feat: Cancel unbonding delegation entry

[gsk967]

Description

Closes: #577

This pull request contains Canceling unbonding delegation entry and delegate back to previous validator

Msg Service

package cosmos.staking.v1beta1;

service Msg {
    // CancelUnbondingDelegation
    rpc CancelUnbondingDelegation(MsgCancelUnbondingDelegation) returns (MsgCancelUnbondingDelegationResponse);
}

// MsgCancelUnbondingDelegation
message MsgCancelUnbondingDelegation {
  option (gogoproto.equal)           = false;
  option (gogoproto.goproto_getters) = false;

  string                   delegator_address = 1 [(cosmos_proto.scalar) = "cosmos.AddressString"];
  string                   validator_address = 2 [(cosmos_proto.scalar) = "cosmos.AddressString"];
  cosmos.base.v1beta1.Coin amount            = 3 [(gogoproto.nullable) = false];
  // creation_height is the height which the unbonding took place.
  int64 creation_height = 4;
}

// MsgCancelUnbondingDelegationResponse
message MsgCancelUnbondingDelegationResponse{
}

Msg Method Implementation

func (k msgServer) CancelUnbondingDelegation(goCtx context.Context, msg *types.MsgCancelUnbondingDelegation) (*types.MsgCancelUnbondingDelegationResponse, error) {
    /*
    // checking the unbonding delegation at creation_height 
         // get the unbonding delegations of delegatorAddress 
        if ubdEntry balance is equal to msg.Amount 
            remove the entry from ubd  
        else 
            update the specific entry with new balance
                
        if len(ubd.Entries) == 0 {
            k.RemoveUnbondingDelegation(ctx, ubd)
        } else {
            k.SetUnbondingDelegation(ctx, ubd)
        }
    */
    

    // update the delegation back to validator 
    // get validator
        validator, found := k.GetValidator(ctx, valAddr)
        if !found {
            return nil, types.ErrNoValidatorFound
        }

        // delegate the unbonding amount to validator back
        _, err = k.Keeper.Delegate(ctx, delegatorAddress, msg.Amount.Amount, types.Unbonding, validator, false)
        if err != nil {
            return nil, err
        }
    
    
        _, err := ms.Keeper.CancelUnbondingDelegation(ctx,delegatorAddress,validatorAddress,amount,creation_height)
        if err != nil {
            return nil, err 
        }


        return &types.MsgCancelUnbondingDelegationResponse{}, nil
}

cli tx Method

simd tx staking cancel-unbond [validator-address] [amount] [creation_height] --from [user] --chain-id [chain-id]
Example: 
simd tx staking cancel-unbond cosmosvaloper1mqtyv4qux68r26mql2hjhgrvz72snjwpulq22m 100000stake 10280 --from test1 --chain-id test-chain

---

Author Checklist

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• included the necessary unit and integration tests
• added a changelog entry to CHANGELOG.md
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• confirmed the correct type prefix in the PR title
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• reviewed state machine logic
• reviewed API design and naming
• reviewed documentation is accurate
• reviewed tests and test coverage
• manually tested (if applicable)

[amaury1093]

I'm not super familiar with this part of the code, so can't think of edge cases, but overall it lgtm

[robert-zaremba]

For general information: we are planning to backport this PR to 0.46

[anilcse]

thanks @gsk967
Minor suggestions. otherwise lgtm.

For future scope, we might need to consider removing CreationHeight input from user or make it optional for improved UX

[atheeshp]

lgtm, great work @gsk967 👏

[amaury1093]

This has 4 approvals. @gsk967 could you address the last 2-3 small formatting/comment nits by Anil, and we can put automerge on?

[gsk967]

This has 4 approvals. @gsk967 could you address the last 2-3 small formatting/comment nits by Anil, and we can put automerge on?

done @AmauryM