Migrate purity checker to vyper LLL

[djrtwo]

Issue

Purity checker is currently written in the deprecated Serpent. We need to make updates to it but should stop relying on Serpent compiler

Proposed implementation

• Migrate current purity checker from serpent to vyper LLL
• Port contract to this repo
• Add sanity check testing to pytest build
• Compile Purity Checker from source instead of using bytecode in the testing setup

Example Vyper LLL and compile techniques here https://github.com/ethereum/casper/blob/master/tests/utils/valcodes.py

[djrtwo]

This should be handled before #66

[djrtwo]

@ralexstokes might be picking this one up

[ChihChengLiang]

These are some test cases rewritten in vyper.

# when submitted to purity checker, these should return True
success_cases = [
    """
    @public
    def foo(x:int128) -> int128:
        return x * 2
    """,
    """
    @public
    def phooey(h:bytes32, v:uint256, r:uint256, s:uint256) -> address:
        return ecrecover(h, v, r, s)
    """
]
# when submitted to purity checker, these should return False
failed_cases = [
    """
    horse: int128

    @public
    def foo() -> int128:
        return self.horse
    """,
    """
    @public
    def foo() -> int128:
        return block.number
    """
]

[gitcoinbot]

Issue Status: 1. Open 2. Started 3. Submitted 4. Done

---

This issue now has a funding of 110.0 DAI (110.0 USD @ $1.0/DAI) attached to it.

• If you would like to work on this issue you can 'start work' on the Gitcoin Issue Details page.
• Questions? Checkout Gitcoin Help or the Gitcoin Slack
• $8,116.90 more funded OSS Work available on the Gitcoin Issue Explorer

[gitcoinbot]

Issue Status: 1. Open 2. Started 3. Submitted 4. Done

---

Work has been started.

1. @ralexstokes

has committed to working on this project to be completed 5 months, 4 weeks from now.

[gitcoinbot]

Issue Status: 1. Open 2. Started 3. Submitted 4. Done

---

Work has been started.

These users each claimed they can complete the work by 4 months, 1 week from now. Please review their questions below:

1. ralexstokes has started work.

[gitcoinbot]

@ralexstokes Hello from Gitcoin Core - are you still working on this issue? Please submit a WIP PR or comment back within the next 3 days or you will be removed from this ticket and it will be returned to an ‘Open’ status. Please let us know if you have questions!

• warning (3 days)
• escalation to mods (6 days)

Funders only: Snooze warnings for 1 day | 3 days | 5 days | 10 days | 100 days

[gitcoinbot]

@ralexstokes Hello from Gitcoin Core - are you still working on this issue? Please submit a WIP PR or comment back within the next 3 days or you will be removed from this ticket and it will be returned to an ‘Open’ status. Please let us know if you have questions!

• warning (3 days)
• escalation to mods (6 days)

Funders only: Snooze warnings for 1 day | 3 days | 5 days | 10 days | 100 days

[ralexstokes]

@gitcoinbot refer #143

[gitcoinbot]

@ralexstokes. 👋 thanks for the atMention, but you need to install @gitcoinbot on this repo for me to be able to respond. More details in the documentation.

✌️
@gitcoinbot

[gitcoinbot]

@ralexstokes Hello from Gitcoin Core - are you still working on this issue? Please submit a WIP PR or comment back within the next 3 days or you will be removed from this ticket and it will be returned to an ‘Open’ status. Please let us know if you have questions!

• warning (3 days)
• escalation to mods (6 days)

Funders only: Snooze warnings for 1 day | 3 days | 5 days | 10 days | 100 days

[ralexstokes]

Leaving a note that we should make sure that external accounts are impure.

Edit: this is handled and there are tests covering this functionality.

[vs77bb]

Snoozed the Gitcoin Bot warnings, @ralexstokes. Thanks for the responses 😄

[djrtwo]

This is complete. How do we pay out @ralexstokes?

[vs77bb]

@djrtwo Expect payout in the next day or two. Great work @ralexstokes!

[vs77bb]

@ralexstokes Can you click 'Submit Work' on Gitcoin here?

If you need a bit of mainnet ETH, let me know on Gitcoin Slack or try the Gitcoin Faucet and we'll get some your way 🙂

[gitcoinbot]

Issue Status: 1. Open 2. Started 3. Submitted 4. Done

---

Work for 300.0 DAI (300.0 USD @ $1.0/DAI) has been submitted by:

1. @ralexstokes

@gdipri01 please take a look at the submitted work:

• PR by @ralexstokes

---

• Learn more on the Gitcoin Issue Details page
• Questions? Checkout Gitcoin Help or the Gitcoin Slack
  $27,030.74 more funded OSS Work available on the Gitcoin Issue Explorer

[gitcoinbot]

Issue Status: 1. Open 2. Started 3. Submitted 4. Done

---

The funding of 300.0 DAI (300.0 USD @ $1.0/DAI) attached to this issue has been approved & issued to @ralexstokes.

• Learn more at on the Gitcoin Issue Details page
• Questions? Checkout Gitcoin Help or the Gitcoin Slack
• $28,368.23 more funded OSS Work available on the Gitcoin Issue Explorer