Fix entire config being invalidated by bad value

src/logid/CMakeLists.txt

@@ -12,6 +12,7 @@ find_package(PkgConfig REQUIRED)
 add_executable(logid
         logid.cpp
         util/log.cpp
+        config/util.cpp
         InputDevice.cpp
         DeviceManager.cpp
         Device.cpp

src/logid/config/types.h

@@ -28,11 +28,11 @@
 #include <list>
 #include <set>
 
-/// TODO: A single element failing should not cause the container to be invalid.
-
 // Containers are chosen specifically so that no iterator is invalidated.
 
 namespace logid::config {
+    void logError(const libconfig::Setting& setting, std::exception& e);
+
     namespace {
         template<typename T>
         struct config_io {
@@ -406,10 +406,17 @@ namespace logid::config {
         struct config_io<std::optional<T>> {
             static inline std::optional<T> get(const libconfig::Setting& parent,
                                                const std::string& name) {
-                if (parent.exists(name))
-                    return config_io<T>::get(parent.lookup(name));
-                else
+                if (parent.exists(name)) {
+                    auto& setting = parent.lookup(name);
+                    try {
+                        return config_io<T>::get(setting);
+                    } catch (libconfig::SettingException& e) {
+                        logError(setting, e);
+                        return {};
+                    }
+                } else {
                     return {};
+                }
             }
 
             static inline void set(libconfig::Setting& parent,

src/logid/config/util.cpp

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2019-2023 PixlOne
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <config/types.h>
+#include <util/log.h>
+
+using namespace logid;
+
+void config::logError(const libconfig::Setting& setting, std::exception& e) {
+    logPrintf(WARN, "Error at line %d: %s", setting.getSourceLine(), e.what());
+}