Merge bitcoin/bitcoin#27279: Add "warnings", deprecate "warning" in {create,load,unload,restore}wallet

7ccdd741fe test: fix importmulti/importdescriptors assertion (Jon Atack)
19d888ce40 rpc: move WALLET_FLAG_CAVEATS to the compilation unit of its caller (Jon Atack)
01df011ca2 doc: release note for wallet RPCs "warning" field deprecation (Jon Atack)
9ea8b3739a test: createwallet "warning" field deprecation test (Jon Atack)
645d7f75ac rpc: deprecate "warning" field in {create,load,unload,restore}wallet (Jon Atack)
2f4a926e95 test: add test coverage for "warnings" field in createwallet (Jon Atack)
4a1e479ca6 rpc: add "warnings" field to RPCs {create,load,unload,restore}wallet (Jon Atack)
079d8cdda8 rpc: extract wallet "warnings" fields to a util helper (Jon Atack)
f73782a903 doc: fix/improve warning helps in {create,load,unload,restore}wallet (Jon Atack)

Pull request description:

  Based on discussion and concept ACKed in #27138, add a `warnings` field to RPCs createwallet, loadwallet, unloadwallet, and restorewallet as a JSON array of strings to replace the `warning` string field in these 4 RPCs. The idea is to more gracefully handle multiple warning messages and for consistency with other wallet RPCs.  Then, deprecate the latter fields, which represent all the remaining RPC `warning` fields.

  The first commit f73782a903 implements https://github.com/bitcoin/bitcoin/pull/27138#issuecomment-1474789198 as an alternative to #27138. One of those two could potentially be backported to our currently supported releases.

ACKs for top commit:
  achow101:
    ACK 7ccdd741fe
  1440000bytes:
    utACK 7ccdd741fe
  vasild:
    ACK 7ccdd741fe
  pinheadmz:
    re-ACK 7ccdd741fe

Tree-SHA512: 314e0a4c41fa383d95e2817bfacf359d449e460529d235c3eb902851e2f4eacbabe646d9a5a4beabc4964cdfabf6397ed8301366a58d344a2f787f83b75e9d64

test/functional/wallet_backwards_compatibility.py

@@ -265,7 +265,12 @@ class BackwardsCompatibilityTest(BitcoinTestFramework):
             )
             load_res = node_master.loadwallet("u1_v16")
             # Make sure this wallet opens without warnings. See https://github.com/bitcoin/bitcoin/pull/19054
-            assert_equal(load_res['warning'], '')
+            if int(node_master.getnetworkinfo()["version"]) >= 249900:
+                # loadwallet#warnings (added in v25) -- only present if there is a warning
+                assert "warnings" not in load_res
+            else:
+                # loadwallet#warning (deprecated in v25) -- always present, but empty string if no warning
+                assert_equal(load_res["warning"], '')
             wallet = node_master.get_wallet_rpc("u1_v16")
             info = wallet.getaddressinfo(v16_addr)
             descriptor = f"wpkh([{info['hdmasterfingerprint']}{hdkeypath[1:]}]{v16_pubkey})"

test/functional/wallet_createwallet.py

@@ -15,12 +15,17 @@ from test_framework.util import (
 )
 from test_framework.wallet_util import bytes_to_wif, generate_wif_key
 
+EMPTY_PASSPHRASE_MSG = "Empty string given as passphrase, wallet will not be encrypted."
+LEGACY_WALLET_MSG = "Wallet created successfully. The legacy wallet type is being deprecated and support for creating and opening legacy wallets will be removed in the future."
+
+
 class CreateWalletTest(BitcoinTestFramework):
     def add_options(self, parser):
         self.add_wallet_options(parser)
 
     def set_test_params(self):
         self.num_nodes = 1
+        self.extra_args = [["-deprecatedrpc=walletwarningfield"]]
 
     def skip_test_if_missing_module(self):
         self.skip_if_no_wallet()
@@ -55,7 +60,7 @@ class CreateWalletTest(BitcoinTestFramework):
         else:
             result = w1.importmulti([{'scriptPubKey': {'address': key_to_p2wpkh(eckey.get_pubkey().get_bytes())}, 'timestamp': 'now', 'keys': [privkey]}])
         assert not result[0]['success']
-        assert 'warning' not in result[0]
+        assert 'warnings' not in result[0]
         assert_equal(result[0]['error']['code'], -4)
         assert_equal(result[0]['error']['message'], 'Cannot import private keys to a wallet with private keys disabled')
 
@@ -159,7 +164,9 @@ class CreateWalletTest(BitcoinTestFramework):
         assert_equal(walletinfo['keypoolsize_hd_internal'], keys)
         # Allow empty passphrase, but there should be a warning
         resp = self.nodes[0].createwallet(wallet_name='w7', disable_private_keys=False, blank=False, passphrase='')
-        assert 'Empty string given as passphrase, wallet will not be encrypted.' in resp['warning']
+        assert_equal(resp["warning"], EMPTY_PASSPHRASE_MSG if self.options.descriptors else f"{EMPTY_PASSPHRASE_MSG}\n{LEGACY_WALLET_MSG}")
+        assert_equal(resp["warnings"], [EMPTY_PASSPHRASE_MSG] if self.options.descriptors else [EMPTY_PASSPHRASE_MSG, LEGACY_WALLET_MSG])
+
         w7 = node.get_wallet_rpc('w7')
         assert_raises_rpc_error(-15, 'Error: running with an unencrypted wallet, but walletpassphrase was called.', w7.walletpassphrase, '', 60)
 
@@ -174,8 +181,24 @@ class CreateWalletTest(BitcoinTestFramework):
 
         if self.is_bdb_compiled():
             self.log.info("Test legacy wallet deprecation")
-            res = self.nodes[0].createwallet(wallet_name="legacy_w0", descriptors=False, passphrase=None)
-            assert_equal(res["warning"], "Wallet created successfully. The legacy wallet type is being deprecated and support for creating and opening legacy wallets will be removed in the future.")
+            result = self.nodes[0].createwallet(wallet_name="legacy_w0", descriptors=False, passphrase=None)
+            assert_equal(result, {
+                "name": "legacy_w0",
+                "warning": LEGACY_WALLET_MSG,
+                "warnings": [LEGACY_WALLET_MSG],
+            })
+            result = self.nodes[0].createwallet(wallet_name="legacy_w1", descriptors=False, passphrase="")
+            assert_equal(result, {
+                "name": "legacy_w1",
+                "warning": f"{EMPTY_PASSPHRASE_MSG}\n{LEGACY_WALLET_MSG}",
+                "warnings": [EMPTY_PASSPHRASE_MSG, LEGACY_WALLET_MSG],
+            })
+
+        self.log.info('Test "warning" field deprecation, i.e. not returned without -deprecatedrpc=walletwarningfield')
+        self.restart_node(0, extra_args=[])
+        result = self.nodes[0].createwallet(wallet_name="w7_again", disable_private_keys=False, blank=False, passphrase="")
+        assert "warning" not in result
+
 
 if __name__ == '__main__':
     CreateWalletTest().main()