improve(cross-chain-oracle): [L04] Stamp ancillary data in hasPrice and getPrice

[nicholaspai]

Motivation

I believe we should stamp ancillary data in these public methods. I originally removed this stamping logic in this PR because the previous stampAncillaryData implementation stamped the msg.sender address, which means that only the original requester could call has/getPrice, but now that we removed it we can add stamping for the caller’s convenience.

This improves the caller's experience as they only need to pass the original ancillary data that was passed into requestPrice.

This PR is possible because stampAncillaryData now only stamps the block.chainId which is not affected by who the msg.sender is.

Testing

Check a box to describe how you tested these changes and list the steps for reviewers to test.

• Ran end-to-end test, running the code as in production
• New unit tests created
• Existing tests adequate, no new tests required
• All existing tests pass
• Untested

[chrismaree]

This is interesting. it definitely makes interacting with the spoke directly easier. importantly, the stamping only includes the chainId so this is forward compatible with upgrades to the spoke, keeping previous requests still functional.

also, this change now makes the has/get price methods consistent with the inputs you would put into requestPrice. previously you would put in one ancillary data, which would then be stamped and would need separate ancillary data when fetching data from the contracts. this would have made implementation integrating with this contract more difficult as they would need to pre-stamp their ancillary data when calling hasPrice and getPrice

[nicholaspai]

This is interesting. it definitely makes interacting with the spoke directly easier. importantly, the stamping only includes the chainId so this is forward compatible with upgrades to the spoke, keeping previous requests still functional.

also, this change now makes the has/get price methods consistent with the inputs you would put into requestPrice. previously you would put in one ancillary data, which would then be stamped and would need separate ancillary data when fetching data from the contracts. this would have made implementation integrating with this contract more difficult as they would need to pre-stamp their ancillary data when calling hasPrice and getPrice

Totally agreed. We originally removed the stamping in the previous PR because the stamping logic added msg.sender, but then we also removed the msg.sender from the stamping logic. I rate it an oversight that we forgot to re-add stamping in has/getPrice