From 3bf1bc6f7372e0d4e49f2d3100f6a2fd39a6a451 Mon Sep 17 00:00:00 2001
From: Jeremy Rifkin <51220084+jeremy-rifkin@users.noreply.github.com>
Date: Sat, 21 Dec 2024 18:18:08 -0600
Subject: [PATCH] Make the default failure handler public and update docs for
 custom failure handlers

---
 README.md                    | 19 ++++++++++++---
 include/libassert/assert.hpp |  2 ++
 src/assert.cpp               | 47 ++++++++++++++++++------------------
 3 files changed, 42 insertions(+), 26 deletions(-)

diff --git a/README.md b/README.md
index c21aaa4..2b3be38 100644
--- a/README.md
+++ b/README.md
@@ -215,7 +215,7 @@ screenshots above. This is to help enhance readability.
 Libassert supports custom assertion failure handlers:
 
 ```cpp
-void handler(assert_type type, const assertion_info& assertion) {
+void handler(const assertion_info& info) {
     throw std::runtime_error("Assertion failed:\n" + assertion.to_string());
 }
 
@@ -224,6 +224,8 @@ int main() {
 }
 ```
 
+More details [below](#custom-failure-handlers-1).
+
 ## Debug Stringification <!-- omit in toc -->
 
 A lot of care is given to producing debug stringifications of values as effectively as possible: Strings, characters,
@@ -689,15 +691,26 @@ Lastly, any types with an ostream `operator<<` overload can be stringified.
 ```cpp
 namespace libassert {
     void set_failure_handler(void (*handler)(const assertion_info&));
+    [[noreturn]] void default_failure_handler(const assertion_info& info);
 }
 ```
 
 - `set_failure_handler`: Sets the assertion handler for the program.
+- `default_failure_handler`: The default failure handler, provided for convenience.
+
+Example: If you wanted to log to a file in addition to the default behavior you could do something along the lines of:
+
+```cpp
+void handler(const assertion_info& info) {
+    logger::error(info.to_string());
+    libassert::default_failure_handler(info);
+}
+```
 
-An example assertion handler similar to the default handler:
+For more complex custom handling you can modify the default handler's logic:
 
 ```cpp
-void libassert_default_failure_handler(const assertion_info& info) {
+void default_failure_handler(const assertion_info& info) {
     libassert::enable_virtual_terminal_processing_if_needed(); // for terminal colors on windows
     std::string message = info.to_string(
         libassert::terminal_width(libassert::stderr_fileno),
diff --git a/include/libassert/assert.hpp b/include/libassert/assert.hpp
index b11296d..fe9bf09 100644
--- a/include/libassert/assert.hpp
+++ b/include/libassert/assert.hpp
@@ -165,6 +165,8 @@ namespace libassert {
 
     struct assertion_info;
 
+    LIBASSERT_EXPORT [[noreturn]] void default_failure_handler(const assertion_info& info);
+
     LIBASSERT_EXPORT void set_failure_handler(void (*handler)(const assertion_info&));
 
     struct LIBASSERT_EXPORT binary_diagnostics_descriptor {
diff --git a/src/assert.cpp b/src/assert.cpp
index 75ec5d0..1ea41f3 100644
--- a/src/assert.cpp
+++ b/src/assert.cpp
@@ -422,32 +422,33 @@ namespace libassert {
             }
         }
 
-        LIBASSERT_ATTR_COLD
-        void libassert_default_failure_handler(const assertion_info& info) {
-            enable_virtual_terminal_processing_if_needed(); // for terminal colors on windows
-            std::string message = info.to_string(
-                terminal_width(STDERR_FILENO),
-                isatty(STDERR_FILENO) ? get_color_scheme() : color_scheme::blank
-            );
-            std::cerr << message << std::endl;
-            switch(info.type) {
-                case assert_type::assertion:
-                case assert_type::debug_assertion:
-                case assert_type::assumption:
-                case assert_type::panic:
-                case assert_type::unreachable:
-                    (void)fflush(stderr);
-                    std::abort();
-                    // Breaking here as debug CRT allows aborts to be ignored, if someone wants to make a debug build of
-                    // this library
-                    break;
-                default:
-                    LIBASSERT_PRIMITIVE_DEBUG_ASSERT(false);
-            }
+    }
+
+    LIBASSERT_ATTR_COLD LIBASSERT_EXPORT [[noreturn]]
+    void default_failure_handler(const assertion_info& info) {
+        enable_virtual_terminal_processing_if_needed(); // for terminal colors on windows
+        std::string message = info.to_string(
+            terminal_width(STDERR_FILENO),
+            isatty(STDERR_FILENO) ? get_color_scheme() : color_scheme::blank
+        );
+        std::cerr << message << std::endl;
+        switch(info.type) {
+            case assert_type::assertion:
+            case assert_type::debug_assertion:
+            case assert_type::assumption:
+            case assert_type::panic:
+            case assert_type::unreachable:
+                (void)fflush(stderr);
+                std::abort();
+                // Breaking here as debug CRT allows aborts to be ignored, if someone wants to make a debug build of
+                // this library
+                break;
+            default:
+                LIBASSERT_PRIMITIVE_PANIC("Unknown assertion type in assertion failure handler");
         }
     }
 
-    static std::atomic failure_handler = detail::libassert_default_failure_handler;
+    static std::atomic failure_handler = default_failure_handler;
 
     LIBASSERT_ATTR_COLD LIBASSERT_EXPORT
     void set_failure_handler(void (*handler)(const assertion_info&)) {