[MISC] Remove subcommand check

include/sharg/parser.hpp

@@ -360,7 +360,6 @@ class parser
      * \throws sharg::too_many_arguments if the command line call contained more arguments than expected.
      * \throws sharg::too_few_arguments if the command line call contained less arguments than expected.
      * \throws sharg::validation_error if the argument was not excepted by the provided validator.
-     * \throws sharg::user_input_error if a subparser was configured at construction but a subcommand is missing.
      *
      * \details
      *
@@ -428,9 +427,6 @@ class parser
         // Determine the format and subcommand.
         determine_format_and_subcommand();
 
-        // If a subcommand was provided, check that it is valid.
-        verify_subcommand();
-
         // Apply all defered operations to the parser, e.g., `add_option`, `add_flag`, `add_positional_option`.
         for (auto & operation : operations)
             operation();
@@ -1077,27 +1073,6 @@ class parser
         }
     }
 
-    /*!\brief Verifies that the subcommand was correctly specified.
-     * \throws sharg::user_input_error if a subparser was configured at construction but a subcommand is missing.
-     */
-    inline void verify_subcommand()
-    {
-        if (std::holds_alternative<detail::format_parse>(format) && !subcommands.empty() && sub_parser == nullptr)
-        {
-            assert(!subcommands.empty());
-            std::string subcommands_str{"["};
-            for (std::string const & command : subcommands)
-                subcommands_str += command + ", ";
-            subcommands_str.replace(subcommands_str.size() - 2, 2, "]"); // replace last ", " by "]"
-
-            throw user_input_error{"You misspelled the subcommand! Please specify which sub-program "
-                                   "you want to use: one of "
-                                   + subcommands_str
-                                   + ". Use -h/--help for more "
-                                     "information."};
-        }
-    }
-
     /*!\brief Parses the command line arguments according to the format.
      * \throws sharg::option_declared_multiple_times if an option that is not a list was declared multiple times.
      * \throws sharg::user_input_error if an incorrect argument is given as (positional) option value.

test/unit/parser/parser_design_error_test.cpp

@@ -263,25 +263,27 @@ TEST_F(design_error_test, subcommand_parser_error)
     EXPECT_THROW(parser.parse(), sharg::design_error);
 
     // no positional options are allowed
-    parser = get_subcommand_parser({"foo"}, {"foo"});
+    parser = get_subcommand_parser({"-f", "foo"}, {"foo"});
 
     EXPECT_THROW(parser.add_positional_option(flag_value, sharg::config{}), sharg::design_error);
     EXPECT_NO_THROW(parser.add_option(flag_value, sharg::config{.short_id = 'o'}));
     EXPECT_NO_THROW(parser.add_flag(flag_value, sharg::config{.short_id = 'f'}));
-    EXPECT_EQ(flag_value, false);
-
     EXPECT_THROW(parser.get_sub_parser(), sharg::design_error);
+    EXPECT_EQ(flag_value, false);
     EXPECT_NO_THROW(parser.parse()); // Prints nothing, but sets sub_parser.
     EXPECT_NO_THROW(parser.get_sub_parser());
+    EXPECT_EQ(flag_value, true);
+
+    flag_value = false;
 
     // options are allowed
     parser = get_subcommand_parser({"-o", "true"}, {"foo"});
 
     EXPECT_THROW(parser.add_positional_option(flag_value, sharg::config{}), sharg::design_error);
     EXPECT_NO_THROW(parser.add_option(flag_value, sharg::config{.short_id = 'o'}));
-    EXPECT_NO_THROW(parser.add_flag(flag_value, sharg::config{.short_id = 'f'}));
     EXPECT_EQ(flag_value, false);
-    EXPECT_THROW(parser.parse(), sharg::user_input_error); // Todo: Subcommand is required?
+    EXPECT_NO_THROW(parser.parse());
+    EXPECT_EQ(flag_value, true);
 }
 
 TEST_F(design_error_test, not_allowed_after_parse)