Change the structure of input configuration

[adithyaov]

The new config is of the form:

# Example of the starting point:
# start:
#   tag: ChainPoint
#   slot: 11617
#   blockHash: 9b65597bb73e21d5b58a1f5958f8b95324b142727efb2746c577998e93df3463

scripts:
  # The target script hash that we want to re-run locally.
  # In this example it's just a random hash, so please replace with your own.
  - script_hash: "22734734b6b0410cf4a0e3bd731fb98c55ac2b2a27b1eecb8d3b438c"
    # List of substitution scripts we want to run on wherever the target script
    # is found.
    substitutions:
      - # Name of the substitution script for easier identification (optional)
        name: "Local Policy"
        # The hash of the substitution script. The plutus-script-reexecutor will
        # check and fail if the hash does not match.
        #
        # Tip: Leave this as an empty string and let plutus-script-reexecutor
        # error out with the expected script hash.
        hash: "6bfbd8fc6567153cbaacdcd0ee9fff9e69ba2a0eb62c129b303ade19"
        source:
          # The source of the substitution script. This can either be a
          # "file_path" or a "cbor_hex".
          cbor_hex: "4e4d01000033222220051200120011"
          # file_path: "local-config/policy-debug.plutus"

[axman6]

Looks good to me, other than making the name required I think this is good to go.

[tweag-ev-ak]

Our discussion summary:

1. the script name for each substitution stays optional
2. we should store the actual script hash and make the actual_script_hash mandatory in the configuration map
3. add validation of the config map and provide calculated script hashes as feedback, fail if not provided (very UX friendly) or incorrect
4. add the optional script name for the target_script_hash

[axman6]

Looks good, a few minor things before it's ready.

[tweag-ev-ak]

LGTM 👍

[tweag-ev-ak]

I personally prefer explicit instances in API and configuration files, since if we omit one field we can break the "contract" established with the user.

[adithyaov]

True, and so we should not omit fields and be careful when updating the fields ensuring backwards compatibility.
That said, having an explicit deserialisation gives us more control but it's too verbose.

Is there a way to have explicit deserialisation that is less verbose?
Something like,

$(deriveJSONSimpleSum ''ScriptSource [ 'SCborHex ~ "cbor", 'SFilePath ~ "file" ])

An interface like this, with explicit options, should be possible.
Opening an issue so we can think more about it: #140

[axman6]

LGTM