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Release crates io v1.6.0 staking backport #4082

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gpestana
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@gpestana gpestana commented Apr 11, 2024

This backport PR should bump the pallet-staking from 28.0.0 to 28.0.1.

Backports for 1.6:

Relevant Issues:

Currently, the staking logic does not prevent a controller from becoming
a stash of *another* ledger (introduced by [removing this
check](https://github.com/paritytech/polkadot-sdk/pull/1484/files#diff-3aa6ceab5aa4e0ab2ed73a7245e0f5b42e0832d8ca5b1ed85d7b2a52fb196524L850)).
Given that the remaining of the code expects that never happens, bonding
a ledger with a stash that is a controller of another ledger may lead to
data inconsistencies and data losses in bonded ledgers. For more
detailed explanation of this issue:
https://hackmd.io/@gpestana/HJoBm2tqo/%2FTPdi28H7Qc2mNUqLSMn15w

In a nutshell, when fetching a ledger with a given controller, we may be
end up getting the wrong ledger which can lead to unexpected ledger
states.

This PR also ensures that `set_controller` does not lead to data
inconsistencies in the staking ledger and bonded storage in the case
when a controller of a stash is a stash of *another* ledger. and
improves the staking `try-runtime` checks to catch potential issues with
the storage preemptively.

In summary, there are two important cases here:

1. **"Sane" double bonded ledger**

When a controller of a ledger is a stash of *another* ledger. In this
case, we have:

```
> Bonded(stash, controller)
(A, B)  // stash A with controller B
(B, C) // B is also a stash of another ledger
(C, D)

> Ledger(controller)
Ledger(B) = L_a (stash = A)
Ledger(C) = L_b (stash = B)
Ledger(D) = L_c (stash = C)
```

In this case, the ledgers can be mutated and all operations are OK.
However, we should not allow `set_controller` to be called if it means
it results in a "corrupt" double bonded ledger (see below).

3. **"Corrupt" double bonded ledger**

```
> Bonded(stash, controller)
(A, B)  // stash A with controller B
(B, B)
(C, D)
```
In this case, B is a stash and controller AND is corrupted, since B is
responsible for 2 ledgers which is not correct and will lead to
inconsistent states. Thus, in this case, in this PR we are preventing
these ledgers from mutating (i.e. operations like bonding extra etc)
until the ledger is brought back to a consistent state.

---

**Changes**:
- Checks if stash is already a controller when calling `Call::bond`
(fixes the regression introduced by [removing this
check](https://github.com/paritytech/polkadot-sdk/pull/1484/files#diff-3aa6ceab5aa4e0ab2ed73a7245e0f5b42e0832d8ca5b1ed85d7b2a52fb196524L850));
- Ensures that all fetching ledgers from storage are done through the
`StakingLedger` API;
- Ensures that -- when fetching a ledger from storage using the
`StakingLedger` API --, a `Error::BadState` is returned if the ledger
bonding is in a bad state. This prevents bad ledgers from mutating (e.g.
`bond_extra`, `set_controller`, etc) its state and avoid further data
inconsistencies.
- Prevents stashes which are controllers or another ledger from calling
`set_controller`, since that may lead to a bad state.
- Adds further try-state runtime checks that check if there are ledgers
in a bad state based on their bonded metadata.

Related to #3245

---------

Co-authored-by: Kian Paimani <[email protected]>
Co-authored-by: kianenigma <[email protected]>
@paritytech-review-bot paritytech-review-bot bot requested a review from a team April 11, 2024 12:10
@gpestana gpestana changed the base branch from release-polkadot-v1.6.0 to release-crates-io-v1.6.0 April 11, 2024 12:11
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The CI pipeline was cancelled due to failure one of the required jobs.
Job name: cargo-clippy
Logs: https://gitlab.parity.io/parity/mirrors/polkadot-sdk/-/jobs/5884004

@gpestana gpestana changed the title Release crates io v1.6.0 staking backports Release crates io v1.6.0 staking backport Apr 11, 2024
@gpestana gpestana added A3-backport Pull request is already reviewed well in another branch. R0-silent Changes should not be mentioned in any release notes and removed A3-backport Pull request is already reviewed well in another branch. labels Apr 11, 2024
@gpestana gpestana closed this Apr 14, 2024
@gpestana
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Closed in lieu of #4116 (for some reason, the PR branch is blocked from updates).

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