BIP 119: CHECKTEMPLATEVERIFY

[JeremyRubin]

I believe now is an appropriate time to apply for a BIP number/Draft Status for OP_CTV. A few elements will require updating before the BIP moves out of draft (e.g., the activation dates) but activation dates are a separate discussion from the technical considerations which are the focus of this BIP.

[JeremyRubin]

BTW I looked into the travis error -- it seems that the linter is reading a code block and failing because a C++ lambda looks like a improperly formatted markdown link.

I am happy to add a revert-able patch as below:

bool filter(const CTxIn& c) {
    return c.scriptSig != CScript();
}
uint256 GetStandardTemplateHash(const CTransaction& tx, const uint256& outputs_hash, const uint256& sequences_hash,
                                    const uint32_t input_index) {
        bool skip_scriptSigs = std::find_if(tx.vin.begin(), tx.vin.end(), filter) == tx.vin.end();
        return skip_scriptSigs ? GetStandardTemplateHashEmptyScript(tx, outputs_hash, sequences_hash, input_index) :
            GetStandardTemplateHashWithScript(tx, outputs_hash, sequences_hash, GetScriptSigsSHA256(tx), input_index);
    }

so that you don't have to muck around with a broken linter/supressions, but I think it's better to fix the linter longer term.

[luke-jr]

@JeremyRubin This is missing a backwards compatibility section.

@kallewoof Can you look into a better fix for the linter issue?

[kallewoof]

Looking.

[JeremyRubin]

@luke-jr it was unclear to me that a backwards compatibility section was needed for this BIP, referencing BIP-65 and BIP-112 as examples. Neither covers the OP_NOP reinterpretation as being an incompatibility.

Regardless, I can push a section noting that there are no Backwards Incompatibilities.

[JeremyRubin]

• BIP 65 -- CLTV/CSV.

[JeremyRubin]

Added a backwards compatibility section; and rebased to pick up the linter fixes.

[luke-jr]

Use BIP 119

[JeremyRubin]

Thanks Luke! I've set the number & fixed links.