FF returns `FF22062: Negative numeric value...` for large numeric input parameters

[matthew1001]

When passing a JSON payload that contains parameters to FireFly (e.g. to deploy a contract that has constructor parameters) evmconnect returns FF22062: Negative numeric value is invalid for component %!!(MISSING)s(uint16=256)%!!(MISSING)(EXTRA string=[0]) if the numeric parameter exceeds the maximum size of a float64.

This appears to be because Golang deserialises large JSON numbers to float64 when deserialising to an interface{}, and silently loses any precision caused by the JSON number exceeding the maximum representable value of a float64.

[matthew1001]

I've done most of the work to fix this under https://github.com/hyperledger/firefly-common/pull/147 and https://github.com/hyperledger/firefly-signer/pull/76. PRs for other repos such as firefly-evmconnect and firefly-transaction-manager will be needed to pull in the updated firefly-common and firefly-signer packages.

[EnriqueL8]

Thanks for the work and context on this one @matthew1001!

This fix is important for all consumers of FireFly and I think warrants a new patch release to v1.3.2.

Things that I would love to be figure out as part of this work for v1.3.2

• [ ] Verify that the generate OpenAPI contract interface enforces/recommends strings for all integers on /invoke and /query calls
• [ ] Upgrade FireFly core to the latest firefly-common and verify in all the places where this fix might apply
  • The first place I would look at would be the /contract/invoke api flow
• [ ] Verify that this fix also works for contract listeners, so emitting an event with
• [ ] This issue has look quiet closely at the EVM path, but we also have Fabric and Tezos (fyi @denisandreenko ) to look at
• [ ] Look at the Javascript based tools in FireFly that might have the same issue
  • The node sdk when invoking APIs...
  • The Sandbox UI
  • DataExchange... try sending a message with a large number in the data payload...
• [ ] FireFly CLI has a deploy command where you can specify constructor parameters this might have the same problem and will need updating to the latest FireFly Common as well
• [ ] Documentation to explain to users that the safest way to pass large numbers into the system is to keep them as strings