Config count anomaly (#1003)

Correct an anomaly when using config file processing with a default. In
this case the count always shows 1 even if the default file were not
actually used. This caused some issues in some applications and was a
change from previous versions.

---------

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

include/CLI/App.hpp

@@ -1231,7 +1231,7 @@ class App {
     void _process_config_file();
 
     /// Read and process a particular configuration file
-    void _process_config_file(const std::string &config_file, bool throw_error);
+    bool _process_config_file(const std::string &config_file, bool throw_error);
 
     /// Get envname options if not yet passed. Runs on *all* subcommands.
     void _process_env();

include/CLI/impl/App_inl.hpp

@@ -1065,18 +1065,23 @@ CLI11_NODISCARD CLI11_INLINE detail::Classifier App::_recognize(const std::strin
     return detail::Classifier::NONE;
 }
 
-CLI11_INLINE void App::_process_config_file(const std::string &config_file, bool throw_error) {
+CLI11_INLINE bool App::_process_config_file(const std::string &config_file, bool throw_error) {
     auto path_result = detail::check_path(config_file.c_str());
     if(path_result == detail::path_type::file) {
         try {
             std::vector<ConfigItem> values = config_formatter_->from_file(config_file);
             _parse_config(values);
+            return true;
         } catch(const FileError &) {
-            if(throw_error)
+            if(throw_error) {
                 throw;
+            }
+            return false;
         }
     } else if(throw_error) {
         throw FileError::Missing(config_file);
+    } else {
+        return false;
     }
 }
 
@@ -1093,14 +1098,25 @@ CLI11_INLINE void App::_process_config_file() {
         config_ptr_->run_callback();
 
         auto config_files = config_ptr_->as<std::vector<std::string>>();
+        bool files_used{file_given};
         if(config_files.empty() || config_files.front().empty()) {
             if(config_required) {
                 throw FileError("config file is required but none was given");
             }
             return;
         }
         for(const auto &config_file : config_files) {
-            _process_config_file(config_file, config_required || file_given);
+            if(_process_config_file(config_file, config_required || file_given)) {
+                files_used = true;
+            }
+        }
+        if(!files_used) {
+            // this is done so the count shows as 0 if no callbacks were processed
+            config_ptr_->clear();
+            bool force = config_ptr_->force_callback_;
+            config_ptr_->force_callback_ = false;
+            config_ptr_->run_callback();
+            config_ptr_->force_callback_ = force;
         }
     }
 }

tests/ConfigFileTest.cpp

@@ -1049,6 +1049,16 @@ TEST_CASE_METHOD(TApp, "IniRequiredNotFound", "[config]") {
     CHECK_THROWS_AS(run(), CLI::FileError);
 }
 
+TEST_CASE_METHOD(TApp, "IniDefaultNotExist", "[config]") {
+
+    std::string noini = "TestIniNotExist.ini";
+    auto *cfg = app.set_config("--config", noini);
+
+    CHECK_NOTHROW(run());
+
+    CHECK(cfg->count() == 0);
+}
+
 TEST_CASE_METHOD(TApp, "IniNotRequiredPassedNotFound", "[config]") {
 
     std::string noini = "TestIniNotExist.ini";
@@ -1084,7 +1094,7 @@ TEST_CASE_METHOD(TApp, "IniRequired", "[config]") {
 
     TempFile tmpini{"TestIniTmp.ini"};
 
-    app.set_config("--config", tmpini, "", true);
+    auto *cfg = app.set_config("--config", tmpini, "", true);
 
     {
         std::ofstream out{tmpini};
@@ -1109,6 +1119,7 @@ TEST_CASE_METHOD(TApp, "IniRequired", "[config]") {
     args = {"--one=1", "--two=2"};
 
     CHECK_NOTHROW(run());
+    CHECK(cfg->count() == 1);
     CHECK(1 == one);
     CHECK(2 == two);
     CHECK(3 == three);