EIP: Coinbase Calls (#2474)

Allow contracts to be called directly by block.coinbase (block validator), without a transaction.

EIPS/eip-2474.md

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+---
+eip: 2474
+title: Coinbase calls
+author: Ricardo Guilherme Schmidt (@3esmit)
+discussions-to: https://ethresear.ch/t/gas-abstraction-non-signed-block-validator-only-procedures/4388/2
+status: Draft
+type: Standards Track
+category: Core
+created: 2020-01-19
+---
+
+## Simple Summary
+
+Allow contracts to be called directly by `block.coinbase` (block validator), without a transaction.
+
+## Abstract
+
+_In proof-of-work blockchains, validators are known as miners._
+
+The validator might want to execute functions directly, without having to sign a transaction. Some examples might be presenting a proof in a contract for an change which also benefits the validator. 
+
+A notable example would be when a validator want to act as an [EIP-1077](./eip-1077.md) Gas Relayer, incentivized to pick up fees from meta transactions.
+Without this change, they can do so by signing from any address a `gasPrice = 0` transaction with the gas relayed call. 
+However this brings an overhead of a signed transaction by validator that does nothing, as `msg.sender` is never used, and there is no gas cost to EVM charge. 
+
+This proposal makes possible to remove this unused ecrecover.
+
+## Motivation
+
+In order to reduce the overhead of calls that don't use `msg.sender` and are being called by validator with `tx.gasPrice = 0`. 
+
+## Specification
+
+The calls to be executed by `block.coinbase` would be included first at block, and would consume normally the gas of block, however they won't pay/cost gas, instead the call logic would pay the validator in other form. 
+
+Would be valid to execute any calls without a transaction by the block coinbase, except when the validator call tries to read `msg.sender`, which would throw an invalid jump.
+
+Calls included by the validator would have `tx.origin = block.coinbase` and `gas.price = 0` for the rest of call stack, the rest follows as normal calls.
+
+## Rationale
+
+TBD
+
+## Backwards Compatibility
+
+`tx.origin = block.coinbase` could cause some issues on bad designed contracts, such as using `tx.origin` to validate a signature, an analysis on how contracts use tx.origin might be useful to decide if this is a good choice.
+
+## Test Cases
+
+TBD
+
+## Implementation
+
+TBD
+
+## Security Considerations
+
+TBD
+
+## Copyright
+
+Copyright and related rights waived via [CC0](https://creativecommons.org/publicdomain/zero/1.0/).