Properly handle startup reporter registration errors

tests/ExtraTests/CMakeLists.txt

@@ -421,6 +421,20 @@ set_tests_properties(
     FAIL_REGULAR_EXPRESSION "error: .* already defined\\."
 )
 
+
+add_executable(DuplicatedReporters ${TESTS_DIR}/X35-DuplicatedReporterNames.cpp)
+target_link_libraries(DuplicatedReporters PRIVATE Catch2::Catch2WithMain)
+add_test(
+  NAME Reporters::RegistrationErrorsAreCaught
+  COMMAND $<TARGET_FILE:DuplicatedReporters>
+)
+set_tests_properties(
+    Reporters::RegistrationErrorsAreCaught
+  PROPERTIES
+    PASS_REGULAR_EXPRESSION "Errors occurred during startup!"
+)
+
+
 #add_executable(DebugBreakMacros ${TESTS_DIR}/X12-CustomDebugBreakMacro.cpp)
 #target_link_libraries(DebugBreakMacros Catch2)
 #add_test(NAME DebugBreakMacros COMMAND DebugBreakMacros --break)

tests/ExtraTests/X35-DuplicatedReporterNames.cpp

@@ -0,0 +1,31 @@
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE_1_0.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
+
+/**\file
+ * Checks that reporter registration errors are caught and handled as
+ * startup errors, by causing a registration error by registering multiple
+ * reporters with the same name.
+ */
+
+#include <catch2/catch_test_macros.hpp>
+
+#include <catch2/reporters/catch_reporter_registrars.hpp>
+#include <catch2/reporters/catch_reporter_streaming_base.hpp>
+
+namespace {
+    //! Trivial custom reporter for registration
+    class TestReporter : public Catch::StreamingReporterBase {
+    public:
+        using StreamingReporterBase::StreamingReporterBase;
+
+        static std::string getDescription() { return "X35 test reporter"; }
+    };
+}
+
+CATCH_REGISTER_REPORTER( "test-reporter", TestReporter )
+CATCH_REGISTER_REPORTER( "test-reporter", TestReporter )