The test passes without this change, so I am still wondering why this is needed.
Also, the commit doesn’t seem to be exhaustive. The wallet.dat/bad should be replaced as well. Also, the usages in tool_wallet.py. See the diff I used for testing:
0diff --git a/src/wallet/db.cpp b/src/wallet/db.cpp
1index bd1d114730..89d7325e1c 100644
2--- a/src/wallet/db.cpp
3+++ b/src/wallet/db.cpp
4@@ -20,6 +20,6 @@ void SplitWalletPath(const fs::path& wallet_path, fs::path& env_directory, std::
5 // Normal case: Interpret wallet path as a directory path containing
6 // data and log files.
7 env_directory = wallet_path;
8- database_filename = "wallet.dat";
9+ database_filename = "wallet_dat";
10 }
11 }
12diff --git a/src/wallet/test/db_tests.cpp b/src/wallet/test/db_tests.cpp
13index 8f0083cd2e..3489d48879 100644
14--- a/src/wallet/test/db_tests.cpp
15+++ b/src/wallet/test/db_tests.cpp
16@@ -29,7 +29,7 @@ BOOST_AUTO_TEST_CASE(getwalletenv_file)
17
18 BOOST_AUTO_TEST_CASE(getwalletenv_directory)
19 {
20- std::string expected_name = "wallet.dat";
21+ std::string expected_name = "wallet_dat";
22 const fs::path datadir = GetDataDir();
23
24 std::string filename;
25diff --git a/src/wallet/walletutil.cpp b/src/wallet/walletutil.cpp
26index e4c72aed98..3a16cb3e75 100644
27--- a/src/wallet/walletutil.cpp
28+++ b/src/wallet/walletutil.cpp
29@@ -71,11 +71,11 @@ std::vector<fs::path> ListWalletDir()
30 // This can be replaced by boost::filesystem::lexically_relative once boost is bumped to 1.60.
31 const fs::path path = it->path().string().substr(offset);
32
33- if (it->status().type() == fs::directory_file && IsBerkeleyBtree(it->path() / "wallet.dat")) {
34+ if (it->status().type() == fs::directory_file && IsBerkeleyBtree(it->path() / "wallet_dat")) {
35 // Found a directory which contains wallet.dat btree file, add it as a wallet.
36 paths.emplace_back(path);
37 } else if (it.level() == 0 && it->symlink_status().type() == fs::regular_file && IsBerkeleyBtree(it->path())) {
38- if (it->path().filename() == "wallet.dat") {
39+ if (it->path().filename() == "wallet_dat") {
40 // Found top-level wallet.dat btree file, add top level directory ""
41 // as a wallet.
42 paths.emplace_back();
43diff --git a/test/functional/test_framework/test_framework.py b/test/functional/test_framework/test_framework.py
44index 100be26c59..fa72420178 100755
45--- a/test/functional/test_framework/test_framework.py
46+++ b/test/functional/test_framework/test_framework.py
47@@ -103,7 +103,7 @@ class BitcoinTestFramework(metaclass=BitcoinTestMetaClass):
48 self.supports_cli = True
49 self.bind_to_localhost_only = True
50 self.default_wallet_name = ""
51- self.wallet_data_filename = "wallet.dat"
52+ self.wallet_data_filename = "wallet_dat"
53 self.set_test_params()
54 self.parse_args()
55 if self.options.timeout_factor == 0 :
56diff --git a/test/functional/tool_wallet.py b/test/functional/tool_wallet.py
57index ef68e224b6..8d3e7f8f62 100755
58--- a/test/functional/tool_wallet.py
59+++ b/test/functional/tool_wallet.py
60@@ -73,7 +73,7 @@ class ToolWalletTest(BitcoinTestFramework):
61 locked_dir = os.path.join(self.options.tmpdir, "node0", "regtest", "wallets")
62 self.assert_raises_tool_error(
63 'Error initializing wallet database environment "{}"!'.format(locked_dir),
64- '-wallet=wallet.dat',
65+ '-wallet=wallet_dat',
66 'info',
67 )
68 path = os.path.join(self.options.tmpdir, "node0", "regtest", "wallets", "nonexistent.dat")
69@@ -104,7 +104,7 @@ class ToolWalletTest(BitcoinTestFramework):
70 Transactions: 0
71 Address Book: 3
72 ''')
73- self.assert_tool_output(out, '-wallet=wallet.dat', 'info')
74+ self.assert_tool_output(out, '-wallet=wallet_dat', 'info')
75 timestamp_after = self.wallet_timestamp()
76 self.log.debug('Wallet file timestamp after calling info: {}'.format(timestamp_after))
77 self.log_wallet_timestamp_comparison(timestamp_before, timestamp_after)
78@@ -143,7 +143,7 @@ class ToolWalletTest(BitcoinTestFramework):
79 Transactions: 1
80 Address Book: 3
81 ''')
82- self.assert_tool_output(out, '-wallet=wallet.dat', 'info')
83+ self.assert_tool_output(out, '-wallet=wallet_dat', 'info')
84 shasum_after = self.wallet_shasum()
85 timestamp_after = self.wallet_timestamp()
86 self.log.debug('Wallet file timestamp after calling info: {}'.format(timestamp_after))
87diff --git a/test/functional/wallet_dump.py b/test/functional/wallet_dump.py
88index 09581d864b..5fdabf89c8 100755
89--- a/test/functional/wallet_dump.py
90+++ b/test/functional/wallet_dump.py
91@@ -203,7 +203,7 @@ class WalletDumpTest(BitcoinTestFramework):
92 assert result['ismine']
93
94 self.log.info('Check that wallet is flushed')
95- with self.nodes[0].assert_debug_log(['Flushing wallet.dat'], timeout=20):
96+ with self.nodes[0].assert_debug_log(['Flushing wallet_dat'], timeout=20):
97 self.nodes[0].getnewaddress()
98
99
100diff --git a/test/functional/wallet_multiwallet.py b/test/functional/wallet_multiwallet.py
101index 7b975af065..71aa86abdb 100755
102--- a/test/functional/wallet_multiwallet.py
103+++ b/test/functional/wallet_multiwallet.py
104@@ -95,7 +95,7 @@ class MultiWalletTest(BitcoinTestFramework):
105 # w8 - to verify existing wallet file is loaded correctly
106 # '' - to verify default wallet file is created correctly
107 wallet_names = ['w1', 'w2', 'w3', 'w', 'sub/w5', os.path.join(self.options.tmpdir, 'extern/w6'), 'w7_symlink', 'w8', self.default_wallet_name]
108- extra_args = ['-nowallet'] + ['-wallet={}'.format(n) for n in wallet_names]
109+ extra_args = ['-wallet={}'.format(n) for n in wallet_names]
110 self.start_node(0, extra_args)
111 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'])
112
113@@ -108,7 +108,7 @@ class MultiWalletTest(BitcoinTestFramework):
114
115 # should not initialize if wallet path can't be created
116 exp_stderr = "boost::filesystem::create_directory:"
117- self.nodes[0].assert_start_raises_init_error(['-wallet=wallet.dat/bad'], exp_stderr, match=ErrorMatch.PARTIAL_REGEX)
118+ self.nodes[0].assert_start_raises_init_error(['-wallet={}/bad'.format(self.wallet_data_filename)], exp_stderr, match=ErrorMatch.PARTIAL_REGEX)
119
120 self.nodes[0].assert_start_raises_init_error(['-walletdir=wallets'], 'Error: Specified -walletdir "wallets" does not exist')
121 self.nodes[0].assert_start_raises_init_error(['-walletdir=wallets'], 'Error: Specified -walletdir "wallets" is a relative path', cwd=data_dir())
