Merge #17578: rpc: simplify getaddressinfo labels, deprecate previous behavior

8925df86c4df16b1070343fef8e4d238f3cc3bd1 doc: update release notes (Jon Atack)
8bb405bbadf11391ccba7b334b4cfe66dc85b390 test: getaddressinfo labels purpose deprecation test (Jon Atack)
60aba1f2f11529add115d963d05599130288ae28 rpc: simplify getaddressinfo labels, deprecate previous behavior (Jon Atack)
7851f14ccf2bcd1e9b2ad48e5e08881be06d9d21 rpc: incorporate review feedback from PR 17283 (Jon Atack)

Pull request description:

  This PR builds on #17283 (now merged) and is followed by #17585.

  It modifies the value returned by rpc getaddressinfo `labels` to an array of label name strings and deprecates the previous behavior of returning an array of JSON hash structures containing label `name` and address `purpose` key/value pairs.

  before
  ```
    "labels": [
      {
        "name": "DOUBLE SPEND",
        "purpose": "receive"
      }
  ```
  after
  ```
    "labels": [
      "DOUBLE SPEND"
    ]
  ```

  The deprecated behavior can be re-enabled by starting bitcoind with `-deprecatedrpc=labelspurpose`.

  For context, see:
  - https://github.com/bitcoin/bitcoin/pull/17283#issuecomment-554458001
  - http://www.erisian.com.au/bitcoin-core-dev/log-2019-12-13.html#l-425 (lines 425-427)
  - http://www.erisian.com.au/bitcoin-core-dev/log-2019-11-22.html#l-622

  Reviewers: This PR may be tested manually by building, then running bitcoind with and without the `-deprecatedrpc=labelspurpose` flag while verifying the rpc getaddressinfo help text and `labels` output.

  Next steps: deprecate the rpc getaddressinfo `label` field (EDIT: done in #17585) and add support for multiple labels per address. This PR will unblock those.

ACKs for top commit:
  jnewbery:
    reACK 8925df8
  promag:
    Code review ACK 8925df86c4df16b1070343fef8e4d238f3cc3bd1.
  meshcollider:
    Code review ACK 8925df86c4df16b1070343fef8e4d238f3cc3bd1

Tree-SHA512: c2b717209996da32b6484de7bb8800e7048410f9ce6afdb3e02a6866bd4a8f2c730f905fca27b10b877b91cf407f546e69e8c4feb9cd934325a6c71c166bd438

10 files changed, 101 insertions, 78 deletions

diff --git a/doc/release-notes-17578.md b/doc/release-notes-17578.md
new file mode 100644
index 0000000000..1b07436bb1
--- /dev/null
+++ b/doc/release-notes-17578.md
@@ -0,0 +1,8 @@
+Deprecated or removed RPCs
+--------------------------
+
+- The `getaddressinfo` RPC `labels` field now returns an array of label name
+  strings. Previously, it returned an array of JSON objects containing `name` and
+  `purpose` key/value pairs, which is now deprecated and will be removed in
+  0.21. To re-enable the previous behavior, launch bitcoind with
+  `-deprecatedrpc=labelspurpose`.
diff --git a/src/wallet/rpcwallet.cpp b/src/wallet/rpcwallet.cpp
index 5978c60d84..85793ef180 100644
--- a/src/wallet/rpcwallet.cpp
+++ b/src/wallet/rpcwallet.cpp
@@ -3726,6 +3726,8 @@ UniValue getaddressinfo(const JSONRPCRequest& request)
         return NullUniValue;
     }
 
+    const std::string example_address = "\"bc1q09vm5lfy0j5reeulh4x5752q25uqqvz34hufdl\"";
+
             RPCHelpMan{"getaddressinfo",
                 "\nReturn information about the given bitcoin address.\n"
                 "Some of the information will only be present if the address is in the active wallet.\n",
@@ -3760,24 +3762,26 @@ UniValue getaddressinfo(const JSONRPCRequest& request)
             "                                                         getaddressinfo output fields for the embedded address, excluding metadata (timestamp, hdkeypath,\n"
             "                                                         hdseedid) and relation to the wallet (ismine, iswatchonly).\n"
             "  \"iscompressed\" : true|false,        (boolean, optional) If the pubkey is compressed.\n"
-            "  \"label\" :  \"label\"                  (string) The label associated with the address. Defaults to \"\". Equivalent to the name field in the labels array.\n"
+            "  \"label\" :  \"label\"                  (string) The label associated with the address. Defaults to \"\". Equivalent to the label name in the labels array below.\n"
             "  \"timestamp\" : timestamp,            (number, optional) The creation time of the key, if available, expressed in " + UNIX_EPOCH_TIME + ".\n"
             "  \"hdkeypath\" : \"keypath\"             (string, optional) The HD keypath, if the key is HD and available.\n"
             "  \"hdseedid\" : \"<hash160>\"            (string, optional) The Hash160 of the HD seed.\n"
             "  \"hdmasterfingerprint\" : \"<hash160>\" (string, optional) The fingerprint of the master key.\n"
-            "  \"labels\"                            (object) An array of labels associated with the address. Currently limited to one label but returned\n"
+            "  \"labels\"                            (json object) An array of labels associated with the address. Currently limited to one label but returned\n"
             "                                               as an array to keep the API stable if multiple labels are enabled in the future.\n"
             "    [\n"
+            "      \"label name\" (string) The label name. Defaults to \"\". Equivalent to the label field above.\n\n"
+            "      DEPRECATED, will be removed in 0.21. To re-enable, launch bitcoind with `-deprecatedrpc=labelspurpose`:\n"
             "      { (json object of label data)\n"
-            "        \"name\": \"label name\" (string) The label name. Defaults to \"\". Equivalent to the label field above.\n"
-            "        \"purpose\": \"purpose\" (string) The purpose of the associated address (send or receive).\n"
-            "      },...\n"
+            "        \"name\" : \"label name\" (string) The label name. Defaults to \"\". Equivalent to the label field above.\n"
+            "        \"purpose\" : \"purpose\" (string) The purpose of the associated address (send or receive).\n"
+            "      }\n"
             "    ]\n"
             "}\n"
                 },
                 RPCExamples{
-                    HelpExampleCli("getaddressinfo", "\"bc1q09vm5lfy0j5reeulh4x5752q25uqqvz34hufdl\"") +
-                    HelpExampleRpc("getaddressinfo", "\"bc1q09vm5lfy0j5reeulh4x5752q25uqqvz34hufdl\"")
+                    HelpExampleCli("getaddressinfo", example_address) +
+                    HelpExampleRpc("getaddressinfo", example_address)
                 },
             }.Check(request);
 
@@ -3785,7 +3789,6 @@ UniValue getaddressinfo(const JSONRPCRequest& request)
 
     UniValue ret(UniValue::VOBJ);
     CTxDestination dest = DecodeDestination(request.params[0].get_str());
-
     // Make sure the destination is valid
     if (!IsValidDestination(dest)) {
         throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid address");
@@ -3811,24 +3814,18 @@ UniValue getaddressinfo(const JSONRPCRequest& request)
 
     ret.pushKV("iswatchonly", bool(mine & ISMINE_WATCH_ONLY));
 
-    // Return DescribeWalletAddress fields.
-    // Always returned: isscript, ischange, iswitness.
-    // Optional: witness_version, witness_program, script, hex, pubkeys (array),
-    // sigsrequired, pubkey, embedded, iscompressed.
     UniValue detail = DescribeWalletAddress(pwallet, dest);
     ret.pushKVs(detail);
 
     // Return label field if existing. Currently only one label can be
     // associated with an address, so the label should be equivalent to the
-    // value of the name key/value pair in the labels hash array below.
+    // value of the name key/value pair in the labels array below.
     if (pwallet->mapAddressBook.count(dest)) {
         ret.pushKV("label", pwallet->mapAddressBook[dest].name);
     }
 
     ret.pushKV("ischange", pwallet->IsChange(scriptPubKey));
 
-    // Fetch KeyMetadata, if present, for the timestamp, hdkeypath, hdseedid,
-    // and hdmasterfingerprint fields.
     ScriptPubKeyMan* spk_man = pwallet->GetScriptPubKeyMan(scriptPubKey);
     if (spk_man) {
         if (const CKeyMetadata* meta = spk_man->GetMetadata(dest)) {
@@ -3841,15 +3838,22 @@ UniValue getaddressinfo(const JSONRPCRequest& request)
         }
     }
 
-    // Return a labels array containing a hash of key/value pairs for the label
-    // name and address purpose. The name value is equivalent to the label field
-    // above. Currently only one label can be associated with an address, but we
-    // return an array so the API remains stable if we allow multiple labels to
-    // be associated with an address in the future.
+    // Return a `labels` array containing the label associated with the address,
+    // equivalent to the `label` field above. Currently only one label can be
+    // associated with an address, but we return an array so the API remains
+    // stable if we allow multiple labels to be associated with an address in
+    // the future.
+    //
+    // DEPRECATED: The previous behavior of returning an array containing a JSON
+    // object of `name` and `purpose` key/value pairs has been deprecated.
     UniValue labels(UniValue::VARR);
     std::map<CTxDestination, CAddressBookData>::iterator mi = pwallet->mapAddressBook.find(dest);
     if (mi != pwallet->mapAddressBook.end()) {
-        labels.push_back(AddressBookDataToJSON(mi->second, true));
+        if (pwallet->chain().rpcEnableDeprecated("labelspurpose")) {
+            labels.push_back(AddressBookDataToJSON(mi->second, true));
+        } else {
+            labels.push_back(mi->second.name);
+        }
     }
     ret.pushKV("labels", std::move(labels));
 
diff --git a/test/functional/rpc_getaddressinfo_labels_purpose_deprecation.py b/test/functional/rpc_getaddressinfo_labels_purpose_deprecation.py
new file mode 100755
index 0000000000..1049440d49
--- /dev/null
+++ b/test/functional/rpc_getaddressinfo_labels_purpose_deprecation.py
@@ -0,0 +1,48 @@
+#!/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 deprecation of RPC getaddressinfo `labels` returning an array
+containing a JSON hash of `name` and purpose` key-value pairs. It now
+returns an array of label names.
+
+"""
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.util import assert_equal
+
+LABELS_TO_TEST = frozenset({"" , "New 𝅘𝅥𝅯 $<#>&!рыба Label"})
+
+class GetAddressInfoLabelsPurposeDeprecationTest(BitcoinTestFramework):
+    def set_test_params(self):
+        self.num_nodes = 2
+        self.setup_clean_chain = False
+        # Start node[0] with -deprecatedrpc=labelspurpose and node[1] without.
+        self.extra_args = [["-deprecatedrpc=labelspurpose"], []]
+
+    def skip_test_if_missing_module(self):
+        self.skip_if_no_wallet()
+
+    def test_labels(self, node_num, label_name, expected_value):
+        node = self.nodes[node_num]
+        address = node.getnewaddress()
+        if label_name != "":
+            node.setlabel(address, label_name)
+            self.log.info("  set label to {}".format(label_name))
+        labels = node.getaddressinfo(address)["labels"]
+        self.log.info("  labels = {}".format(labels))
+        assert_equal(labels, expected_value)
+
+    def run_test(self):
+        """Test getaddressinfo labels with and without -deprecatedrpc flag."""
+        self.log.info("Test getaddressinfo labels with -deprecatedrpc flag")
+        for label in LABELS_TO_TEST:
+            self.test_labels(node_num=0, label_name=label, expected_value=[{"name": label, "purpose": "receive"}])
+
+        self.log.info("Test getaddressinfo labels without -deprecatedrpc flag")
+        for label in LABELS_TO_TEST:
+            self.test_labels(node_num=1, label_name=label, expected_value=[label])
+
+
+if __name__ == '__main__':
+    GetAddressInfoLabelsPurposeDeprecationTest().main()
diff --git a/test/functional/test_framework/wallet_util.py b/test/functional/test_framework/wallet_util.py
index 881df80f64..487acd75d9 100755
--- a/test/functional/test_framework/wallet_util.py
+++ b/test/functional/test_framework/wallet_util.py
@@ -88,11 +88,6 @@ def get_multisig(node):
                     p2sh_p2wsh_script=CScript([OP_HASH160, witness_script, OP_EQUAL]).hex(),
                     p2sh_p2wsh_addr=script_to_p2sh_p2wsh(script_code))
 
-def labels_value(name="", purpose="receive"):
-    """Generate a getaddressinfo labels array from a name and purpose.
-    Often used as the value of a labels kwarg for calling test_address below."""
-    return [{"name": name, "purpose": purpose}]
-
 def test_address(node, address, **kwargs):
     """Get address info for `address` and test whether the returned values are as expected."""
     addr_info = node.getaddressinfo(address)
diff --git a/test/functional/test_runner.py b/test/functional/test_runner.py
index 110733c529..acb559911b 100755
--- a/test/functional/test_runner.py
+++ b/test/functional/test_runner.py
@@ -212,6 +212,7 @@ BASE_SCRIPTS = [
     'p2p_permissions.py',
     'feature_blocksdir.py',
     'feature_config_args.py',
+    'rpc_getaddressinfo_labels_purpose_deprecation.py',
     'rpc_help.py',
     'feature_help.py',
     'feature_shutdown.py',
diff --git a/test/functional/wallet_basic.py b/test/functional/wallet_basic.py
index 2606afa0e4..4780e9263e 100755
--- a/test/functional/wallet_basic.py
+++ b/test/functional/wallet_basic.py
@@ -15,10 +15,7 @@ from test_framework.util import (
     connect_nodes,
     wait_until,
 )
-from test_framework.wallet_util import (
-    labels_value,
-    test_address,
-)
+from test_framework.wallet_util import test_address
 
 
 class WalletTest(BitcoinTestFramework):
@@ -395,7 +392,7 @@ class WalletTest(BitcoinTestFramework):
             for label in [u'рыба', u'𝅘𝅥𝅯']:
                 addr = self.nodes[0].getnewaddress()
                 self.nodes[0].setlabel(addr, label)
-                test_address(self.nodes[0], addr, label=label, labels=labels_value(name=label))
+                test_address(self.nodes[0], addr, label=label, labels=[label])
                 assert label in self.nodes[0].listlabels()
         self.nodes[0].rpc.ensure_ascii = True  # restore to default
 
diff --git a/test/functional/wallet_import_with_label.py b/test/functional/wallet_import_with_label.py
index 651ecd18b2..64d227b30f 100755
--- a/test/functional/wallet_import_with_label.py
+++ b/test/functional/wallet_import_with_label.py
@@ -11,10 +11,7 @@ with and without a label.
 """
 
 from test_framework.test_framework import BitcoinTestFramework
-from test_framework.wallet_util import (
-    labels_value,
-    test_address,
-)
+from test_framework.wallet_util import test_address
 
 
 class ImportWithLabel(BitcoinTestFramework):
@@ -40,7 +37,7 @@ class ImportWithLabel(BitcoinTestFramework):
                      iswatchonly=True,
                      ismine=False,
                      label=label,
-                     labels=labels_value(name=label))
+                     labels=[label])
 
         self.log.info(
             "Import the watch-only address's private key without a "
@@ -48,11 +45,7 @@ class ImportWithLabel(BitcoinTestFramework):
         )
         priv_key = self.nodes[0].dumpprivkey(address)
         self.nodes[1].importprivkey(priv_key)
-
-        test_address(self.nodes[1],
-                     address,
-                     label=label,
-                     labels=labels_value(name=label))
+        test_address(self.nodes[1], address, label=label, labels=[label])
 
         self.log.info(
             "Test importaddress without label and importprivkey with label."
@@ -65,7 +58,7 @@ class ImportWithLabel(BitcoinTestFramework):
                      iswatchonly=True,
                      ismine=False,
                      label="",
-                     labels=labels_value())
+                     labels=[""])
 
         self.log.info(
             "Import the watch-only address's private key with a "
@@ -75,10 +68,7 @@ class ImportWithLabel(BitcoinTestFramework):
         label2 = "Test Label 2"
         self.nodes[1].importprivkey(priv_key2, label2)
 
-        test_address(self.nodes[1],
-                     address2,
-                     label=label2,
-                     labels=labels_value(name=label2))
+        test_address(self.nodes[1], address2, label=label2, labels=[label2])
 
         self.log.info("Test importaddress with label and importprivkey with label.")
         self.log.info("Import a watch-only address with a label.")
@@ -90,7 +80,7 @@ class ImportWithLabel(BitcoinTestFramework):
                      iswatchonly=True,
                      ismine=False,
                      label=label3_addr,
-                     labels=labels_value(name=label3_addr))
+                     labels=[label3_addr])
 
         self.log.info(
             "Import the watch-only address's private key with a "
@@ -100,10 +90,7 @@ class ImportWithLabel(BitcoinTestFramework):
         label3_priv = "Test Label 3 for importprivkey"
         self.nodes[1].importprivkey(priv_key3, label3_priv)
 
-        test_address(self.nodes[1],
-                     address3,
-                     label=label3_priv,
-                     labels=labels_value(name=label3_priv))
+        test_address(self.nodes[1], address3, label=label3_priv, labels=[label3_priv])
 
         self.log.info(
             "Test importprivkey won't label new dests with the same "
@@ -118,7 +105,7 @@ class ImportWithLabel(BitcoinTestFramework):
                      iswatchonly=True,
                      ismine=False,
                      label=label4_addr,
-                     labels=labels_value(name=label4_addr),
+                     labels=[label4_addr],
                      embedded=None)
 
         self.log.info(
@@ -131,15 +118,9 @@ class ImportWithLabel(BitcoinTestFramework):
         self.nodes[1].importprivkey(priv_key4)
         embedded_addr = self.nodes[1].getaddressinfo(address4)['embedded']['address']
 
-        test_address(self.nodes[1],
-                     embedded_addr,
-                     label="",
-                     labels=labels_value())
+        test_address(self.nodes[1], embedded_addr, label="", labels=[""])
 
-        test_address(self.nodes[1],
-                     address4,
-                     label=label4_addr,
-                     labels=labels_value(name=label4_addr))
+        test_address(self.nodes[1], address4, label=label4_addr, labels=[label4_addr])
 
         self.stop_nodes()
 
diff --git a/test/functional/wallet_importmulti.py b/test/functional/wallet_importmulti.py
index 5febac5998..eb55578bfd 100755
--- a/test/functional/wallet_importmulti.py
+++ b/test/functional/wallet_importmulti.py
@@ -29,7 +29,6 @@ from test_framework.util import (
 from test_framework.wallet_util import (
     get_key,
     get_multisig,
-    labels_value,
     test_address,
 )
 
@@ -571,7 +570,7 @@ class ImportMultiTest(BitcoinTestFramework):
                      solvable=True,
                      ismine=True,
                      label=p2sh_p2wpkh_label,
-                     labels=labels_value(name=p2sh_p2wpkh_label))
+                     labels=[p2sh_p2wpkh_label])
 
         # Test ranged descriptor fails if range is not specified
         xpriv = "tprv8ZgxMBicQKsPeuVhWwi6wuMQGfPKi9Li5GtX35jVNknACgqe3CY4g5xgkfDDJcmtF7o1QnxWDRYw4H5P26PXq7sbcUkEqeR4fg3Kxp2tigg"
@@ -643,7 +642,7 @@ class ImportMultiTest(BitcoinTestFramework):
                      solvable=True,
                      ismine=False,
                      label=p2pkh_label,
-                     labels=labels_value(name=p2pkh_label))
+                     labels=[p2pkh_label])
 
         # Test import fails if both desc and scriptPubKey are provided
         key = get_key(self.nodes[0])
diff --git a/test/functional/wallet_labels.py b/test/functional/wallet_labels.py
index 33e067601e..f795202d72 100755
--- a/test/functional/wallet_labels.py
+++ b/test/functional/wallet_labels.py
@@ -13,10 +13,8 @@ from collections import defaultdict
 
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import assert_equal, assert_raises_rpc_error
-from test_framework.wallet_util import (
-    labels_value,
-    test_address,
-)
+from test_framework.wallet_util import test_address
+
 
 class WalletLabelsTest(BitcoinTestFramework):
     def set_test_params(self):
@@ -157,12 +155,7 @@ class Label:
         if self.receive_address is not None:
             assert self.receive_address in self.addresses
         for address in self.addresses:
-            test_address(
-                node,
-                address,
-                label=self.name,
-                labels=labels_value(name=self.name, purpose=self.purpose[address])
-             )
+            test_address(node, address, label=self.name, labels=[self.name])
         assert self.name in node.listlabels()
         assert_equal(
             node.getaddressesbylabel(self.name),
diff --git a/test/functional/wallet_listreceivedby.py b/test/functional/wallet_listreceivedby.py
index afd473306d..4b83e1613f 100755
--- a/test/functional/wallet_listreceivedby.py
+++ b/test/functional/wallet_listreceivedby.py
@@ -11,10 +11,7 @@ from test_framework.util import (
     assert_equal,
     assert_raises_rpc_error,
 )
-from test_framework.wallet_util import (
-    labels_value,
-    test_address,
-)
+from test_framework.wallet_util import test_address
 
 
 class ReceivedByTest(BitcoinTestFramework):
@@ -131,7 +128,7 @@ class ReceivedByTest(BitcoinTestFramework):
         # set pre-state
         label = ''
         address = self.nodes[1].getnewaddress()
-        test_address(self.nodes[1], address, label=label, labels=labels_value(name=label))
+        test_address(self.nodes[1], address, label=label, labels=[label])
         received_by_label_json = [r for r in self.nodes[1].listreceivedbylabel() if r["label"] == label][0]
         balance_by_label = self.nodes[1].getreceivedbylabel(label)