From 3536becb819731f0c24a0b00f8c33d4136b257c5 Mon Sep 17 00:00:00 2001
From: Eugene Gershnik <gershnik@users.noreply.github.com>
Date: Thu, 18 Jan 2024 13:19:18 -0800
Subject: [PATCH] XCTestUtil: using `__builtin_dump_struct` as a fallback to
 print object description

---
 include/objc-helpers/XCTestUtil.h | 32 +++++++++++++++++++++----------
 test/XCTestUtilTests.mm           |  2 +-
 2 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/include/objc-helpers/XCTestUtil.h b/include/objc-helpers/XCTestUtil.h
index 38e1bad..9c18027 100644
--- a/include/objc-helpers/XCTestUtil.h
+++ b/include/objc-helpers/XCTestUtil.h
@@ -18,7 +18,8 @@
 #import <XCTest/XCTest.h>
 
 #include <sstream>
-#include <cxxabi.h>
+#include <string>
+#include <stdarg.h>
 
 namespace TestUtil {
     using std::to_string;
@@ -40,14 +41,23 @@ namespace TestUtil {
         { str << obj };
     };
     
-    inline auto demangle(const char * name) -> std::string {
-
-        int status = 0;
-        std::unique_ptr<char, void(*)(void*)> res {
-            abi::__cxa_demangle(name, nullptr, nullptr, &status),
-            std::free
-        };
-        return (status==0) ? res.get() : name ;
+    auto sprintf(std::string & res, const char * format, ...) -> int {
+        va_list vl;
+        va_start(vl, format);
+        const int size = vsnprintf(0, 0, format, vl);
+        va_end(vl);
+        if (size <= 0)
+            return size;
+        size_t appendPos = res.size();
+        size_t appendSize = size_t(size) + 1;
+        res.resize(appendPos + appendSize);
+        va_start(vl, format);
+        const int ret = vsnprintf(&res[appendPos], appendSize, format, vl);
+        va_end(vl);
+        if (ret <= 0)
+            return ret;
+        res.resize(appendPos + size_t(ret));
+        return ret;
     }
     
     template<class T>
@@ -64,7 +74,9 @@ namespace TestUtil {
             str << val;
             return @(str.str().c_str());
         } else {
-            return [NSString stringWithFormat:@"%s object", demangle(typeid(T).name()).c_str()];
+            std::string res;
+            __builtin_dump_struct(&val, sprintf, res);
+            return @(res.c_str());
         }
     }
 }
diff --git a/test/XCTestUtilTests.mm b/test/XCTestUtilTests.mm
index fc56dbb..dc65de4 100644
--- a/test/XCTestUtilTests.mm
+++ b/test/XCTestUtilTests.mm
@@ -173,7 +173,7 @@ void _XCTFailureHandler(XCTestCase * _Nullable test, BOOL expected, const char *
 TEST_CASE( "Generic" ) {
     failures.clear();
     XCTAssertCppEqual(bar{1}, bar{2});
-    CHECK_FAILURE(__LINE__ - 1, true, "((bar{1}) equal to (bar{2})) failed: (\"(anonymous namespace)::bar object\") is not equal to (\"(anonymous namespace)::bar object\")", "");
+    CHECK_FAILURE(__LINE__ - 1, true, "((bar{1}) equal to (bar{2})) failed: (\"(anonymous namespace)::bar {\n  int i = 1\n}\n\") is not equal to (\"(anonymous namespace)::bar {\n  int i = 2\n}\n\")", "");
 }
 
 namespace {