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    • Oliver Tale-Yazdi's avatar
      Multi-Block-Migrations, `poll` hook and new System callbacks (#1781) · eefd5fe4
      Oliver Tale-Yazdi authored 
      This MR is the merge of
https://github.com/paritytech/substrate/pull/14414 and
https://github.com/paritytech/substrate/pull/14275. It implements
[RFC#13](https://github.com/polkadot-fellows/RFCs/pull/13), closes
https://github.com/paritytech/polkadot-sdk/issues/198.

----- 

This Merge request introduces three major topicals:

1. Multi-Block-Migrations
1. New pallet `poll` hook for periodic service work
1. Replacement hooks for `on_initialize` and `on_finalize` in cases
where `poll` cannot be used

and some more general changes to FRAME.  
The changes for each topical span over multiple crates. They are listed
in topical order below.

# 1.) Multi-Block-Migrations

Multi-Block-Migrations are facilitated by creating `pallet_migrations`
and configuring `System::Config::MultiBlockMigrator` to point to it.
Executive picks this up and triggers one step of the migrations pallet
per block.
The chain is in lockdown mode for as long as an MBM is ongoing.
Executive does this by polling `MultiBlockMigrator::ongoing` and not
allowing any transaction in a block, if true.

A MBM is defined through trait `SteppedMigration`. A condensed version
looks like this:
```rust
/// A migration that can proceed in multiple steps.
pub trait SteppedMigration {
	type Cursor: FullCodec + MaxEncodedLen;
	type Identifier: FullCodec + MaxEncodedLen;

	fn id() -> Self::Identifier;

	fn max_steps() -> Option<u32>;

	fn step(
		cursor: Option<Self::Cursor>,
		meter: &mut WeightMeter,
	) -> Result<Option<Self::Cursor>, SteppedMigrationError>;
}
```

`pallet_migrations` can be configured with an aggregated tuple of these
migrations. It then starts to migrate them one-by-one on the next
runtime upgrade.
Two things are important here:
- 1. Doing another runtime upgrade while MBMs are ongoing is not a good
idea and can lead to messed up state.
- 2. **Pallet Migrations MUST BE CONFIGURED IN `System::Config`,
otherwise it is not used.**

The pallet supports an `UpgradeStatusHandler` that can be used to notify
external logic of upgrade start/finish (for example to pause XCM
dispatch).

Error recovery is very limited in the case that a migration errors or
times out (exceeds its `max_steps`). Currently the runtime dev can
decide in `FailedMigrationHandler::failed` how to handle this. One
follow-up would be to pair this with the `SafeMode` pallet and enact
safe mode when an upgrade fails, to allow governance to rescue the
chain. This is currently not possible, since governance is not
`Mandatory`.

## Runtime API

- `Core`: `initialize_block` now returns `ExtrinsicInclusionMode` to
inform the Block Author whether they can push transactions.

### Integration

Add it to your runtime implementation of `Core` and `BlockBuilder`:
```patch
diff --git a/runtime/src/lib.rs b/runtime/src/lib.rs
@@ impl_runtime_apis! {
	impl sp_block_builder::Core<Block> for Runtime {
-		fn initialize_block(header: &<Block as BlockT>::Header) {
+		fn initialize_block(header: &<Block as BlockT>::Header) -> RuntimeExecutiveMode {
			Executive::initialize_block(header)
		}

		...
	}
```

# 2.) `poll` hook

A new pallet hook is introduced: `poll`. `Poll` is intended to replace
mostly all usage of `on_initialize`.
The reason for this is that any code that can be called from
`on_initialize` cannot be migrated through an MBM. Currently there is no
way to statically check this; the implication is to use `on_initialize`
as rarely as possible.
Failing to do so can result in broken storage invariants.

The implementation of the poll hook depends on the `Runtime API` changes
that are explained above.

# 3.) Hard-Deadline callbacks

Three new callbacks are introduced and configured on `System::Config`:
`PreInherents`, `PostInherents` and `PostTransactions`.
These hooks are meant as replacement for `on_initialize` and
`on_finalize` in cases where the code that runs cannot be moved to
`poll`.
The reason for this is to make the usage of HD-code (hard deadline) more
explicit - again to prevent broken invariants by MBMs.

# 4.) FRAME (general changes)

## `frame_system` pallet

A new memorize storage item `InherentsApplied` is added. It is used by
executive to track whether inherents have already been applied.
Executive and can then execute the MBMs directly between inherents and
transactions.

The `Config` gets five new items:
- `SingleBlockMigrations` this is the new way of configuring migrations
that run in a single block. Previously they were defined as last generic
argument of `Executive`. This shift is brings all central configuration
about migrations closer into view of the developer (migrations that are
configured in `Executive` will still work for now but is deprecated).
- `MultiBlockMigrator` this can be configured to an engine that drives
MBMs. One example would be the `pallet_migrations`. Note that this is
only the engine; the exact MBMs are injected into the engine.
- `PreInherents` a callback that executes after `on_initialize` but
before inherents.
- `PostInherents` a callback that executes after all inherents ran
(including MBMs and `poll`).
- `PostTransactions` in symmetry to `PreInherents`, this one is called
before `on_finalize` but after all transactions.

A sane default is to set all of these to `()`. Example diff suitable for
any chain:
```patch
@@ impl frame_system::Config for Test {
 	type MaxConsumers = ConstU32<16>;
+	type SingleBlockMigrations = ();
+	type MultiBlockMigrator = ();
+	type PreInherents = ();
+	type PostInherents = ();
+	type PostTransactions = ();
 }
```

An overview of how the block execution now looks like is here. The same
graph is also in the rust doc.

<details><summary>Block Execution Flow</summary>
<p>

![Screenshot 2023-12-04 at 19 11
29](https://github.com/paritytech/polkadot-sdk/assets/10380170/e88a80c4-ef11-4faa-8df5-8b33a724c054)

</p>
</details> 

## Inherent Order

Moved to https://github.com/paritytech/polkadot-sdk/pull/2154



---------------


## TODO

- [ ] Check that `try-runtime` still works
- [ ] Ensure backwards compatibility with old Runtime APIs
- [x] Consume weight correctly
- [x] Cleanup

---------

Signed-off-by: default avatarOliver Tale-Yazdi <[email protected]>
Co-authored-by: default avatarLiam Aharon <[email protected]>
Co-authored-by: default avatarJuan Girini <[email protected]>
Co-authored-by: command-bot <>
Co-authored-by: default avatarFrancisco Aguirre <[email protected]>
Co-authored-by: default avatarGavin Wood <[email protected]>
Co-authored-by: default avatarBastian Köcher <[email protected]>
      eefd5fe4
    • Liam Aharon's avatar
      Runtime Upgrade ref docs and Single Block Migration example pallet (#1554) · 12ce4f7d
      Liam Aharon authored 
      Closes https://github.com/paritytech/polkadot-sdk-docs/issues/55

- Changes 'current storage version' terminology to less ambiguous
'in-code storage version' (suggestion by @ggwpez)
- Adds a new example pallet `pallet-example-single-block-migrations`
- Adds a new reference doc to replace
https://docs.substrate.io/maintain/runtime-upgrades/ (temporarily living
in the pallet while we wait for developer hub PR to merge)
- Adds documentation for the `storage_alias` macro
- Improves `trait Hooks` docs 
- Improves `trait GetStorageVersion` docs
- Update the suggested patterns for using `VersionedMigration`, so that
version unchecked migrations are never exported
- Prevents accidental usage of version unchecked migrations in runtimes

https://github.com/paritytech/substrate/pull/14421#discussion_r1255467895
- Unversioned migration code is kept inside `mod version_unchecked`,
versioned code is kept in `pub mod versioned`
- It is necessary to use modules to limit visibility because the inner
migration must be `pub`. See
https://github.com/rust-lang/rust/issues/30905 and

https://internals.rust-lang.org/t/lang-team-minutes-private-in-public-rules/4504/40
for more.

### todo

- [x] move to reference docs to proper place within sdk-docs (now that
https://github.com/paritytech/polkadot-sdk/pull/2102

 is merged)
- [x] prdoc

---------

Co-authored-by: default avatarKian Paimani <[email protected]>
Co-authored-by: default avatarJuan <[email protected]>
Co-authored-by: default avatarOliver Tale-Yazdi <[email protected]>
Co-authored-by: command-bot <>
Co-authored-by: default avatargupnik <[email protected]>
      12ce4f7d
  7. Feb 26, 2024
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  25. Feb 12, 2024
  27. Feb 09, 2024
  29. Feb 08, 2024
    • Gonçalo Pestana's avatar
      Fixes `TotalValueLocked` out of sync in nomination pools (#3052) · aac07af0
      Gonçalo Pestana authored 
      The `TotalLockedValue` storage value in nomination pools pallet may get
out of sync if the staking pallet does implicit withdrawal of unlocking
chunks belonging to a bonded pool stash. This fix is based on a new
method in the `OnStakingUpdate` traits, `on_withdraw`, which allows the
nomination pools pallet to adjust the `TotalLockedValue` every time
there is an implicit or explicit withdrawal from a bonded pool's stash.

This PR also adds a migration that checks and updates the on-chain TVL
if it got out of sync due to the bug this PR fixes.

**Changes to `trait OnStakingUpdate`**

In order for staking to notify the nomination pools pallet that chunks
where withdrew, we add a new method, `on_withdraw` to the
`OnStakingUpdate` trait. The nomination pools pallet filters the
withdraws that are related to bonded pool accounts and updates the
`TotalValueLocked` accordingly.

**Others**
- Adds try-state checks to the EPM/staking e2e tests
- Adds tests for auto withdrawing in the context of nomination pools

**To-do**
- [x] check if we need a migration to fix the current `TotalValueLocked`
(run try-runtime)
- [x] migrations to fix the current on-chain TVL value 

 ✅ **Kusama**:
```
TotalValueLocked: 99.4559 kKSM
TotalValueLocked (calculated) 99.4559 kKSM
```
⚠️ **Westend**:
```
TotalValueLocked: 18.4060 kWND
TotalValueLocked (calculated) 18.4050 kWND
```
**Polkadot**: TVL not released yet.

Closes https://github.com/paritytech/polkadot-sdk/issues/3055



---------

Co-authored-by: command-bot <>
Co-authored-by: default avatarRoss Bulat <[email protected]>
Co-authored-by: default avatarDónal Murray <[email protected]>
      aac07af0
  31. Feb 06, 2024
  33. Feb 02, 2024
  35. Jan 31, 2024
    • Oliver Tale-Yazdi's avatar
      [FRAME] Make `core-fellowship` ans `salary` work for swapped members (#3156) · 07e55006
      Oliver Tale-Yazdi authored 
      Fixup for https://github.com/paritytech/polkadot-sdk/pull/2587 to make
the `core-fellowship` crate work with swapped members.

Adds a `MemberSwappedHandler` to the `ranked-collective` pallet that are
implemented by `core-fellowship+salary`.
There is are exhaustive tests
[here](https://github.com/paritytech/polkadot-sdk/blob/72aa7ac17a0e5b16faab5d2992aa2db2e01b05d0/substrate/frame/core-fellowship/src/tests/integration.rs#L338)
and
[here](https://github.com/paritytech/polkadot-sdk/blob/ab3cdb05a5ebc1ff841f8dda67edef0ea40bbba5/substrate/frame/salary/src/tests/integration.rs#L224

)
to check that adding member `1` is equivalent to adding member `0` and
then swapping.

---------

Signed-off-by: default avatarOliver Tale-Yazdi <[email protected]>
      07e55006
    • Branislav Kontur's avatar
      [frame] `#[pallet::composite_enum]` improved variant count handling + removed... · bb8ddc46
      Branislav Kontur authored 
      [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: default avatarBastian Köcher <[email protected]>
Co-authored-by: default avatarDónal Murray <[email protected]>
Co-authored-by: default avatargupnik <[email protected]>
      bb8ddc46
  37. Jan 30, 2024
  39. Jan 26, 2024
  41. Jan 24, 2024
  43. Jan 23, 2024
  45. Jan 22, 2024