fix: Suppress spurious error output for --help (#1607)

examples/cli/main.cpp

@@ -169,8 +169,9 @@ struct SDCliParams {
             return 1;
         };
 
-        auto on_help_arg = [&](int argc, const char** argv, int index) {
+        auto on_help_arg = [&](int argc, const char** argv, int index, bool& valid) {
             normal_exit = true;
+            valid       = true;
             return -1;
         };
 

examples/common/common.cpp

@@ -245,6 +245,7 @@ bool parse_options(int argc, const char** argv, const std::vector<ArgOptions>& o
         return false;
     };
 
+    bool valid = false;
     for (int i = 1; i < argc; i++) {
         arg            = argv[i];
         bool found_arg = false;
@@ -287,7 +288,7 @@ bool parse_options(int argc, const char** argv, const std::vector<ArgOptions>& o
                 break;
 
             if (match_and_apply(options.manual_options, [&](auto& option) {
-                    int ret = option.cb(argc, argv, i);
+                    int ret = option.cb(argc, argv, i, valid);
                     if (ret < 0) {
                         invalid_arg = true;
                         return;
@@ -299,7 +300,9 @@ bool parse_options(int argc, const char** argv, const std::vector<ArgOptions>& o
         }
 
         if (invalid_arg) {
-            LOG_ERROR("error: invalid parameter for argument: %s", arg.c_str());
+            if (!valid) {
+                LOG_ERROR("error: invalid parameter for argument: %s", arg.c_str());
+            }
             return false;
         }
         if (!found_arg) {

examples/common/common.h

@@ -56,11 +56,42 @@ struct BoolOption {
     bool* target;
 };
 
+struct ManualFunction {
+    std::function<int(int, const char**, int, bool&)> _func;
+
+    ManualFunction() = default;
+
+    ManualFunction(std::function<int(int argc, const char** argv, int index, bool& valid)> func)
+        : _func(std::move(func)) {
+    }
+
+    template <typename F>
+    ManualFunction(F func)
+        : _func(make_function(func)) {
+    }
+
+    int operator()(int argc, const char** argv, int index, bool& valid) const {
+        return _func(argc, argv, index, valid);
+    }
+
+private:
+    template <typename F>
+    static std::function<int(int, const char**, int, bool&)> make_function(F func) {
+        if constexpr (std::is_invocable_v<F, int, const char**, int, bool&>) {
+            return func;
+        } else {
+            return [func](int argc, const char** argv, int index, bool&) {
+                return func(argc, argv, index);
+            };
+        }
+    }
+};
+
 struct ManualOption {
     std::string short_name;
     std::string long_name;
     std::string desc;
-    std::function<int(int argc, const char** argv, int index)> cb;
+    ManualFunction cb;
 };
 
 struct ArgOptions {

examples/server/runtime.cpp

@@ -203,8 +203,9 @@ ArgOptions SDSvrParams::get_options() {
         {"", "--color", "colors the logging tags according to level", true, &color},
     };
 
-    auto on_help_arg = [&](int, const char**, int) {
+    auto on_help_arg = [&](int, const char**, int, bool& valid) {
         normal_exit = true;
+        valid       = true;
         return -1;
     };