fix(shell): fix the validation for the command while there is not any…

… positional argument (#2166)

Fix #2168.

src/replica/replica_backup.cpp

@@ -28,7 +28,6 @@
 #include <map>
 #include <memory>
 #include <string>
-#include <type_traits>
 #include <utility>
 #include <vector>
 

src/shell/command_utils.h

@@ -38,12 +38,13 @@ class host_port;
 
 struct shell_context;
 
-// Check if positional arguments are empty, and they should also be empty, which means only
+// Check if there is not any other positional argument except the command, which means only
 // parameters and flags are needed.
-inline dsn::error_s empty_pos_args(const argh::parser &cmd)
+inline dsn::error_s no_pos_arg(const argh::parser &cmd)
 {
-    if (cmd.size() > 0) {
-        return FMT_ERR(dsn::ERR_INVALID_PARAMETERS, "there shouldn't be any positional arguments");
+    // 1 means there is not any other positional argument except the command.
+    if (cmd.size() > 1) {
+        return FMT_ERR(dsn::ERR_INVALID_PARAMETERS, "there shouldn't be any positional argument");
     }
 
     return dsn::error_s::ok();
@@ -74,13 +75,22 @@ validate_cmd(const argh::parser &cmd,
         }
 
         if (flags.find(flag) == flags.end()) {
-            return FMT_ERR(dsn::ERR_INVALID_PARAMETERS, "unknown flag\n", flag);
+            return FMT_ERR(dsn::ERR_INVALID_PARAMETERS, "unknown flag", flag);
         }
     }
 
     return dsn::error_s::ok();
 }
 
+// Check if the parameters and flags are in the given set while there is not any positional
+// argument.
+inline dsn::error_s validate_cmd(const argh::parser &cmd,
+                                 const std::set<std::string> &params,
+                                 const std::set<std::string> &flags)
+{
+    return validate_cmd(cmd, params, flags, no_pos_arg);
+}
+
 bool validate_ip(shell_context *sc,
                  const std::string &host_port_str,
                  /*out*/ dsn::host_port &target_hp,

src/shell/commands/detect_hotkey.cpp

@@ -87,7 +87,7 @@ bool detect_hotkey(command_executor *e, shell_context *sc, arguments args)
 
     argh::parser cmd(args.argc, args.argv, argh::parser::PREFER_PARAM_FOR_UNREG_OPTION);
 
-    const auto &check = validate_cmd(cmd, params, flags, empty_pos_args);
+    const auto &check = validate_cmd(cmd, params, flags);
     if (!check) {
         // TODO(wangdan): use SHELL_PRINT* macros instead.
         fmt::print(stderr, "{}\n", check.description());

src/shell/commands/duplication.cpp

@@ -637,7 +637,7 @@ bool ls_dups(command_executor *e, shell_context *sc, arguments args)
     argh::parser cmd(args.argc, args.argv, argh::parser::PREFER_PARAM_FOR_UNREG_OPTION);
 
     // Check if input parameters and flags are valid.
-    const auto &check = validate_cmd(cmd, params, flags, empty_pos_args);
+    const auto &check = validate_cmd(cmd, params, flags);
     if (!check) {
         SHELL_PRINTLN_ERROR("{}", check.description());
         return false;