Add check for UnverifiedCovenantError

[dagurval]

While trying to narrow down an issue with items left on the stack, I stumbled on a different issue:

$ ts-node bug.ts 
Contract address: bitcoincash:pzq7x3fpxgus4dcwsyu8mxh6gcttxncf3y2qjakgsu
Contract balance: 20000
contract opcount: undefined
contract bytesize: undefined
{ TfTypeError: Expected property "3" of type UInt32, got Number -1
    at captureStackTrace (/home/dagurval/cashscript/node_modules/typeforce/errors.js:20:11)
    at tfSubError (/home/dagurval/cashscript/node_modules/typeforce/errors.js:99:3)
    at /home/dagurval/cashscript/node_modules/typeforce/index.js:190:17
    at Array.every (<anonymous>)
    at _tuple (/home/dagurval/cashscript/node_modules/typeforce/index.js:186:20)
    at typeforce (/home/dagurval/cashscript/node_modules/typeforce/index.js:233:9)
    at Transaction.sigHashPreimageBufChunks (/home/dagurval/cashscript/node_modules/cramer-bch/src/transaction.js:321:3)
    at Transaction.sigHashPreimageBuf (/home/dagurval/cashscript/node_modules/cramer-bch/src/transaction.js:416:29)
    at inputs.forEach (/home/dagurval/cashscript/examples/node_modules/cashscript/src/Transaction.ts:154:22)
    at Array.forEach (<anonymous>)
  message: 'Expected property "3" of type UInt32, got Number -1',
  __label: undefined,
  __property: 3,
  __type: { [Function: UInt32] toJSON: [Function: bound ] },
  __value: -1,
  __valueTypeName: 'Number' }
transaction details: undefined

Code: dagurval@53ff201

[rkalis]

Thanks for the bug report. Will check it out.

[rkalis]

I found the problem. It's a really stupid bug in the compiler 😅

So when you are using covenant fields (like tx.hashOutputs) you need to "verify" the covenant by including a require(checkSig(..., ...));. The compiler has a traversal to ensure that this is included, otherwise it should throw a UnverifiedCovenantError. The code for this is in place and is properly unit tested. But then I forgot to actually activate the functionality in the compile function. So it doesn't actually check this and compiles even though the contract is invalid. This creates problems down the line because the CashScript SDK expects a correct contract. I will put a fix for this in the next release.

[dagurval]

So it was a user error :-). Thanks for looking into it so quickly. After adding checkSig, I managed to reproduce the issue with stack elements and create an issue for it #57

[rkalis]

This is released in v0.3.2