Merge #18032: rpc: Output a descriptor in createmultisig and addmultisigaddress

19a354b11f Output a descriptor in createmultisig and addmultisigaddress (Andrew Chow)

Pull request description:

  Give a descriptor from `createmultisig` and `addmultisigaddress`.

  Extracted from #16528 with `addmultisgaddress` and tests added.

ACKs for top commit:
  Sjors:
    tACK 19a354b11f
  MarcoFalke:
    ACK 19a354b11f
  promag:
    Code review ACK 19a354b11f.
  meshcollider:
    utACK 19a354b11f

Tree-SHA512: e813125fbbc358ea8d45b1748de16a29a94efd83175b748fb8fa3b0bfc8e783ed36b6c554d84f5d4ead1ba252a83a3e937b6c3f75da7b8d3b4e55f94d6013771

src/rpc/misc.cpp

@@ -83,6 +83,7 @@ static UniValue createmultisig(const JSONRPCRequest& request)
             "{\n"
             "  \"address\":\"multisigaddress\",  (string) The value of the new multisig address.\n"
             "  \"redeemScript\":\"script\"       (string) The string value of the hex-encoded redemption script.\n"
+            "  \"descriptor\":\"descriptor\"     (string) The descriptor for this multisig\n"
             "}\n"
                 },
                 RPCExamples{
@@ -119,9 +120,13 @@ static UniValue createmultisig(const JSONRPCRequest& request)
     CScript inner;
     const CTxDestination dest = AddAndGetMultisigDestination(required, pubkeys, output_type, keystore, inner);
 
+    // Make the descriptor
+    std::unique_ptr<Descriptor> descriptor = InferDescriptor(GetScriptForDestination(dest), keystore);
+
     UniValue result(UniValue::VOBJ);
     result.pushKV("address", EncodeDestination(dest));
     result.pushKV("redeemScript", HexStr(inner.begin(), inner.end()));
+    result.pushKV("descriptor", descriptor->ToString());
 
     return result;
 }