Fix dex ed

[zqhxuyuan]

Description

fix dex ed when last user remove liquidity failed.

DEX commit: Manta-Network/Zenlink@853f41c#diff-48b4d8abc9afad5d3c79f61c7ad9b831eb830423e5709aaff6b6fd67acc3be3cR105-R110

PS: did some refactor on zenlink

i.e. A pair of(KMA,KSM), when add liquidity, user's KMA and KSM transfer to pair acocunt. And the liquidity amount is record as total_supply on pair account. when user remove liquidity, KMA and KSM return back to user account.

https://github.com/Manta-Network/Zenlink/blob/c2acc36bea02e6c2aa38f3b290e255dfd5c164dd/zenlink-protocol/src/swap/mod.rs#L135-L143

let reserve_0 = T::MultiAssetsHandler::balance_of(asset_0, lp_account);
let reserve_1 = T::MultiAssetsHandler::balance_of(asset_1, lp_account);

let (amount_0, amount_1) = calculate_share_amounts(
	remove_liquidity,
	status.total_supply,
	reserve_0,
	reserve_1,
);

amount = remove_liquidity * reserve / total_supply, Let's say there's only one user add liquidity, now when user remove liquidity, remove_liquidity=total_supply, so the amount=reserve. amount_0 = KMA_balance(lp_account).

deposit ED of KMA to pair account is not going to work, because amount = KMA balance of pair account, and all the KMA on pair account will be transfer to user.

https://github.com/Manta-Network/Zenlink/blob/c2acc36bea02e6c2aa38f3b290e255dfd5c164dd/zenlink-protocol/src/swap/mod.rs#L176

The T::MultiAssetsHandler::transfer on original zenlink when transfer native token is using KeepAlive:

https://github.com/zenlinkpro/Zenlink-DEX-Module/blob/7662acbff71cea3b35db918ceb9370e8929be991/zenlink-protocol/src/multiassets.rs#L100-L106

T::MultiAssetsHandler::transfer(asset_0, lp_account, recipient, amount_0)?; 

This will failed, because pair account can't transfer all KMA while keep alive at the same time.

For non native token, we already set as AllowDeath:

Manta/runtime/manta/src/zenlink.rs

Lines 153 to 157 in 51038df

	<MantaConcreteFungibleLedger as FungibleLedger>::withdraw_burning(
	manta_asset_id,
	origin,
	amount,
	ExistenceRequirement::AllowDeath,

transfer on LocalAssetHandler is local_withdraw + local_deposit: https://github.com/zenlinkpro/Zenlink-DEX-Module/blob/7662acbff71cea3b35db918ceb9370e8929be991/zenlink-protocol/src/traits.rs#L17-L24

---

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Situational Notes:

• If adding functionality, write unit tests!
• If importing a new pallet, choose a proper module index for it, and allow it in BaseFilter. Ensure every extrinsic works from front-end. If there's corresponding tool, ensure both work for each other.
• If needed, update our Javascript/Typescript APIs. These APIs are officially used by exchanges or community developers.
• If modifying existing runtime storage items, make sure to implement storage migrations for the runtime and test them with try-runtime. This includes migrations inherited from upstream changes, and you can search the diffs for modifications of #[pallet::storage] items to check for any.

[github-actions]

⚠️ Congestion test: 1-day congestion cost (manta-runtime) is NOT above target_daily_congestion_cost_kma

[github-actions]

⚠️ Congestion test: 1-day congestion cost (calamari-runtime) is NOT above target_daily_congestion_cost_kma

[ferrell-code]

Could reaping the dex account cause any other problems? I'd have to dive deeper but I feel like then the state of the dex could not match the account balance of dex account.

Maybe we could just send ed of manta, or create allowlist for non-reapable accounts

[Apokalip]

Could reaping the dex account cause any other problems? I'd have to dive deeper but I feel like then the state of the dex could not match the account balance of dex account.

Maybe we could just send ed of manta, or create allowlist for non-reapable accounts

How big would that list grow to be? 🤔

[ghzlatarev]

Can we have a real description please what problem this is solving and how exactly.

[ghzlatarev]

Could reaping the dex account cause any other problems? I'd have to dive deeper but I feel like then the state of the dex could not match the account balance of dex account.

Maybe we could just send ed of manta, or create allowlist for non-reapable accounts

what is the concrete scenario you're worried about ?

[Dengjianping]

Does zenlink team know this issue or have they fixed it already in later release?

[zqhxuyuan]

Does zenlink team know this issue or have they fixed it already in later release?

yes, I've told them this issue. We may consider add some integration test into our chain. As zenlink's testcase is using tokens module not pallet_assets.

[zqhxuyuan]

Can we have a real description please what problem this is solving and how exactly.

add more info in the description.