CircleCI build should fail if parameters.json manifest is out of date or if files referenced in manifest aren't fetchable from IPFS

[porcuquine]

Description

Create a way to verify that all required groth parameters have been published, and add it as a CI check.

In order to ensure the checked parameters correspond exactly to those which would be generated by paramcache, it probably makes sense to extend that utility with a --check option.

This would:

• Determine the names of the parameters which would be generated by paramcache.
• Check to ensure that these are the parameters specified in parameters.json.
• If so, verify that each parameter's Cid is fetchable via IPFS.
• If any of these checks fail, exit with non-zero exit code.

NOTE: this assumes that if a Cid for a parameters file exists in IPFS, then it does indeed correspond to the generated parameters. If we cannot make this assumption, we have to run paramcache again to generate the real parameters, which is impractical as a check.

Once implemented, add a CI job which runs the check and fails the job if all required parameters have not been published.

Acceptance criteria

CI fails when parameters.json is not up-to-date or contains references to Cids which cannot be fetch from IPFS.

Risks + pitfalls

Where to begin

[vmx]

This was most useful pre mainnet. But now the parameters won't change that often. Hence I dare to close that issue as "won't fix".