Merge #19779: Remove gArgs global from init

fa9d590 scripted-diff: gArgs -> args (MarcoFalke)
fa33bc2 init: Capture copy of blocknotify setting for BlockNotifyCallback (MarcoFalke)
fa40017 init: Pass reference to ArgsManager around instead of relying on global (MarcoFalke)

Pull request description:

  The gArgs global has several issues:

  * gArgs is used by each process (bitcoind, bitcoin-qt, bitcoin-wallet, bitcoin-cli, bitcoin-tx, ...), but it is hard to determine which arguments are actually used by each process. For example arguments that have never been registered, but are still used, will always return the fallback value.
  * Tests may run several sub-tests, which need different settings. So globals will have to be overwritten, but that is fragile on its own: e.g. bitcoin/bitcoin#19704 (comment) or #19511

  The goal is to remove gArgs, but as a first step in that direction this pull will change gArgs in init to use a passed-in reference instead.

ACKs for top commit:
  ryanofsky:
    Code review ACK fa9d590. Looks good. Nice day to remove some globals, and add some lambdas 👍
  fanquake:
    ACK fa9d590 - I'm not as familiar with the settings & argument handling code, but this make sense, and is a step in the right direction towards a reduction in the usage of globals. Not a huge fan of the clang-formatting in the scripted diff.
  jonasschnelli:
    Concept ACK fa9d590

Tree-SHA512: ed00db5f826566c7e3b4d0b3d2ee0fc1a49a6e748e04e5c93bdd694ac7da5598749e73937047d5fce86150d764a067d2ca344ba4ae3eb2704cc5c4fa0d20940f

Author: fanquake

src/bitcoind.cpp

@@ -50,28 +50,23 @@ static bool AppInit(int argc, char* argv[])
 
     util::ThreadSetInternalName("init");
 
-    //
-    // Parameters
-    //
     // If Qt is used, parameters/bitcoin.conf are parsed in qt/bitcoin.cpp's main()
     SetupServerArgs(node);
+    ArgsManager& args = *Assert(node.args);
     std::string error;
-    if (!gArgs.ParseParameters(argc, argv, error)) {
+    if (!args.ParseParameters(argc, argv, error)) {
         return InitError(Untranslated(strprintf("Error parsing command line arguments: %s\n", error)));
     }
 
     // Process help and version before taking care about datadir
-    if (HelpRequested(gArgs) || gArgs.IsArgSet("-version")) {
+    if (HelpRequested(args) || args.IsArgSet("-version")) {
         std::string strUsage = PACKAGE_NAME " version " + FormatFullVersion() + "\n";
 
-        if (gArgs.IsArgSet("-version"))
-        {
+        if (args.IsArgSet("-version")) {
             strUsage += FormatParagraph(LicenseInfo()) + "\n";
-        }
-        else
-        {
+        } else {
             strUsage += "\nUsage:  bitcoind [options]                     Start " PACKAGE_NAME "\n";
-            strUsage += "\n" + gArgs.GetHelpMessage();
+            strUsage += "\n" + args.GetHelpMessage();
         }
 
         tfm::format(std::cout, "%s", strUsage);
@@ -82,14 +77,14 @@ static bool AppInit(int argc, char* argv[])
     try
     {
         if (!CheckDataDirOption()) {
-            return InitError(Untranslated(strprintf("Specified data directory \"%s\" does not exist.\n", gArgs.GetArg("-datadir", ""))));
+            return InitError(Untranslated(strprintf("Specified data directory \"%s\" does not exist.\n", args.GetArg("-datadir", ""))));
         }
-        if (!gArgs.ReadConfigFiles(error, true)) {
+        if (!args.ReadConfigFiles(error, true)) {
             return InitError(Untranslated(strprintf("Error reading configuration file: %s\n", error)));
         }
         // Check for -chain, -testnet or -regtest parameter (Params() calls are only valid after this clause)
         try {
-            SelectParams(gArgs.GetChainName());
+            SelectParams(args.GetChainName());
         } catch (const std::exception& e) {
             return InitError(Untranslated(strprintf("%s\n", e.what())));
         }
@@ -101,23 +96,21 @@ static bool AppInit(int argc, char* argv[])
             }
         }
 
-        if (!gArgs.InitSettings(error)) {
+        if (!args.InitSettings(error)) {
             InitError(Untranslated(error));
             return false;
         }
 
         // -server defaults to true for bitcoind but not for the GUI so do this here
-        gArgs.SoftSetBoolArg("-server", true);
+        args.SoftSetBoolArg("-server", true);
         // Set this early so that parameter interactions go to console
-        InitLogging();
-        InitParameterInteraction();
-        if (!AppInitBasicSetup())
-        {
+        InitLogging(args);
+        InitParameterInteraction(args);
+        if (!AppInitBasicSetup(args)) {
             // InitError will have been called with detailed error, which ends up on console
             return false;
         }
-        if (!AppInitParameterInteraction())
-        {
+        if (!AppInitParameterInteraction(args)) {
             // InitError will have been called with detailed error, which ends up on console
             return false;
         }
@@ -126,8 +119,7 @@ static bool AppInit(int argc, char* argv[])
             // InitError will have been called with detailed error, which ends up on console
             return false;
         }
-        if (gArgs.GetBoolArg("-daemon", false))
-        {
+        if (args.GetBoolArg("-daemon", false)) {
 #if HAVE_DECL_DAEMON
 #if defined(MAC_OSX)
 #pragma GCC diagnostic push