fix: fix opchecksig bug

[dlaciport]

• fixes [bug] [bitcoin-core test] ScriptSig: '0x27 0x3024021077777777777777777777777777777777020a7777777777777777777777777777777701' -- ScriptPubKey: '0 CHECKSIG NOT' #211
• fixes [bug] [bitcoin-core test] ScriptSig: '0x27 0x302402107777777777777777777777777777777702108777777777777777777777777777777701' -- ScriptPubKey: '0 CHECKSIG NOT' #212
• follows contribution guide
• code change includes tests

[vercel]

@bloomingpeach is attempting to deploy a commit to the keep-starknet-strange Team on Vercel.

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[b-j-roberts]

Hey, were you able to track down which line was giving the index out-of-bounds error? I'm curious where it was failing

[dlaciport]

it fails here: https://github.com/keep-starknet-strange/shinigami/blob/main/packages/engine/src/signature/signature.cairo#L298

By the way I think it is not supposed to go that far with an empty pubkey, https://github.com/keep-starknet-strange/shinigami/blob/main/packages/engine/src/signature/signature.cairo#L252 I think we should at least have a check for empty pubkey before or inside this function.

[b-j-roberts]

I see, thanks for the info! I think how you did it is a good solution.

However, I think we should also add a check here for if the pk_bytes.len != 65 and return an error, since uncompressed pub keys should always be of length 65 I think.

Would need to make parse_pub_key return an error too.

[dlaciport]

Would you like me to include the check in this PR or should it be in another PR? @b-j-roberts

[b-j-roberts]

Would you like me to include the check in this PR or should it be in another PR? @b-j-roberts

In this PR if you can, thanks

[dlaciport]

@b-j-roberts please review sir

[b-j-roberts]

Sorry for taking forever to get to this, thank you! And great work as always.