[frame] #[pallet::composite_enum] improved variant count handling + removed pallet_balances's MaxHolds config (#2657)

I started this investigation/issue based on @liamaharon question
[here](https://github.com/paritytech/polkadot-sdk/pull/1801#discussion_r1410452499).

## Problem

The `pallet_balances` integrity test should correctly detect that the
runtime has correct distinct `HoldReasons` variant count. I assume the
same situation exists for RuntimeFreezeReason.

It is not a critical problem, if we set `MaxHolds` with a sufficiently
large value, everything should be ok. However, in this case, the
integrity_test check becomes less useful.

**Situation for "any" runtime:**
- `HoldReason` enums from different pallets:
```rust
        /// from pallet_nis
        #[pallet::composite_enum]
	pub enum HoldReason {
		NftReceipt,
	}

        /// from pallet_preimage
        #[pallet::composite_enum]
	pub enum HoldReason {
		Preimage,
	}

        // from pallet_state-trie-migration
        #[pallet::composite_enum]
	pub enum HoldReason {
		SlashForContinueMigrate,
		SlashForMigrateCustomTop,
		SlashForMigrateCustomChild,
	}
```

- generated `RuntimeHoldReason` enum looks like:
```rust
pub enum RuntimeHoldReason {

    #[codec(index = 32u8)]
    Preimage(pallet_preimage::HoldReason),

    #[codec(index = 38u8)]
    Nis(pallet_nis::HoldReason),

    #[codec(index = 42u8)]
    StateTrieMigration(pallet_state_trie_migration::HoldReason),
}
```

- composite enum `RuntimeHoldReason` variant count is detected as `3`
- we set `type MaxHolds = ConstU32<3>`
- `pallet_balances::integrity_test` is ok with `3`(at least 3)

However, the real problem can occur in a live runtime where some
functionality might stop working. This is due to a total of 5 distinct
hold reasons (for pallets with multi-instance support, it is even more),
and not all of them can be used because of an incorrect `MaxHolds`,
which is deemed acceptable according to the `integrity_test`:
  ```
  // pseudo-code - if we try to call all of these:

T::Currency::hold(&pallet_nis::HoldReason::NftReceipt.into(),
&nft_owner, deposit)?;
T::Currency::hold(&pallet_preimage::HoldReason::Preimage.into(),
&nft_owner, deposit)?;

T::Currency::hold(&pallet_state_trie_migration::HoldReason::SlashForContinueMigrate.into(),
&nft_owner, deposit)?;

  // With `type MaxHolds = ConstU32<3>` these two will fail

T::Currency::hold(&pallet_state_trie_migration::HoldReason::SlashForMigrateCustomTop.into(),
&nft_owner, deposit)?;

T::Currency::hold(&pallet_state_trie_migration::HoldReason::SlashForMigrateCustomChild.into(),
&nft_owner, deposit)?;
  ```  


## Solutions

A macro `#[pallet::*]` expansion is extended of `VariantCount`
implementation for the `#[pallet::composite_enum]` enum type. This
expansion generates the `VariantCount` implementation for pallets'
`HoldReason`, `FreezeReason`, `LockId`, and `SlashReason`. Enum variants
must be plain enum values without fields to ensure a deterministic
count.

The composite runtime enum, `RuntimeHoldReason` and
`RuntimeFreezeReason`, now sets `VariantCount::VARIANT_COUNT` as the sum
of pallets' enum `VariantCount::VARIANT_COUNT`:
```rust
#[frame_support::pallet(dev_mode)]
mod module_single_instance {

	#[pallet::composite_enum]
	pub enum HoldReason {
		ModuleSingleInstanceReason1,
		ModuleSingleInstanceReason2,
	}
...
}

#[frame_support::pallet(dev_mode)]
mod module_multi_instance {

	#[pallet::composite_enum]
	pub enum HoldReason<I: 'static = ()> {
		ModuleMultiInstanceReason1,
		ModuleMultiInstanceReason2,
		ModuleMultiInstanceReason3,
	}
...
}


impl self::sp_api_hidden_includes_construct_runtime::hidden_include::traits::VariantCount
    for RuntimeHoldReason
{
    const VARIANT_COUNT: u32 = 0
        + module_single_instance::HoldReason::VARIANT_COUNT
        + module_multi_instance::HoldReason::<module_multi_instance::Instance1>::VARIANT_COUNT
        + module_multi_instance::HoldReason::<module_multi_instance::Instance2>::VARIANT_COUNT
        + module_multi_instance::HoldReason::<module_multi_instance::Instance3>::VARIANT_COUNT;
}
```

In addition, `MaxHolds` is removed (as suggested
[here](https://github.com/paritytech/polkadot-sdk/pull/2657#discussion_r1443324573))
from `pallet_balances`, and its `Holds` are now bounded to
`RuntimeHoldReason::VARIANT_COUNT`. Therefore, there is no need to let
the runtime specify `MaxHolds`.


## For reviewers

Relevant changes can be found here:
- `substrate/frame/support/procedural/src/lib.rs` 
-  `substrate/frame/support/procedural/src/pallet/parse/composite.rs`
-  `substrate/frame/support/procedural/src/pallet/expand/composite.rs`
-
`substrate/frame/support/procedural/src/construct_runtime/expand/composite_helper.rs`
-
`substrate/frame/support/procedural/src/construct_runtime/expand/hold_reason.rs`
-
`substrate/frame/support/procedural/src/construct_runtime/expand/freeze_reason.rs`
- `substrate/frame/support/src/traits/misc.rs`

And the rest of the files is just about removed `MaxHolds` from
`pallet_balances`

## Next steps

Do the same for `MaxFreezes`
https://github.com/paritytech/polkadot-sdk/issues/2997.

---------

Co-authored-by: command-bot <>
Co-authored-by: Bastian Köcher <git@kchr.de>
Co-authored-by: Dónal Murray <donal.murray@parity.io>
Co-authored-by: gupnik <nikhilgupta.iitk@gmail.com>
This commit is contained in:
Branislav Kontur
2024-01-31 07:19:16 +01:00
committed by GitHub
parent cc4805b51e
commit bb8ddc46c1
118 changed files with 610 additions and 315 deletions
@@ -219,7 +219,6 @@ impl pallet_balances::Config for Runtime {
type RuntimeHoldReason = RuntimeHoldReason;
type RuntimeFreezeReason = RuntimeFreezeReason;
type FreezeIdentifier = ();
type MaxHolds = ConstU32<0>;
type MaxFreezes = ConstU32<0>;
}
@@ -16,10 +16,10 @@
//! Autogenerated weights for `pallet_balances`
//!
//! THIS FILE WAS AUTO-GENERATED USING THE SUBSTRATE BENCHMARK CLI VERSION 4.0.0-dev
//! DATE: 2024-01-20, STEPS: `50`, REPEAT: `20`, LOW RANGE: `[]`, HIGH RANGE: `[]`
//! THIS FILE WAS AUTO-GENERATED USING THE SUBSTRATE BENCHMARK CLI VERSION 32.0.0
//! DATE: 2024-01-31, STEPS: `50`, REPEAT: `20`, LOW RANGE: `[]`, HIGH RANGE: `[]`
//! WORST CASE MAP SIZE: `1000000`
//! HOSTNAME: `runner-j8vvqcjr-project-674-concurrent-0`, CPU: `Intel(R) Xeon(R) CPU @ 2.60GHz`
//! HOSTNAME: `runner-8idpd4bs-project-674-concurrent-0`, CPU: `Intel(R) Xeon(R) CPU @ 2.60GHz`
//! WASM-EXECUTION: `Compiled`, CHAIN: `Some("coretime-westend-dev")`, DB CACHE: 1024
// Executed Command:
@@ -54,8 +54,8 @@ impl<T: frame_system::Config> pallet_balances::WeightInfo for WeightInfo<T> {
// Proof Size summary in bytes:
// Measured: `0`
// Estimated: `3593`
// Minimum execution time: 42_533_000 picoseconds.
Weight::from_parts(43_470_000, 0)
// Minimum execution time: 41_147_000 picoseconds.
Weight::from_parts(41_829_000, 0)
.saturating_add(Weight::from_parts(0, 3593))
.saturating_add(T::DbWeight::get().reads(1))
.saturating_add(T::DbWeight::get().writes(1))
@@ -66,8 +66,8 @@ impl<T: frame_system::Config> pallet_balances::WeightInfo for WeightInfo<T> {
// Proof Size summary in bytes:
// Measured: `0`
// Estimated: `3593`
// Minimum execution time: 33_442_000 picoseconds.
Weight::from_parts(34_851_000, 0)
// Minimum execution time: 32_566_000 picoseconds.
Weight::from_parts(33_012_000, 0)
.saturating_add(Weight::from_parts(0, 3593))
.saturating_add(T::DbWeight::get().reads(1))
.saturating_add(T::DbWeight::get().writes(1))
@@ -78,8 +78,8 @@ impl<T: frame_system::Config> pallet_balances::WeightInfo for WeightInfo<T> {
// Proof Size summary in bytes:
// Measured: `103`
// Estimated: `3593`
// Minimum execution time: 11_890_000 picoseconds.
Weight::from_parts(12_324_000, 0)
// Minimum execution time: 11_435_000 picoseconds.
Weight::from_parts(11_717_000, 0)
.saturating_add(Weight::from_parts(0, 3593))
.saturating_add(T::DbWeight::get().reads(1))
.saturating_add(T::DbWeight::get().writes(1))
@@ -90,8 +90,8 @@ impl<T: frame_system::Config> pallet_balances::WeightInfo for WeightInfo<T> {
// Proof Size summary in bytes:
// Measured: `103`
// Estimated: `3593`
// Minimum execution time: 16_583_000 picoseconds.
Weight::from_parts(17_116_000, 0)
// Minimum execution time: 15_941_000 picoseconds.
Weight::from_parts(16_341_000, 0)
.saturating_add(Weight::from_parts(0, 3593))
.saturating_add(T::DbWeight::get().reads(1))
.saturating_add(T::DbWeight::get().writes(1))
@@ -102,8 +102,8 @@ impl<T: frame_system::Config> pallet_balances::WeightInfo for WeightInfo<T> {
// Proof Size summary in bytes:
// Measured: `103`
// Estimated: `6196`
// Minimum execution time: 43_979_000 picoseconds.
Weight::from_parts(44_662_000, 0)
// Minimum execution time: 42_592_000 picoseconds.
Weight::from_parts(43_111_000, 0)
.saturating_add(Weight::from_parts(0, 6196))
.saturating_add(T::DbWeight::get().reads(2))
.saturating_add(T::DbWeight::get().writes(2))
@@ -114,8 +114,8 @@ impl<T: frame_system::Config> pallet_balances::WeightInfo for WeightInfo<T> {
// Proof Size summary in bytes:
// Measured: `0`
// Estimated: `3593`
// Minimum execution time: 43_140_000 picoseconds.
Weight::from_parts(43_575_000, 0)
// Minimum execution time: 40_925_000 picoseconds.
Weight::from_parts(41_743_000, 0)
.saturating_add(Weight::from_parts(0, 3593))
.saturating_add(T::DbWeight::get().reads(1))
.saturating_add(T::DbWeight::get().writes(1))
@@ -126,8 +126,8 @@ impl<T: frame_system::Config> pallet_balances::WeightInfo for WeightInfo<T> {
// Proof Size summary in bytes:
// Measured: `103`
// Estimated: `3593`
// Minimum execution time: 14_748_000 picoseconds.
Weight::from_parts(15_097_000, 0)
// Minimum execution time: 14_117_000 picoseconds.
Weight::from_parts(14_418_000, 0)
.saturating_add(Weight::from_parts(0, 3593))
.saturating_add(T::DbWeight::get().reads(1))
.saturating_add(T::DbWeight::get().writes(1))
@@ -139,11 +139,11 @@ impl<T: frame_system::Config> pallet_balances::WeightInfo for WeightInfo<T> {
// Proof Size summary in bytes:
// Measured: `0 + u * (136 ±0)`
// Estimated: `990 + u * (2603 ±0)`
// Minimum execution time: 14_502_000 picoseconds.
Weight::from_parts(14_803_000, 0)
// Minimum execution time: 13_855_000 picoseconds.
Weight::from_parts(14_108_000, 0)
.saturating_add(Weight::from_parts(0, 990))
// Standard Error: 11_903
.saturating_add(Weight::from_parts(13_484_935, 0).saturating_mul(u.into()))
// Standard Error: 11_673
.saturating_add(Weight::from_parts(12_675_264, 0).saturating_mul(u.into()))
.saturating_add(T::DbWeight::get().reads((1_u64).saturating_mul(u.into())))
.saturating_add(T::DbWeight::get().writes((1_u64).saturating_mul(u.into())))
.saturating_add(Weight::from_parts(0, 2603).saturating_mul(u.into()))
@@ -154,8 +154,8 @@ impl<T: frame_system::Config> pallet_balances::WeightInfo for WeightInfo<T> {
// Proof Size summary in bytes:
// Measured: `0`
// Estimated: `1501`
// Minimum execution time: 5_035_000 picoseconds.
Weight::from_parts(5_255_000, 0)
// Minimum execution time: 4_820_000 picoseconds.
Weight::from_parts(5_152_000, 0)
.saturating_add(Weight::from_parts(0, 1501))
.saturating_add(T::DbWeight::get().reads(1))
}