wallet: Reverse order of arguments to z_getaddressforaccount

We now use the empty array of pools to indicate that the default pools
should be used when providing a diversifier index parameter, instead of
needing a default sentinel value for the diversifier index parameter
(which was previously suggested as '*' which would have caused issues
for defining a consistent type for that parameter).

qa/rpc-tests/wallet_accounts.py

@@ -46,13 +46,13 @@ class WalletAccountsTest(BitcoinTestFramework):
         # address in account 0; this is however not necessarily at diversifier index 0.
         # We should be able to generate it directly and get the exact same data.
         j = addr0['diversifier_index']
-        assert_equal(self.nodes[0].z_getaddressforaccount(0, j), addr0)
+        assert_equal(self.nodes[0].z_getaddressforaccount(0, [], j), addr0)
         if j > 0:
             # We should get an error if we generate the address at diversifier index 0.
             assert_raises_message(
                 JSONRPCException,
                 'no address at diversifier index 0',
-                self.nodes[0].z_getaddressforaccount, 0, 0)
+                self.nodes[0].z_getaddressforaccount, 0, [], 0)
 
         # The first address for account 1 is different to account 0.
         addr1 = self.nodes[0].z_getaddressforaccount(1)

src/wallet/rpcwallet.cpp

@@ -3057,13 +3057,13 @@ UniValue z_getaddressforaccount(const UniValue& params, bool fHelp)
         return NullUniValue;
     if (fHelp || params.size() < 1 || params.size() > 3)
         throw runtime_error(
-            "z_getaddressforaccount account ( diversifier_index [\"pool\", ...] )\n"
+            "z_getaddressforaccount account ( [\"pool\", ...] diversifier_index )\n"
             "\nFor the given account number, derives a Unified Address in accordance"
             "\nwith the remaining arguments:\n"
-            "\n- If no list of pools is given, the best and second-best shielded pools,"
+            "\n- If no list of pools is given (or the empty list \"[]\"), the best and"
-            "\n  along with the transparent pool, will be used."
+            "\n  second-best shielded pools, along with the transparent pool, will be used."
-            "\n- If no diversifier index is given (or the string \"*\"), the next unused"
+            "\n- If no diversifier index is given, the next unused index (that is valid"
-            "\n  index (that is valid for the list of pools) will be selected.\n"
+            "\n  for the list of pools) will be selected.\n"
             "\nThe account number must have been previously generated by a call to the"
             "\nz_getnewaccount RPC method.\n"
             "\nOnce a Unified Address has been derived at a specific diversifier index,"
@@ -3079,8 +3079,8 @@ UniValue z_getaddressforaccount(const UniValue& params, bool fHelp)
             "}\n"
             "\nExamples:\n"
             + HelpExampleCli("z_getaddressforaccount", "4")
-            + HelpExampleCli("z_getaddressforaccount", "4 1")
+            + HelpExampleCli("z_getaddressforaccount", "4 '[]' 1")
-            + HelpExampleCli("z_getaddressforaccount", "4 1 '[\"transparent\",\"sapling\",\"orchard\"]'")
+            + HelpExampleCli("z_getaddressforaccount", "4 '[\"transparent\",\"sapling\",\"orchard\"]' 1")
             + HelpExampleRpc("z_getaddressforaccount", "4")
         );
 
@@ -3096,28 +3096,9 @@ UniValue z_getaddressforaccount(const UniValue& params, bool fHelp)
     }
     libzcash::AccountId account = accountInt;
 
-    std::optional<libzcash::diversifier_index_t> j = std::nullopt;
-    if (params.size() >= 2) {
-        // TODO: Handle '*'
-        if (params[1].getType() != UniValue::VNUM) {
-            throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid diversifier index, must be an unsigned integer.");
-        }
-        auto parsed_diversifier_index_opt = ParseArbitraryInt(params[1].getValStr());
-        if (!parsed_diversifier_index_opt.has_value()) {
-            throw JSONRPCError(RPC_INVALID_PARAMETER, "diversifier index must be a decimal integer.");
-        }
-        auto parsed_diversifier_index = parsed_diversifier_index_opt.value();
-        if (parsed_diversifier_index.size() > ZC_DIVERSIFIER_SIZE) {
-            throw JSONRPCError(RPC_INVALID_PARAMETER, "diversifier index is too large.");
-        }
-        // Extend the byte array to the correct length for diversifier_index_t.
-        parsed_diversifier_index.resize(ZC_DIVERSIFIER_SIZE);
-        j = libzcash::diversifier_index_t(parsed_diversifier_index);
-    }
-
     std::set<libzcash::ReceiverType> receivers;
-    if (params.size() >= 3) {
+    if (params.size() >= 2) {
-        const auto& pools = params[2].get_array();
+        const auto& pools = params[1].get_array();
         for (unsigned int i = 0; i < pools.size(); i++) {
             const std::string& p = pools[i].get_str();
             if (p == "transparent") {
@@ -3128,11 +3109,30 @@ UniValue z_getaddressforaccount(const UniValue& params, bool fHelp)
                 throw JSONRPCError(RPC_INVALID_PARAMETER, "pool arguments must be \"transparent\", or \"sapling\"");
             }
         }
-    } else {
+    }
+    if (receivers.empty()) {
         // Default is the best and second-best shielded pools, and the transparent pool.
         receivers = {ReceiverType::P2PKH, ReceiverType::Sapling};
     }
 
+    std::optional<libzcash::diversifier_index_t> j = std::nullopt;
+    if (params.size() >= 3) {
+        if (params[2].getType() != UniValue::VNUM) {
+            throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid diversifier index, must be an unsigned integer.");
+        }
+        auto parsed_diversifier_index_opt = ParseArbitraryInt(params[2].getValStr());
+        if (!parsed_diversifier_index_opt.has_value()) {
+            throw JSONRPCError(RPC_INVALID_PARAMETER, "diversifier index must be a decimal integer.");
+        }
+        auto parsed_diversifier_index = parsed_diversifier_index_opt.value();
+        if (parsed_diversifier_index.size() > ZC_DIVERSIFIER_SIZE) {
+            throw JSONRPCError(RPC_INVALID_PARAMETER, "diversifier index is too large.");
+        }
+        // Extend the byte array to the correct length for diversifier_index_t.
+        parsed_diversifier_index.resize(ZC_DIVERSIFIER_SIZE);
+        j = libzcash::diversifier_index_t(parsed_diversifier_index);
+    }
+
     EnsureWalletIsUnlocked();
 
     // Generate the first UA for this account, using the best and next-best shielded pools
@@ -3158,7 +3158,7 @@ UniValue z_getaddressforaccount(const UniValue& params, bool fHelp)
                 case AddressGenerationError::ExistingAddressMismatch:
                     strErr = tfm::format(
                         "Error: address at diversifier index %s was already generated with different receiver types.",
-                        params[1].getValStr());
+                        params[2].getValStr());
                     break;
                 case AddressGenerationError::NoAddressForDiversifier:
                     strErr = tfm::format(