Merge bitcoin/bitcoin#21500: wallet, rpc: add an option to list private descriptors

bb822a7af86897a9b6a5d616f193c258e8e76729 wallet, rpc: add listdescriptors private option (S3RK)

Pull request description:

  Rationale: make it possible to backup your wallet with `listdescriptors` command

  * The default behaviour is still to show public version
  * For private version only the root xprv is returned

  Example use-case:
  ```
  > bitcoin-cli -regtest -named createwallet wallet_name=old descriptors=true
  > bitcoin-cli -regtest -rpcwallet=old listdescriptors true | jq '.descriptors' > descriptors.txt

  > bitcoin-cli -regtest -named createwallet wallet_name=new descriptors=true blank=true
  > bitcoin-cli -regtest -rpcwallet=new importdescriptors "$(cat descriptors.txt)"
  ```

  In case of watch-only wallet without private keys there will be following output:
  ```
  error code: -4
  error message:
  Can't get descriptor string.
  ```

ACKs for top commit:
  achow101:
    re-ACK bb822a7af86897a9b6a5d616f193c258e8e76729
  Rspigler:
    tACK bb822a7af86897a9b6a5d616f193c258e8e76729
  jonatack:
    ACK bb822a7af86897a9b6a5d616f193c258e8e76729 per `git diff 2854ddc bb822a7`
  prayank23:
    tACK https://github.com/bitcoin/bitcoin/pull/21500/commits/bb822a7af86897a9b6a5d616f193c258e8e76729
  meshcollider:
    Code review ACK bb822a7af86897a9b6a5d616f193c258e8e76729

Tree-SHA512: f6dddc72a74e5667071ccd77f8dce578382e8e29e7ed6a0834ac2e114a6d3918b59c2f194f4079b3259e13d9ba3b4f405619940c3ecb7a1a0344615aed47c43d

1 files changed, 28 insertions, 0 deletions

diff --git a/test/functional/wallet_listdescriptors.py b/test/functional/wallet_listdescriptors.py
index c2565d84f6..221f5262d9 100755
--- a/test/functional/wallet_listdescriptors.py
+++ b/test/functional/wallet_listdescriptors.py
@@ -72,11 +72,39 @@ class ListDescriptorsTest(BitcoinTestFramework):
             ],
         }
         assert_equal(expected, wallet.listdescriptors())
+        assert_equal(expected, wallet.listdescriptors(False))
+
+        self.log.info('Test list private descriptors')
+        expected_private = {
+            'wallet_name': 'w2',
+            'descriptors': [
+                {'desc': descsum_create('wpkh(' + xprv + hardened_path + '/0/*)'),
+                 'timestamp': 1296688602,
+                 'active': False,
+                 'range': [0, 0],
+                 'next': 0},
+            ],
+        }
+        assert_equal(expected_private, wallet.listdescriptors(True))
 
         self.log.info("Test listdescriptors with encrypted wallet")
         wallet.encryptwallet("pass")
         assert_equal(expected, wallet.listdescriptors())
 
+        self.log.info('Test list private descriptors with encrypted wallet')
+        assert_raises_rpc_error(-13, 'Please enter the wallet passphrase with walletpassphrase first.', wallet.listdescriptors, True)
+        wallet.walletpassphrase(passphrase="pass", timeout=1000000)
+        assert_equal(expected_private, wallet.listdescriptors(True))
+
+        self.log.info('Test list private descriptors with watch-only wallet')
+        node.createwallet(wallet_name='watch-only', descriptors=True, disable_private_keys=True)
+        watch_only_wallet = node.get_wallet_rpc('watch-only')
+        watch_only_wallet.importdescriptors([{
+            'desc': descsum_create('wpkh(' + xpub_acc + ')'),
+            'timestamp': 1296688602,
+        }])
+        assert_raises_rpc_error(-4, 'Can\'t get descriptor string', watch_only_wallet.listdescriptors, True)
+
         self.log.info('Test non-active non-range combo descriptor')
         node.createwallet(wallet_name='w4', blank=True, descriptors=True)
         wallet = node.get_wallet_rpc('w4')