From e6f5e05ebcc46355fe737d8d747f8ed95edc99d1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Ho=C5=99e=C5=88ovsk=C3=BD?=
 <martin.horenovsky@gmail.com>
Date: Tue, 6 Oct 2020 11:07:53 +0200
Subject: [PATCH] Improve detection of std::uncaught_exceptions support

The problem was that Catch2 did not reliably include `<exception>`
before it checked for the feature test macro for
`std::uncaught_exceptions`. To avoid overhead of including
`<exception>` everywhere, the configuration check was split out
into a separate header.

Closes #2021
---
 .../internal/catch_compiler_capabilities.h    | 11 -----
 .../catch_config_uncaught_exceptions.hpp      | 44 +++++++++++++++++++
 .../internal/catch_uncaught_exceptions.cpp    |  2 +
 projects/CMakeLists.txt                       |  1 +
 4 files changed, 47 insertions(+), 11 deletions(-)
 create mode 100644 include/internal/catch_config_uncaught_exceptions.hpp

diff --git a/include/internal/catch_compiler_capabilities.h b/include/internal/catch_compiler_capabilities.h
index 9c6d45c8..93e191c2 100644
--- a/include/internal/catch_compiler_capabilities.h
+++ b/include/internal/catch_compiler_capabilities.h
@@ -39,10 +39,6 @@
 
 #endif
 
-#if defined(__cpp_lib_uncaught_exceptions)
-#  define CATCH_INTERNAL_CONFIG_CPP17_UNCAUGHT_EXCEPTIONS
-#endif
-
 // We have to avoid both ICC and Clang, because they try to mask themselves
 // as gcc, and we want only GCC in this block
 #if defined(__GNUC__) && !defined(__clang__) && !defined(__ICC) && !defined(__CUDACC__)
@@ -153,9 +149,6 @@
 #  define CATCH_INTERNAL_START_WARNINGS_SUPPRESSION __pragma( warning(push) )
 #  define CATCH_INTERNAL_STOP_WARNINGS_SUPPRESSION  __pragma( warning(pop) )
 
-#  if _MSC_VER >= 1900 // Visual Studio 2015 or newer
-#    define CATCH_INTERNAL_CONFIG_CPP17_UNCAUGHT_EXCEPTIONS
-#  endif
 
 // Universal Windows platform does not support SEH
 // Or console colours (or console at all...)
@@ -287,10 +280,6 @@
 #  define CATCH_CONFIG_CPP17_OPTIONAL
 #endif
 
-#if defined(CATCH_INTERNAL_CONFIG_CPP17_UNCAUGHT_EXCEPTIONS) && !defined(CATCH_CONFIG_NO_CPP17_UNCAUGHT_EXCEPTIONS) && !defined(CATCH_CONFIG_CPP17_UNCAUGHT_EXCEPTIONS)
-#  define CATCH_CONFIG_CPP17_UNCAUGHT_EXCEPTIONS
-#endif
-
 #if defined(CATCH_INTERNAL_CONFIG_CPP17_STRING_VIEW) && !defined(CATCH_CONFIG_NO_CPP17_STRING_VIEW) && !defined(CATCH_CONFIG_CPP17_STRING_VIEW)
 #  define CATCH_CONFIG_CPP17_STRING_VIEW
 #endif
diff --git a/include/internal/catch_config_uncaught_exceptions.hpp b/include/internal/catch_config_uncaught_exceptions.hpp
new file mode 100644
index 00000000..eac9078e
--- /dev/null
+++ b/include/internal/catch_config_uncaught_exceptions.hpp
@@ -0,0 +1,44 @@
+
+//              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
+ * Wrapper for UNCAUGHT_EXCEPTIONS configuration option
+ *
+ * For some functionality, Catch2 requires to know whether there is
+ * an active exception. Because `std::uncaught_exception` is deprecated
+ * in C++17, we want to use `std::uncaught_exceptions` if possible.
+ */
+
+#ifndef CATCH_CONFIG_UNCAUGHT_EXCEPTIONS_HPP
+#define CATCH_CONFIG_UNCAUGHT_EXCEPTIONS_HPP
+
+#if defined(_MSC_VER)
+#  if _MSC_VER >= 1900 // Visual Studio 2015 or newer
+#    define CATCH_INTERNAL_CONFIG_CPP17_UNCAUGHT_EXCEPTIONS
+#  endif
+#endif
+
+
+#include <exception>
+
+#if defined(__cpp_lib_uncaught_exceptions) \
+    && !defined(CATCH_INTERNAL_CONFIG_CPP17_UNCAUGHT_EXCEPTIONS)
+
+#  define CATCH_INTERNAL_CONFIG_CPP17_UNCAUGHT_EXCEPTIONS
+#endif // __cpp_lib_uncaught_exceptions
+
+
+#if defined(CATCH_INTERNAL_CONFIG_CPP17_UNCAUGHT_EXCEPTIONS) \
+    && !defined(CATCH_CONFIG_NO_CPP17_UNCAUGHT_EXCEPTIONS) \
+    && !defined(CATCH_CONFIG_CPP17_UNCAUGHT_EXCEPTIONS)
+
+#  define CATCH_CONFIG_CPP17_UNCAUGHT_EXCEPTIONS
+#endif
+
+
+#endif // CATCH_CONFIG_UNCAUGHT_EXCEPTIONS_HPP
diff --git a/include/internal/catch_uncaught_exceptions.cpp b/include/internal/catch_uncaught_exceptions.cpp
index 22b1ed43..cbe7f941 100644
--- a/include/internal/catch_uncaught_exceptions.cpp
+++ b/include/internal/catch_uncaught_exceptions.cpp
@@ -8,6 +8,8 @@
 
 #include "catch_compiler_capabilities.h"
 #include "catch_uncaught_exceptions.h"
+#include "catch_config_uncaught_exceptions.hpp"
+
 #include <exception>
 
 namespace Catch {
diff --git a/projects/CMakeLists.txt b/projects/CMakeLists.txt
index 914af8d6..ece7f0f6 100644
--- a/projects/CMakeLists.txt
+++ b/projects/CMakeLists.txt
@@ -124,6 +124,7 @@ set(INTERNAL_HEADERS
         ${HEADER_DIR}/internal/catch_common.h
         ${HEADER_DIR}/internal/catch_compiler_capabilities.h
         ${HEADER_DIR}/internal/catch_config.hpp
+        ${HEADER_DIR}/internal/catch_config_uncaught_exceptions.hpp
         ${HEADER_DIR}/internal/catch_console_colour.h
         ${HEADER_DIR}/internal/catch_context.h
         ${HEADER_DIR}/internal/catch_debug_console.h