ArgsManager: drop m_negated_args

When a -nofoo option is seen, instead of adding it to a separate
set of negated args, set the arg as being an empty vector of strings.

This changes the behaviour in some ways:
 - -nofoo=0 still sets foo=1 but no longer treats it as a negated arg
 - -nofoo=1 -foo=2 has GetArgs() return [2] rather than [2,0]
 - "foo=2 \n -nofoo=1" in a config file no longer returns [2,0], just [0]
 - GetArgs returns an empty vector for negated args

3 files changed, 64 insertions, 54 deletions

diff --git a/src/test/util_tests.cpp b/src/test/util_tests.cpp
index f33cda6ff5..f04f6cf171 100644
--- a/src/test/util_tests.cpp
+++ b/src/test/util_tests.cpp
@@ -189,7 +189,6 @@ struct TestArgsManager : public ArgsManager
 {
     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; }
-    const std::unordered_set<std::string>& GetNegatedArgs() { return m_negated_args; }
     void ReadConfigString(const std::string str_config)
     {
         std::istringstream streamConfig(str_config);
@@ -250,7 +249,6 @@ BOOST_AUTO_TEST_CASE(util_GetBoolArg)
 
     // 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.
@@ -275,8 +273,8 @@ 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
@@ -285,12 +283,12 @@ 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
@@ -300,18 +298,15 @@ 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)
@@ -364,8 +359,8 @@ 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"
                );
 
@@ -376,8 +371,8 @@ 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
                    );
     }
@@ -389,19 +384,15 @@ 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);
 
@@ -410,7 +401,7 @@ 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"));
diff --git a/src/util.cpp b/src/util.cpp
index f8366fe694..3e69574022 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -519,35 +519,44 @@ public:
 /**
  * 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") {
         bool bool_val = InterpretBool(val);
+        key.erase(1, 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;
 }
 
 void ArgsManager::ParseParameters(int argc, const char* const argv[])
 {
     LOCK(cs_args);
     m_override_args.clear();
-    m_negated_args.clear();
 
     for (int i = 1; i < argc; i++) {
         std::string key(argv[i]);
@@ -570,16 +579,19 @@ 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);
-
-        m_override_args[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);
     ArgsManagerHelper::AddArgs(result, m_override_args, strArg);
@@ -589,17 +601,26 @@ std::vector<std::string> ArgsManager::GetArgs(const std::string& strArg) const
 
 bool ArgsManager::IsArgSet(const std::string& strArg) const
 {
+    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();
+
+    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
 {
+    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;
@@ -607,6 +628,7 @@ std::string ArgsManager::GetArg(const std::string& strArg, const std::string& st
 
 int64_t ArgsManager::GetArg(const std::string& strArg, int64_t nDefault) const
 {
+    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;
@@ -614,6 +636,7 @@ int64_t ArgsManager::GetArg(const std::string& strArg, int64_t nDefault) const
 
 bool ArgsManager::GetBoolArg(const std::string& strArg, bool fDefault) const
 {
+    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;
@@ -801,11 +824,13 @@ 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);
-        m_config_args[strKey].push_back(strValue);
+        if (InterpretNegatedOption(strKey, strValue)) {
+            m_config_args[strKey].clear();
+        } else {
+            m_config_args[strKey].push_back(strValue);
+        }
     }
 }
 
diff --git a/src/util.h b/src/util.h
index 01ff5992fb..6b80afc58f 100644
--- a/src/util.h
+++ b/src/util.h
@@ -228,7 +228,6 @@ protected:
     mutable CCriticalSection cs_args;
     std::map<std::string, std::vector<std::string>> m_override_args;
     std::map<std::string, std::vector<std::string>> m_config_args;
-    std::unordered_set<std::string> m_negated_args;
     void ReadConfigStream(std::istream& stream);
 
 public:
@@ -314,11 +313,6 @@ 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;