Fix lack of warning of unrecognized section names

1. Fix lack of warning by collecting all section names by moving
   m_config_sections.clear() to ArgsManager::ReadConfigFiles().
2. Add info(file name, line number) to warning message.
3. Add a test code to confirm this situation.
3. Do clear() in ReadConfigString().

2 files changed, 23 insertions, 20 deletions

diff --git a/src/util/system.cpp b/src/util/system.cpp
index 27ed24d012..9e02a227cb 100644
--- a/src/util/system.cpp
+++ b/src/util/system.cpp
@@ -354,8 +354,7 @@ const std::set<std::string> ArgsManager::GetUnsuitableSectionOnlyArgs() const
     return unsuitables;
 }
 
-
-const std::set<std::string> ArgsManager::GetUnrecognizedSections() const
+const std::list<SectionInfo> ArgsManager::GetUnrecognizedSections() const
 {
     // Section names to be recognized in the config file.
     static const std::set<std::string> available_sections{
@@ -363,14 +362,11 @@ const std::set<std::string> ArgsManager::GetUnrecognizedSections() const
         CBaseChainParams::TESTNET,
         CBaseChainParams::MAIN
     };
-    std::set<std::string> diff;
 
     LOCK(cs_args);
-    std::set_difference(
-        m_config_sections.begin(), m_config_sections.end(),
-        available_sections.begin(), available_sections.end(),
-        std::inserter(diff, diff.end()));
-    return diff;
+    std::list<SectionInfo> unrecognized = m_config_sections;
+    unrecognized.remove_if([](const SectionInfo& appeared){ return available_sections.find(appeared.m_name) != available_sections.end(); });
+    return unrecognized;
 }
 
 void ArgsManager::SelectConfigNetwork(const std::string& network)
@@ -794,7 +790,7 @@ static std::string TrimString(const std::string& str, const std::string& pattern
     return str.substr(front, end - front + 1);
 }
 
-static bool GetConfigOptions(std::istream& stream, std::string& error, std::vector<std::pair<std::string, std::string>>& options, std::set<std::string>& sections)
+static bool GetConfigOptions(std::istream& stream, const std::string& filepath, std::string& error, std::vector<std::pair<std::string, std::string>>& options, std::list<SectionInfo>& sections)
 {
     std::string str, prefix;
     std::string::size_type pos;
@@ -810,7 +806,7 @@ static bool GetConfigOptions(std::istream& stream, std::string& error, std::vect
         if (!str.empty()) {
             if (*str.begin() == '[' && *str.rbegin() == ']') {
                 const std::string section = str.substr(1, str.size() - 2);
-                sections.insert(section);
+                sections.emplace_back(SectionInfo{section, filepath, linenr});
                 prefix = section + '.';
             } else if (*str.begin() == '-') {
                 error = strprintf("parse error on line %i: %s, options in configuration file must be specified without leading -", linenr, str);
@@ -823,8 +819,8 @@ static bool GetConfigOptions(std::istream& stream, std::string& error, std::vect
                     return false;
                 }
                 options.emplace_back(name, value);
-                if ((pos = name.rfind('.')) != std::string::npos) {
-                    sections.insert(name.substr(0, pos));
+                if ((pos = name.rfind('.')) != std::string::npos && prefix.length() <= pos) {
+                    sections.emplace_back(SectionInfo{name.substr(0, pos), filepath, linenr});
                 }
             } else {
                 error = strprintf("parse error on line %i: %s", linenr, str);
@@ -839,12 +835,11 @@ static bool GetConfigOptions(std::istream& stream, std::string& error, std::vect
     return true;
 }
 
-bool ArgsManager::ReadConfigStream(std::istream& stream, std::string& error, bool ignore_invalid_keys)
+bool ArgsManager::ReadConfigStream(std::istream& stream, const std::string& filepath, std::string& error, bool ignore_invalid_keys)
 {
     LOCK(cs_args);
     std::vector<std::pair<std::string, std::string>> options;
-    m_config_sections.clear();
-    if (!GetConfigOptions(stream, error, options, m_config_sections)) {
+    if (!GetConfigOptions(stream, filepath, error, options, m_config_sections)) {
         return false;
     }
     for (const std::pair<std::string, std::string>& option : options) {
@@ -875,6 +870,7 @@ bool ArgsManager::ReadConfigFiles(std::string& error, bool ignore_invalid_keys)
     {
         LOCK(cs_args);
         m_config_args.clear();
+        m_config_sections.clear();
     }
 
     const std::string confPath = GetArg("-conf", BITCOIN_CONF_FILENAME);
@@ -882,7 +878,7 @@ bool ArgsManager::ReadConfigFiles(std::string& error, bool ignore_invalid_keys)
 
     // ok to not have a config file
     if (stream.good()) {
-        if (!ReadConfigStream(stream, error, ignore_invalid_keys)) {
+        if (!ReadConfigStream(stream, confPath, error, ignore_invalid_keys)) {
             return false;
         }
         // if there is an -includeconf in the override args, but it is empty, that means the user
@@ -913,7 +909,7 @@ bool ArgsManager::ReadConfigFiles(std::string& error, bool ignore_invalid_keys)
             for (const std::string& to_include : includeconf) {
                 fsbridge::ifstream include_config(GetConfigFile(to_include));
                 if (include_config.good()) {
-                    if (!ReadConfigStream(include_config, error, ignore_invalid_keys)) {
+                    if (!ReadConfigStream(include_config, to_include, error, ignore_invalid_keys)) {
                         return false;
                     }
                     LogPrintf("Included configuration file %s\n", to_include.c_str());
diff --git a/src/util/system.h b/src/util/system.h
index 8867e49478..cb66c470a6 100644
--- a/src/util/system.h
+++ b/src/util/system.h
@@ -132,6 +132,13 @@ enum class OptionsCategory {
     HIDDEN // Always the last option to avoid printing these in the help
 };
 
+struct SectionInfo
+{
+    std::string m_name;
+    std::string m_file;
+    int m_line;
+};
+
 class ArgsManager
 {
 protected:
@@ -152,9 +159,9 @@ protected:
     std::string m_network GUARDED_BY(cs_args);
     std::set<std::string> m_network_only_args GUARDED_BY(cs_args);
     std::map<OptionsCategory, std::map<std::string, Arg>> m_available_args GUARDED_BY(cs_args);
-    std::set<std::string> m_config_sections GUARDED_BY(cs_args);
+    std::list<SectionInfo> m_config_sections GUARDED_BY(cs_args);
 
-    NODISCARD bool ReadConfigStream(std::istream& stream, std::string& error, bool ignore_invalid_keys = false);
+    NODISCARD bool ReadConfigStream(std::istream& stream, const std::string& filepath, std::string& error, bool ignore_invalid_keys = false);
 
 public:
     ArgsManager();
@@ -178,7 +185,7 @@ public:
     /**
      * Log warnings for unrecognized section names in the config file.
      */
-    const std::set<std::string> GetUnrecognizedSections() const;
+    const std::list<SectionInfo> GetUnrecognizedSections() const;
 
     /**
      * Return a vector of strings of the given argument