ArgsManager: limit some options to only apply on mainnet when in default section

When specified in bitcoin.conf without using the [regtest] or [test]
section header, or a "regtest." or "test." prefix, the "addnode",
"connect", "port", "bind", "rpcport", "rpcbind", and "wallet" settings
will only be applied when running on mainnet.

src/util.cpp

@@ -460,6 +460,13 @@ class ArgsManagerHelper {
 public:
     typedef std::map<std::string, std::vector<std::string>> MapArgs;
 
+    /** Determine whether to use config settings in the default section,
+     *  See also comments around ArgsManager::ArgsManager() below. */
+    static inline bool UseDefaultSection(const ArgsManager& am, const std::string& arg)
+    {
+        return (am.m_network == CBaseChainParams::MAIN || am.m_network_only_args.count(arg) == 0);
+    }
+
     /** Convert regular argument into the network-specific setting */
     static inline std::string NetworkArg(const ArgsManager& am, const std::string& arg)
     {
@@ -521,10 +528,12 @@ public:
             }
         }
 
+        if (UseDefaultSection(am, arg)) {
             found_result = GetArgHelper(am.m_config_args, arg);
             if (found_result.first) {
                 return found_result;
             }
+        }
 
         return found_result;
     }
@@ -575,6 +584,22 @@ static bool InterpretNegatedOption(std::string& key, std::string& val)
     return false;
 }
 
+ArgsManager::ArgsManager() :
+    /* These options would cause cross-contamination if values for
+     * mainnet were used while running on regtest/testnet (or vice-versa).
+     * Setting them as section_only_args ensures that sharing a config file
+     * between mainnet and regtest/testnet won't cause problems due to these
+     * parameters by accident. */
+    m_network_only_args{
+      "-addnode", "-connect",
+      "-port", "-bind",
+      "-rpcport", "-rpcbind",
+      "-wallet",
+    }
+{
+    // nothing to do
+}
+
 void ArgsManager::SelectConfigNetwork(const std::string& network)
 {
     m_network = network;
@@ -621,11 +646,16 @@ std::vector<std::string> ArgsManager::GetArgs(const std::string& strArg) const
     if (IsArgNegated(strArg)) return result; // special case
 
     LOCK(cs_args);
+
     ArgsManagerHelper::AddArgs(result, m_override_args, strArg);
     if (!m_network.empty()) {
         ArgsManagerHelper::AddArgs(result, m_config_args, ArgsManagerHelper::NetworkArg(*this, strArg));
     }
+
+    if (ArgsManagerHelper::UseDefaultSection(*this, strArg)) {
         ArgsManagerHelper::AddArgs(result, m_config_args, strArg);
+    }
+
     return result;
 }
 

src/util.h

@@ -24,6 +24,7 @@
 #include <exception>
 #include <map>
 #include <memory>
+#include <set>
 #include <stdint.h>
 #include <string>
 #include <unordered_set>
@@ -229,9 +230,13 @@ protected:
     std::map<std::string, std::vector<std::string>> m_override_args;
     std::map<std::string, std::vector<std::string>> m_config_args;
     std::string m_network;
+    std::set<std::string> m_network_only_args;
+
     void ReadConfigStream(std::istream& stream);
 
 public:
+    ArgsManager();
+
     /**
      * Select the network in use
      */