Merge #11862: Network specific conf sections

c25321f Add config changes to release notes (Anthony Towns)
5e3cbe0 [tests] Unit tests for -testnet/-regtest in [test]/[regtest] sections (Anthony Towns)
005ad26 ArgsManager: special handling for -regtest and -testnet (Anthony Towns)
608415d [tests] Unit tests for network-specific config entries (Anthony Towns)
68797e2 ArgsManager: Warn when ignoring network-specific config setting (Anthony Towns)
d1fc4d9 ArgsManager: limit some options to only apply on mainnet when in default section (Anthony Towns)
8a9817d [tests] Use regtest section in functional tests configs (Anthony Towns)
30f9407 [tests] Unit tests for config file sections (Anthony Towns)
95eb66d ArgsManager: support config file sections (Anthony Towns)
4d34fcc ArgsManager: drop m_negated_args (Anthony Towns)
3673ca3 ArgsManager: keep command line and config file arguments separate (Anthony Towns)

Pull request description:

  The weekly meeting on [2017-12-07](http://www.erisian.com.au/meetbot/bitcoin-core-dev/2017/bitcoin-core-dev.2017-12-07-19.00.log.html) discussed allowing options to bitcoin to have some sensitivity to what network is in use. @theuni suggested having sections in the config file:

      <cfields> an alternative to that would be sections in a config file. and on the
                cmdline they'd look like namespaces. so, [testnet] port=5. or -testnet::port=5.

  This approach is (more or less) supported by `boost::program_options::detail::config_file_iterator` -- when it sees a `[testnet]` section with `port=5`, it will treat that the same as "testnet.port=5". So `[testnet] port=5` (or `testnet.port=5` without the section header) in bitcoin.conf and `-testnet.port=5` on the command line.

  The other aspect to this question is possibly limiting some options so that there is no possibility of accidental cross-contamination across networks. For example, if you're using a particular wallet.dat on mainnet, you may not want to accidentally use the same wallet on testnet and risk reusing keys.

  I've set this up so that the `-addnode` and `-wallet` options are `NETWORK_ONLY`, so that if you have a bitcoin.conf:

      wallet=/secret/wallet.dat
      upnp=1

  and you run `bitcoind -testnet` or `bitcoind -regtest`, then the `wallet=` setting will be ignored, and should behave as if your bitcoin.conf had specified:

      upnp=1

      [main]
      wallet=/secret/wallet.dat

  For any `NETWORK_ONLY` options, if you're using `-testnet` or `-regtest`, you'll have to add the prefix to any command line options. This was necessary for `multiwallet.py` for instance.

  I've left the "default" options as taking precedence over network specific ones, which might be backwards. So if you have:

      maxmempool=200
      [regtest]
      maxmempool=100

  your maxmempool will still be 200 on regtest. The advantage of doing it this way is that if you have `[regtest] maxmempool=100` in bitcoin.conf, and then say `bitcoind -regtest -maxmempool=200`, the same result is probably in line with what you expect...

  The other thing to note is that I'm using the chain names from `chainparamsbase.cpp` / `ChainNameFromCommandLine`, so the sections are `[main]`, `[test]` and `[regtest]`; not `[mainnet]` or `[testnet]` as might be expected.

  Thoughts? Ping @MeshCollider @laanwj @jonasschnelli @morcos

Tree-SHA512: f00b5eb75f006189987e5c15e154a42b66ee251777768c1e185d764279070fcb7c41947d8794092b912a03d985843c82e5189871416995436a6260520fb7a4db

8 files changed, 480 insertions, 115 deletions

diff --git a/doc/release-notes-pr12823.md b/doc/release-notes-pr12823.md
new file mode 100644
index 0000000000..b493908716
--- /dev/null
+++ b/doc/release-notes-pr12823.md
@@ -0,0 +1,20 @@
+Configuration sections for testnet and regtest
+----------------------------------------------
+
+It is now possible for a single configuration file to set different
+options for different networks. This is done by using sections or by
+prefixing the option with the network, such as:
+
+    main.uacomment=bitcoin
+    test.uacomment=bitcoin-testnet
+    regtest.uacomment=regtest
+    [main]
+    mempoolsize=300
+    [test]
+    mempoolsize=100
+    [regtest]
+    mempoolsize=20
+
+The `addnode=`, `connect=`, `port=`, `bind=`, `rpcport=`, `rpcbind=`
+and `wallet=` options will only apply to mainnet when specified in the
+configuration file, unless a network is specified.
diff --git a/src/chainparamsbase.cpp b/src/chainparamsbase.cpp
index e840a2ed30..3ef9c2cfe5 100644
--- a/src/chainparamsbase.cpp
+++ b/src/chainparamsbase.cpp
@@ -47,4 +47,5 @@ std::unique_ptr<CBaseChainParams> CreateBaseChainParams(const std::string& chain
 void SelectBaseParams(const std::string& chain)
 {
     globalChainBaseParams = CreateBaseChainParams(chain);
+    gArgs.SelectConfigNetwork(chain);
 }
diff --git a/src/init.cpp b/src/init.cpp
index 486c84f5a3..abff5ec79d 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -803,6 +803,11 @@ void InitParameterInteraction()
         if (gArgs.SoftSetBoolArg("-whitelistrelay", true))
             LogPrintf("%s: parameter interaction: -whitelistforcerelay=1 -> setting -whitelistrelay=1\n", __func__);
     }
+
+    // Warn if network-specific options (-addnode, -connect, etc) are
+    // specified in default section of config file, but not overridden
+    // on the command line or in this network's section of the config file.
+    gArgs.WarnForSectionOnlyArgs();
 }
 
 static std::string ResolveErrMsg(const char * const optname, const std::string& strBind)
diff --git a/src/test/util_tests.cpp b/src/test/util_tests.cpp
index e8c7b80c3a..344113b60c 100644
--- a/src/test/util_tests.cpp
+++ b/src/test/util_tests.cpp
@@ -176,13 +176,22 @@ BOOST_AUTO_TEST_CASE(util_FormatISO8601Time)
 
 struct TestArgsManager : public ArgsManager
 {
-    std::map<std::string, std::string>& GetMapArgs() { return mapArgs; }
-    const std::map<std::string, std::vector<std::string> >& GetMapMultiArgs() { return mapMultiArgs; }
-    const std::unordered_set<std::string>& GetNegatedArgs() { return m_negated_args; }
+    TestArgsManager() { m_network_only_args.clear(); }
+    std::map<std::string, std::vector<std::string> >& GetOverrideArgs() { return m_override_args; }
+    std::map<std::string, std::vector<std::string> >& GetConfigArgs() { return m_config_args; }
     void ReadConfigString(const std::string str_config)
     {
-        std::istringstream stream(str_config);
-        ReadConfigStream(stream);
+        std::istringstream streamConfig(str_config);
+        {
+            LOCK(cs_args);
+            m_config_args.clear();
+        }
+        ReadConfigStream(streamConfig);
+    }
+    void SetNetworkOnlyArg(const std::string arg)
+    {
+        LOCK(cs_args);
+        m_network_only_args.insert(arg);
     }
 };
 
@@ -192,22 +201,26 @@ BOOST_AUTO_TEST_CASE(util_ParseParameters)
     const char *argv_test[] = {"-ignored", "-a", "-b", "-ccc=argument", "-ccc=multiple", "f", "-d=e"};
 
     testArgs.ParseParameters(0, (char**)argv_test);
-    BOOST_CHECK(testArgs.GetMapArgs().empty() && testArgs.GetMapMultiArgs().empty());
+    BOOST_CHECK(testArgs.GetOverrideArgs().empty() && testArgs.GetConfigArgs().empty());
 
     testArgs.ParseParameters(1, (char**)argv_test);
-    BOOST_CHECK(testArgs.GetMapArgs().empty() && testArgs.GetMapMultiArgs().empty());
+    BOOST_CHECK(testArgs.GetOverrideArgs().empty() && testArgs.GetConfigArgs().empty());
 
     testArgs.ParseParameters(7, (char**)argv_test);
     // expectation: -ignored is ignored (program name argument),
     // -a, -b and -ccc end up in map, -d ignored because it is after
     // a non-option argument (non-GNU option parsing)
-    BOOST_CHECK(testArgs.GetMapArgs().size() == 3 && testArgs.GetMapMultiArgs().size() == 3);
+    BOOST_CHECK(testArgs.GetOverrideArgs().size() == 3 && testArgs.GetConfigArgs().empty());
     BOOST_CHECK(testArgs.IsArgSet("-a") && testArgs.IsArgSet("-b") && testArgs.IsArgSet("-ccc")
                 && !testArgs.IsArgSet("f") && !testArgs.IsArgSet("-d"));
-    BOOST_CHECK(testArgs.GetMapMultiArgs().count("-a") && testArgs.GetMapMultiArgs().count("-b") && testArgs.GetMapMultiArgs().count("-ccc")
-                && !testArgs.GetMapMultiArgs().count("f") && !testArgs.GetMapMultiArgs().count("-d"));
-
-    BOOST_CHECK(testArgs.GetMapArgs()["-a"] == "" && testArgs.GetMapArgs()["-ccc"] == "multiple");
+    BOOST_CHECK(testArgs.GetOverrideArgs().count("-a") && testArgs.GetOverrideArgs().count("-b") && testArgs.GetOverrideArgs().count("-ccc")
+                && !testArgs.GetOverrideArgs().count("f") && !testArgs.GetOverrideArgs().count("-d"));
+
+    BOOST_CHECK(testArgs.GetOverrideArgs()["-a"].size() == 1);
+    BOOST_CHECK(testArgs.GetOverrideArgs()["-a"].front() == "");
+    BOOST_CHECK(testArgs.GetOverrideArgs()["-ccc"].size() == 2);
+    BOOST_CHECK(testArgs.GetOverrideArgs()["-ccc"].front() == "argument");
+    BOOST_CHECK(testArgs.GetOverrideArgs()["-ccc"].back() == "multiple");
     BOOST_CHECK(testArgs.GetArgs("-ccc").size() == 2);
 }
 
@@ -223,15 +236,14 @@ BOOST_AUTO_TEST_CASE(util_GetBoolArg)
         BOOST_CHECK(testArgs.IsArgSet({'-', opt}) || !opt);
 
     // Nothing else should be in the map
-    BOOST_CHECK(testArgs.GetMapArgs().size() == 6 &&
-                testArgs.GetMapMultiArgs().size() == 6);
+    BOOST_CHECK(testArgs.GetOverrideArgs().size() == 6 &&
+                testArgs.GetConfigArgs().empty());
 
     // The -no prefix should get stripped on the way in.
     BOOST_CHECK(!testArgs.IsArgSet("-nob"));
 
     // The -b option is flagged as negated, and nothing else is
     BOOST_CHECK(testArgs.IsArgNegated("-b"));
-    BOOST_CHECK(testArgs.GetNegatedArgs().size() == 1);
     BOOST_CHECK(!testArgs.IsArgNegated("-a"));
 
     // Check expected values.
@@ -256,8 +268,8 @@ BOOST_AUTO_TEST_CASE(util_GetBoolArgEdgeCases)
     BOOST_CHECK(!testArgs.IsArgNegated("-foo"));
     BOOST_CHECK(testArgs.GetArg("-foo", "xxx") == "");
 
-    // A double negative is a positive.
-    BOOST_CHECK(testArgs.IsArgNegated("-bar"));
+    // A double negative is a positive, and not marked as negated.
+    BOOST_CHECK(!testArgs.IsArgNegated("-bar"));
     BOOST_CHECK(testArgs.GetArg("-bar", "xxx") == "1");
 
     // Config test
@@ -266,12 +278,12 @@ BOOST_AUTO_TEST_CASE(util_GetBoolArgEdgeCases)
     testArgs.ReadConfigString(conf_test);
 
     // This was passed twice, second one overrides the negative setting,
-    // but not the value.
+    // and the value.
     BOOST_CHECK(!testArgs.IsArgNegated("-foo"));
-    BOOST_CHECK(testArgs.GetArg("-foo", "xxx") == "0");
+    BOOST_CHECK(testArgs.GetArg("-foo", "xxx") == "1");
 
-    // A double negative is a positive.
-    BOOST_CHECK(testArgs.IsArgNegated("-bar"));
+    // A double negative is a positive, and does not count as negated.
+    BOOST_CHECK(!testArgs.IsArgNegated("-bar"));
     BOOST_CHECK(testArgs.GetArg("-bar", "xxx") == "1");
 
     // Combined test
@@ -281,18 +293,15 @@ BOOST_AUTO_TEST_CASE(util_GetBoolArgEdgeCases)
     testArgs.ReadConfigString(combo_test_conf);
 
     // Command line overrides, but doesn't erase old setting
-    BOOST_CHECK(!testArgs.IsArgNegated("-foo"));
+    BOOST_CHECK(testArgs.IsArgNegated("-foo"));
     BOOST_CHECK(testArgs.GetArg("-foo", "xxx") == "0");
-    BOOST_CHECK(testArgs.GetArgs("-foo").size() == 2
-                && testArgs.GetArgs("-foo").front() == "0"
-                && testArgs.GetArgs("-foo").back() == "1");
+    BOOST_CHECK(testArgs.GetArgs("-foo").size() == 0);
 
     // Command line overrides, but doesn't erase old setting
-    BOOST_CHECK(testArgs.IsArgNegated("-bar"));
+    BOOST_CHECK(!testArgs.IsArgNegated("-bar"));
     BOOST_CHECK(testArgs.GetArg("-bar", "xxx") == "");
-    BOOST_CHECK(testArgs.GetArgs("-bar").size() == 2
-                && testArgs.GetArgs("-bar").front() == ""
-                && testArgs.GetArgs("-bar").back() == "0");
+    BOOST_CHECK(testArgs.GetArgs("-bar").size() == 1
+                && testArgs.GetArgs("-bar").front() == "");
 }
 
 BOOST_AUTO_TEST_CASE(util_ReadConfigStream)
@@ -308,24 +317,39 @@ BOOST_AUTO_TEST_CASE(util_ReadConfigStream)
        "h=1\n"
        "noh=1\n"
        "noi=1\n"
-       "i=1\n";
+       "i=1\n"
+       "sec1.ccc=extend1\n"
+       "\n"
+       "[sec1]\n"
+       "ccc=extend2\n"
+       "d=eee\n"
+       "h=1\n"
+       "[sec2]\n"
+       "ccc=extend3\n"
+       "iii=2\n";
 
     TestArgsManager test_args;
 
     test_args.ReadConfigString(str_config);
     // expectation: a, b, ccc, d, fff, ggg, h, i end up in map
-
-    BOOST_CHECK(test_args.GetMapArgs().size() == 8);
-    BOOST_CHECK(test_args.GetMapMultiArgs().size() == 8);
-
-    BOOST_CHECK(test_args.GetMapArgs().count("-a")
-                && test_args.GetMapArgs().count("-b")
-                && test_args.GetMapArgs().count("-ccc")
-                && test_args.GetMapArgs().count("-d")
-                && test_args.GetMapArgs().count("-fff")
-                && test_args.GetMapArgs().count("-ggg")
-                && test_args.GetMapArgs().count("-h")
-                && test_args.GetMapArgs().count("-i")
+    // so do sec1.ccc, sec1.d, sec1.h, sec2.ccc, sec2.iii
+
+    BOOST_CHECK(test_args.GetOverrideArgs().empty());
+    BOOST_CHECK(test_args.GetConfigArgs().size() == 13);
+
+    BOOST_CHECK(test_args.GetConfigArgs().count("-a")
+                && test_args.GetConfigArgs().count("-b")
+                && test_args.GetConfigArgs().count("-ccc")
+                && test_args.GetConfigArgs().count("-d")
+                && test_args.GetConfigArgs().count("-fff")
+                && test_args.GetConfigArgs().count("-ggg")
+                && test_args.GetConfigArgs().count("-h")
+                && test_args.GetConfigArgs().count("-i")
+               );
+    BOOST_CHECK(test_args.GetConfigArgs().count("-sec1.ccc")
+                && test_args.GetConfigArgs().count("-sec1.h")
+                && test_args.GetConfigArgs().count("-sec2.ccc")
+                && test_args.GetConfigArgs().count("-sec2.iii")
                );
 
     BOOST_CHECK(test_args.IsArgSet("-a")
@@ -337,6 +361,7 @@ BOOST_AUTO_TEST_CASE(util_ReadConfigStream)
                 && test_args.IsArgSet("-h")
                 && test_args.IsArgSet("-i")
                 && !test_args.IsArgSet("-zzz")
+                && !test_args.IsArgSet("-iii")
                );
 
     BOOST_CHECK(test_args.GetArg("-a", "xxx") == ""
@@ -345,9 +370,10 @@ BOOST_AUTO_TEST_CASE(util_ReadConfigStream)
                 && test_args.GetArg("-d", "xxx") == "e"
                 && test_args.GetArg("-fff", "xxx") == "0"
                 && test_args.GetArg("-ggg", "xxx") == "1"
-                && test_args.GetArg("-h", "xxx") == "1" // 1st value takes precedence
-                && test_args.GetArg("-i", "xxx") == "0" // 1st value takes precedence
+                && test_args.GetArg("-h", "xxx") == "0"
+                && test_args.GetArg("-i", "xxx") == "1"
                 && test_args.GetArg("-zzz", "xxx") == "xxx"
+                && test_args.GetArg("-iii", "xxx") == "xxx"
                );
 
     for (bool def : {false, true}) {
@@ -357,9 +383,10 @@ BOOST_AUTO_TEST_CASE(util_ReadConfigStream)
                      && !test_args.GetBoolArg("-d", def)
                      && !test_args.GetBoolArg("-fff", def)
                      && test_args.GetBoolArg("-ggg", def)
-                     && test_args.GetBoolArg("-h", def)
-                     && !test_args.GetBoolArg("-i", def)
+                     && !test_args.GetBoolArg("-h", def)
+                     && test_args.GetBoolArg("-i", def)
                      && test_args.GetBoolArg("-zzz", def) == def
+                     && test_args.GetBoolArg("-iii", def) == def
                    );
     }
 
@@ -370,19 +397,15 @@ BOOST_AUTO_TEST_CASE(util_ReadConfigStream)
     BOOST_CHECK(test_args.GetArgs("-ccc").size() == 2
                 && test_args.GetArgs("-ccc").front() == "argument"
                 && test_args.GetArgs("-ccc").back() == "multiple");
-    BOOST_CHECK(test_args.GetArgs("-fff").size() == 1
-                && test_args.GetArgs("-fff").front() == "0");
+    BOOST_CHECK(test_args.GetArgs("-fff").size() == 0);
     BOOST_CHECK(test_args.GetArgs("-nofff").size() == 0);
     BOOST_CHECK(test_args.GetArgs("-ggg").size() == 1
                 && test_args.GetArgs("-ggg").front() == "1");
     BOOST_CHECK(test_args.GetArgs("-noggg").size() == 0);
-    BOOST_CHECK(test_args.GetArgs("-h").size() == 2
-                && test_args.GetArgs("-h").front() == "1"
-                && test_args.GetArgs("-h").back() == "0");
+    BOOST_CHECK(test_args.GetArgs("-h").size() == 0);
     BOOST_CHECK(test_args.GetArgs("-noh").size() == 0);
-    BOOST_CHECK(test_args.GetArgs("-i").size() == 2
-                && test_args.GetArgs("-i").front() == "0"
-                && test_args.GetArgs("-i").back() == "1");
+    BOOST_CHECK(test_args.GetArgs("-i").size() == 1
+                && test_args.GetArgs("-i").front() == "1");
     BOOST_CHECK(test_args.GetArgs("-noi").size() == 0);
     BOOST_CHECK(test_args.GetArgs("-zzz").size() == 0);
 
@@ -391,25 +414,98 @@ BOOST_AUTO_TEST_CASE(util_ReadConfigStream)
     BOOST_CHECK(!test_args.IsArgNegated("-ccc"));
     BOOST_CHECK(!test_args.IsArgNegated("-d"));
     BOOST_CHECK(test_args.IsArgNegated("-fff"));
-    BOOST_CHECK(test_args.IsArgNegated("-ggg")); // IsArgNegated==true when noggg=0
+    BOOST_CHECK(!test_args.IsArgNegated("-ggg"));
     BOOST_CHECK(test_args.IsArgNegated("-h")); // last setting takes precedence
     BOOST_CHECK(!test_args.IsArgNegated("-i")); // last setting takes precedence
     BOOST_CHECK(!test_args.IsArgNegated("-zzz"));
+
+    // Test sections work
+    test_args.SelectConfigNetwork("sec1");
+
+    // same as original
+    BOOST_CHECK(test_args.GetArg("-a", "xxx") == ""
+                && test_args.GetArg("-b", "xxx") == "1"
+                && test_args.GetArg("-fff", "xxx") == "0"
+                && test_args.GetArg("-ggg", "xxx") == "1"
+                && test_args.GetArg("-zzz", "xxx") == "xxx"
+                && test_args.GetArg("-iii", "xxx") == "xxx"
+               );
+    // d is overridden
+    BOOST_CHECK(test_args.GetArg("-d", "xxx") == "eee");
+    // section-specific setting
+    BOOST_CHECK(test_args.GetArg("-h", "xxx") == "1");
+    // section takes priority for multiple values
+    BOOST_CHECK(test_args.GetArg("-ccc", "xxx") == "extend1");
+    // check multiple values works
+    const std::vector<std::string> sec1_ccc_expected = {"extend1","extend2","argument","multiple"};
+    const auto& sec1_ccc_res = test_args.GetArgs("-ccc");
+    BOOST_CHECK_EQUAL_COLLECTIONS(sec1_ccc_res.begin(), sec1_ccc_res.end(), sec1_ccc_expected.begin(), sec1_ccc_expected.end());
+
+    test_args.SelectConfigNetwork("sec2");
+
+    // same as original
+    BOOST_CHECK(test_args.GetArg("-a", "xxx") == ""
+                && test_args.GetArg("-b", "xxx") == "1"
+                && test_args.GetArg("-d", "xxx") == "e"
+                && test_args.GetArg("-fff", "xxx") == "0"
+                && test_args.GetArg("-ggg", "xxx") == "1"
+                && test_args.GetArg("-zzz", "xxx") == "xxx"
+                && test_args.GetArg("-h", "xxx") == "0"
+               );
+    // section-specific setting
+    BOOST_CHECK(test_args.GetArg("-iii", "xxx") == "2");
+    // section takes priority for multiple values
+    BOOST_CHECK(test_args.GetArg("-ccc", "xxx") == "extend3");
+    // check multiple values works
+    const std::vector<std::string> sec2_ccc_expected = {"extend3","argument","multiple"};
+    const auto& sec2_ccc_res = test_args.GetArgs("-ccc");
+    BOOST_CHECK_EQUAL_COLLECTIONS(sec2_ccc_res.begin(), sec2_ccc_res.end(), sec2_ccc_expected.begin(), sec2_ccc_expected.end());
+
+    // Test section only options
+
+    test_args.SetNetworkOnlyArg("-d");
+    test_args.SetNetworkOnlyArg("-ccc");
+    test_args.SetNetworkOnlyArg("-h");
+
+    test_args.SelectConfigNetwork(CBaseChainParams::MAIN);
+    BOOST_CHECK(test_args.GetArg("-d", "xxx") == "e");
+    BOOST_CHECK(test_args.GetArgs("-ccc").size() == 2);
+    BOOST_CHECK(test_args.GetArg("-h", "xxx") == "0");
+
+    test_args.SelectConfigNetwork("sec1");
+    BOOST_CHECK(test_args.GetArg("-d", "xxx") == "eee");
+    BOOST_CHECK(test_args.GetArgs("-d").size() == 1);
+    BOOST_CHECK(test_args.GetArgs("-ccc").size() == 2);
+    BOOST_CHECK(test_args.GetArg("-h", "xxx") == "1");
+
+    test_args.SelectConfigNetwork("sec2");
+    BOOST_CHECK(test_args.GetArg("-d", "xxx") == "xxx");
+    BOOST_CHECK(test_args.GetArgs("-d").size() == 0);
+    BOOST_CHECK(test_args.GetArgs("-ccc").size() == 1);
+    BOOST_CHECK(test_args.GetArg("-h", "xxx") == "0");
 }
 
 BOOST_AUTO_TEST_CASE(util_GetArg)
 {
     TestArgsManager testArgs;
-    testArgs.GetMapArgs().clear();
-    testArgs.GetMapArgs()["strtest1"] = "string...";
+    testArgs.GetOverrideArgs().clear();
+    testArgs.GetOverrideArgs()["strtest1"] = {"string..."};
     // strtest2 undefined on purpose
-    testArgs.GetMapArgs()["inttest1"] = "12345";
-    testArgs.GetMapArgs()["inttest2"] = "81985529216486895";
+    testArgs.GetOverrideArgs()["inttest1"] = {"12345"};
+    testArgs.GetOverrideArgs()["inttest2"] = {"81985529216486895"};
     // inttest3 undefined on purpose
-    testArgs.GetMapArgs()["booltest1"] = "";
+    testArgs.GetOverrideArgs()["booltest1"] = {""};
     // booltest2 undefined on purpose
-    testArgs.GetMapArgs()["booltest3"] = "0";
-    testArgs.GetMapArgs()["booltest4"] = "1";
+    testArgs.GetOverrideArgs()["booltest3"] = {"0"};
+    testArgs.GetOverrideArgs()["booltest4"] = {"1"};
+
+    // priorities
+    testArgs.GetOverrideArgs()["pritest1"] = {"a", "b"};
+    testArgs.GetConfigArgs()["pritest2"] = {"a", "b"};
+    testArgs.GetOverrideArgs()["pritest3"] = {"a"};
+    testArgs.GetConfigArgs()["pritest3"] = {"b"};
+    testArgs.GetOverrideArgs()["pritest4"] = {"a","b"};
+    testArgs.GetConfigArgs()["pritest4"] = {"c","d"};
 
     BOOST_CHECK_EQUAL(testArgs.GetArg("strtest1", "default"), "string...");
     BOOST_CHECK_EQUAL(testArgs.GetArg("strtest2", "default"), "default");
@@ -420,6 +516,11 @@ BOOST_AUTO_TEST_CASE(util_GetArg)
     BOOST_CHECK_EQUAL(testArgs.GetBoolArg("booltest2", false), false);
     BOOST_CHECK_EQUAL(testArgs.GetBoolArg("booltest3", false), false);
     BOOST_CHECK_EQUAL(testArgs.GetBoolArg("booltest4", false), true);
+
+    BOOST_CHECK_EQUAL(testArgs.GetArg("pritest1", "default"), "b");
+    BOOST_CHECK_EQUAL(testArgs.GetArg("pritest2", "default"), "a");
+    BOOST_CHECK_EQUAL(testArgs.GetArg("pritest3", "default"), "a");
+    BOOST_CHECK_EQUAL(testArgs.GetArg("pritest4", "default"), "b");
 }
 
 BOOST_AUTO_TEST_CASE(util_GetChainName)
@@ -432,7 +533,8 @@ BOOST_AUTO_TEST_CASE(util_GetChainName)
     const char* argv_both[] = {"cmd", "-testnet", "-regtest"};
 
     // equivalent to "-testnet"
-    const char* testnetconf = "testnet=1\nregtest=0\n";
+    // regtest in testnet section is ignored
+    const char* testnetconf = "testnet=1\nregtest=0\n[test]\nregtest=1";
 
     test_args.ParseParameters(0, (char**)argv_testnet);
     BOOST_CHECK_EQUAL(test_args.GetChainName(), "main");
@@ -468,6 +570,30 @@ BOOST_AUTO_TEST_CASE(util_GetChainName)
     test_args.ParseParameters(3, (char**)argv_both);
     test_args.ReadConfigString(testnetconf);
     BOOST_CHECK_THROW(test_args.GetChainName(), std::runtime_error);
+
+    // check setting the network to test (and thus making
+    // [test] regtest=1 potentially relevent) doesn't break things
+    test_args.SelectConfigNetwork("test");
+
+    test_args.ParseParameters(0, (char**)argv_testnet);
+    test_args.ReadConfigString(testnetconf);
+    BOOST_CHECK_EQUAL(test_args.GetChainName(), "test");
+
+    test_args.ParseParameters(2, (char**)argv_testnet);
+    test_args.ReadConfigString(testnetconf);
+    BOOST_CHECK_EQUAL(test_args.GetChainName(), "test");
+
+    test_args.ParseParameters(2, (char**)argv_regtest);
+    test_args.ReadConfigString(testnetconf);
+    BOOST_CHECK_THROW(test_args.GetChainName(), std::runtime_error);
+
+    test_args.ParseParameters(2, (char**)argv_test_no_reg);
+    test_args.ReadConfigString(testnetconf);
+    BOOST_CHECK_EQUAL(test_args.GetChainName(), "test");
+
+    test_args.ParseParameters(3, (char**)argv_both);
+    test_args.ReadConfigString(testnetconf);
+    BOOST_CHECK_THROW(test_args.GetChainName(), std::runtime_error);
 }
 
 BOOST_AUTO_TEST_CASE(util_FormatMoney)
diff --git a/src/util.cpp b/src/util.cpp
index f55c9c8c34..1fb40ae7a1 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -455,39 +455,204 @@ static bool InterpretBool(const std::string& strValue)
     return (atoi(strValue) != 0);
 }
 
+/** Internal helper functions for ArgsManager */
+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)
+    {
+        assert(arg.length() > 1 && arg[0] == '-');
+        return "-" + am.m_network + "." + arg.substr(1);
+    }
+
+    /** Find arguments in a map and add them to a vector */
+    static inline void AddArgs(std::vector<std::string>& res, const MapArgs& map_args, const std::string& arg)
+    {
+        auto it = map_args.find(arg);
+        if (it != map_args.end()) {
+            res.insert(res.end(), it->second.begin(), it->second.end());
+        }
+    }
+
+    /** Return true/false if an argument is set in a map, and also
+     *  return the first (or last) of the possibly multiple values it has
+     */
+    static inline std::pair<bool,std::string> GetArgHelper(const MapArgs& map_args, const std::string& arg, bool getLast = false)
+    {
+        auto it = map_args.find(arg);
+
+        if (it == map_args.end() || it->second.empty()) {
+            return std::make_pair(false, std::string());
+        }
+
+        if (getLast) {
+            return std::make_pair(true, it->second.back());
+        } else {
+            return std::make_pair(true, it->second.front());
+        }
+    }
+
+    /* Get the string value of an argument, returning a pair of a boolean
+     * indicating the argument was found, and the value for the argument
+     * if it was found (or the empty string if not found).
+     */
+    static inline std::pair<bool,std::string> GetArg(const ArgsManager &am, const std::string& arg)
+    {
+        LOCK(am.cs_args);
+        std::pair<bool,std::string> found_result(false, std::string());
+
+        // We pass "true" to GetArgHelper in order to return the last
+        // argument value seen from the command line (so "bitcoind -foo=bar
+        // -foo=baz" gives GetArg(am,"foo")=={true,"baz"}
+        found_result = GetArgHelper(am.m_override_args, arg, true);
+        if (found_result.first) {
+            return found_result;
+        }
+
+        // But in contrast we return the first argument seen in a config file,
+        // so "foo=bar \n foo=baz" in the config file gives
+        // GetArg(am,"foo")={true,"bar"}
+        if (!am.m_network.empty()) {
+            found_result = GetArgHelper(am.m_config_args, NetworkArg(am, arg));
+            if (found_result.first) {
+                return found_result;
+            }
+        }
+
+        if (UseDefaultSection(am, arg)) {
+            found_result = GetArgHelper(am.m_config_args, arg);
+            if (found_result.first) {
+                return found_result;
+            }
+        }
+
+        return found_result;
+    }
+
+    /* Special test for -testnet and -regtest args, because we
+     * don't want to be confused by craziness like "[regtest] testnet=1"
+     */
+    static inline bool GetNetBoolArg(const ArgsManager &am, const std::string& net_arg)
+    {
+        std::pair<bool,std::string> found_result(false,std::string());
+        found_result = GetArgHelper(am.m_override_args, net_arg, true);
+        if (!found_result.first) {
+            found_result = GetArgHelper(am.m_config_args, net_arg, true);
+            if (!found_result.first) {
+                return false; // not set
+            }
+        }
+        return InterpretBool(found_result.second); // is set, so evaluate
+    }
+};
+
 /**
  * Interpret -nofoo as if the user supplied -foo=0.
  *
- * This method also tracks when the -no form was supplied, and treats "-foo" as
- * a negated option when this happens. This can be later checked using the
+ * This method also tracks when the -no form was supplied, and if so,
+ * checks whether there was a double-negative (-nofoo=0 -> -foo=1).
+ *
+ * If there was not a double negative, it removes the "no" from the key,
+ * and returns true, indicating the caller should clear the args vector
+ * to indicate a negated option.
+ *
+ * If there was a double negative, it removes "no" from the key, sets the
+ * value to "1" and returns false.
+ *
+ * If there was no "no", it leaves key and value untouched and returns
+ * false.
+ *
+ * Where an option was negated can be later checked using the
  * IsArgNegated() method. One use case for this is to have a way to disable
  * options that are not normally boolean (e.g. using -nodebuglogfile to request
  * that debug log output is not sent to any file at all).
  */
-void ArgsManager::InterpretNegatedOption(std::string& key, std::string& val)
+static bool InterpretNegatedOption(std::string& key, std::string& val)
 {
-    if (key.substr(0, 3) == "-no") {
+    assert(key[0] == '-');
+
+    size_t option_index = key.find('.');
+    if (option_index == std::string::npos) {
+        option_index = 1;
+    } else {
+        ++option_index;
+    }
+    if (key.substr(option_index, 2) == "no") {
         bool bool_val = InterpretBool(val);
+        key.erase(option_index, 2);
         if (!bool_val ) {
             // Double negatives like -nofoo=0 are supported (but discouraged)
             LogPrintf("Warning: parsed potentially confusing double-negative %s=%s\n", key, val);
+            val = "1";
+        } else {
+            return true;
         }
-        key.erase(1, 2);
-        m_negated_args.insert(key);
-        val = bool_val ? "0" : "1";
-    } else {
-        // In an invocation like "bitcoind -nofoo -foo" we want to unmark -foo
-        // as negated when we see the second option.
-        m_negated_args.erase(key);
     }
+    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::WarnForSectionOnlyArgs()
+{
+    // if there's no section selected, don't worry
+    if (m_network.empty()) return;
+
+    // if it's okay to use the default section for this network, don't worry
+    if (m_network == CBaseChainParams::MAIN) return;
+
+    for (const auto& arg : m_network_only_args) {
+        std::pair<bool, std::string> found_result;
+
+        // if this option is overridden it's fine
+        found_result = ArgsManagerHelper::GetArgHelper(m_override_args, arg);
+        if (found_result.first) continue;
+
+        // if there's a network-specific value for this option, it's fine
+        found_result = ArgsManagerHelper::GetArgHelper(m_config_args, ArgsManagerHelper::NetworkArg(*this, arg));
+        if (found_result.first) continue;
+
+        // if there isn't a default value for this option, it's fine
+        found_result = ArgsManagerHelper::GetArgHelper(m_config_args, arg);
+        if (!found_result.first) continue;
+
+        // otherwise, issue a warning
+        LogPrintf("Warning: Config setting for %s only applied on %s network when in [%s] section.\n", arg, m_network, m_network);
+    }
+}
+
+void ArgsManager::SelectConfigNetwork(const std::string& network)
+{
+    m_network = network;
 }
 
 void ArgsManager::ParseParameters(int argc, const char* const argv[])
 {
     LOCK(cs_args);
-    mapArgs.clear();
-    mapMultiArgs.clear();
-    m_negated_args.clear();
+    m_override_args.clear();
 
     for (int i = 1; i < argc; i++) {
         std::string key(argv[i]);
@@ -510,55 +675,79 @@ void ArgsManager::ParseParameters(int argc, const char* const argv[])
         if (key.length() > 1 && key[1] == '-')
             key.erase(0, 1);
 
-        // Transform -nofoo to -foo=0
-        InterpretNegatedOption(key, val);
-
-        mapArgs[key] = val;
-        mapMultiArgs[key].push_back(val);
+        // Check for -nofoo
+        if (InterpretNegatedOption(key, val)) {
+            m_override_args[key].clear();
+        } else {
+            m_override_args[key].push_back(val);
+        }
     }
 }
 
 std::vector<std::string> ArgsManager::GetArgs(const std::string& strArg) const
 {
+    std::vector<std::string> result = {};
+    if (IsArgNegated(strArg)) return result; // special case
+
     LOCK(cs_args);
-    auto it = mapMultiArgs.find(strArg);
-    if (it != mapMultiArgs.end()) return it->second;
-    return {};
+
+    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;
 }
 
 bool ArgsManager::IsArgSet(const std::string& strArg) const
 {
-    LOCK(cs_args);
-    return mapArgs.count(strArg);
+    if (IsArgNegated(strArg)) return true; // special case
+    return ArgsManagerHelper::GetArg(*this, strArg).first;
 }
 
 bool ArgsManager::IsArgNegated(const std::string& strArg) const
 {
     LOCK(cs_args);
-    return m_negated_args.find(strArg) != m_negated_args.end();
+
+    const auto& ov = m_override_args.find(strArg);
+    if (ov != m_override_args.end()) return ov->second.empty();
+
+    if (!m_network.empty()) {
+        const auto& cfs = m_config_args.find(ArgsManagerHelper::NetworkArg(*this, strArg));
+        if (cfs != m_config_args.end()) return cfs->second.empty();
+    }
+
+    const auto& cf = m_config_args.find(strArg);
+    if (cf != m_config_args.end()) return cf->second.empty();
+
+    return false;
 }
 
 std::string ArgsManager::GetArg(const std::string& strArg, const std::string& strDefault) const
 {
-    LOCK(cs_args);
-    auto it = mapArgs.find(strArg);
-    if (it != mapArgs.end()) return it->second;
+    if (IsArgNegated(strArg)) return "0";
+    std::pair<bool,std::string> found_res = ArgsManagerHelper::GetArg(*this, strArg);
+    if (found_res.first) return found_res.second;
     return strDefault;
 }
 
 int64_t ArgsManager::GetArg(const std::string& strArg, int64_t nDefault) const
 {
-    LOCK(cs_args);
-    auto it = mapArgs.find(strArg);
-    if (it != mapArgs.end()) return atoi64(it->second);
+    if (IsArgNegated(strArg)) return 0;
+    std::pair<bool,std::string> found_res = ArgsManagerHelper::GetArg(*this, strArg);
+    if (found_res.first) return atoi64(found_res.second);
     return nDefault;
 }
 
 bool ArgsManager::GetBoolArg(const std::string& strArg, bool fDefault) const
 {
-    LOCK(cs_args);
-    auto it = mapArgs.find(strArg);
-    if (it != mapArgs.end()) return InterpretBool(it->second);
+    if (IsArgNegated(strArg)) return false;
+    std::pair<bool,std::string> found_res = ArgsManagerHelper::GetArg(*this, strArg);
+    if (found_res.first) return InterpretBool(found_res.second);
     return fDefault;
 }
 
@@ -581,8 +770,7 @@ bool ArgsManager::SoftSetBoolArg(const std::string& strArg, bool fValue)
 void ArgsManager::ForceSetArg(const std::string& strArg, const std::string& strValue)
 {
     LOCK(cs_args);
-    mapArgs[strArg] = strValue;
-    mapMultiArgs[strArg] = {strValue};
+    m_override_args[strArg] = {strValue};
 }
 
 bool HelpRequested(const ArgsManager& args)
@@ -745,18 +933,23 @@ void ArgsManager::ReadConfigStream(std::istream& stream)
 
     for (boost::program_options::detail::config_file_iterator it(stream, setOptions), end; it != end; ++it)
     {
-        // Don't overwrite existing settings so command line settings override bitcoin.conf
         std::string strKey = std::string("-") + it->string_key;
         std::string strValue = it->value[0];
-        InterpretNegatedOption(strKey, strValue);
-        if (mapArgs.count(strKey) == 0)
-            mapArgs[strKey] = strValue;
-        mapMultiArgs[strKey].push_back(strValue);
+        if (InterpretNegatedOption(strKey, strValue)) {
+            m_config_args[strKey].clear();
+        } else {
+            m_config_args[strKey].push_back(strValue);
+        }
     }
 }
 
 void ArgsManager::ReadConfigFile(const std::string& confPath)
 {
+    {
+        LOCK(cs_args);
+        m_config_args.clear();
+    }
+
     fs::ifstream stream(GetConfigFile(confPath));
 
     // ok to not have a config file
@@ -773,8 +966,8 @@ void ArgsManager::ReadConfigFile(const std::string& confPath)
 
 std::string ArgsManager::GetChainName() const
 {
-    bool fRegTest = GetBoolArg("-regtest", false);
-    bool fTestNet = GetBoolArg("-testnet", false);
+    bool fRegTest = ArgsManagerHelper::GetNetBoolArg(*this, "-regtest");
+    bool fTestNet = ArgsManagerHelper::GetNetBoolArg(*this, "-testnet");
 
     if (fTestNet && fRegTest)
         throw std::runtime_error("Invalid combination of -regtest and -testnet.");
diff --git a/src/util.h b/src/util.h
index 18d2076a05..ffdee99d27 100644
--- a/src/util.h
+++ b/src/util.h
@@ -24,6 +24,7 @@
 #include <exception>
 #include <map>
 #include <memory>
+#include <set>
 #include <stdint.h>
 #include <string>
 #include <unordered_set>
@@ -225,18 +226,36 @@ inline bool IsSwitchChar(char c)
 class ArgsManager
 {
 protected:
+    friend class ArgsManagerHelper;
+
     mutable CCriticalSection cs_args;
-    std::map<std::string, std::string> mapArgs;
-    std::map<std::string, std::vector<std::string>> mapMultiArgs;
-    std::unordered_set<std::string> m_negated_args;
+    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
+     */
+    void SelectConfigNetwork(const std::string& network);
+
     void ParseParameters(int argc, const char*const argv[]);
     void ReadConfigFile(const std::string& confPath);
 
     /**
+     * Log warnings for options in m_section_only_args when
+     * they are specified in the default section but not overridden
+     * on the command line or in a network-specific section in the
+     * config file.
+     */
+    void WarnForSectionOnlyArgs();
+
+    /**
      * Return a vector of strings of the given argument
      *
      * @param strArg Argument to get (e.g. "-foo")
@@ -315,11 +334,6 @@ public:
      * @return CBaseChainParams::MAIN by default; raises runtime error if an invalid combination is given.
      */
     std::string GetChainName() const;
-
-private:
-
-    // Munge -nofoo into -foo=0 and track the value as negated.
-    void InterpretNegatedOption(std::string &key, std::string &val);
 };
 
 extern ArgsManager gArgs;
diff --git a/test/functional/feature_config_args.py b/test/functional/feature_config_args.py
index a1d22191af..e9924451d1 100755
--- a/test/functional/feature_config_args.py
+++ b/test/functional/feature_config_args.py
@@ -29,8 +29,13 @@ class ConfArgsTest(BitcoinTestFramework):
 
         # Check that using non-existent datadir in conf file fails
         conf_file = os.path.join(default_data_dir, "bitcoin.conf")
-        with open(conf_file, 'a', encoding='utf8') as f:
+
+        # datadir needs to be set before [regtest] section
+        conf_file_contents = open(conf_file, encoding='utf8').read()
+        with open(conf_file, 'w', encoding='utf8') as f:
             f.write("datadir=" + new_data_dir + "\n")
+            f.write(conf_file_contents)
+
         self.nodes[0].assert_start_raises_init_error(['-conf=' + conf_file], 'Error reading configuration file: specified data directory "' + new_data_dir + '" does not exist.')
 
         # Create the directory and ensure the config file now works
diff --git a/test/functional/test_framework/util.py b/test/functional/test_framework/util.py
index f22322fbbc..4ec3175cd6 100644
--- a/test/functional/test_framework/util.py
+++ b/test/functional/test_framework/util.py
@@ -294,6 +294,7 @@ def initialize_datadir(dirname, n):
         os.makedirs(datadir)
     with open(os.path.join(datadir, "bitcoin.conf"), 'w', encoding='utf8') as f:
         f.write("regtest=1\n")
+        f.write("[regtest]\n")
         f.write("port=" + str(p2p_port(n)) + "\n")
         f.write("rpcport=" + str(rpc_port(n)) + "\n")
         f.write("server=1\n")