feat[ux]: allow "compiling" .vyi files

[sandbubbles]

What I did

fix #4232

How I did it

How to verify it

Commit message

This commit allows "compiling" `.vyi` files with ast, annotated_ast,
interface, external_interface and abi output formats. Even though they
don't produce bytecode, the above output formats can still be useful
for users and tooling (even just to validate a `.vyi` file).

Description for the changelog

Cute Animal Picture

[charles-cooper]

looking good to me. @cyberthirst can you take a look?

[cyberthirst]

bit unrelated, but if an interface implements other interface and doesn't implement all the methods, we get the following exception:

vyper.exceptions.InterfaceViolation: Contract does not implement all interface functions: foobar()

Contract does not implement.. although it can be triggered via eg vyper -f abi i.vyi

[cyberthirst]

-f interface doesn't include Flags. is it intended?

[charles-cooper]

-f interface doesn't include Flags. is it intended?

Not intended. May be the order in which we merged flag and -f interfave PRs

[cyberthirst]

shouldn't -f interface be basically an identity when called on interface files?

import ITest2

implements: ITest2

def bar() -> uint256:
    ...

def foo() -> uint8:
    ...


def foobar() -> uint8:
    ...

outputs:

# Functions

@external
def bar() -> uint256:
    ...


@external
def foo() -> uint8:
    ...


@external
def foobar() -> uint8:
    ...

ie implements is lost in the translation

[cyberthirst]

shouldn't -f interface be basically an identity when called on interface files?

import ITest2

implements: ITest2

def bar() -> uint256:
    ...

def foo() -> uint8:
    ...


def foobar() -> uint8:
    ...

outputs:

# Functions

@external
def bar() -> uint256:
    ...


@external
def foo() -> uint8:
    ...


@external
def foobar() -> uint8:
    ...

ie implements is lost in the translation

also, if ITest2.vyi contains a struct (or flag), then those don't propagate for -f interface - not sure whether that's intentional

[cyberthirst]

would it make sense to use this here? https://github.com/vyperlang/vyper/pull/4290/files#diff-d428d4c971c9f7166899f6f2d3da5e17ca4478d8d371d803e735d6ee36b39d30R49

so we don't have to maintain the list on 2 places

[cyberthirst]

 vyper -f external_interface tests/custom/ITest.vyi

# External Interfaces
interface Itest:
    def bar() -> uint256: nonpayable
    def foo() -> uint8: nonpayable
    def foobar() -> uint8: nonpayable

name discrepancy - Itest vs ITest

[cyberthirst]

what about _.vyi

[charles-cooper]

maybe we should also check that the output compiles again (similar to a round trip)

[sandbubbles]

I've added that check for primitive types, for external interface it does not work with user defined ones.

[cyberthirst]

let's please link: #4290 (comment)