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

8925df86c4 doc: update release notes (Jon Atack)
8bb405bbad test: getaddressinfo labels purpose deprecation test (Jon Atack)
60aba1f2f1 rpc: simplify getaddressinfo labels, deprecate previous behavior (Jon Atack)
7851f14ccf 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 8925df86c4.
  meshcollider:
    Code review ACK 8925df86c4

Tree-SHA512: c2b717209996da32b6484de7bb8800e7048410f9ce6afdb3e02a6866bd4a8f2c730f905fca27b10b877b91cf407f546e69e8c4feb9cd934325a6c71c166bd438

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()