Better error messages for invalid addresses

This commit addresses #20809.

We add an additional 'error' property in the result of 'validateaddress' in case the address is not valid that gives a short description of why the address in invalid. We also change the error message returned by 'getaddressinfo' in case the address is invalid.

test/functional/rpc_invalid_address_message.py

@@ -0,0 +1,78 @@
+#!/usr/bin/env python3
+# Copyright (c) 2020 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+"""Test error messages for 'getaddressinfo' and 'validateaddress' RPC commands."""
+
+from test_framework.test_framework import BitcoinTestFramework
+
+from test_framework.util import (
+    assert_equal,
+    assert_raises_rpc_error,
+)
+
+BECH32_VALID = 'bcrt1qtmp74ayg7p24uslctssvjm06q5phz4yrxucgnv'
+BECH32_INVALID_SIZE = 'bcrt1sqqpl9r5c'
+BECH32_INVALID_PREFIX = 'bc1qw508d6qejxtdg4y5r3zarvary0c5xw7kv8f3t4'
+
+BASE58_VALID = 'mipcBbFg9gMiCh81Kj8tqqdgoZub1ZJRfn'
+BASE58_INVALID_PREFIX = '17VZNX1SN5NtKa8UQFxwQbFeFc3iqRYhem'
+
+INVALID_ADDRESS = 'asfah14i8fajz0123f'
+
+class InvalidAddressErrorMessageTest(BitcoinTestFramework):
+    def set_test_params(self):
+        self.setup_clean_chain = True
+        self.num_nodes = 1
+
+    def skip_test_if_missing_module(self):
+        self.skip_if_no_wallet()
+
+    def test_validateaddress(self):
+        node = self.nodes[0]
+
+        # Bech32
+        info = node.validateaddress(BECH32_INVALID_SIZE)
+        assert not info['isvalid']
+        assert_equal(info['error'], 'Invalid Bech32 address data size')
+
+        info = node.validateaddress(BECH32_INVALID_PREFIX)
+        assert not info['isvalid']
+        assert_equal(info['error'], 'Invalid prefix for Bech32 address')
+
+        info = node.validateaddress(BECH32_VALID)
+        assert info['isvalid']
+        assert 'error' not in info
+
+        # Base58
+        info = node.validateaddress(BASE58_INVALID_PREFIX)
+        assert not info['isvalid']
+        assert_equal(info['error'], 'Invalid prefix for Base58-encoded address')
+
+        info = node.validateaddress(BASE58_VALID)
+        assert info['isvalid']
+        assert 'error' not in info
+
+        # Invalid address format
+        info = node.validateaddress(INVALID_ADDRESS)
+        assert not info['isvalid']
+        assert_equal(info['error'], 'Invalid address format')
+
+    def test_getaddressinfo(self):
+        node = self.nodes[0]
+
+        assert_raises_rpc_error(-5, "Invalid Bech32 address data size", node.getaddressinfo, BECH32_INVALID_SIZE)
+
+        assert_raises_rpc_error(-5, "Invalid prefix for Bech32 address", node.getaddressinfo, BECH32_INVALID_PREFIX)
+
+        assert_raises_rpc_error(-5, "Invalid prefix for Base58-encoded address", node.getaddressinfo, BASE58_INVALID_PREFIX)
+
+        assert_raises_rpc_error(-5, "Invalid address format", node.getaddressinfo, INVALID_ADDRESS)
+
+    def run_test(self):
+        self.test_validateaddress()
+        self.test_getaddressinfo()
+
+
+if __name__ == '__main__':
+    InvalidAddressErrorMessageTest().main()