added traced_error

Author: dk949

.gitmodules

@@ -55,3 +55,6 @@
 [submodule "include/breakpoint/include/ut/breakpoint"]
 	path = include/breakpoint/include/ut/breakpoint
 	url = https://gist.github.com/dk949/e36f1a7ecc9a8aff296ee6e76a06ba68
+[submodule "include/traced_error/include/ut/traced_error"]
+	path = include/traced_error/include/ut/traced_error
+	url = https://gist.github.com/dk949/392c55c65e3c4efb89c7b89bd4390ba4

README.md

@@ -46,6 +46,7 @@ target_link_libraries(MY_TARGET UT::target_name)
 * `UT::err`: convenient error type for use with std::expected
 * `UT::add_noexcept`: add the `noexcept` specifier to a function type
 * `UT::change_observer`: wrapper class that invokes callbacks when it's held value changes
+* `UT::traced_error`: an exception type that automatically stores a C++23 standard stacktrace
 * `UT::sv_to_num`: convert `std::string_view` to a number
 * `UT::copy_traits`: copy cvref qualifiers from one type to another
 * `UT::realloc_unique_ptr`: `realloc` functionality for `std::uniqur_ptr`

include/traced_error/CMakeLists.txt

@@ -0,0 +1,14 @@
+cmake_minimum_required(VERSION 3.21)
+project(libut LANGUAGES CXX)
+
+add_library(libut_target_traced_error INTERFACE)
+target_sources(libut_target_traced_error PUBLIC
+    FILE_SET HEADERS
+    BASE_DIRS ${CMAKE_CURRENT_SOURCE_DIR}/include
+    FILES
+        ${CMAKE_CURRENT_SOURCE_DIR}/include/ut/traced_error/traced_error.hpp
+)
+
+message(STATUS "libut: adding UT::traced_error")
+add_library(UT::traced_error ALIAS libut_target_traced_error)
+    

include/traced_error/include/ut/traced_error

@@ -32,6 +32,7 @@ set(cxx_23_files
     ${cxx_20_files}
     ${CMAKE_CURRENT_SOURCE_DIR}/err.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/switchboard.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/traced_error.cpp
 )
 
 function(setup_target target)
@@ -59,3 +60,6 @@ target_compile_features(libut_tests_23 PUBLIC cxx_std_23)
 setup_target(libut_tests_17)
 setup_target(libut_tests_20)
 setup_target(libut_tests_23)
+if(NOT MSVC)
+    target_link_libraries(libut_tests_23 PUBLIC stdc++exp)
+endif()

tests/CMakeLists.txt

@@ -0,0 +1,53 @@
+#include <catch.hpp>
+#include <catch2/catch_test_macros.hpp>
+#include <ut/traced_error/traced_error.hpp>
+using namespace std::string_view_literals;
+
+void throwsTracedError() {
+    throw ut::TracedError("Hello {}", "world");
+};
+
+TEST_CASE("Basic usage", "[traced_error]") {
+
+    try {
+        throwsTracedError();
+    } catch (ut::TracedError const &t) {
+        auto trace = t.trace();
+        INFO(trace);
+        REQUIRE(!trace.empty());
+        REQUIRE(t.what() == "Hello world"sv);
+    }
+}
+
+class MyError : public ut::TracedError {
+public:
+    template<typename... Args>
+    MyError(std::format_string<Args...> fmt, Args &&...args)
+            : TracedError(1, fmt, std::forward<Args>(args)...) { }
+};
+
+void throwsMyError() {
+    throw MyError("Hello {}", "world");
+};
+
+TEST_CASE("Inheriting from exception", "[traced_error]") {
+
+    try {
+        throwsMyError();
+    } catch (MyError const &t) {
+        auto trace = t.trace();
+        INFO(trace);
+        REQUIRE(!trace.empty());
+        REQUIRE(t.what() == "Hello world"sv);
+    } catch (ut::TracedError const &t) {
+        FAIL("This handler should never be entered");
+    }
+    try {
+        throwsMyError();
+    } catch (ut::TracedError const &t) {
+        auto trace = t.trace();
+        INFO(trace);
+        REQUIRE(!trace.empty());
+        REQUIRE(t.what() == "Hello world"sv);
+    }
+}