Change sdk.Msg.GetSigners() return type to []string

[aaronc]

sdk.Msg.GetSigners() currently returns []sdk.AccAddress which depends on global bech32 prefixes. Changing the return type to []string was already mentioned in #9011. This seems like low-hanging fruit and a pathway to #7448 (removing global bech32 prefixes).

[aaronc]

In the last architecture call we agreed to do this.

One note is that we want to make sure we are validating signers in CLI calls where we now call ValidateBasic to do that. I propose a ValidateMsg function to use in those places:

func ValidateMsg(msg sdk.Msg) error {
  err := msg.ValidateBasic()
  if err != nil {
   return err
  }
 
  signers := msg.GetSigners()
  for signer := range signers {
    _, err = sdk.AccAddressFromBech32(signer)
    if err != nil {
      return err
    }
  }
}

[amaury1093]

One note is that we want to make sure we are validating signers in CLI calls where we now call ValidateBasic to do that. I propose a ValidateMsg function to use in those places:

Is ValidateMsg only for CLI? How about validation for grpc and rest calls? I would prefer an audit of all ValidateBasics to make sure they validate all their bech32 addresses.

Edit: proposing to put ValidateMsg in the antehandlers: #9418 (comment)

[robert-zaremba]

Removing "DO NOT MERGE" flag - master is already in the v0.44 cycle.