Newer
Older
DefaultByteGetter(&__GetByteStructGenericData2DM(PhantomData::<Test>))
),
documentation: DecodeDifferent::Encode(&[]),
},
]
),
};
#[test]
fn store_metadata() {
let metadata = Module::<Test>::storage_metadata();
pretty_assertions::assert_eq!(EXPECTED_METADATA, metadata);
parameter_types! {
storage StorageParameter: u64 = 10;
}
#[test]
fn check_storage_parameter_type_works() {
TestExternalities::default().execute_with(|| {
assert_eq!(sp_io::hashing::twox_128(b":StorageParameter:"), StorageParameter::key());
assert_eq!(10, StorageParameter::get());
StorageParameter::set(&300);
assert_eq!(300, StorageParameter::get());
})
}
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
/// Prelude to be used alongside pallet macro, for ease of use.
pub mod pallet_prelude {
pub use sp_std::marker::PhantomData;
#[cfg(feature = "std")]
pub use frame_support::traits::GenesisBuild;
pub use frame_support::{
EqNoBound, PartialEqNoBound, RuntimeDebugNoBound, DebugNoBound, CloneNoBound, Twox256,
Twox128, Blake2_256, Blake2_128, Identity, Twox64Concat, Blake2_128Concat, debug, ensure,
RuntimeDebug, storage,
traits::{Get, Hooks, IsType, GetPalletVersion, EnsureOrigin},
dispatch::{DispatchResultWithPostInfo, Parameter, DispatchError},
weights::{DispatchClass, Pays, Weight},
storage::types::{StorageValue, StorageMap, StorageDoubleMap, ValueQuery, OptionQuery},
};
pub use codec::{Encode, Decode};
pub use sp_inherents::{InherentData, InherentIdentifier, ProvideInherent};
pub use sp_runtime::{
traits::{MaybeSerializeDeserialize, Member, ValidateUnsigned},
transaction_validity::{
TransactionSource, TransactionValidity, ValidTransaction, TransactionPriority,
TransactionTag, TransactionLongevity, TransactionValidityError, InvalidTransaction,
UnknownTransaction,
},
};
}
/// `pallet` attribute macro allows to define a pallet to be used in `construct_runtime!`.
///
/// It is define by a module item:
/// ```ignore
/// #[pallet]
/// pub mod pallet {
/// ...
/// }
/// ```
///
/// Inside the module the macro will parse item with the attribute: `#[pallet::*]`, some attributes
/// are mandatory, some other optional.
///
/// The attribute are explained with the syntax of non instantiable pallets, to see how pallet with
/// instance work see below example.
///
/// Note various type can be automatically imported using pallet_prelude in frame_support and
/// frame_system:
/// ```ignore
/// #[pallet]
/// pub mod pallet {
/// use frame_support::pallet_prelude::*;
/// use frame_system::pallet_prelude::*;
/// ...
/// }
/// ```
///
/// # Config trait: `#[pallet::config]` mandatory
///
/// The trait defining generics of the pallet.
///
/// Item must be defined as
/// ```ignore
/// #[pallet::config]
/// pub trait Config: frame_system::Config + $optionally_some_other_supertraits
/// $optional_where_clause
/// {
/// ...
/// }
/// ```
/// I.e. a regular trait definition named `Config`, with supertrait `frame_system::Config`,
/// optionally other supertrait and where clause.
///
/// The associated type `Event` is reserved, if defined it must bounds `From<Event>` and
/// `IsType<<Self as frame_system::Config>::Event>`, see `#[pallet::event]` for more information.
///
/// To put `Get` associated type into metadatas, use the attribute `#[pallet::constant]`, e.g.:
/// ```ignore
/// #[pallet::config]
/// pub trait Config: frame_system::Config {
/// #[pallet::constant]
/// type Foo: Get<u32>;
/// }
/// ```
///
/// To bypass the `frame_system::Config` supertrait check, use the attribute
/// `#[pallet::disable_frame_system_supertrait_check]`, e.g.:
/// ```ignore
/// #[pallet::config]
/// #[pallet::disable_frame_system_supertrait_check]
/// pub trait Config: pallet_timestamp::Config {}
/// ```
///
/// ### Macro expansion:
///
/// The macro expand pallet constant metadata with the information given by `#[pallet::constant]`.
///
/// # Pallet struct placeholder: `#[pallet::pallet]` mandatory
///
/// The placeholder struct, on which is implemented pallet informations.
///
/// Item must be defined as followed:
/// ```ignore
/// #[pallet::pallet]
/// pub struct Pallet<T>(PhantomData<T>);
/// ```
/// I.e. a regular struct definition named `Pallet`, with generic T and no where clause.
///
/// To generate a `Store` trait associating all storages, use the attribute
/// `#[pallet::generate_store($vis trait Store)]`, e.g.:
/// ```ignore
/// #[pallet::pallet]
/// #[pallet::generate_store(pub(super) trait Store)]
/// pub struct Pallet<T>(PhantomData<T>);
/// ```
/// More precisely the store trait contains an associated type for each storage. It is implemented
/// for `Pallet` allowing to access the storage from pallet struct.
///
/// Thus when defining a storage named `Foo`, it can later be accessed from `Pallet` using
/// `<Pallet as Store>::Foo`.
///
/// ### Macro expansion:
///
/// The macro add this attribute to the struct definition:
/// ```ignore
/// #[derive(
/// frame_support::CloneNoBound,
/// frame_support::EqNoBound,
/// frame_support::PartialEqNoBound,
/// frame_support::RuntimeDebugNoBound,
/// )]
/// ```
///
/// It implements on pallet:
/// * [`traits::GetPalletVersion`]
/// * [`traits::OnGenesis`]: contains some logic to write pallet version into storage.
/// * `ModuleErrorMetadata`: using error declared or no metadata.
///
/// It declare `type Module` type alias for `Pallet`, used by [`construct_runtime`].
///
/// If attribute generate_store then macro create the trait `Store` and implement it on `Pallet`.
///
/// # Hooks: `#[pallet::hooks]` mandatory
///
/// Implementation of `Hooks` on `Pallet` allowing to define some specific pallet logic.
///
/// Item must be defined as
/// ```ignore
/// #[pallet::hooks]
/// impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> $optional_where_clause {
/// }
/// ```
/// I.e. a regular trait implementation with generic bound: `T: Config`, for the trait
/// `Hooks<BlockNumberFor<T>>` (they are defined in preludes), for the type `Pallet<T>`
/// and with an optional where clause.
///
/// ### Macro expansion:
///
/// The macro implements the traits `OnInitialize`, `OnFinalize`, `OnRuntimeUpgrade`,
/// `OffchainWorker`, `IntegrityTest` using `Hooks` implementation.
///
/// NOTE: OnRuntimeUpgrade is implemented with `Hooks::on_runtime_upgrade` and some additional
/// logic. E.g. logic to write pallet version into storage.
///
/// # Call: `#[pallet::call]` mandatory
///
/// Implementation of pallet dispatchables.
///
/// Item must be defined as:
/// ```ignore
/// #[pallet::call]
/// impl<T: Config> Pallet<T> {
/// /// $some_doc
/// #[pallet::weight($ExpressionResultingInWeight)]
/// $vis fn $fn_name(
/// origin: OriginFor<T>,
/// $some_arg: $some_type,
/// // or with compact attribute: #[pallet::compact] $some_arg: $some_type,
/// ...
/// ) -> DispatchResultWithPostInfo {
/// ...
/// }
/// ...
/// }
/// ```
/// I.e. a regular type implementation, with generic `T: Config`, on type `Pallet<T>`, with
/// optional where clause.
///
/// Each dispatchable needs to define a weight with `#[pallet::weight($expr)]` attribute,
/// the first argument must be `origin: OriginFor<T>`, compact encoding for argument can be used
/// using `#[pallet::compact]`, function must return DispatchResultWithPostInfo.
///
/// All arguments must implement `Debug`, `PartialEq`, `Eq`, `Decode`, `Encode`, `Clone`. For ease
/// of use just bound trait `Member` available in frame_support::pallet_prelude.
///
/// **WARNING**: modifying dispatchables, changing their order, removing some must be done with
/// care. Indeed this will change the outer runtime call type (which is an enum with one variant
/// per pallet), this outer runtime call can be stored on-chain (e.g. in pallet-scheduler).
/// Thus migration might be needed.
///
/// ### Macro expansion
///
/// The macro create an enum `Call` with one variant per dispatchable. This enum implements:
/// `Clone`, `Eq`, `PartialEq`, `Debug` (with stripped implementation in `not("std")`), `Encode`,
/// `Decode`, `GetDispatchInfo`, `GetCallName`, `UnfilteredDispatchable`.
///
/// The macro implement on `Pallet`, the `Callable` trait and a function `call_functions` which
/// returns the dispatchable metadatas.
///
/// # Extra constants: `#[pallet::extra_constants]` optional
///
/// Allow to define some extra constants to put into constant metadata.
///
/// Item must be defined as:
/// ```ignore
/// #[pallet::extra_constants]
/// impl<T: Config> Pallet<T> where $optional_where_clause {
/// /// $some_doc
/// $vis fn $fn_name() -> $some_return_type {
/// ...
/// }
/// ...
/// }
/// ```
/// I.e. a regular rust implement block with some optional where clause and functions with 0 args,
/// 0 generics, and some return type.
///
/// ### Macro expansion
///
/// The macro add some extra constant to pallet constant metadata.
///
/// # Error: `#[pallet::error]` optional
///
/// Allow to define an error type to be return from dispatchable on error.
/// This error type informations are put into metadata.
///
/// Item must be defined as:
/// ```ignore
/// #[pallet::error]
/// pub enum Error<T> {
/// /// $some_optional_doc
/// $SomeFieldLessVariant,
/// ...
/// }
/// ```
/// I.e. a regular rust enum named `Error`, with generic `T` and fieldless variants.
/// The generic `T` mustn't bound anything and where clause is not allowed. But bounds and where
/// clause shouldn't be needed for any usecase.
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
///
/// ### Macro expansion
///
/// The macro implements `Debug` trait and functions `as_u8` using variant position, and `as_str`
/// using variant doc.
///
/// The macro implements `From<Error<T>>` for `&'static str`.
/// The macro implements `From<Error<T>>` for `DispatchError`.
///
/// The macro implements `ModuleErrorMetadata` on `Pallet` defining the `ErrorMetadata` of the
/// pallet.
///
/// # Event: `#[pallet::event]` optional
///
/// Allow to define pallet events, pallet events are stored in the block when they deposited (and
/// removed in next block).
///
/// Item is defined as:
/// ```ignore
/// #[pallet::event]
/// #[pallet::metadata($SomeType = "$Metadata", $SomeOtherType = "$Metadata", ..)] // Optional
/// #[pallet::generate_deposit($visbility fn deposit_event)] // Optional
/// pub enum Event<$some_generic> $optional_where_clause {
/// /// Some doc
/// $SomeName($SomeType, $YetanotherType, ...),
/// ...
/// }
/// ```
/// I.e. an enum (with named or unnamed fields variant), named Event, with generic: none or `T` or
/// `T: Config`, and optional where clause.
///
/// Each field must implement `Clone`, `Eq`, `PartialEq`, `Encode`, `Decode`, and `Debug` (on std
/// only).
/// For ease of use just bound trait `Member` available in frame_support::pallet_prelude.
///
/// Variant documentations and field types are put into metadata.
/// The attribute `#[pallet::metadata(..)]` allows to specify the metadata to put for some types.
///
/// The metadata of a type is defined by:
/// * if matching a type in `#[pallet::metadata(..)]`, then the corresponding metadata.
/// * otherwise the type stringified.
///
/// E.g.:
/// ```ignore
/// #[pallet::event]
/// #[pallet::metadata(u32 = "SpecialU32")]
/// pub enum Event<T: Config> {
/// Proposed(u32, T::AccountId),
/// }
/// ```
/// will write in event variant metadata `"SpecialU32"` and `"T::AccountId"`.
///
/// The attribute `#[pallet::generate_deposit($visbility fn deposit_event)]` generate a helper
/// function on `Pallet` to deposit event.
///
/// NOTE: For instantiable pallet, event must be generic over T and I.
///
/// ### Macro expansion:
///
/// Macro will add on enum `Event` the attributes:
/// * `#[derive(frame_support::CloneNoBound)]`,
/// * `#[derive(frame_support::EqNoBound)]`,
/// * `#[derive(frame_support::PartialEqNoBound)]`,
/// * `#[derive(codec::Encode)]`,
/// * `#[derive(codec::Decode)]`,
/// * `#[derive(frame_support::RuntimeDebugNoBound)]`
///
/// Macro implements `From<Event<..>>` for ().
///
/// Macro implements metadata function on `Event` returning the `EventMetadata`.
///
/// If `#[pallet::generate_deposit]` then macro implement `fn deposit_event` on `Pallet`.
///
/// # Storage: `#[pallet::storage]` optional
///
/// Allow to define some abstract storage inside runtime storage and also set its metadata.
/// This attribute can be used multiple times.
///
/// Item is defined as:
/// ```ignore
/// #[pallet::storage]
/// #[pallet::getter(fn $getter_name)] // optional
/// $vis type $StorageName<$some_generic> $optional_where_clause
/// = $StorageType<_, $some_generics, ...>;
/// ```
/// I.e. it must be a type alias, with generics: `T` or `T: Config`, aliased type must be one
/// of `StorageValue`, `StorageMap` or `StorageDoubleMap` (defined in frame_support).
/// Their first generic must be `_` as it is written by the macro itself.
///
/// The Prefix generic written by the macro is generated using `PalletInfo::name::<Pallet<..>>()`
/// and the name of the storage type.
/// E.g. if runtime names the pallet "MyExample" then the storage `type Foo<T> = ...` use the
/// prefix: `Twox128(b"MyExample") ++ Twox128(b"Foo")`.
///
/// The optional attribute `#[pallet::getter(fn $my_getter_fn_name)]` allow to define a
/// getter function on `Pallet`.
///
/// E.g:
/// ```ignore
/// #[pallet::storage]
/// #[pallet::getter(fn my_storage)]
/// pub(super) type MyStorage<T> = StorageMap<_, Blake2_128Concat, u32, u32>;
/// ```
///
/// NOTE: if the querykind generic parameter is still generic at this stage or is using some type
/// alias then the generation of the getter might fail. In this case getter can be implemented
/// manually.
///
/// ### Macro expansion
///
/// For each storage the macro generate a struct named
/// `_GeneratedPrefixForStorage$NameOfStorage`, implements `StorageInstance` on it using pallet
/// name and storage name. And use it as first generic of the aliased type.
///
///
/// The macro implement the function `storage_metadata` on `Pallet` implementing the metadata for
/// storages.
///
/// # Type value: `#[pallet::type_value]` optional
///
/// Helper to define a struct implementing `Get` trait. To ease use of storage types.
/// This attribute can be used multiple time.
///
/// Item is defined as
/// ```ignore
/// #[pallet::type_value]
/// fn $MyDefaultName<$some_generic>() -> $default_type $optional_where_clause { $expr }
/// ```
/// I.e.: a function definition with generics none or `T: Config` and a returned type.
///
/// E.g.:
/// ```ignore
/// #[pallet::type_value]
/// fn MyDefault<T: Config>() -> T::Balance { 3.into() }
/// ```
///
/// NOTE: This attribute is meant to be used alongside `#[pallet::storage]` to defined some
/// specific default value in storage.
///
/// ### Macro expansion
///
/// Macro renames the function to some internal name, generate a struct with the original name of
/// the function and its generic, and implement `Get<$ReturnType>` by calling the user defined
/// function.
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
///
/// # Genesis config: `#[pallet::genesis_config]` optional
///
/// Allow to define the genesis configuration of the pallet.
///
/// Item is defined as either an enum or a struct.
/// It needs to be public and implement trait GenesisBuild with `#[pallet::genesis_build]`.
/// The type generics is constrained to be either none, or `T` or `T: Config`.
///
/// E.g:
/// ```ignore
/// #[pallet::genesis_config]
/// pub struct GenesisConfig<T: Config> {
/// _myfield: BalanceOf<T>,
/// }
/// ```
///
/// ### Macro expansion
///
/// Macro will add the following attribute on it:
/// * `#[cfg(feature = "std")]`
/// * `#[derive(Serialize, Deserialize)]`
/// * `#[serde(rename_all = "camelCase")]`
/// * `#[serde(deny_unknown_fields)]`
/// * `#[serde(bound(serialize = ""))]`
/// * `#[serde(bound(deserialize = ""))]`
///
/// # Genesis build: `#[pallet::genesis_build]` optional
///
/// Allow to define how genesis_configuration is built.
///
/// Item is defined as
/// ```ignore
/// #[pallet::genesis_build]
/// impl<T: Config> GenesisBuild<T> for GenesisConfig<$maybe_generics> {
/// fn build(&self) { $expr }
/// }
/// ```
/// I.e. a rust trait implementation with generic `T: Config`, of trait `GenesisBuild<T>` on type
/// `GenesisConfig` with generics none or `T`.
///
/// E.g.:
/// ```ignore
/// #[pallet::genesis_build]
/// impl<T: Config> GenesisBuild<T> for GenesisConfig {
/// fn build(&self) {}
/// }
/// ```
///
/// ### Macro expansion
///
/// Macro will add the following attribute on it:
/// * `#[cfg(feature = "std")]`
///
/// Macro will implement `sp_runtime::BuildModuleGenesisStorage` using `()` as second generic for
/// non-instantiable pallets.
///
/// # Inherent: `#[pallet::inherent]` optional
///
/// Allow the pallet to provide some inherent:
///
/// Item is defined as:
/// ```ignore
/// #[pallet::inherent]
/// impl<T: Config> ProvideInherent for Pallet<T> {
/// // ... regular trait implementation
/// }
/// ```
/// I.e. a trait implementation with bound `T: Config`, of trait `ProvideInherent` for type
/// `Pallet<T>`, and some optional where clause.
///
/// ### Macro expansion
///
/// Macro make currently no use of this information, but it might use this information in the
/// future to give information directly to construct_runtime.
///
/// # Validate unsigned: `#[pallet::validate_unsigned]` optional
///
/// Allow the pallet to validate some unsigned transaction:
///
/// Item is defined as:
/// ```ignore
/// #[pallet::validate_unsigned]
/// impl<T: Config> ValidateUnsigned for Pallet<T> {
/// // ... regular trait implementation
/// }
/// ```
/// I.e. a trait implementation with bound `T: Config`, of trait `ValidateUnsigned` for type
/// `Pallet<T>`, and some optional where clause.
///
/// NOTE: There is also `sp_runtime::traits::SignedExtension` that can be used to add some specific
/// logic for transaction validation.
///
/// ### Macro expansion
///
/// Macro make currently no use of this information, but it might use this information in the
/// future to give information directly to construct_runtime.
///
/// # Origin: `#[pallet::origin]` optional
///
/// Allow to define some origin for the pallet.
///
/// Item must be either a type alias or an enum or a struct. It needs to be public.
///
/// E.g.:
/// ```ignore
/// #[pallet::origin]
/// pub struct Origin<T>(PhantomData<(T)>);
/// ```
///
/// **WARNING**: modifying origin changes the outer runtime origin. This outer runtime origin can
/// be stored on-chain (e.g. in pallet-scheduler), thus any change must be done with care as it
/// might require some migration.
///
/// NOTE: for instantiable pallet, origin must be generic over T and I.
///
/// # General notes on instantiable pallet
///
/// An instantiable pallet is one where Config is generic, i.e. `Config<I>`. This allow runtime to
/// implement multiple instance of the pallet, by using different type for the generic.
/// This is the sole purpose of the generic `I`.
/// But because `PalletInfo` requires `Pallet` placeholder to be static it is important to bound
/// `'static` whenever `PalletInfo` can be used.
/// And in order to have instantiable pallet usable as a regular pallet without instance, it is
/// important to bound `= ()` on every types.
///
/// Thus impl bound look like `impl<T: Config<I>, I: 'static>`, and types look like
/// `SomeType<T, I=()>` or `SomeType<T: Config<I>, I: 'static = ()>`.
///
/// # Example for pallet without instance.
///
/// ```
/// #[frame_support::pallet]
/// // NOTE: Example is name of the pallet, it will be used as unique identifier for storage
/// pub mod pallet {
/// use frame_support::pallet_prelude::*; // Import various types used in pallet definition
/// use frame_system::pallet_prelude::*; // OriginFor helper type for implementing dispatchables.
///
/// type BalanceOf<T> = <T as Config>::Balance;
///
/// // Define the generic parameter of the pallet
/// // The macro checks trait generics: is expected none or `I = ()`.
/// // The macro parses `#[pallet::constant]` attributes: used to generate constant metadata,
/// // expected syntax is `type $IDENT: Get<$TYPE>;`.
/// #[pallet::config]
/// pub trait Config: frame_system::Config {
/// #[pallet::constant] // put the constant in metadata
/// type MyGetParam: Get<u32>;
/// type Balance: Parameter + From<u8>;
/// type Event: From<Event<Self>> + IsType<<Self as frame_system::Config>::Event>;
/// }
///
/// // Define some additional constant to put into the constant metadata.
/// #[pallet::extra_constants]
/// impl<T: Config> Pallet<T> {
/// /// Some description
/// fn exra_constant_name() -> u128 { 4u128 }
/// }
///
/// // Define the pallet struct placeholder, various pallet function are implemented on it.
/// // The macro checks struct generics: is expected `T` or `T, I = DefaultInstance`
/// #[pallet::pallet]
/// #[pallet::generate_store(pub(super) trait Store)]
/// pub struct Pallet<T>(PhantomData<T>);
///
/// // Implement on the pallet hooks on pallet.
/// // The macro checks:
/// // * trait is `Hooks` (imported from pallet_prelude)
/// // * struct is `Pallet<T>` or `Pallet<T, I>`
/// #[pallet::hooks]
/// impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {
/// }
///
/// // Declare Call struct and implement dispatchables.
/// //
/// // WARNING: Each parameter used in functions must implement: Clone, Debug, Eq, PartialEq,
/// // Codec.
/// //
/// // The macro checks:
/// // * pallet is `Pallet<T>` or `Pallet<T, I>`
/// // * trait is `Call`
/// // * each dispatchable functions first argument is `origin: OriginFor<T>` (OriginFor is
/// // imported from frame_system.
/// //
/// // The macro parse `#[pallet::compact]` attributes, function parameter with this attribute
/// // will be encoded/decoded using compact codec in implementation of codec for the enum
/// // `Call`.
/// //
/// // The macro generate the enum `Call` with a variant for each dispatchable and implements
/// // codec, Eq, PartialEq, Clone and Debug.
/// #[pallet::call]
/// impl<T: Config> Pallet<T> {
/// /// Doc comment put in metadata
/// #[pallet::weight(0)] // Defines weight for call (function parameters are in scope)
/// fn toto(
/// origin: OriginFor<T>,
/// #[pallet::compact] _foo: u32
/// ) -> DispatchResultWithPostInfo {
/// let _ = origin;
/// unimplemented!();
/// }
/// }
///
/// // Declare pallet Error enum. (this is optional)
/// // The macro checks enum generics and that each variant is unit.
/// // The macro generate error metadata using doc comment on each variant.
/// #[pallet::error]
/// pub enum Error<T> {
/// /// doc comment put into metadata
/// InsufficientProposersBalance,
/// }
///
/// // Declare pallet Event enum. (this is optional)
/// //
/// // WARNING: Each type used in variants must implement: Clone, Debug, Eq, PartialEq, Codec.
/// //
/// // The macro generates event metadata, and derive Clone, Debug, Eq, PartialEq and Codec
/// #[pallet::event]
/// // Additional argument to specify the metadata to use for given type.
/// #[pallet::metadata(BalanceOf<T> = "Balance", u32 = "Other")]
/// // Generate a funciton on Pallet to deposit an event.
/// #[pallet::generate_deposit(pub(super) fn deposit_event)]
/// pub enum Event<T: Config> {
/// /// doc comment put in metadata
/// // `<T as frame_system::Config>::AccountId` is not defined in metadata list, the last
/// // Thus the metadata is `<T as frame_system::Config>::AccountId`.
/// Proposed(<T as frame_system::Config>::AccountId),
/// /// doc
/// // here metadata will be `Balance` as define in metadata list
/// Spending(BalanceOf<T>),
/// // here metadata will be `Other` as define in metadata list
/// Something(u32),
/// }
///
/// // Define a struct which implements `frame_support::traits::Get<T::Balance>`
/// #[pallet::type_value]
/// pub(super) fn MyDefault<T: Config>() -> T::Balance { 3.into() }
///
/// // Declare a storage, any amount of storage can be declared.
/// //
/// // Is expected either `StorageValue`, `StorageMap` or `StorageDoubleMap`.
/// // The macro generates for struct `$identP` (for storage of name `$ident`) and implement
/// // storage instance on it.
/// // The macro macro expand the metadata for the storage with the type used:
/// // * For storage value the type for value will be copied into metadata
/// // * For storage map the type for value and the type for key will be copied into metadata
/// // * For storage double map the type for value, key1, and key2 will be copied into
/// // metadata.
/// //
/// // NOTE: for storage hasher, the type is not copied because storage hasher trait already
/// // implements metadata. Thus generic storage hasher is supported.
/// #[pallet::storage]
/// pub(super) type MyStorageValue<T: Config> =
/// StorageValue<_, T::Balance, ValueQuery, MyDefault<T>>;
///
/// // Another declaration
/// #[pallet::storage]
/// #[pallet::getter(fn my_storage)]
/// pub(super) type MyStorage<T> = StorageMap<_, Blake2_128Concat, u32, u32>;
///
/// // Declare genesis config. (This is optional)
/// //
/// // The macro accept either type alias or struct or enum, it checks generics are consistent.
/// //
/// // Type must implement `Default` traits
/// #[pallet::genesis_config]
/// #[derive(Default)]
/// pub struct GenesisConfig {
/// _myfield: u32,
/// }
///
/// // Declare genesis builder. (This is need only if GenesisConfig is declared)
/// #[pallet::genesis_build]
/// impl<T: Config> GenesisBuild<T> for GenesisConfig {
/// fn build(&self) {}
/// }
///
/// // Declare a pallet origin. (this is optional)
/// //
/// // The macro accept type alias or struct or enum, it checks generics are consistent.
/// #[pallet::origin]
/// pub struct Origin<T>(PhantomData<T>);
///
/// // Declare validate_unsigned implementation.
/// #[pallet::validate_unsigned]
/// impl<T: Config> ValidateUnsigned for Pallet<T> {
/// type Call = Call<T>;
/// fn validate_unsigned(
/// source: TransactionSource,
/// call: &Self::Call
/// ) -> TransactionValidity {
/// Err(TransactionValidityError::Invalid(InvalidTransaction::Call))
/// }
/// }
///
/// // Declare inherent provider for pallet. (this is optional)
/// //
/// // The macro checks pallet is `Pallet<T>` or `Pallet<T, I>` and trait is `ProvideInherent`
/// #[pallet::inherent]
/// impl<T: Config> ProvideInherent for Pallet<T> {
/// type Call = Call<T>;
/// type Error = InherentError;
///
/// const INHERENT_IDENTIFIER: InherentIdentifier = INHERENT_IDENTIFIER;
///
/// fn create_inherent(_data: &InherentData) -> Option<Self::Call> {
/// unimplemented!();
/// }
/// }
///
/// // Regular rust code needed for implementing ProvideInherent trait
///
/// #[derive(codec::Encode, sp_runtime::RuntimeDebug)]
/// #[cfg_attr(feature = "std", derive(codec::Decode))]
/// pub enum InherentError {
/// }
///
/// impl sp_inherents::IsFatalError for InherentError {
/// fn is_fatal_error(&self) -> bool {
/// unimplemented!();
/// }
/// }
///
/// pub const INHERENT_IDENTIFIER: sp_inherents::InherentIdentifier = *b"testpall";
/// }
/// ```
///
/// # Example for pallet with instance.
///
/// ```
/// #[frame_support::pallet]
/// pub mod pallet {
/// use frame_support::pallet_prelude::*;
/// use frame_system::pallet_prelude::*;
///
/// type BalanceOf<T, I = ()> = <T as Config<I>>::Balance;
///
/// #[pallet::config]
/// pub trait Config<I: 'static = ()>: frame_system::Config {
/// #[pallet::constant]
/// type MyGetParam: Get<u32>;
/// type Balance: Parameter + From<u8>;
/// type Event: From<Event<Self, I>> + IsType<<Self as frame_system::Config>::Event>;
/// }
///
/// #[pallet::extra_constants]
/// impl<T: Config<I>, I: 'static> Pallet<T, I> {
/// /// Some description
/// fn exra_constant_name() -> u128 { 4u128 }
/// }
///
/// #[pallet::pallet]
/// #[pallet::generate_store(pub(super) trait Store)]
/// pub struct Pallet<T, I = ()>(PhantomData<(T, I)>);
///
/// #[pallet::hooks]
/// impl<T: Config<I>, I: 'static> Hooks<BlockNumberFor<T>> for Pallet<T, I> {
/// }
///
/// #[pallet::call]
/// impl<T: Config<I>, I: 'static> Pallet<T, I> {
/// /// Doc comment put in metadata
/// #[pallet::weight(0)]
/// fn toto(origin: OriginFor<T>, #[pallet::compact] _foo: u32) -> DispatchResultWithPostInfo {
/// let _ = origin;
/// unimplemented!();
/// }
/// }
///
/// #[pallet::error]
/// pub enum Error<T, I = ()> {
/// /// doc comment put into metadata
/// InsufficientProposersBalance,
/// }
///
/// #[pallet::event]
/// #[pallet::metadata(BalanceOf<T> = "Balance", u32 = "Other")]
/// #[pallet::generate_deposit(pub(super) fn deposit_event)]
/// pub enum Event<T: Config<I>, I: 'static = ()> {
/// /// doc comment put in metadata
/// Proposed(<T as frame_system::Config>::AccountId),
/// /// doc
/// Spending(BalanceOf<T, I>),
/// Something(u32),
/// }
///
/// #[pallet::type_value]
/// pub(super) fn MyDefault<T: Config<I>, I: 'static>() -> T::Balance { 3.into() }
///
/// #[pallet::storage]
/// pub(super) type MyStorageValue<T: Config<I>, I: 'static = ()> =
/// StorageValue<_, T::Balance, ValueQuery, MyDefault<T, I>>;
///
/// #[pallet::storage]
/// #[pallet::getter(fn my_storage)]
/// pub(super) type MyStorage<T, I = ()> =
/// StorageMap<_, Blake2_128Concat, u32, u32>;
///
/// #[pallet::genesis_config]
/// #[derive(Default)]
/// pub struct GenesisConfig {
/// _myfield: u32,
/// }
///
/// #[pallet::genesis_build]
/// impl<T: Config<I>, I: 'static> GenesisBuild<T, I> for GenesisConfig {
/// fn build(&self) {}
/// }
///
/// #[pallet::origin]
/// pub struct Origin<T, I = ()>(PhantomData<(T, I)>);
///
/// #[pallet::validate_unsigned]
/// impl<T: Config<I>, I: 'static> ValidateUnsigned for Pallet<T, I> {
/// type Call = Call<T, I>;
/// fn validate_unsigned(
/// source: TransactionSource,
/// call: &Self::Call
/// ) -> TransactionValidity {
/// Err(TransactionValidityError::Invalid(InvalidTransaction::Call))
/// }
/// }
///
/// #[pallet::inherent]
/// impl<T: Config<I>, I: 'static> ProvideInherent for Pallet<T, I> {
/// type Call = Call<T, I>;
/// type Error = InherentError;
///
/// const INHERENT_IDENTIFIER: InherentIdentifier = INHERENT_IDENTIFIER;
///
/// fn create_inherent(_data: &InherentData) -> Option<Self::Call> {
/// unimplemented!();
/// }
/// }
///
/// // Regular rust code needed for implementing ProvideInherent trait
///
/// #[derive(codec::Encode, sp_runtime::RuntimeDebug)]
/// #[cfg_attr(feature = "std", derive(codec::Decode))]
/// pub enum InherentError {
/// }
///
/// impl sp_inherents::IsFatalError for InherentError {
/// fn is_fatal_error(&self) -> bool {
/// unimplemented!();
/// }
/// }
///
/// pub const INHERENT_IDENTIFIER: sp_inherents::InherentIdentifier = *b"testpall";
/// }
/// ```
///
/// ## Upgrade guidelines:
///
/// 1. make crate compiling: rename usage of frame_system::Trait to frame_system::Config.
/// 2. export metadata of the pallet for later checks
/// 3. generate the template upgrade for the pallet provided by decl_storage with environment
/// variable `PRINT_PALLET_UPGRADE`: `PRINT_PALLET_UPGRADE=1 cargo check -p my_pallet`
/// This template can be used as information it contains all information for storages, genesis
/// config and genesis build.
/// 4. reorganize pallet to have trait Trait, decl_* macros, ValidateUnsigned, ProvideInherent,
/// Origin all together in one file. suggested order:
/// * trait,
/// * decl_module,
/// * decl_event,
/// * decl_error,
/// * decl_storage,
/// * origin,
/// * validate_unsigned,
/// * provide_inherent,
/// so far it should compile and all be correct.
/// 5. start writing new pallet module
/// ```ignore
/// pub use pallet::*;
///
/// #[frame_support::pallet]
/// pub mod pallet {
/// pub use frame_support::pallet_prelude::*;
/// pub use frame_system::pallet_prelude::*;
/// use super::*;
///
/// #[pallet::pallet]
/// #[pallet::generete($visibility_of_trait_store trait Store)]
/// // NOTE: if the visibility of trait store is private but you want to make it available
/// // in super, then use `pub(super)` or `pub(crate)` to make it available in crate.
/// pub struct Pallet<T>(PhantomData<T>);
/// // pub struct Pallet<T, I = ()>(PhantomData<T>); // for instantiable pallet
/// }
/// ```
/// 6. **migrate trait**: move trait into the module with
/// * rename `Trait` to `Config`
/// * all const in decl_module to `#[pallet::constant]`
/// 7. **migrate decl_module**: write:
/// ```ignore
/// #[pallet::hooks]
/// impl<T: Trait> Hooks for Pallet<T> {
/// }
/// ```
/// and write inside on_initialize/on_finalize/on_runtime_upgrade/offchain_worker/integrity_test
///
/// then write:
/// ```ignore
/// #[pallet::call]
/// impl<T: Trait> Pallet<T> {
/// }
/// ```
/// and write inside all the call in decl_module with a few changes in the signature:
/// - origin must now be written completely, e.g. `origin: OriginFor<T>`
/// - result type must be `DispatchResultWithPostInfo`, you need to write it and also you might
/// need to put `Ok(().into())` at the end or the function.
/// - `#[compact]` must now be written `#[pallet::compact]`
/// - `#[weight = ..]` must now be written `#[pallet::weight(..)]`
///
/// 8. **migrate event**:
/// rewrite as a simple enum under with the attribute `#[pallet::event]`,
/// use `#[pallet::generate_deposit($vis fn deposit_event)]` to generate deposit_event,
/// use `#[pallet::metadata(...)]` to configure the metadata for types in order not to break them.
/// 9. **migrate error**: just rewrite it with attribute `#[pallet::error]`.
/// 10. **migrate storage**:
/// decl_storage provide an upgrade template (see 3.). All storages, genesis config, genesis
/// build and default implementation of genesis config can be taken from it directly.
///
/// Otherwise here is the manual process:
///
/// first migrate the genesis logic. write:
/// ```ignore
/// #[pallet::genesis_config]
/// struct GenesisConfig {
/// // fields of add_extra_genesis
/// }
/// impl Default for GenesisConfig {
/// // type default or default provided for fields
/// }
/// #[pallet::genesis_build]
/// impl<T: Config> GenesisBuild<T> for GenesisConfig {
/// // impl<T: Config, I: 'static> GenesisBuild<T, I> for GenesisConfig { for instantiable pallet
/// fn build() {
/// // The add_extra_genesis build logic
/// }
/// }
/// ```
/// for each storages, if it contains config(..) then add a fields, and make its default to the
/// value in `= ..;` or the type default if none, if it contains no build then also add the
/// logic to build the value.
/// for each storages if it contains build(..) then add the logic to genesis_build.
///
/// NOTE: in decl_storage: is executed first the individual config and build and at the end the
/// add_extra_genesis build
///
/// Once this is done you can migrate storage individually, a few notes:
/// - for private storage use `pub(crate) type ` or `pub(super) type` or nothing,
/// - for storage with `get(fn ..)` use `#[pallet::getter(fn ...)]`
/// - for storage with value being `Option<$something>` make generic `Value` being `$something`
/// and generic `QueryKind` being `OptionQuery` (note: this is default). Otherwise make
/// `Value` the complete value type and `QueryKind` being `ValueQuery`.
/// - for storage with default value: `= $expr;` provide some specific OnEmpty generic. To do so
/// use of `#[pallet::type_value]` to generate the wanted struct to put.
/// example: `MyStorage: u32 = 3u32` would be written:
/// ```ignore
/// #[pallet::type_value] fn MyStorageOnEmpty() -> u32 { 3u32 }
/// #[pallet::storage]
/// pub(super) type MyStorage<T> = StorageValue<u32, ValueQuery, MyStorageOnEmpty>;
/// ```
///
/// NOTE: decl_storage also generates functions `assimilate_storage` and `build_storage`
/// directly on GenesisConfig, those are sometimes used in tests. In order not to break they
/// can be implemented manually, just implement those functions by calling `GenesisBuild`
/// implementation.
///
/// 11. **migrate origin**: just move the origin to the pallet module under `#[pallet::origin]`
/// 12. **migrate validate_unsigned**: just move the ValidateUnsigned implementation to the pallet
/// module under `#[pallet::validate_unsigned]`
/// 13. **migrate provide_inherent**: just move the ValidateUnsigned implementation to the pallet
/// module under `#[pallet::provide_inherent]`
/// 14. rename the usage of Module to Pallet and the usage of Config to Trait inside the crate.
/// 15. migration is done, now double check migration with the checking migration guidelines.
///
/// ## Checking upgrade guidelines:
///
/// * compare metadata. This checks for:
/// * call, names, signature, doc