Add warnings field to addmultisigaddress to warn about uncompressed keys

src/wallet/rpc/addresses.cpp

@@ -238,6 +238,10 @@ RPCHelpMan addmultisigaddress()
                         {RPCResult::Type::STR, "address", "The value of the new multisig address"},
                         {RPCResult::Type::STR_HEX, "redeemScript", "The string value of the hex-encoded redemption script"},
                         {RPCResult::Type::STR, "descriptor", "The descriptor for this multisig"},
+                        {RPCResult::Type::ARR, "warnings", /* optional */ true, "Any warnings resulting from the creation of this multisig",
+                        {
+                            {RPCResult::Type::STR, "", ""},
+                        }},
                     }
                 },
                 RPCExamples{
@@ -295,6 +299,14 @@ RPCHelpMan addmultisigaddress()
     result.pushKV("address", EncodeDestination(dest));
     result.pushKV("redeemScript", HexStr(inner));
     result.pushKV("descriptor", descriptor->ToString());
+
+    UniValue warnings(UniValue::VARR);
+    if (!request.params[3].isNull() && OutputTypeFromDestination(dest) != output_type) {
+        // Only warns if the user has explicitly chosen an address type we cannot generate
+        warnings.push_back("Unable to make chosen address type, please ensure no uncompressed public keys are present.");
+    }
+    if (warnings.size()) result.pushKV("warnings", warnings);
+
     return result;
 },
     };

test/functional/rpc_createmultisig.py

@@ -75,7 +75,9 @@ class RpcCreateMultiSigTest(BitcoinTestFramework):
         for keys in itertools.permutations([pk0, pk1, pk2]):
             # Results should be the same as this legacy one
             legacy_addr = node0.createmultisig(2, keys, 'legacy')['address']
-            assert_equal(legacy_addr, wmulti0.addmultisigaddress(2, keys, '', 'legacy')['address'])
+            result = wmulti0.addmultisigaddress(2, keys, '', 'legacy')
+            assert_equal(legacy_addr, result['address'])
+            assert 'warnings' not in result
 
             # Generate addresses with the segwit types. These should all make legacy addresses
             for addr_type in ['bech32', 'p2sh-segwit']:
@@ -83,8 +85,9 @@ class RpcCreateMultiSigTest(BitcoinTestFramework):
                 assert_equal(legacy_addr, result['address'])
                 assert_equal(result['warnings'], ["Unable to make chosen address type, please ensure no uncompressed public keys are present."])
 
-            assert_equal(legacy_addr, wmulti0.addmultisigaddress(2, keys, '', 'bech32')['address'])
-            assert_equal(legacy_addr, wmulti0.addmultisigaddress(2, keys, '', 'p2sh-segwit')['address'])
+                result = wmulti0.addmultisigaddress(2, keys, '', addr_type)
+                assert_equal(legacy_addr, result['address'])
+                assert_equal(result['warnings'], ["Unable to make chosen address type, please ensure no uncompressed public keys are present."])
 
         self.log.info('Testing sortedmulti descriptors with BIP 67 test vectors')
         with open(os.path.join(os.path.dirname(os.path.realpath(__file__)), 'data/rpc_bip67.json'), encoding='utf-8') as f: