VIP: add revert_on_failure= kwarg to all external calls

[charles-cooper]

Simple Summary

as title

Motivation

catching external call reversion currently requires using raw_call(), but it would be nice not to have to drop down to that.

Specification

add revert_on_failure to all external calls. if it is set to False, the external call returns a tuple of (success, return_value). for instance:

interface Bar:
    def return_something() -> address: nonpayable

def foo(bar: Bar) -> address:
    success: bool = False
    ret: address = empty(address)
    success, ret = bar.return_something(revert_on_failure=False)
    if success:
        return ret
    return empty(address)

Backwards Compatibility

no backwards compatibility issues

Copyright

Copyright and related rights waived via CC0

[charles-cooper]

meeting notes: approved