fix an issue with default strings of arrays and config out. (#1155)

Fixes #1154

---------

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

Author: phlptp

include/CLI/impl/Config_inl.hpp

@@ -549,7 +549,9 @@ ConfigBase::to_config(const App *app, bool default_also, bool write_description,
                 bool isDefault = false;
                 if(value.empty() && default_also) {
                     if(!opt->get_default_str().empty()) {
-                        value = detail::convert_arg_for_ini(opt->get_default_str(), stringQuote, literalQuote, false);
+                        results_t res;
+                        opt->results(res);
+                        value = detail::ini_join(res, arraySeparator, arrayStart, arrayEnd, stringQuote, literalQuote);
                     } else if(opt->get_expected_min() == 0) {
                         value = "false";
                     } else if(opt->get_run_callback_for_default() || !opt->get_required()) {

include/CLI/impl/Option_inl.hpp

@@ -686,7 +686,8 @@ CLI11_INLINE int Option::_add_result(std::string &&result, std::vector<std::stri
         }
     }
 
-    if((allow_extra_args_ || get_expected_max() > 1) && !result.empty() && result.front() == '[' &&
+    if((allow_extra_args_ || get_expected_max() > 1 || get_type_size() > 1) && !result.empty() &&
+       result.front() == '[' &&
        result.back() == ']') {  // this is now a vector string likely from the default or user entry
 
         result.pop_back();

tests/ConfigFileTest.cpp

@@ -14,6 +14,8 @@
 #include <tuple>
 #include <vector>
 
+#include <array>
+
 TEST_CASE("StringBased: convert_arg_for_ini", "[config]") {
 
     CHECK("\"\"" == CLI::detail::convert_arg_for_ini(std::string{}));
@@ -4114,3 +4116,20 @@ TEST_CASE_METHOD(TApp, "RoundTripEmptyVector", "[config]") {
     app.parse_from_stream(out);
     CHECK(cv.empty());
 }
+
+TEST_CASE_METHOD(TApp, "RoundTripArrayFloat", "[config]") {
+    std::array<float, 2> cv{-1.0F, 1.0F};
+    app.add_option("-c", cv)->capture_default_str();
+
+    args = {};
+
+    run();
+    std::string configOut = app.config_to_str(true, true);
+    app.clear();
+    std::stringstream out(configOut);
+    cv[0] = -3.0F;
+    cv[1] = 4.0F;
+    app.parse_from_stream(out);
+    CHECK(cv[0] == -1.0F);
+    CHECK(cv[1] == 1.0F);
+}