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

src/util.h

@@ -24,6 +24,7 @@
 #include <exception>
 #include <map>
 #include <memory>
+#include <set>
 #include <stdint.h>
 #include <string>
 #include <unordered_set>
@@ -225,17 +226,35 @@ 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
      *
@@ -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;