wallet: Make -wallet setting not create wallets

This changes -wallet setting to only load existing wallets, not create new ones.

- Fixes settings.json corner cases reported by sjors & promag:
  https://github.com/bitcoin-core/gui/issues/95,
  https://github.com/bitcoin/bitcoin/pull/19754#issuecomment-685858578,
  https://github.com/bitcoin/bitcoin/pull/19754#issuecomment-685858578

- Prevents accidental creation of wallets reported most recently by jb55
  http://www.erisian.com.au/bitcoin-core-dev/log-2020-09-14.html#l-355

- Simplifies behavior after #15454. #15454 took the big step of disabling
  creation of the default wallet. This PR extends it to avoid creating other
  wallets as well. With this change, new wallets just aren't created on
  startup, instead of sometimes being created, sometimes not. #15454 release
  notes are updated here and are simpler.

This change should be targeted for 0.21.0. It's a bug fix and simplifies
behavior of the #15937 / #19754 / #15454 features added in 0.21.0.

1 files changed, 23 insertions, 11 deletions

diff --git a/test/functional/wallet_multiwallet.py b/test/functional/wallet_multiwallet.py
index 61791a756c..63af9e8720 100755
--- a/test/functional/wallet_multiwallet.py
+++ b/test/functional/wallet_multiwallet.py
@@ -41,6 +41,7 @@ class MultiWalletTest(BitcoinTestFramework):
         self.setup_clean_chain = True
         self.num_nodes = 2
         self.rpc_timeout = 120
+        self.extra_args = [["-nowallet"], []]
 
     def skip_test_if_missing_module(self):
         self.skip_if_no_wallet()
@@ -80,7 +81,9 @@ class MultiWalletTest(BitcoinTestFramework):
         # rename wallet.dat to make sure plain wallet file paths (as opposed to
         # directory paths) can be loaded
         # create another dummy wallet for use in testing backups later
-        self.start_node(0, ["-nowallet", "-wallet=empty", "-wallet=plain"])
+        self.start_node(0)
+        node.createwallet("empty", descriptors=False)
+        node.createwallet("plain", descriptors=False)
         node.createwallet("created")
         self.stop_nodes()
         empty_wallet = os.path.join(self.options.tmpdir, 'empty.dat')
@@ -101,21 +104,23 @@ class MultiWalletTest(BitcoinTestFramework):
         #   w8         - to verify existing wallet file is loaded correctly
         #   ''         - to verify default wallet file is created correctly
         wallet_names = ['w1', 'w2', 'w3', 'w', 'sub/w5', os.path.join(self.options.tmpdir, 'extern/w6'), 'w7_symlink', 'w8', self.default_wallet_name]
-        extra_args = ['-nowallet'] + ['-wallet={}'.format(n) for n in wallet_names]
-        self.start_node(0, extra_args)
+        self.start_node(0)
+        for wallet_name in wallet_names[:-2]:
+            self.nodes[0].createwallet(wallet_name, descriptors=False)
+        for wallet_name in wallet_names[-2:]:
+            self.nodes[0].loadwallet(wallet_name)
         assert_equal(sorted(map(lambda w: w['name'], self.nodes[0].listwalletdir()['wallets'])), [self.default_wallet_name, os.path.join('sub', 'w5'), 'w', 'w1', 'w2', 'w3', 'w7', 'w7_symlink', 'w8'])
 
         assert_equal(set(node.listwallets()), set(wallet_names))
 
+        # should raise rpc error if wallet path can't be created
+        assert_raises_rpc_error(-1, "boost::filesystem::create_directory:", self.nodes[0].createwallet, "w8/bad", descriptors=False)
+
         # check that all requested wallets were created
         self.stop_node(0)
         for wallet_name in wallet_names:
             assert_equal(os.path.isfile(wallet_file(wallet_name)), True)
 
-        # should not initialize if wallet path can't be created
-        exp_stderr = "boost::filesystem::create_directory:"
-        self.nodes[0].assert_start_raises_init_error(['-wallet=w8/bad'], exp_stderr, match=ErrorMatch.PARTIAL_REGEX)
-
         self.nodes[0].assert_start_raises_init_error(['-walletdir=wallets'], 'Error: Specified -walletdir "wallets" does not exist')
         self.nodes[0].assert_start_raises_init_error(['-walletdir=wallets'], 'Error: Specified -walletdir "wallets" is a relative path', cwd=data_dir())
         self.nodes[0].assert_start_raises_init_error(['-walletdir=debug.log'], 'Error: Specified -walletdir "debug.log" is not a directory', cwd=data_dir())
@@ -142,14 +147,18 @@ class MultiWalletTest(BitcoinTestFramework):
         # if wallets/ doesn't exist, datadir should be the default wallet dir
         wallet_dir2 = data_dir('walletdir')
         os.rename(wallet_dir(), wallet_dir2)
-        self.start_node(0, ['-nowallet', '-wallet=w4', '-wallet=w5'])
+        self.start_node(0)
+        self.nodes[0].createwallet("w4")
+        self.nodes[0].createwallet("w5")
         assert_equal(set(node.listwallets()), {"w4", "w5"})
         w5 = wallet("w5")
         node.generatetoaddress(nblocks=1, address=w5.getnewaddress())
 
         # now if wallets/ exists again, but the rootdir is specified as the walletdir, w4 and w5 should still be loaded
         os.rename(wallet_dir2, wallet_dir())
-        self.restart_node(0, ['-nowallet', '-wallet=w4', '-wallet=w5', '-walletdir=' + data_dir()])
+        self.restart_node(0, ['-nowallet', '-walletdir=' + data_dir()])
+        self.nodes[0].loadwallet("w4")
+        self.nodes[0].loadwallet("w5")
         assert_equal(set(node.listwallets()), {"w4", "w5"})
         w5 = wallet("w5")
         w5_info = w5.getwalletinfo()
@@ -157,11 +166,14 @@ class MultiWalletTest(BitcoinTestFramework):
 
         competing_wallet_dir = os.path.join(self.options.tmpdir, 'competing_walletdir')
         os.mkdir(competing_wallet_dir)
-        self.restart_node(0, ['-walletdir=' + competing_wallet_dir])
+        self.restart_node(0, ['-nowallet', '-walletdir=' + competing_wallet_dir])
+        self.nodes[0].createwallet(self.default_wallet_name, descriptors=False)
         exp_stderr = r"Error: Error initializing wallet database environment \"\S+competing_walletdir\S*\"!"
         self.nodes[1].assert_start_raises_init_error(['-walletdir=' + competing_wallet_dir], exp_stderr, match=ErrorMatch.PARTIAL_REGEX)
 
-        self.restart_node(0, extra_args)
+        self.restart_node(0)
+        for wallet_name in wallet_names:
+            self.nodes[0].loadwallet(wallet_name)
 
         assert_equal(sorted(map(lambda w: w['name'], self.nodes[0].listwalletdir()['wallets'])), [self.default_wallet_name, os.path.join('sub', 'w5'), 'w', 'w1', 'w2', 'w3', 'w7', 'w7_symlink', 'w8', 'w8_copy'])