provides descriptive names for event
1361	/// 		/// parameters. [something, who]
1362	/// 		SomethingStored { something: u32, who: T::AccountId },
1363	/// 	}
1364	/// }
1365	///
1366	/// #[import_section(events)]
1367	/// #[frame_support::pallet]
1368	/// mod pallet {
1369	/// # 	use frame_support::pallet_prelude::*;
1370	/// #
1371	/// 	#[pallet::pallet]
1372	/// 	pub struct Pallet<T>(_);
1373	/// #
1374	/// # 	#[pallet::config]
1375	/// # 	pub trait Config: frame_system::Config {
1376	/// # 		type RuntimeEvent: From<Event<Self>> + IsType<<Self as frame_system::Config>::RuntimeEvent>;
1377	/// # 	}
1378	/// }
1379	/// ```
1380	///
1381	/// This will result in the contents of `some_section` being _verbatim_ imported into
1382	/// the pallet above. Note that since the tokens for `some_section` are essentially
1383	/// copy-pasted into the target pallet, you cannot refer to imports that don't also
1384	/// exist in the target pallet, but this is easily resolved by including all relevant
1385	/// `use` statements within your pallet section, so they are imported as well, or by
1386	/// otherwise ensuring that you have the same imports on the target pallet.
1387	///
1388	/// It is perfectly permissible to import multiple pallet sections into the same pallet,
1389	/// which can be done by having multiple `#[import_section(something)]` attributes
1390	/// attached to the pallet.
1391	///
1392	/// Note that sections are imported by their module name/ident, and should be referred to
1393	/// by their _full path_ from the perspective of the target pallet.
1394	pub use frame_support_procedural::import_section;
1395
1396	/// Allows defining getter functions on `Pallet` storage.
1397	///
1398	/// ## Example
1399	///
1400	/// ```
1401	/// #[frame_support::pallet]
1402	/// mod pallet {
1403	/// # 	use frame_support::pallet_prelude::*;
1404	/// #
1405	/// 	#[pallet::pallet]
1406	/// 	pub struct Pallet<T>(_);
1407	///
1408	/// 	#[pallet::storage]
1409	/// 	#[pallet::getter(fn my_getter_fn_name)]
1410	/// 	pub type MyStorage<T> = StorageValue<_, u32>;
1411	/// #
1412	/// # 	#[pallet::config]
1413	/// # 	pub trait Config: frame_system::Config {}
1414	/// }
1415	/// ```
1416	///
1417	/// See [`pallet::storage`](`frame_support::pallet_macros::storage`) for more info.
1418	pub use frame_support_procedural::getter;
1419
1420	/// Defines constants that are added to the constant field of
1421	/// [`PalletMetadata`](frame_metadata::v15::PalletMetadata) struct for this pallet.
1422	///
1423	/// Must be defined like:
1424	///
1425	/// ```
1426	/// #[frame_support::pallet]
1427	/// mod pallet {
1428	/// # 	use frame_support::pallet_prelude::*;
1429	/// #
1430	/// 	#[pallet::pallet]
1431	/// 	pub struct Pallet<T>(_);
1432	///
1433	/// # 	#[pallet::config]
1434	/// # 	pub trait Config: frame_system::Config {}
1435	/// #
1436	/// 	#[pallet::extra_constants]
1437	/// 	impl<T: Config> Pallet<T> // $optional_where_clause
1438	/// 	{
1439	/// 	#[pallet::constant_name(SomeU32ConstantName)]
1440	/// 		/// Some doc
1441	/// 		fn some_u32_constant() -> u32 {
1442	/// 			100u32
1443	/// 		}
1444	/// 	}
1445	/// }
1446	/// ```
1447	///
1448	/// I.e. a regular rust `impl` block with some optional where clause and functions with 0
1449	/// args, 0 generics, and some return type.
1450	pub use frame_support_procedural::extra_constants;
1451
1452	#[rustfmt::skip]
1453	/// Allows bypassing the `frame_system::Config` supertrait check.
1454	///
1455	/// To bypass the syntactic `frame_system::Config` supertrait check, use the attribute
1456	/// `pallet::disable_frame_system_supertrait_check`.
1457	///
1458	/// Note this bypass is purely syntactic, and does not actually remove the requirement that your
1459	/// pallet implements `frame_system::Config`. When using this check, your config is still required to implement
1460	/// `frame_system::Config` either via
1461	/// - Implementing a trait that itself implements `frame_system::Config`
1462	/// - Tightly coupling it with another pallet which itself implements `frame_system::Config`
1463	///
1464	/// e.g.
1465	///
1466	/// ```
1467	/// #[frame_support::pallet]
1468	/// mod pallet {
1469	/// # 	use frame_support::pallet_prelude::*;
1470	/// # 	use frame_system::pallet_prelude::*;
1471	/// 	trait OtherTrait: frame_system::Config {}
1472	///
1473	/// 	#[pallet::pallet]
1474	/// 	pub struct Pallet<T>(_);
1475	///
1476	/// 	#[pallet::config]
1477	/// 	#[pallet::disable_frame_system_supertrait_check]
1478	/// 	pub trait Config: OtherTrait {}
1479	/// }
1480	/// ```
1481	///
1482	/// To learn more about supertraits, see the
1483	/// [trait_based_programming](../../polkadot_sdk_docs/reference_docs/trait_based_programming/index.html)
1484	/// reference doc.
1485	pub use frame_support_procedural::disable_frame_system_supertrait_check;
1486
1487	/// The mandatory attribute allowing definition of configurable types for the pallet.
1488	///
1489	/// Item must be defined as:
1490	///
1491	/// ```
1492	/// #[frame_support::pallet]
1493	/// mod pallet {
1494	/// # 	use frame_support::pallet_prelude::*;
1495	/// #
1496	/// 	#[pallet::pallet]
1497	/// 	pub struct Pallet<T>(_);
1498	///
1499	/// 	#[pallet::config]
1500	/// 	pub trait Config: frame_system::Config // + $optionally_some_other_supertraits
1501	/// 	// $optional_where_clause
1502	/// 	{
1503	/// 		// config items here
1504	/// 	}
1505	/// }
1506	/// ```
1507	///
1508	/// I.e. a regular trait definition named `Config`, with the supertrait
1509	/// [`frame_system::pallet::Config`](../../frame_system/pallet/trait.Config.html), and
1510	/// optionally other supertraits and a where clause. (Specifying other supertraits here is
1511	/// known as [tight coupling](https://docs.substrate.io/reference/how-to-guides/pallet-design/use-tight-coupling/))
1512	///
1513	/// The associated type `RuntimeEvent` is reserved. If defined, it must have the bounds
1514	/// `From<Event>` and `IsType<<Self as frame_system::Config>::RuntimeEvent>`.
1515	///
1516	/// [`#[pallet::event]`](`event`) must be present if `RuntimeEvent`
1517	/// exists as a config item in your `#[pallet::config]`.
1518	///
1519	/// ## Optional: `with_default`
1520	///
1521	/// An optional `with_default` argument may also be specified. Doing so will automatically
1522	/// generate a `DefaultConfig` trait inside your pallet which is suitable for use with
1523	/// [`#[derive_impl(..)`](`frame_support::derive_impl`) to derive a default testing
1524	/// config:
1525	///
1526	/// ```
1527	/// #[frame_support::pallet]
1528	/// mod pallet {
1529	/// # 	use frame_support::pallet_prelude::*;
1530	/// # 	use frame_system::pallet_prelude::*;
1531	/// # 	use core::fmt::Debug;
1532	/// # 	use frame_support::traits::Contains;
1533	/// #
1534	/// # 	pub trait SomeMoreComplexBound {}
1535	/// #
1536	/// 	#[pallet::pallet]
1537	/// 	pub struct Pallet<T>(_);
1538	///
1539	/// 	#[pallet::config(with_default)] // <- with_default is optional
1540	/// 	pub trait Config: frame_system::Config {
1541	/// 		/// The overarching event type.
1542	/// 		#[pallet::no_default_bounds] // Default with bounds is not supported for RuntimeEvent
1543	/// 		type RuntimeEvent: From<Event<Self>> + IsType<<Self as frame_system::Config>::RuntimeEvent>;
1544	///
1545	/// 		/// A more complex type.
1546	/// 		#[pallet::no_default] // Example of type where no default should be provided
1547	/// 		type MoreComplexType: SomeMoreComplexBound;
1548	///
1549	/// 		/// A simple type.
1550	/// 		// Default with bounds is supported for simple types
1551	/// 		type SimpleType: From<u32>;
1552	/// 	}
1553	///
1554	/// 	#[pallet::event]
1555	/// 	pub enum Event<T: Config> {
1556	/// 		SomeEvent(u16, u32),
1557	/// 	}
1558	/// }
1559	/// ```
1560	///
1561	/// As shown above:
1562	/// * you may attach the [`#[pallet::no_default]`](`no_default`)
1563	/// attribute to specify that a particular trait item _cannot_ be used as a default when a
1564	/// test `Config` is derived using the [`#[derive_impl(..)]`](`frame_support::derive_impl`)
1565	/// attribute macro. This will cause that particular trait item to simply not appear in
1566	/// default testing configs based on this config (the trait item will not be included in
1567	/// `DefaultConfig`).
1568	/// * you may attach the [`#[pallet::no_default_bounds]`](`no_default_bounds`)
1569	/// attribute to specify that a particular trait item can be used as a default when a
1570	/// test `Config` is derived using the [`#[derive_impl(..)]`](`frame_support::derive_impl`)
1571	/// attribute macro. But its bounds cannot be enforced at this point and should be
1572	/// discarded when generating the default config trait.
1573	/// * you may not specify any attribute to generate a trait item in the default config
1574	///   trait.
1575	///
1576	/// In case origin of error is not clear it is recommended to disable all default with
1577	/// [`#[pallet::no_default]`](`no_default`) and enable them one by one.
1578	///
1579	/// ### `DefaultConfig` Caveats
1580	///
1581	/// The auto-generated `DefaultConfig` trait:
1582	/// - is always a _subset_ of your pallet's `Config` trait.
1583	/// - can only contain items that don't rely on externalities, such as
1584	///   `frame_system::Config`.
1585	///
1586	/// Trait items that _do_ rely on externalities should be marked with
1587	/// [`#[pallet::no_default]`](`no_default`)
1588	///
1589	/// Consequently:
1590	/// - Any items that rely on externalities _must_ be marked with
1591	///   [`#[pallet::no_default]`](`no_default`) or your trait will fail to compile when used
1592	///   with [`derive_impl`](`frame_support::derive_impl`).
1593	/// - Items marked with [`#[pallet::no_default]`](`no_default`) are entirely excluded from
1594	///   the `DefaultConfig` trait, and therefore any impl of `DefaultConfig` doesn't need to
1595	///   implement such items.
1596	///
1597	/// For more information, see:
1598	/// * [`frame_support::derive_impl`].
1599	/// * [`#[pallet::no_default]`](`no_default`)
1600	/// * [`#[pallet::no_default_bounds]`](`no_default_bounds`)
1601	///
1602	/// ## Optional: `without_automatic_metadata`
1603	///
1604	/// By default, the associated types of the `Config` trait that require the `TypeInfo` or
1605	/// `Parameter` bounds are included in the metadata of the pallet.
1606	///
1607	/// The optional `without_automatic_metadata` argument can be used to exclude these
1608	/// associated types from the metadata collection.
1609	///
1610	/// Furthermore, the `without_automatic_metadata` argument can be used in combination with
1611	/// the [`#[pallet::include_metadata]`](`include_metadata`) attribute to selectively
1612	/// include only certain associated types in the metadata collection.
1613	///
1614	/// ```
1615	/// #[frame_support::pallet]
1616	/// mod pallet {
1617	/// # 	use frame_support::pallet_prelude::*;
1618	/// # 	use frame_system::pallet_prelude::*;
1619	/// # 	use core::fmt::Debug;
1620	/// # 	use frame_support::traits::Contains;
1621	/// #
1622	/// # 	pub trait SomeMoreComplexBound {}
1623	/// #
1624	/// 	#[pallet::pallet]
1625	/// 	pub struct Pallet<T>(_);
1626	///
1627	/// 	#[pallet::config(with_default, without_automatic_metadata)] // <- with_default and without_automatic_metadata are optional
1628	/// 	pub trait Config: frame_system::Config {
1629	/// 		/// The overarching event type.
1630	/// 		#[pallet::no_default_bounds] // Default with bounds is not supported for RuntimeEvent
1631	/// 		type RuntimeEvent: From<Event<Self>> + IsType<<Self as frame_system::Config>::RuntimeEvent>;
1632	///
1633	/// 		/// A simple type.
1634	/// 		// Type that would have been included in metadata, but is now excluded.
1635	/// 		type SimpleType: From<u32> + TypeInfo;
1636	///
1637	/// 		// The `pallet::include_metadata` is used to selectively include this type in metadata.
1638	/// 		#[pallet::include_metadata]
1639	/// 		type SelectivelyInclude: From<u32> + TypeInfo;
1640	/// 	}
1641	///
1642	/// 	#[pallet::event]
1643	/// 	pub enum Event<T: Config> {
1644	/// 		SomeEvent(u16, u32),
1645	/// 	}
1646	/// }
1647	/// ```
1648	pub use frame_support_procedural::config;
1649
1650	/// Allows defining an enum that gets composed as an aggregate enum by `construct_runtime`.
1651	///
1652	/// The `#[pallet::composite_enum]` attribute allows you to define an enum that gets
1653	/// composed as an aggregate enum by `construct_runtime`. This is similar in principle with
1654	/// [frame_support_procedural::event] and [frame_support_procedural::error].
1655	///
1656	/// The attribute currently only supports enum definitions, and identifiers that are named
1657	/// `FreezeReason`, `HoldReason`, `LockId` or `SlashReason`. Arbitrary identifiers for the
1658	/// enum are not supported. The aggregate enum generated by
1659	/// [`frame_support::construct_runtime`] will have the name of `RuntimeFreezeReason`,
1660	/// `RuntimeHoldReason`, `RuntimeLockId` and `RuntimeSlashReason` respectively.
1661	///
1662	/// NOTE: The aggregate enum generated by `construct_runtime` generates a conversion
1663	/// function from the pallet enum to the aggregate enum, and automatically derives the
1664	/// following traits:
1665	///
1666	/// ```ignore
1667	/// Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Encode, Decode, MaxEncodedLen, TypeInfo,
1668	/// RuntimeDebug
1669	/// ```
1670	///
1671	/// For ease of usage, when no `#[derive]` attributes are found for the enum under
1672	/// [`#[pallet::composite_enum]`](composite_enum), the aforementioned traits are
1673	/// automatically derived for it. The inverse is also true: if there are any `#[derive]`
1674	/// attributes found for the enum, then no traits will automatically be derived for it.
1675	///
1676	/// e.g, defining `HoldReason` in a pallet
1677	///
1678	/// ```
1679	/// #[frame_support::pallet]
1680	/// mod pallet {
1681	/// # 	use frame_support::pallet_prelude::*;
1682	/// #
1683	/// 	#[pallet::pallet]
1684	/// 	pub struct Pallet<T>(_);
1685	///
1686	/// 	#[pallet::composite_enum]
1687	/// 	pub enum HoldReason {
1688	/// 		/// The NIS Pallet has reserved it for a non-fungible receipt.
1689	/// 		#[codec(index = 0)]
1690	/// 		SomeHoldReason,
1691	/// 		#[codec(index = 1)]
1692	/// 		SomeOtherHoldReason,
1693	/// 	}
1694	/// #
1695	/// # 	#[pallet::config]
1696	/// # 	pub trait Config: frame_system::Config {}
1697	/// }
1698	pub use frame_support_procedural::composite_enum;
1699
1700	/// Allows the pallet to validate unsigned transactions.
1701	///
1702	/// Item must be defined as:
1703	///
1704	/// ```
1705	/// #[frame_support::pallet]
1706	/// mod pallet {
1707	/// # 	use frame_support::pallet_prelude::*;
1708	/// #
1709	/// 	#[pallet::pallet]
1710	/// 	pub struct Pallet<T>(_);
1711	///
1712	/// 	#[pallet::validate_unsigned]
1713	/// 	impl<T: Config> sp_runtime::traits::ValidateUnsigned for Pallet<T> {
1714	/// 		type Call = Call<T>;
1715	///
1716	/// 		fn validate_unsigned(_source: TransactionSource, _call: &Self::Call) -> TransactionValidity {
1717	/// 			// Your implementation details here
1718	/// 			unimplemented!()
1719	/// 		}
1720	/// 	}
1721	/// #
1722	/// # 	#[pallet::config]
1723	/// # 	pub trait Config: frame_system::Config {}
1724	/// }
1725	/// ```
1726	///
1727	/// I.e. a trait implementation with bound `T: Config`, of trait
1728	/// [`ValidateUnsigned`](frame_support::pallet_prelude::ValidateUnsigned) for
1729	/// type `Pallet<T>`, and some optional where clause.
1730	///
1731	/// NOTE: There is also the [`sp_runtime::traits::TransactionExtension`] trait that can be
1732	/// used to add some specific logic for transaction validation.
1733	///
1734	/// ## Macro expansion
1735	///
1736	/// The macro currently makes no use of this information, but it might use this information
1737	/// in the future to give information directly to [`frame_support::construct_runtime`].
1738	pub use frame_support_procedural::validate_unsigned;
1739
1740	/// Allows defining	view functions on a pallet.
1741	///
1742	/// A pallet view function is a read-only function providing access to the state of the
1743	/// pallet from both outside and inside the runtime. It should provide a _stable_ interface
1744	/// for querying the state of the pallet, avoiding direct storage access and upgrading
1745	/// along with the runtime.
1746	///
1747	/// ## Syntax
1748	/// View functions methods must be read-only and always return some output. A
1749	/// `view_functions_experimental` impl block only allows methods to be defined inside of
1750	/// it.
1751	///
1752	/// ## Example
1753	/// ```
1754	/// #[frame_support::pallet]
1755	/// pub mod pallet {
1756	/// 	use frame_support::pallet_prelude::*;
1757	///
1758	///  	#[pallet::config]
1759	///  	pub trait Config: frame_system::Config {}
1760	///
1761	///  	#[pallet::pallet]
1762	///  	pub struct Pallet<T>(_);
1763	///
1764	///     #[pallet::storage]
1765	/// 	pub type SomeMap<T: Config> = StorageMap<_, Twox64Concat, u32, u32, OptionQuery>;
1766	///
1767	///     #[pallet::view_functions_experimental]
1768	///     impl<T: Config> Pallet<T> {
1769	/// 		/// Retrieve a map storage value by key.
1770	///         pub fn get_value_with_arg(key: u32) -> Option<u32> {
1771	/// 			SomeMap::<T>::get(key)
1772	/// 		}
1773	///     }
1774	/// }
1775	/// ```
1776	///
1777	///
1778	/// ## Usage and implementation details
1779	/// To allow outside access to pallet view functions, you need to add a runtime API that
1780	/// accepts view function queries and dispatches them to the right pallet. You can do that
1781	/// by implementing the
1782	/// [`RuntimeViewFunction`](frame_support::view_functions::runtime_api::RuntimeViewFunction)
1783	/// trait for the runtime inside an [`impl_runtime_apis!`](sp_api::impl_runtime_apis)
1784	/// block.
1785	///
1786	/// The `RuntimeViewFunction` trait implements a hashing-based dispatching mechanism to
1787	/// dispatch view functions to the right method in the right pallet based on their IDs. A
1788	/// view function ID depends both on its pallet and on its method signature, so it remains
1789	/// stable as long as those two elements are not modified. In general, pallet view
1790	/// functions should expose a _stable_ interface and changes to the method signature are
1791	/// strongly discouraged. For more details on the dispatching mechanism, see the
1792	/// [`DispatchViewFunction`](frame_support::view_functions::DispatchViewFunction) trait.
1793	pub use frame_support_procedural::view_functions_experimental;
1794
1795	/// Allows defining a struct implementing the [`Get`](frame_support::traits::Get) trait to
1796	/// ease the use of storage types.
1797	///
1798	/// This attribute is meant to be used alongside [`#[pallet::storage]`](`storage`) to
1799	/// define a storage's default value. This attribute can be used multiple times.
1800	///
1801	/// Item must be defined as:
1802	///
1803	/// ```
1804	/// #[frame_support::pallet]
1805	/// mod pallet {
1806	/// # 	use sp_runtime::FixedU128;
1807	/// # 	use frame_support::pallet_prelude::*;
1808	/// #
1809	/// 	#[pallet::pallet]
1810	/// 	pub struct Pallet<T>(_);
1811	///
1812	/// 	#[pallet::storage]
1813	/// 	pub(super) type SomeStorage<T: Config> =
1814	/// 		StorageValue<_, FixedU128, ValueQuery, DefaultForSomeValue>;
1815	///
1816	/// 	// Define default for ParachainId
1817	/// 	#[pallet::type_value]
1818	/// 	pub fn DefaultForSomeValue() -> FixedU128 {
1819	/// 		FixedU128::from_u32(1)
1820	/// 	}
1821	/// #
1822	/// # 	#[pallet::config]
1823	/// # 	pub trait Config: frame_system::Config {}
1824	/// }
1825	/// ```
1826	///
1827	/// ## Macro expansion
1828	///
1829	/// The macro renames the function to some internal name, generates a struct with the
1830	/// original name of the function and its generic, and implements `Get<$ReturnType>` by
1831	/// calling the user defined function.
1832	pub use frame_support_procedural::type_value;
1833
1834	/// Allows defining a storage version for the pallet.
1835	///
1836	/// Because the `pallet::pallet` macro implements
1837	/// [`GetStorageVersion`](frame_support::traits::GetStorageVersion), the current storage
1838	/// version needs to be communicated to the macro. This can be done by using the
1839	/// `pallet::storage_version` attribute:
1840	///
1841	/// ```
1842	/// #[frame_support::pallet]
1843	/// mod pallet {
1844	/// # 	use frame_support::pallet_prelude::StorageVersion;
1845	/// # 	use frame_support::traits::GetStorageVersion;
1846	/// #
1847	/// 	const STORAGE_VERSION: StorageVersion = StorageVersion::new(5);
1848	///
1849	/// 	#[pallet::pallet]
1850	/// 	#[pallet::storage_version(STORAGE_VERSION)]
1851	/// 	pub struct Pallet<T>(_);
1852	/// #
1853	/// # 	#[pallet::config]
1854	/// # 	pub trait Config: frame_system::Config {}
1855	/// }
1856	/// ```
1857	///
1858	/// If not present, the current storage version is set to the default value.
1859	pub use frame_support_procedural::storage_version;
1860
1861	/// The `#[pallet::hooks]` attribute allows you to specify a
1862	/// [`frame_support::traits::Hooks`] implementation for `Pallet` that specifies
1863	/// pallet-specific logic.
1864	///
1865	/// The item the attribute attaches to must be defined as follows:
1866	///
1867	/// ```
1868	/// #[frame_support::pallet]
1869	/// mod pallet {
1870	/// # 	use frame_support::pallet_prelude::*;
1871	/// # 	use frame_system::pallet_prelude::*;
1872	/// #
1873	/// 	#[pallet::pallet]
1874	/// 	pub struct Pallet<T>(_);
1875	///
1876	/// 	#[pallet::hooks]
1877	/// 	impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {
1878	/// 		// Implement hooks here
1879	/// 	}
1880	/// #
1881	/// # 	#[pallet::config]
1882	/// # 	pub trait Config: frame_system::Config {}
1883	/// }
1884	/// ```
1885	/// I.e. a regular trait implementation with generic bound: `T: Config`, for the trait
1886	/// `Hooks<BlockNumberFor<T>>` (they are defined in preludes), for the type `Pallet<T>`.
1887	///
1888	/// Optionally, you could add a where clause.
1889	///
1890	/// ## Macro expansion
1891	///
1892	/// The macro implements the traits
1893	/// [`OnInitialize`](frame_support::traits::OnInitialize),
1894	/// [`OnIdle`](frame_support::traits::OnIdle),
1895	/// [`OnFinalize`](frame_support::traits::OnFinalize),
1896	/// [`OnRuntimeUpgrade`](frame_support::traits::OnRuntimeUpgrade),
1897	/// [`OffchainWorker`](frame_support::traits::OffchainWorker), and
1898	/// [`IntegrityTest`](frame_support::traits::IntegrityTest) using
1899	/// the provided [`Hooks`](frame_support::traits::Hooks) implementation.
1900	///
1901	/// NOTE: `OnRuntimeUpgrade` is implemented with `Hooks::on_runtime_upgrade` and some
1902	/// additional logic. E.g. logic to write the pallet version into storage.
1903	///
1904	/// NOTE: The macro also adds some tracing logic when implementing the above traits. The
1905	/// following hooks emit traces: `on_initialize`, `on_finalize` and `on_runtime_upgrade`.
1906	pub use frame_support_procedural::hooks;
1907
1908	/// Generates a helper function on `Pallet` that handles deposit events.
1909	///
1910	/// NOTE: For instantiable pallets, the event must be generic over `T` and `I`.
1911	///
1912	/// ## Macro expansion
1913	///
1914	/// The macro will add on enum `Event` the attributes:
1915	/// * `#[derive(`[`frame_support::CloneNoBound`]`)]`
1916	/// * `#[derive(`[`frame_support::EqNoBound`]`)]`
1917	/// * `#[derive(`[`frame_support::PartialEqNoBound`]`)]`
1918	/// * `#[derive(`[`frame_support::RuntimeDebugNoBound`]`)]`
1919	/// * `#[derive(`[`codec::Encode`]`)]`
1920	/// * `#[derive(`[`codec::Decode`]`)]`
1921	///
1922	/// The macro implements `From<Event<..>>` for ().
1923	///
1924	/// The macro implements a metadata function on `Event` returning the `EventMetadata`.
1925	///
1926	/// If `#[pallet::generate_deposit]` is present then the macro implements `fn
1927	/// deposit_event` on `Pallet`.
1928	pub use frame_support_procedural::generate_deposit;
1929
1930	/// Allows defining logic to make an extrinsic call feeless.
1931	///
1932	/// Each dispatchable may be annotated with the `#[pallet::feeless_if($closure)]`
1933	/// attribute, which explicitly defines the condition for the dispatchable to be feeless.
1934	///
1935	/// The arguments for the closure must be the referenced arguments of the dispatchable
1936	/// function.
1937	///
1938	/// The closure must return `bool`.
1939	///
1940	/// ### Example
1941	///
1942	/// ```
1943	/// #[frame_support::pallet(dev_mode)]
1944	/// mod pallet {
1945	/// # 	use frame_support::pallet_prelude::*;
1946	/// # 	use frame_system::pallet_prelude::*;
1947	/// #
1948	/// 	#[pallet::pallet]
1949	/// 	pub struct Pallet<T>(_);
1950	///
1951	/// 	#[pallet::call]
1952	/// 	impl<T: Config> Pallet<T> {
1953	/// 		#[pallet::call_index(0)]
1954	/// 		/// Marks this call as feeless if `foo` is zero.
1955	/// 		#[pallet::feeless_if(|_origin: &OriginFor<T>, foo: &u32| -> bool {
1956	/// 			*foo == 0
1957	/// 		})]
1958	/// 		pub fn something(
1959	/// 			_: OriginFor<T>,
1960	/// 			foo: u32,
1961	/// 		) -> DispatchResult {
1962	/// 			unimplemented!()
1963	/// 		}
1964	/// 	}
1965	/// #
1966	/// # 	#[pallet::config]
1967	/// # 	pub trait Config: frame_system::Config {}
1968	/// }
1969	/// ```
1970	///
1971	/// Please note that this only works for signed dispatchables and requires a transaction
1972	/// extension such as [`pallet_skip_feeless_payment::SkipCheckIfFeeless`] to wrap the
1973	/// existing payment extension. Else, this is completely ignored and the dispatchable is
1974	/// still charged.
1975	///
1976	/// Also this will not allow accountless caller to send a transaction if some transaction
1977	/// extension such as `frame_system::CheckNonce` is used.
1978	/// Extensions such as `frame_system::CheckNonce` require a funded account to validate
1979	/// the transaction.
1980	///
1981	/// ### Macro expansion
1982	///
1983	/// The macro implements the [`pallet_skip_feeless_payment::CheckIfFeeless`] trait on the
1984	/// dispatchable and calls the corresponding closure in the implementation.
1985	///
1986	/// [`pallet_skip_feeless_payment::SkipCheckIfFeeless`]: ../../pallet_skip_feeless_payment/struct.SkipCheckIfFeeless.html
1987	/// [`pallet_skip_feeless_payment::CheckIfFeeless`]: ../../pallet_skip_feeless_payment/struct.SkipCheckIfFeeless.html
1988	pub use frame_support_procedural::feeless_if;
1989
1990	/// Allows defining an error enum that will be returned from the dispatchable when an error
1991	/// occurs.
1992	///
1993	/// The information for this error type is then stored in runtime metadata.
1994	///
1995	/// Item must be defined as so:
1996	///
1997	/// ```
1998	/// #[frame_support::pallet(dev_mode)]
1999	/// mod pallet {
2000	/// 	#[pallet::pallet]
2001	/// 	pub struct Pallet<T>(_);
2002	///
2003	/// 	#[pallet::error]
2004	/// 	pub enum Error<T> {
2005	/// 		/// SomeFieldLessVariant doc
2006	/// 		SomeFieldLessVariant,
2007	/// 		/// SomeVariantWithOneField doc
2008	/// 		SomeVariantWithOneField(u32),
2009	/// 	}
2010	/// #
2011	/// # 	#[pallet::config]
2012	/// # 	pub trait Config: frame_system::Config {}
2013	/// }
2014	/// ```
2015	/// I.e. a regular enum named `Error`, with generic `T` and fieldless or multiple-field
2016	/// variants.
2017	///
2018	/// Any field type in the enum variants must implement [`scale_info::TypeInfo`] in order to
2019	/// be properly used in the metadata, and its encoded size should be as small as possible,
2020	/// preferably 1 byte in size in order to reduce storage size. The error enum itself has an
2021	/// absolute maximum encoded size specified by
2022	/// [`frame_support::MAX_MODULE_ERROR_ENCODED_SIZE`].
2023	///
2024	/// (1 byte can still be 256 different errors. The more specific the error, the easier it
2025	/// is to diagnose problems and give a better experience to the user. Don't skimp on having
2026	/// lots of individual error conditions.)
2027	///
2028	/// Field types in enum variants must also implement [`frame_support::PalletError`],
2029	/// otherwise the pallet will fail to compile. Rust primitive types have already
2030	/// implemented the [`frame_support::PalletError`] trait along with some commonly used
2031	/// stdlib types such as [`Option`] and [`core::marker::PhantomData`], and hence
2032	/// in most use cases, a manual implementation is not necessary and is discouraged.
2033	///
2034	/// The generic `T` must not bound anything and a `where` clause is not allowed. That said,
2035	/// bounds and/or a where clause should not needed for any use-case.
2036	///
2037	/// ## Macro expansion
2038	///
2039	/// The macro implements the [`Debug`] trait and functions `as_u8` using variant position,
2040	/// and `as_str` using variant doc.
2041	///
2042	/// The macro also implements `From<Error<T>>` for `&'static str` and `From<Error<T>>` for
2043	/// `DispatchError`.
2044	///
2045	/// ## Note on deprecation of Errors
2046	///
2047	/// - Usage of `deprecated` attribute will propagate deprecation information to the pallet
2048	///   metadata where the item was declared.
2049	/// - For general usage examples of `deprecated` attribute please refer to <https://doc.rust-lang.org/nightly/reference/attributes/diagnostics.html#the-deprecated-attribute>
2050	/// - It's possible to deprecated either certain variants inside the `Error` or the whole
2051	///   `Error` itself. If both the `Error` and its variants are deprecated a compile error
2052	///   will be returned.
2053	pub use frame_support_procedural::error;
2054
2055	/// Allows defining pallet events.
2056	///
2057	/// Pallet events are stored under the `system` / `events` key when the block is applied
2058	/// (and then replaced when the next block writes it's events).
2059	///
2060	/// The Event enum can be defined as follows:
2061	///
2062	/// ```
2063	/// #[frame_support::pallet(dev_mode)]
2064	/// mod pallet {
2065	/// #     use frame_support::pallet_prelude::IsType;
2066	/// #
2067	/// 	#[pallet::pallet]
2068	/// 	pub struct Pallet<T>(_);
2069	///
2070	/// 	#[pallet::event]
2071	/// 	#[pallet::generate_deposit(fn deposit_event)] // Optional
2072	/// 	pub enum Event<T> {
2073	/// 		/// SomeEvent doc
2074	/// 		SomeEvent(u16, u32), // SomeEvent with two fields
2075	/// 	}
2076	///
2077	/// 	#[pallet::config]
2078	/// 	pub trait Config: frame_system::Config {
2079	/// 		/// The overarching runtime event type.
2080	/// 		type RuntimeEvent: From<Event<Self>>
2081	/// 			+ IsType<<Self as frame_system::Config>::RuntimeEvent>;
2082	/// 	}
2083	/// }
2084	/// ```
2085	///
2086	/// I.e. an enum (with named or unnamed fields variant), named `Event`, with generic: none
2087	/// or `T` or `T: Config`, and optional w here clause.
2088	///
2089	/// `RuntimeEvent` must be defined in the `Config`, as shown in the example.
2090	///
2091	/// Each field must implement [`Clone`], [`Eq`], [`PartialEq`], [`codec::Encode`],
2092	/// [`codec::Decode`], and [`Debug`] (on std only). For ease of use, bound by the trait
2093	/// `Member`, available in [`frame_support::pallet_prelude`].
2094	///
2095	/// ## Note on deprecation of Events
2096	///
2097	/// - Usage of `deprecated` attribute will propagate deprecation information to the pallet
2098	///   metadata where the item was declared.
2099	/// - For general usage examples of `deprecated` attribute please refer to <https://doc.rust-lang.org/nightly/reference/attributes/diagnostics.html#the-deprecated-attribute>
2100	/// - It's possible to deprecated either certain variants inside the `Event` or the whole
2101	///   `Event` itself. If both the `Event` and its variants are deprecated a compile error
2102	///   will be returned.
2103	pub use frame_support_procedural::event;
2104
2105	/// Selectively includes associated types in the metadata.
2106	///
2107	/// The optional attribute allows you to selectively include associated types in the
2108	/// metadata. This can be attached to trait items that implement `TypeInfo`.
2109	///
2110	/// By default all collectable associated types are included in the metadata.
2111	///
2112	/// This attribute can be used in combination with the
2113	/// [`#[pallet::config(without_automatic_metadata)]`](`config`).
2114	pub use frame_support_procedural::include_metadata;
2115
2116	/// Allows a pallet to declare a set of functions as a *dispatchable extrinsic*.
2117	///
2118	/// In slightly simplified terms, this macro declares the set of "transactions" of a
2119	/// pallet.
2120	///
2121	/// > The exact definition of **extrinsic** can be found in
2122	/// > [`sp_runtime::generic::UncheckedExtrinsic`].
2123	///
2124	/// A **dispatchable** is a common term in FRAME, referring to process of constructing a
2125	/// function, and dispatching it with the correct inputs. This is commonly used with
2126	/// extrinsics, for example "an extrinsic has been dispatched". See
2127	/// [`sp_runtime::traits::Dispatchable`] and [`crate::traits::UnfilteredDispatchable`].
2128	///
2129	/// ## Call Enum
2130	///
2131	/// The macro is called `call` (rather than `#[pallet::extrinsics]`) because of the
2132	/// generation of a `enum Call`. This enum contains only the encoding of the function
2133	/// arguments of the dispatchable, alongside the information needed to route it to the
2134	/// correct function.
2135	///
2136	/// ```
2137	/// #[frame_support::pallet(dev_mode)]
2138	/// pub mod custom_pallet {
2139	/// #   use frame_support::pallet_prelude::*;
2140	/// #   use frame_system::pallet_prelude::*;
2141	/// #   #[pallet::config]
2142	/// #   pub trait Config: frame_system::Config {}
2143	/// #   #[pallet::pallet]
2144	/// #   pub struct Pallet<T>(_);
2145	/// #   use frame_support::traits::BuildGenesisConfig;
2146	///     #[pallet::call]
2147	///     impl<T: Config> Pallet<T> {
2148	///         pub fn some_dispatchable(_origin: OriginFor<T>, _input: u32) -> DispatchResult {
2149	///             Ok(())
2150	///         }
2151	///         pub fn other(_origin: OriginFor<T>, _input: u64) -> DispatchResult {
2152	///             Ok(())
2153	///         }
2154	///     }
2155	///
2156	///     // generates something like:
2157	///     // enum Call<T: Config> {
2158	///     //  some_dispatchable { input: u32 }
2159	///     //  other { input: u64 }
2160	///     // }
2161	/// }
2162	///
2163	/// fn main() {
2164	/// #   use frame_support::{derive_impl, construct_runtime};
2165	/// #   use frame_support::__private::codec::Encode;
2166	/// #   use frame_support::__private::TestExternalities;
2167	/// #   use frame_support::traits::UnfilteredDispatchable;
2168	/// #    impl custom_pallet::Config for Runtime {}
2169	/// #    #[derive_impl(frame_system::config_preludes::TestDefaultConfig)]
2170	/// #    impl frame_system::Config for Runtime {
2171	/// #        type Block = frame_system::mocking::MockBlock<Self>;
2172	/// #    }
2173	///     construct_runtime! {
2174	///         pub enum Runtime {
2175	///             System: frame_system,
2176	///             Custom: custom_pallet
2177	///         }
2178	///     }
2179	///
2180	/// #    TestExternalities::new_empty().execute_with(|| {
2181	///     let origin: RuntimeOrigin = frame_system::RawOrigin::Signed(10).into();
2182	///     // calling into a dispatchable from within the runtime is simply a function call.
2183	///         let _ = custom_pallet::Pallet::<Runtime>::some_dispatchable(origin.clone(), 10);
2184	///
2185	///     // calling into a dispatchable from the outer world involves constructing the bytes of
2186	///     let call = custom_pallet::Call::<Runtime>::some_dispatchable { input: 10 };
2187	///     let _ = call.clone().dispatch_bypass_filter(origin);
2188	///
2189	///     // the routing of a dispatchable is simply done through encoding of the `Call` enum,
2190	///     // which is the index of the variant, followed by the arguments.
2191	///     assert_eq!(call.encode(), vec![0u8, 10, 0, 0, 0]);
2192	///
2193	///     // notice how in the encoding of the second function, the first byte is different and
2194	///     // referring to the second variant of `enum Call`.
2195	///     let call = custom_pallet::Call::<Runtime>::other { input: 10 };
2196	///     assert_eq!(call.encode(), vec![1u8, 10, 0, 0, 0, 0, 0, 0, 0]);
2197	///     #    });
2198	/// }
2199	/// ```
2200	///
2201	/// Further properties of dispatchable functions are as follows:
2202	///
2203	/// - Unless if annotated by `dev_mode`, it must contain [`weight`] to denote the
2204	///   pre-dispatch weight consumed.
2205	/// - The dispatchable must declare its index via [`call_index`], which can override the
2206	///   position of a function in `enum Call`.
2207	/// - The first argument is always an `OriginFor` (or `T::RuntimeOrigin`).
2208	/// - The return type is always [`crate::dispatch::DispatchResult`] (or
2209	///   [`crate::dispatch::DispatchResultWithPostInfo`]).
2210	///
2211	/// **WARNING**: modifying dispatchables, changing their order (i.e. using [`call_index`]),
2212	/// removing some, etc., must be done with care. This will change the encoding of the call,
2213	/// and the call can be stored on-chain (e.g. in `pallet-scheduler`). Thus, migration
2214	/// might be needed. This is why the use of `call_index` is mandatory by default in FRAME.
2215	///
2216	/// ## Weight info
2217	///
2218	/// Each call needs to define a weight.
2219	/// * The weight can be defined explicitly using the attribute `#[pallet::weight($expr)]`
2220	///   (Note that argument of the call are available inside the expression).
2221	/// * Or it can be defined implicitly, the weight info for the calls needs to be specified
2222	///   in the call attribute: `#[pallet::call(weight = $WeightInfo)]`, then each call that
2223	///   doesn't have explicit weight will use `$WeightInfo::$call_name` as the weight.
2224	///
2225	/// * Or it can be simply ignored when the pallet is in `dev_mode`.
2226	///
2227	/// ```
2228	/// #[frame_support::pallet]
2229	/// mod pallet {
2230	///     use frame_support::pallet_prelude::*;
2231	///     use frame_system::pallet_prelude::*;
2232	///
2233	///     #[pallet::pallet]
2234	///     pub struct Pallet<T>(_);
2235	///
2236	///     #[pallet::config]
2237	///     pub trait Config: frame_system::Config {
2238	///         /// Type for specifying dispatchable weights.
2239	///         type WeightInfo: WeightInfo;
2240	///     }
2241	///
2242	///     /// The `WeightInfo` trait defines weight functions for dispatchable calls.
2243	///     pub trait WeightInfo {
2244	///         fn do_something() -> Weight;
2245	///         fn do_something_else() -> Weight;
2246	///     }
2247	///
2248	///     #[pallet::call(weight = <T as Config>::WeightInfo)]
2249	///     impl<T: Config> Pallet<T> {
2250	///         // Explicit weight definition using `#[pallet::weight(...)]`
2251	///         #[pallet::weight(<T as Config>::WeightInfo::do_something())]
2252	///         #[pallet::call_index(0)]
2253	///         pub fn do_something(
2254	///             origin: OriginFor<T>,
2255	///             foo: u32,
2256	///         ) -> DispatchResult {
2257	///             // Function logic here
2258	///             Ok(())
2259	///         }
2260	///
2261	///         // Implicit weight definition, the macro looks up to the weight info defined in
2262	///         // `#[pallet::call(weight = $WeightInfo)]` attribute. Then use
2263	///         // `$WeightInfo::do_something_else` as the weight function.
2264	///         #[pallet::call_index(1)]
2265	///         pub fn do_something_else(
2266	///             origin: OriginFor<T>,
2267	///             bar: u64,
2268	///         ) -> DispatchResult {
2269	///             // Function logic here
2270	///             Ok(())
2271	///         }
2272	///     }
2273	/// }
2274	/// ```
2275	///
2276	/// ## Default Behavior
2277	///
2278	/// If no `#[pallet::call]` exists, then a default implementation corresponding to the
2279	/// following code is automatically generated:
2280	///
2281	/// ```
2282	/// #[frame_support::pallet(dev_mode)]
2283	/// mod pallet {
2284	/// 	#[pallet::pallet]
2285	/// 	pub struct Pallet<T>(_);
2286	///
2287	/// 	#[pallet::call] // <- automatically generated
2288	/// 	impl<T: Config> Pallet<T> {} // <- automatically generated
2289	///
2290	/// 	#[pallet::config]
2291	/// 	pub trait Config: frame_system::Config {}
2292	/// }
2293	/// ```
2294	///
2295	/// ## Note on deprecation of Calls
2296	///
2297	/// - Usage of `deprecated` attribute will propagate deprecation information to the pallet
2298	///   metadata where the item was declared.
2299	/// - For general usage examples of `deprecated` attribute please refer to <https://doc.rust-lang.org/nightly/reference/attributes/diagnostics.html#the-deprecated-attribute>
2300	pub use frame_support_procedural::call;
2301
2302	/// Enforce the index of a variant in the generated `enum Call`.
2303	///
2304	/// See [`call`] for more information.
2305	///
2306	/// All call indexes start from 0, until it encounters a dispatchable function with a
2307	/// defined call index. The dispatchable function that lexically follows the function with
2308	/// a defined call index will have that call index, but incremented by 1, e.g. if there are
2309	/// 3 dispatchable functions `fn foo`, `fn bar` and `fn qux` in that order, and only `fn
2310	/// bar` has a call index of 10, then `fn qux` will have an index of 11, instead of 1.
2311	pub use frame_support_procedural::call_index;
2312
2313	/// Declares the arguments of a [`call`] function to be encoded using
2314	/// [`codec::Compact`].
2315	///
2316	/// This will results in smaller extrinsic encoding.
2317	///
2318	/// A common example of `compact` is for numeric values that are often times far far away
2319	/// from their theoretical maximum. For example, in the context of a crypto-currency, the
2320	/// balance of an individual account is oftentimes way less than what the numeric type
2321	/// allows. In all such cases, using `compact` is sensible.
2322	///
2323	/// ```
2324	/// #[frame_support::pallet(dev_mode)]
2325	/// pub mod custom_pallet {
2326	/// #   use frame_support::pallet_prelude::*;
2327	/// #   use frame_system::pallet_prelude::*;
2328	/// #   #[pallet::config]
2329	/// #   pub trait Config: frame_system::Config {}
2330	/// #   #[pallet::pallet]
2331	/// #   pub struct Pallet<T>(_);
2332	/// #   use frame_support::traits::BuildGenesisConfig;
2333	///     #[pallet::call]
2334	///     impl<T: Config> Pallet<T> {
2335	///         pub fn some_dispatchable(_origin: OriginFor<T>, #[pallet::compact] _input: u32) -> DispatchResult {
2336	///             Ok(())
2337	///         }
2338	///     }
2339	/// }
2340	pub use frame_support_procedural::compact;
2341
2342	/// Allows you to define the genesis configuration for the pallet.
2343	///
2344	/// Item is defined as either an enum or a struct. It needs to be public and implement the
2345	/// trait [`frame_support::traits::BuildGenesisConfig`].
2346	///
2347	/// See [`genesis_build`] for an example.
2348	pub use frame_support_procedural::genesis_config;
2349
2350	/// Allows you to define how the state of your pallet at genesis is built. This
2351	/// takes as input the `GenesisConfig` type (as `self`) and constructs the pallet's initial
2352	/// state.
2353	///
2354	/// The fields of the `GenesisConfig` can in turn be populated by the chain-spec.
2355	///
2356	/// ## Example
2357	///
2358	/// ```
2359	/// #[frame_support::pallet]
2360	/// pub mod pallet {
2361	/// # 	#[pallet::config]
2362	/// # 	pub trait Config: frame_system::Config {}
2363	/// # 	#[pallet::pallet]
2364	/// # 	pub struct Pallet<T>(_);
2365	/// # 	use frame_support::traits::BuildGenesisConfig;
2366	///     #[pallet::genesis_config]
2367	///     #[derive(frame_support::DefaultNoBound)]
2368	///     pub struct GenesisConfig<T: Config> {
2369	///         foo: Vec<T::AccountId>
2370	///     }
2371	///
2372	///     #[pallet::genesis_build]
2373	///     impl<T: Config> BuildGenesisConfig for GenesisConfig<T> {
2374	///         fn build(&self) {
2375	///             // use &self to access fields.
2376	///             let foo = &self.foo;
2377	///             todo!()
2378	///         }
2379	///     }
2380	/// }
2381	/// ```
2382	///
2383	/// ## Former Usage
2384	///
2385	/// Prior to <https://github.com/paritytech/substrate/pull/14306>, the following syntax was used.
2386	/// This is deprecated and will soon be removed.
2387	///
2388	/// ```
2389	/// #[frame_support::pallet]
2390	/// pub mod pallet {
2391	/// #     #[pallet::config]
2392	/// #     pub trait Config: frame_system::Config {}
2393	/// #     #[pallet::pallet]
2394	/// #     pub struct Pallet<T>(_);
2395	/// #     use frame_support::traits::GenesisBuild;
2396	///     #[pallet::genesis_config]
2397	///     #[derive(frame_support::DefaultNoBound)]
2398	///     pub struct GenesisConfig<T: Config> {
2399	/// 		foo: Vec<T::AccountId>
2400	/// 	}
2401	///
2402	///     #[pallet::genesis_build]
2403	///     impl<T: Config> GenesisBuild<T> for GenesisConfig<T> {
2404	///         fn build(&self) {
2405	///             todo!()
2406	///         }
2407	///     }
2408	/// }
2409	/// ```
2410	pub use frame_support_procedural::genesis_build;
2411
2412	/// Allows adding an associated type trait bounded by
2413	/// [`Get`](frame_support::pallet_prelude::Get) from [`pallet::config`](`macro@config`)
2414	/// into metadata.
2415	///
2416	/// ## Example
2417	///
2418	/// ```
2419	/// #[frame_support::pallet]
2420	/// mod pallet {
2421	///     use frame_support::pallet_prelude::*;
2422	///     # #[pallet::pallet]
2423	///     # pub struct Pallet<T>(_);
2424	///     #[pallet::config]
2425	///     pub trait Config: frame_system::Config {
2426	/// 		/// This is like a normal `Get` trait, but it will be added into metadata.
2427	/// 		#[pallet::constant]
2428	/// 		type Foo: Get<u32>;
2429	/// 	}
2430	/// }
2431	/// ```
2432	///
2433	/// ## Note on deprecation of constants
2434	///
2435	/// - Usage of `deprecated` attribute will propagate deprecation information to the pallet
2436	///   metadata where the item was declared.
2437	/// - For general usage examples of `deprecated` attribute please refer to <https://doc.rust-lang.org/nightly/reference/attributes/diagnostics.html#the-deprecated-attribute>
2438	pub use frame_support_procedural::constant;
2439
2440	/// Declares a type alias as a storage item.
2441	///
2442	/// Storage items are pointers to data stored on-chain (the *blockchain state*), under a
2443	/// specific key. The exact key is dependent on the type of the storage.
2444	///
2445	/// > From the perspective of this pallet, the entire blockchain state is abstracted behind
2446	/// > a key-value api, namely [`sp_io::storage`].
2447	///
2448	/// ## Storage Types
2449	///
2450	/// The following storage types are supported by the `#[storage]` macro. For specific
2451	/// information about each storage type, refer to the documentation of the respective type.
2452	///
2453	/// * [`StorageValue`](crate::storage::types::StorageValue)
2454	/// * [`StorageMap`](crate::storage::types::StorageMap)
2455	/// * [`CountedStorageMap`](crate::storage::types::CountedStorageMap)
2456	/// * [`StorageDoubleMap`](crate::storage::types::StorageDoubleMap)
2457	/// * [`StorageNMap`](crate::storage::types::StorageNMap)
2458	/// * [`CountedStorageNMap`](crate::storage::types::CountedStorageNMap)
2459	///
2460	/// ## Storage Type Usage
2461	///
2462	/// The following details are relevant to all of the aforementioned storage types.
2463	/// Depending on the exact storage type, it may require the following generic parameters:
2464	///
2465	/// * [`Prefix`](#prefixes) - Used to give the storage item a unique key in the underlying
2466	///   storage.
2467	/// * `Key` - Type of the keys used to store the values,
2468	/// * `Value` - Type of the value being stored,
2469	/// * [`Hasher`](#hashers) - Used to ensure the keys of a map are uniformly distributed,
2470	/// * [`QueryKind`](#querykind) - Used to configure how to handle queries to the underlying
2471	///   storage,
2472	/// * `OnEmpty` - Used to handle missing values when querying the underlying storage,
2473	/// * `MaxValues` - _not currently used_.
2474	///
2475	/// Each `Key` type requires its own designated `Hasher` declaration, so that
2476	/// [`StorageDoubleMap`](frame_support::storage::types::StorageDoubleMap) needs two of
2477	/// each, and [`StorageNMap`](frame_support::storage::types::StorageNMap) needs `N` such
2478	/// pairs. Since [`StorageValue`](frame_support::storage::types::StorageValue) only stores
2479	/// a single element, no configuration of hashers is needed.
2480	///
2481	/// ### Syntax
2482	///
2483	/// Two general syntaxes are supported, as demonstrated below:
2484	///
2485	/// 1. Named type parameters, e.g., `type Foo<T> = StorageValue<Value = u32>`.
2486	/// 2. Positional type parameters, e.g., `type Foo<T> = StorageValue<_, u32>`.
2487	///
2488	/// In both instances, declaring the generic parameter `<T>` is mandatory. Optionally, it
2489	/// can also be explicitly declared as `<T: Config>`. In the compiled code, `T` will
2490	/// automatically include the trait bound `Config`.
2491	///
2492	/// Note that in positional syntax, the first generic type parameter must be `_`.
2493	///
2494	/// #### Example
2495	///
2496	/// ```
2497	/// #[frame_support::pallet]
2498	/// mod pallet {
2499	///     # use frame_support::pallet_prelude::*;
2500	///     # #[pallet::config]
2501	///     # pub trait Config: frame_system::Config {}
2502	///     # #[pallet::pallet]
2503	///     # pub struct Pallet<T>(_);
2504	///     /// Positional syntax, without bounding `T`.
2505	///     #[pallet::storage]
2506	///     pub type Foo<T> = StorageValue<_, u32>;
2507	///
2508	///     /// Positional syntax, with bounding `T`.
2509	///     #[pallet::storage]
2510	///     pub type Bar<T: Config> = StorageValue<_, u32>;
2511	///
2512	///     /// Named syntax.
2513	///     #[pallet::storage]
2514	///     pub type Baz<T> = StorageMap<Hasher = Blake2_128Concat, Key = u32, Value = u32>;
2515	/// }
2516	/// ```
2517	///
2518	/// ### Value Trait Bounds
2519	///
2520	/// To use a type as the value of a storage type, be it `StorageValue`, `StorageMap` or
2521	/// anything else, you need to meet a number of trait bound constraints.
2522	///
2523	/// See: <https://paritytech.github.io/polkadot-sdk/master/polkadot_sdk_docs/reference_docs/frame_storage_derives/index.html>.
2524	///
2525	/// Notably, all value types need to implement `Encode`, `Decode`, `MaxEncodedLen` and
2526	/// `TypeInfo`, and possibly `Default`, if
2527	/// [`ValueQuery`](frame_support::storage::types::ValueQuery) is used, explained in the
2528	/// next section.
2529	///
2530	/// ### QueryKind
2531	///
2532	/// Every storage type mentioned above has a generic type called
2533	/// [`QueryKind`](frame_support::storage::types::QueryKindTrait) that determines its
2534	/// "query" type. This refers to the kind of value returned when querying the storage, for
2535	/// instance, through a `::get()` method.
2536	///
2537	/// There are three types of queries:
2538	///
2539	/// 1. [`OptionQuery`](frame_support::storage::types::OptionQuery): The default query type.
2540	///    It returns `Some(V)` if the value is present, or `None` if it isn't, where `V` is
2541	///    the value type.
2542	/// 2. [`ValueQuery`](frame_support::storage::types::ValueQuery): Returns the value itself
2543	///    if present; otherwise, it returns `Default::default()`. This behavior can be
2544	///    adjusted with the `OnEmpty` generic parameter, which defaults to `OnEmpty =
2545	///    GetDefault`.
2546	/// 3. [`ResultQuery`](frame_support::storage::types::ResultQuery): Returns `Result<V, E>`,
2547	///    where `V` is the value type.
2548	///
2549	/// See [`QueryKind`](frame_support::storage::types::QueryKindTrait) for further examples.
2550	///
2551	/// ### Optimized Appending
2552	///
2553	/// All storage items — such as
2554	/// [`StorageValue`](frame_support::storage::types::StorageValue),
2555	/// [`StorageMap`](frame_support::storage::types::StorageMap), and their variants—offer an
2556	/// `::append()` method optimized for collections. Using this method avoids the
2557	/// inefficiency of decoding and re-encoding entire collections when adding items. For
2558	/// instance, consider the storage declaration `type MyVal<T> = StorageValue<_, Vec<u8>,
2559	/// ValueQuery>`. With `MyVal` storing a large list of bytes, `::append()` lets you
2560	/// directly add bytes to the end in storage without processing the full list. Depending on
2561	/// the storage type, additional key specifications may be needed.
2562	///
2563	/// #### Example
2564	#[doc = docify::embed!("src/lib.rs", example_storage_value_append)]
2565	/// Similarly, there also exists a `::try_append()` method, which can be used when handling
2566	/// types where an append operation might fail, such as a
2567	/// [`BoundedVec`](frame_support::BoundedVec).
2568	///
2569	/// #### Example
2570	#[doc = docify::embed!("src/lib.rs", example_storage_value_try_append)]
2571	/// ### Optimized Length Decoding
2572	///
2573	/// All storage items — such as
2574	/// [`StorageValue`](frame_support::storage::types::StorageValue),
2575	/// [`StorageMap`](frame_support::storage::types::StorageMap), and their counterparts —
2576	/// incorporate the `::decode_len()` method. This method allows for efficient retrieval of
2577	/// a collection's length without the necessity of decoding the entire dataset.
2578	/// #### Example
2579	#[doc = docify::embed!("src/lib.rs", example_storage_value_decode_len)]
2580	/// ### Hashers
2581	///
2582	/// For all storage types, except
2583	/// [`StorageValue`](frame_support::storage::types::StorageValue), a set of hashers needs
2584	/// to be specified. The choice of hashers is crucial, especially in production chains. The
2585	/// purpose of storage hashers in maps is to ensure the keys of a map are
2586	/// uniformly distributed. An unbalanced map/trie can lead to inefficient performance.
2587	///
2588	/// In general, hashers are categorized as either cryptographically secure or not. The
2589	/// former is slower than the latter. `Blake2` and `Twox` serve as examples of each,
2590	/// respectively.
2591	///
2592	/// As a rule of thumb:
2593	///
2594	/// 1. If the map keys are not controlled by end users, or are cryptographically secure by
2595	/// definition (e.g., `AccountId`), then the use of cryptographically secure hashers is NOT
2596	/// required.
2597	/// 2. If the map keys are controllable by the end users, cryptographically secure hashers
2598	/// should be used.
2599	///
2600	/// For more information, look at the types that implement
2601	/// [`frame_support::StorageHasher`](frame_support::StorageHasher).
2602	///
2603	/// Lastly, it's recommended for hashers with "concat" to have reversible hashes. Refer to
2604	/// the implementors section of
2605	/// [`hash::ReversibleStorageHasher`](frame_support::hash::ReversibleStorageHasher).
2606	///
2607	/// ### Prefixes
2608	///
2609	/// Internally, every storage type generates a "prefix". This prefix serves as the initial
2610	/// segment of the key utilized to store values in the on-chain state (i.e., the final key
2611	/// used in [`sp_io::storage`](sp_io::storage)). For all storage types, the following rule
2612	/// applies:
2613	///
2614	/// > The storage prefix begins with `twox128(pallet_prefix) ++ twox128(STORAGE_PREFIX)`,
2615	/// > where
2616	/// > `pallet_prefix` is the name assigned to the pallet instance in
2617	/// > [`frame_support::construct_runtime`](frame_support::construct_runtime), and
2618	/// > `STORAGE_PREFIX` is the name of the `type` aliased to a particular storage type, such
2619	/// > as
2620	/// > `Foo` in `type Foo<T> = StorageValue<..>`.
2621	///
2622	/// For [`StorageValue`](frame_support::storage::types::StorageValue), no additional key is
2623	/// required. For map types, the prefix is extended with one or more keys defined by the
2624	/// map.
2625	///
2626	/// #### Example
2627	#[doc = docify::embed!("src/lib.rs", example_storage_value_map_prefixes)]
2628	/// ## Related Macros
2629	///
2630	/// The following attribute macros can be used in conjunction with the `#[storage]` macro:
2631	///
2632	/// * [`macro@getter`]: Creates a custom getter function.
2633	/// * [`macro@storage_prefix`]: Overrides the default prefix of the storage item.
2634	/// * [`macro@unbounded`]: Declares the storage item as unbounded.
2635	/// * [`macro@disable_try_decode_storage`]: Declares that try-runtime checks should not
2636	///   attempt to decode the storage item.
2637	///
2638	/// #### Example
2639	/// ```
2640	/// #[frame_support::pallet]
2641	/// mod pallet {
2642	///     # use frame_support::pallet_prelude::*;
2643	///     # #[pallet::config]
2644	///     # pub trait Config: frame_system::Config {}
2645	///     # #[pallet::pallet]
2646	///     # pub struct Pallet<T>(_);
2647	/// 	/// A kitchen-sink StorageValue, with all possible additional attributes.
2648	///     #[pallet::storage]
2649	/// 	#[pallet::getter(fn foo)]
2650	/// 	#[pallet::storage_prefix = "OtherFoo"]
2651	/// 	#[pallet::unbounded]
2652	/// 	#[pallet::disable_try_decode_storage]
2653	///     pub type Foo<T> = StorageValue<_, u32, ValueQuery>;
2654	/// }
2655	/// ```
2656	///
2657	/// ## Note on deprecation of storage items
2658	///
2659	/// - Usage of `deprecated` attribute will propagate deprecation information to the pallet
2660	///   metadata where the storage item was declared.
2661	/// - For general usage examples of `deprecated` attribute please refer to <https://doc.rust-lang.org/nightly/reference/attributes/diagnostics.html#the-deprecated-attribute>
2662	pub use frame_support_procedural::storage;
2663
2664	pub use frame_support_procedural::{
2665		task_condition, task_index, task_list, task_weight, tasks_experimental,
2666	};
2667
2668	/// Allows a pallet to declare a type as an origin.
2669	///
2670	/// If defined as such, this type will be amalgamated at the runtime level into
2671	/// `RuntimeOrigin`, very similar to [`call`], [`error`] and [`event`]. See
2672	/// [`composite_enum`] for similar cases.
2673	///
2674	/// Origin is a complex FRAME topics and is further explained in `polkadot_sdk_docs`.
2675	///
2676	/// ## Syntax Variants
2677	///
2678	/// ```
2679	/// #[frame_support::pallet]
2680	/// mod pallet {
2681	///     # use frame_support::pallet_prelude::*;
2682	///     # #[pallet::config]
2683	///     # pub trait Config: frame_system::Config {}
2684	///     # #[pallet::pallet]
2685	///     # pub struct Pallet<T>(_);
2686	/// 	/// On the spot declaration.
2687	///     #[pallet::origin]
2688	/// 	#[derive(PartialEq, Eq, Clone, RuntimeDebug, Encode, Decode, TypeInfo, MaxEncodedLen)]
2689	/// 	pub enum Origin {
2690	/// 		Foo,
2691	/// 		Bar,
2692	/// 	}
2693	/// }
2694	/// ```
2695	///
2696	/// Or, more commonly used:
2697	///
2698	/// ```
2699	/// #[frame_support::pallet]
2700	/// mod pallet {
2701	///     # use frame_support::pallet_prelude::*;
2702	///     # #[pallet::config]
2703	///     # pub trait Config: frame_system::Config {}
2704	///     # #[pallet::pallet]
2705	///     # pub struct Pallet<T>(_);
2706	/// 	#[derive(PartialEq, Eq, Clone, RuntimeDebug, Encode, Decode, TypeInfo, MaxEncodedLen)]
2707	/// 	pub enum RawOrigin {
2708	/// 		Foo,
2709	/// 		Bar,
2710	/// 	}
2711	///
2712	/// 	#[pallet::origin]
2713	/// 	pub type Origin = RawOrigin;
2714	/// }
2715	/// ```
2716	///
2717	/// ## Warning
2718	///
2719	/// Modifying any pallet's origin type will cause the runtime level origin type to also
2720	/// change in encoding. If stored anywhere on-chain, this will require a data migration.
2721	///
2722	/// Read more about origins at the [Origin Reference
2723	/// Docs](../../polkadot_sdk_docs/reference_docs/frame_origin/index.html).
2724	pub use frame_support_procedural::origin;
2725}
2726
2727#[deprecated(note = "Will be removed after July 2023; Use `sp_runtime::traits` directly instead.")]
2728pub mod error {
2729	#[doc(hidden)]
2730	pub use sp_runtime::traits::{BadOrigin, LookupError};
2731}
2732
2733#[doc(inline)]
2734pub use frame_support_procedural::register_default_impl;
2735
2736// Generate a macro that will enable/disable code based on `std` feature being active.
2737sp_core::generate_feature_enabled_macro!(std_enabled, feature = "std", $);
2738// Generate a macro that will enable/disable code based on `try-runtime` feature being active.
2739sp_core::generate_feature_enabled_macro!(try_runtime_enabled, feature = "try-runtime", $);
2740sp_core::generate_feature_enabled_macro!(try_runtime_or_std_enabled, any(feature = "try-runtime", feature = "std"), $);
2741sp_core::generate_feature_enabled_macro!(try_runtime_and_std_not_enabled, all(not(feature = "try-runtime"), not(feature = "std")), $);
2742
2743/// Helper for implementing GenesisBuilder runtime API
2744pub mod genesis_builder_helper;
2745
2746/// Helper for generating the `RuntimeGenesisConfig` instance for presets.
2747pub mod generate_genesis_config;
2748
2749#[cfg(test)]
2750mod test {
2751	// use super::*;
2752	use crate::{
2753		hash::*,
2754		storage::types::{StorageMap, StorageValue, ValueQuery},
2755		traits::{ConstU32, StorageInstance},
2756		BoundedVec,
2757	};
2758	use sp_io::{hashing::twox_128, TestExternalities};
2759
2760	struct Prefix;
2761	impl StorageInstance for Prefix {
2762		fn pallet_prefix() -> &'static str {
2763			"test"
2764		}
2765		const STORAGE_PREFIX: &'static str = "foo";
2766	}
2767
2768	struct Prefix1;
2769	impl StorageInstance for Prefix1 {
2770		fn pallet_prefix() -> &'static str {
2771			"test"
2772		}
2773		const STORAGE_PREFIX: &'static str = "MyVal";
2774	}
2775	struct Prefix2;
2776	impl StorageInstance for Prefix2 {
2777		fn pallet_prefix() -> &'static str {
2778			"test"
2779		}
2780		const STORAGE_PREFIX: &'static str = "MyMap";
2781	}
2782
2783	#[docify::export]
2784	#[test]
2785	pub fn example_storage_value_try_append() {
2786		type MyVal = StorageValue<Prefix, BoundedVec<u8, ConstU32<10>>, ValueQuery>;
2787
2788		TestExternalities::default().execute_with(|| {
2789			MyVal::set(BoundedVec::try_from(vec![42, 43]).unwrap());
2790			assert_eq!(MyVal::get(), vec![42, 43]);
2791			// Try to append a single u32 to BoundedVec stored in `MyVal`
2792			assert_ok!(MyVal::try_append(40));
2793			assert_eq!(MyVal::get(), vec![42, 43, 40]);
2794		});
2795	}
2796
2797	#[docify::export]
2798	#[test]
2799	pub fn example_storage_value_append() {
2800		type MyVal = StorageValue<Prefix, Vec<u8>, ValueQuery>;
2801
2802		TestExternalities::default().execute_with(|| {
2803			MyVal::set(vec![42, 43]);
2804			assert_eq!(MyVal::get(), vec![42, 43]);
2805			// Append a single u32 to Vec stored in `MyVal`
2806			MyVal::append(40);
2807			assert_eq!(MyVal::get(), vec![42, 43, 40]);
2808		});
2809	}
2810
2811	#[docify::export]
2812	#[test]
2813	pub fn example_storage_value_decode_len() {
2814		type MyVal = StorageValue<Prefix, BoundedVec<u8, ConstU32<10>>, ValueQuery>;
2815
2816		TestExternalities::default().execute_with(|| {
2817			MyVal::set(BoundedVec::try_from(vec![42, 43]).unwrap());
2818			assert_eq!(MyVal::decode_len().unwrap(), 2);
2819		});
2820	}
2821
2822	#[docify::export]
2823	#[test]
2824	pub fn example_storage_value_map_prefixes() {
2825		type MyVal = StorageValue<Prefix1, u32, ValueQuery>;
2826		type MyMap = StorageMap<Prefix2, Blake2_128Concat, u16, u32, ValueQuery>;
2827		TestExternalities::default().execute_with(|| {
2828			// This example assumes `pallet_prefix` to be "test"
2829			// Get storage key for `MyVal` StorageValue
2830			assert_eq!(
2831				MyVal::hashed_key().to_vec(),
2832				[twox_128(b"test"), twox_128(b"MyVal")].concat()
2833			);
2834			// Get storage key for `MyMap` StorageMap and `key` = 1
2835			let mut k: Vec<u8> = vec![];
2836			k.extend(&twox_128(b"test"));
2837			k.extend(&twox_128(b"MyMap"));
2838			k.extend(&1u16.blake2_128_concat());
2839			assert_eq!(MyMap::hashed_key_for(1).to_vec(), k);
2840		});
2841	}
2842}