Sort metadata keys for no-schema json for canonical CBOR

[carbolymer]

Changelog

- description: |
    Sort metadata keys for no-schema json for canonical CBOR
# uncomment types applicable to the change:
  type:
  # - feature        # introduces a new feature
   - breaking       # the API has changed in a breaking way
  # - compatible     # the API has changed but is non-breaking
  # - optimisation   # measurable performance improvements
  # - improvement    # QoL changes e.g. refactoring
   - bugfix         # fixes a defect
  # - test           # fixes/modifies tests
  # - maintenance    # not directly related to the code
  # - release        # related to a new release preparation
  # - documentation  # change in code docs, haddocks...

Context

This PR changes sorting for --json-metadata-no-schema JSON to canonical CBOR. It changes transaction file output CBOR representation (reorders metadata keys for this case), so it's marked as a breaking change.

Note that there's always --json-metadata-schema JSON format available which allows to specify metadata keys ordering. See example.

Fixes IntersectMBO/cardano-node#4335

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• New tests are added if needed and existing tests are updated. See Running tests for more details
• Self-reviewed the diff

[carbolymer]

The JSON map was previously sorted lexicographically by keys and then it was processed down the line as a list of pairs until it got serialised to CBOR. So this place was deciding about the sorting order of the object fields' names.

[Jimbo4350]

So this will work but I think a more robust solution would be to do something similar to HashableScriptData. We should serialize the metadata to CBOR once and carry around the canonical representation. I think this distinction is useful for the reader.

[carbolymer]

I see. This would complicate things a bit because here we're converting here our type:

cardano-api/cardano-api/internal/Cardano/Api/TxMetadata.hs

Line 135 in 03de67a

. toShelleyMetadata

to ledger type (isomorphic to ours): https://github.com/IntersectMBO/cardano-ledger/blob/dbce4e4a3ad508b2bfd2df897b617c19b7f049de/eras/shelley/impl/src/Cardano/Ledger/Shelley/TxAuxData.hs#L95
So I guess I'd have to modify SerialiseAsCBOR to handle different metadata types 🤔

[Jimbo4350]

It would look like HashableScriptData's SerialiseAsCBOR instance:

instance SerialiseAsCBOR HashableScriptData where
    serialiseToCBOR (HashableScriptData origBytes _) = origBytes

Upon constructing "HashableTxMetaData" you would already have the CBOR of the metadata.

[smelc]

Great work ❤️

[smelc]

Suggested change

	-> ByteString -- ^ json string to test
	-> TxMetadata -- ^ expected metadata
	-> ByteString -- ^ Json string to test
	-> TxMetadata -- ^ Expected metadata