Coverage to 100% (#929)

remove old code since all arguments are quoted now and the code was not
being used, add coverage exclusion on some code that should never be
executed and add an additional test

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

include/CLI/StringTools.hpp

@@ -220,9 +220,6 @@ CLI11_INLINE std::vector<std::string> split_up(std::string str, char delimiter =
 /// the return value is the offset+1 which is required by the find_and_modify function.
 CLI11_INLINE std::size_t escape_detect(std::string &str, std::size_t offset);
 
-/// Add quotes if the string contains spaces
-CLI11_INLINE std::string &add_quotes_if_needed(std::string &str);
-
 /// get the value of an environmental variable or empty string if empty
 CLI11_INLINE std::string get_environment_value(const std::string &env_name);
 }  // namespace detail

include/CLI/impl/StringTools_inl.hpp

@@ -244,17 +244,6 @@ CLI11_INLINE std::size_t escape_detect(std::string &str, std::size_t offset) {
     return offset + 1;
 }
 
-CLI11_INLINE std::string &add_quotes_if_needed(std::string &str) {
-    if((str.front() != '"' && str.front() != '\'') || str.front() != str.back()) {
-        char quote = str.find('"') < str.find('\'') ? '\'' : '"';
-        if(str.find(' ') != std::string::npos) {
-            str.insert(0, 1, quote);
-            str.append(1, quote);
-        }
-    }
-    return str;
-}
-
 std::string get_environment_value(const std::string &env_name) {
     char *buffer = nullptr;
     std::string ename_string;

include/CLI/impl/Validators_inl.hpp

@@ -135,7 +135,7 @@ CLI11_INLINE path_type check_path(const char *file) noexcept {
     switch(stat.type()) {
     case std::filesystem::file_type::none:  // LCOV_EXCL_LINE
     case std::filesystem::file_type::not_found:
-        return path_type::nonexistent;
+        return path_type::nonexistent;  // LCOV_EXCL_LINE
     case std::filesystem::file_type::directory:
         return path_type::directory;
     case std::filesystem::file_type::symlink:

tests/AppTest.cpp

@@ -1101,6 +1101,42 @@ TEST_CASE_METHOD(TApp, "emptyVectorReturn", "[app]") {
     CHECK_FALSE(strs3.empty());
 }
 
+TEST_CASE_METHOD(TApp, "emptyVectorReturnReduce", "[app]") {
+
+    std::vector<std::string> strs;
+    std::vector<std::string> strs2;
+    std::vector<std::string> strs3;
+    auto *opt1 = app.add_option("--str", strs)->required()->expected(0, 2);
+    app.add_option("--str3", strs3)->expected(1, 3);
+    app.add_option("--str2", strs2)->expected(1, 1)->take_first();
+    args = {"--str"};
+
+    CHECK_NOTHROW(run());
+    CHECK(std::vector<std::string>({""}) == strs);
+    args = {"--str", "one", "two"};
+
+    run();
+
+    CHECK(std::vector<std::string>({"one", "two"}) == strs);
+
+    args = {"--str", "{}", "--str2", "{}", "test"};
+
+    run();
+
+    CHECK(strs.empty());
+    CHECK(std::vector<std::string>{"{}"} == strs2);
+    opt1->default_str("{}");
+    args = {"--str"};
+
+    CHECK_NOTHROW(run());
+    CHECK(strs.empty());
+    opt1->required(false);
+    args = {"--str3", "{}"};
+
+    CHECK_NOTHROW(run());
+    CHECK_FALSE(strs3.empty());
+}
+
 TEST_CASE_METHOD(TApp, "RequiredOptsDoubleShort", "[app]") {
 
     std::vector<std::string> strs;