✨ Slashing behavior for pallet vesting

[JuaniRios]

What?

• Reduce vesting schedules of pallet-vesting after a slash is made when an evaluation is settled

Why?

• A user could have negative transferable balance if they had some tokens locked for vesting and then got slashed.

How?

• Semi-generic solution which should be easily adapted to the Polkadot SDK. PR is here.
• pallet-funding (in the future pallet-balances) accepts a tuple of items that implement a trait called on_slash.
• pallet funding calls this after slashing the evaluator (we don't use the slash interface so we call the trait directly. In the future this trait should also be called when using the slash function)
• We implement on pallet vesting the trait where we see how many tokens should be released at the moment of slashing, and then apply the slash on the remaining frozen amount. We recalculate the per_block amount to keep the same end block

Testing?

• 2 tests in the new crate on-slash-vesting
• 1 integration test

Anything Else?

• For now the trait for slashing needs to be in the same crate we implement it since we can't impl a foreign trait on a foreign crate.
• Soon we should submit a PR to polkadot-sdk where we submit this new slash interface on the tokens::fungible trait, and also add our vesting impl directly inside pallet-vesting.

[JuaniRios]

• #398
• #396 👈
• #395
• #394
• #393
• #392
• #391
• #389 : 1 other dependent PR (#390 )
• #386 : 1 other dependent PR (#387 )
• #383
• #384
• #385
• #388
• main

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[JuaniRios]

[!WARNING] This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite. Learn more

• #396 👈
• #395
• #394
• #393
• #392
• #391
• #390
• #389
• #386 : 1 other dependent PR (#387 )
• #383
• #384
• #385
• #388
• main

This stack of pull requests is managed by Graphite. Learn more about stacking.

Join @JuaniRios and the rest of your teammates on Graphite

[JuaniRios]

Merge activity

• Sep 12, 9:39 AM EDT: @JuaniRios started a stack merge that includes this pull request via Graphite.
• Sep 12, 9:54 AM EDT: Graphite rebased this pull request as part of a merge.
• Sep 12, 9:55 AM EDT: @JuaniRios merged this pull request with Graphite.