Charge for decoding JSON

[edmundnoble]

PR checklist:

• [x] Test coverage for the proposed changes
• [x] PR description contains example output from repl interaction or a snippet from unit test output
  • The proposed change results in a change of gas consumption, which is visible in quite a few golden tests.
• [x] Documentation has been updated if new natives or FV properties have been added. To generate new documentation, issue cabal run tests. If they pass locally, docs are generated.
  • No such natives or properties were added.
• [x] Any changes that could be relevant to users have been recorded in the changelog
• [x] In case of changes to the Pact trace output (pact -t), make sure pact-lsp is in sync.
  • I think there are none.

Additionally, please justify why you should or should not do the following:

• [ ] Confirm replay/back compat
  • This has to be done for completeness' sake but there is no reason to think it would fail, because the changes are guarded by the fork flag.
• [ ] Benchmark regressions
  • Not sure what exactly this entails, but I can do it.
• [x] (For Kadena engineers) Run integration-tests against a Chainweb built with this version of Pact
  • CI did this for me for the chainweb-node PR.

[larskuhtz]

Does this PR attach gas costs to operations that haven't been part of public language specification until now?

I wonder whether this makes gas cost dependent on implementation details that are not part of the surface semantics of pact. In particular, does this mean that changing the underlying serialization and storage format would become a forking change?

[jwiegley]

@edmundnoble This PR needs to be rebased, it contains an inverse of the prettyprinter PR, for example.

[edmundnoble]

@jwiegley it's based on the microgas branch, maybe it doesn't have it yet?

@larskuhtz yeah, it's not nice, but write's already gassed this way.

[jwiegley]

@edmundnoble In that case, perhaps the PR merge base should be changed to reflect which branch you're changes are a delta for?

[edmundnoble]

The base is microgas. I think the trouble is I merged master and microgas is still out of date. Once that's fixed I can rebase.

[edmundnoble]

Postponing for now.