SIP-033: Clarity 4: high-demand new builtins

[obycode]

The Clarity smart contract language powers decentralized applications across a
wide range of domains. Over years of real-world use, developers have encountered
several pain points when interacting with other, sometimes untrusted, contracts.
Securely calling unknown contracts unlocks powerful use cases, but demands
careful safeguards.

This SIP addresses common feedback and requests from builders in the ecosystem.
It proposes new Clarity features to make it easier for developers to write
secure and composable smart contracts. Specifically, it proposes:

1. A new Clarity function to fetch the hash of a contract's code body. This
   enables on-chain contract code validation, for example allowing contract A to
   validate that contract B follows a specific template and is therefore safe to
   interact with. This is especially useful for enabling bridges and
   marketplaces to safely and trustlessly support a dynamic set of assets.
2. A new set of Clarity functions to allow a contract to set post-conditions
   to protect its assets. These allow a contract to safely call arbitrary
   external contracts (e.g. passed in as traits) while ensuring that if the
   executed code moves assets beyond those specified, the changes will be rolled
   back.
3. A new Clarity function to convert simple values into string-ascii
   values. This function will enable developers to easily convert values like
   bools and principals into their ASCII string representations,
   facilitating the generation of string-based messages for interacting with
   cross-chain protocols.

Note

Additional feature added 👇

4. A new Clarity keyword to get the timestamp of the current block. This
   keyword will allow developers to easily access the timestamp of the block
   currently being processed, enabling time-based logic and features in their
   smart contracts. This is especially important for DeFi applications.

[Rapha-btc]

Thank you for adding secp256r1 support to SIP-033. This allows Stacks developers to build applications with native passkey integration, unlocking use cases like 2FA for VCs in multisig setups, embedded mints on X with Touch ID purchases, and instant wallet creation with Face ID in seconds. All secured by the user's device secure enclave without third parties.

[wileyj]

@obycode now that sip number is assigned, can you rename the folder to sip-033 from sip-clarity4 ?

[obycode]

@obycode now that sip number is assigned, can you rename the folder to sip-033 from sip-clarity4 ?

Done ✅

[Rapha-btc]

I'm looking for examples of contract-hash? usage to verify DEX templates before they can self-register for token transfers. This would enforce royalties when users sell tokens to DEX contracts by creating an auto-allowlist of compliant exchanges that implement a required royalty-collecting function. My first implementation is at https://github.com/Rapha-btc/pizza-square/blob/main/contracts/pizza-faktory.clar copy @obycode

[314159265359879]

This is looking great to me. I am hereby signing-off on SIP033.

I see one open comment, I would like to see addressed but I consider that non-blocking for this editor sign-off.

[mphizi]

Hi @obycode, did the proposal for type-aliases (clarity-lang/reference#6) especially for tuples and list definitions get into this SIP or SIP-034?

I think this would really great ergonomic improvement. Thanks for all the great work taking place in the ecosystem!

[obycode]

Hi @obycode, did the proposal for type-aliases (clarity-lang/reference#6) especially for tuples and list definitions get into this SIP or SIP-034?

Hi @mphizi. Thanks for the input. No, this set of changes described here is all that is included in Clarity 4, but that one is definitely still on the list to include in a future version.