Cosmos-sdk: Add slashing for signing an invalid block.

[ValarDragon]

We currently aren't slashing for evidence being brought forward of a validator signing an invalid block. This should be a slashable condition. Otherwise a validator didn't do their job of validating the state transition being sent through the network.

[jackzampolin]

Is this still an issue? What needs to be done to move this out of proposal and into proposal-accepted?

[ValarDragon]

This is still an issue. Moving this from proposal to proposal-accepted is just someone else agreeing, and there not being disagreement.

[jackzampolin]

I agree for one!

[jackzampolin]

Is this something we still want to do cc @rigelrozanski @cwgoes

[alexanderbez]

Yes it is @jackzampolin. We need to at the very least decide on what parameters we need and update the slashing module accordingly to handle when this evidence is submitted. Thing is, does Tendermint currently pass on this evidence @ValarDragon? I don't see the ABCI type defined.

[ValarDragon]

No, this set of evidence needs to be added to both Tendermint and the SDK.

[jackzampolin]

cc @cosmos/all-in-bits

[jackzampolin]

I think this is related to the evidence module work? cc @alexanderbez

[alexanderbez]

yeah. The evidence module could/will handle this. Namely, what is still up for discussion is if Tendermint will record and submit this.