Remove `reqSigs` from output of decoderawtransaction and other RPCs #20102

IRC logs

sanket1729: How can decoderawtransaction RPC know reqSigs if the output scriptpubkey is p2sh/p2wsh? I think it is returning 1 everytime. sipa: sanket1729: it only works for bare multisig sipa: we should probably just remove it

The output parameter for reqSigs is confusing as it outputs 1 for all scripts but bare multisig in the scriptpubkey. Considering the limited applicability of reqSigs and (slightly) confusing output(1) in almost all cases, I think it is best if we remove it.

I don't have the bandwidth to tackle this, so opening up the issue for book-keeping. I also think this is a good first issue for new contributors if there are no concept NACKs.

Affected RPCs:

• gettxout

• decodescript

• decoderawtransaction

• getrawtransaction

Another option to removing it would be to only have it present when a bare multisig is found

Another option to removing it would be to only have it present when a bare multisig is found

meh, nobody care about bare multisig anymore anyway

Ok, made it a "good first issue" to remove.

Useful skills:

• Bitcoin Script
• Bitcoin Core RPC server

Want to work on this issue?

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I can work on this. Removing L1107 https://github.com/bitcoin/bitcoin/blob/dde104963b3ba2e24bb3b383351ddcbef52a0240/src/rpc/blockchain.cpp#L1107 should fix gettxout I guess or maybe need to make more changes.

Was looking at this PR for reference: https://github.com/bitcoin/bitcoin/pull/19646

Agreed, nobody uses bare multi-sig. We should probably remove it.

Hi @prayank23, here is a possible workflow that I would use.

• You can start by looking at all the RPCs listed in the remove the reqSigs field from that.
• You can also grep for reqSigs in the root directory to find all occurrences.
• Try to run unit tests and let the failures guide you where things need to the fixed/removed.
• My suspicion is that we can also remove the code that has the bare multisig logic that computes this field.
• You may also need to run python functional tests (see test/functional) to check if there are tests that are broken because of this.
• Since this field is being removed, try to find comments around the code are removing and remove those too.

@sanket1729 I made changes in https://github.com/prayank23/bitcoin/commit/33d3757688b5269a1d033aea8aae7e358141dc4d

But getting errors while running the command make check because tests are failing even though I removed reqSigs from json files used for testing except txcreatemultisig1.json (wasn't sure about it):

<pre> ERROR - Output formatting mismatch 2020-10-10 22:15:17,871 - ERROR - FAILED_TESTCASES: ['Deletes a single input from a transaction (output in json)', 'Deletes a single output from a transaction (output in json)', 'Adds an nlocktime to a transaction (output in json)', 'Creates a new transaction with three inputs and two outputs (output in json)', 'Create a new transaction with a single output script (OP_DROP) in a P2SH (output as json)', 'Create a new transaction with a single output script (OP_DROP) in a P2WSH (output as json)', 'Create a new transaction with a single output script (OP_DROP) in a P2SH, wrapped in a P2SH (output as json)', 'Creates a new v1 transaction with a single input and a single output, and then signs the transaction (output in json)', 'Creates a new transaction with a single pay-to-witness-pubkey output (output as json)', 'Creates a new transaction with a single pay-to-pub-key output, wrapped in P2SH (output as json)', 'Creates a new v1 transaction with one input, one address output and one data output (output in json)', 'Creates a new transaction with one input, one address output and one data (zero value) output (output in json)', 'Creates a new transaction with one input with sequence number and one address output (output in json)', 'Adds a new input with sequence number to a transaction (output in json)', 'Creates a new transaction with a single 2-of-3 multisig output (output in json)', 'Creates a new transaction with a single 2-of-3 multisig in a P2SH output (output in json)', 'Creates a new transaction with a single 2-of-3 multisig in a P2WSH output (output in json)', 'Creates a new transaction with a single 2-of-3 multisig in a P2WSH output, wrapped in P2SH (output in json)', 'Uncompressed pubkeys should work just fine for non-witness outputs'] </pre>

Hello, does this issue still require work to be done on it?

It is being worked on in #20286.