Allow throwing from exit handler

For example for unit testing purposes we may want to replace SIGABRT with
throwing an exception, so that unit tests for CHECK()s can be written.

src/g3log/logcapture.hpp

@@ -42,7 +42,7 @@ struct LogCapture {
    // At destruction the message will be forwarded to the g3log worker.
    // In the case of dynamically (at runtime) loaded libraries, the important thing to know is that
    // all strings are copied, so the original are not destroyed at the receiving end, only the copy
-   virtual ~LogCapture();
+   virtual ~LogCapture() noexcept (false);
 
 
 

src/logcapture.cpp

@@ -38,7 +38,7 @@ void g3::only_change_at_initialization::setMaxMessageSize(size_t max_size) {
 * As a safety precaution: No memory allocated here will be moved into the background
 * worker in case of dynamic loaded library reasons instead the arguments are copied
 * inside of g3log.cpp::saveMessage*/
-LogCapture::~LogCapture() {
+LogCapture::~LogCapture() noexcept (false) {
    using namespace g3::internal;
    SIGNAL_HANDLER_VERIFY();
    saveMessage(_stream.str().c_str(), _file, _line, _function, _level, _expression, _fatal_signal, _stack_trace.c_str());

test_unit/test_io.cpp

@@ -601,7 +601,34 @@ TEST(CHECK, CHECK_ThatWontThrow) {
    EXPECT_FALSE(verifyContent(mockFatalMessage(), msg3));
 }
 
+TEST(CHECK, CHECK_runtimeError) {
+   RestoreFileLogger logger(log_directory);
+
+   g3::setFatalExitHandler([](g3::FatalMessagePtr msg) {
+     throw std::runtime_error("fatal test handler");
+   });
+
+   class dynamic_int_array {
+     std::unique_ptr<int[]> data_;
+     const int size_;
+   public:
+     explicit dynamic_int_array(int size)
+         : data_{std::make_unique<int[]>(size)}
+         , size_(size)
+    {}
+
+    int& at(int i) {
+      CHECK(i < size_);
+
+      // unreachable if i >= size_
+      return data_[i];
+    }
+   };
 
+   dynamic_int_array arr{3};
+
+   EXPECT_THROW(arr.at(3) = 1, std::runtime_error);
+}
 
 TEST(CustomLogLevels, AddANonFatal) {
    RestoreFileLogger logger(log_directory);