Merge #16115: On bitcoind startup, write config args to debug.log

b951b0973cfd4e0db4607a00d434a04afb0d6199 on startup, write config options to debug.log (Larry Ruane)

Pull request description:

  When a developer is examining `debug.log` after something goes wrong, it's often useful to know the exact options the failing instance of `bitcoind` was started with. Sometimes the `debug.log` file is all that's available for the analysis. This PR logs the `bitcoin.conf` entries and command-line arguments to `debug.log` on startup.

ACKs for top commit:
  MarcoFalke:
    ACK b951b0973cfd4e0db4607a00d434a04afb0d6199 🐪
  jonatack:
    ACK b951b0973c reviewed diff, re-code review, built, ran tests, launched bitcoind and reviewed debug log output, verified value of  `str` debug log in the added unit test.

Tree-SHA512: bbca4fb3d49f99261758302bde0b8b67300ccc72e7380b01f1f66a146ae8a008a045df0ca5ca9664caff034d0ee38ea7ef38a50f38374525608c07ba52790358

1 files changed, 28 insertions, 0 deletions

diff --git a/src/test/getarg_tests.cpp b/src/test/getarg_tests.cpp
index 4c64d8c833..10fb05ca8a 100644
--- a/src/test/getarg_tests.cpp
+++ b/src/test/getarg_tests.cpp
@@ -183,4 +183,32 @@ BOOST_AUTO_TEST_CASE(boolargno)
     BOOST_CHECK(gArgs.GetBoolArg("-foo", false));
 }
 
+BOOST_AUTO_TEST_CASE(logargs)
+{
+    const auto okaylog_bool = std::make_pair("-okaylog-bool", ArgsManager::ALLOW_BOOL);
+    const auto okaylog_negbool = std::make_pair("-okaylog-negbool", ArgsManager::ALLOW_BOOL);
+    const auto okaylog = std::make_pair("-okaylog", ArgsManager::ALLOW_ANY);
+    const auto dontlog = std::make_pair("-dontlog", ArgsManager::ALLOW_ANY | ArgsManager::SENSITIVE);
+    SetupArgs({okaylog_bool, okaylog_negbool, okaylog, dontlog});
+    ResetArgs("-okaylog-bool -nookaylog-negbool -okaylog=public -dontlog=private");
+
+    // Everything logged to debug.log will also append to str
+    std::string str;
+    auto print_connection = LogInstance().PushBackCallback(
+        [&str](const std::string& s) {
+            str += s;
+        });
+
+    // Log the arguments
+    gArgs.LogArgs();
+
+    LogInstance().DeleteCallback(print_connection);
+    // Check that what should appear does, and what shouldn't doesn't.
+    BOOST_CHECK(str.find("Command-line arg: okaylog-bool=\"\"") != std::string::npos);
+    BOOST_CHECK(str.find("Command-line arg: okaylog-negbool=false") != std::string::npos);
+    BOOST_CHECK(str.find("Command-line arg: okaylog=\"public\"") != std::string::npos);
+    BOOST_CHECK(str.find("dontlog=****") != std::string::npos);
+    BOOST_CHECK(str.find("private") == std::string::npos);
+}
+
 BOOST_AUTO_TEST_SUITE_END()