Make PADDLE_ENFORCE_EQ support types that cannot be converted to std::string (#19243)

* make PADDLE_ENFORCE_EQ support cannot to string types, test=develop

* follow huihuang's comments, test=develop

paddle/fluid/platform/enforce.h

@@ -27,6 +27,7 @@ limitations under the License. */
 #endif  // PADDLE_WITH_CUDA
 
 #include <iomanip>
+#include <iostream>
 #include <memory>
 #include <sstream>
 #include <stdexcept>
@@ -307,7 +308,7 @@ DEFINE_CUDA_STATUS_TYPE(ncclResult_t, ncclSuccess);
   do {                                                                         \
     throw ::paddle::platform::EOFException("There is no next data.", __FILE__, \
                                            __LINE__);                          \
-  } while (false)
+  } while (0)
 
 /*
  * Some enforce helpers here, usage:
@@ -366,6 +367,45 @@ using CommonType1 = typename std::add_lvalue_reference<
 template <typename T1, typename T2>
 using CommonType2 = typename std::add_lvalue_reference<
     typename std::add_const<typename TypeConverter<T1, T2>::Type2>::type>::type;
+
+// Here, we use SFINAE to check whether T can be converted to std::string
+template <typename T>
+struct CanToString {
+ private:
+  using YesType = uint8_t;
+  using NoType = uint16_t;
+
+  template <typename U>
+  static YesType Check(decltype(std::cout << std::declval<U>())) {
+    return 0;
+  }
+
+  template <typename U>
+  static NoType Check(...) {
+    return 0;
+  }
+
+ public:
+  static constexpr bool kValue =
+      std::is_same<YesType, decltype(Check<T>(std::cout))>::value;
+};
+
+template <bool kCanToString /* = true */>
+struct BinaryCompareMessageConverter {
+  template <typename T>
+  static std::string Convert(const char* expression, const T& value) {
+    return expression + std::string(":") + string::to_string(value);
+  }
+};
+
+template <>
+struct BinaryCompareMessageConverter<false> {
+  template <typename T>
+  static const char* Convert(const char* expression, const T& value) {
+    return expression;
+  }
+};
+
 }  // namespace details
 
 #define __PADDLE_BINARY_COMPARE(__VAL1, __VAL2, __CMP, __INV_CMP, ...)         \
@@ -381,11 +421,16 @@ using CommonType2 = typename std::add_lvalue_reference<
     bool __is_not_error = (static_cast<__COMMON_TYPE1__>(__val1))__CMP(        \
         static_cast<__COMMON_TYPE2__>(__val2));                                \
     if (UNLIKELY(!__is_not_error)) {                                           \
+      constexpr bool __kCanToString__ =                                        \
+          ::paddle::platform::details::CanToString<__TYPE1__>::kValue &&       \
+          ::paddle::platform::details::CanToString<__TYPE2__>::kValue;         \
       PADDLE_THROW("Enforce failed. Expected %s " #__CMP                       \
-                   " %s, but received %s:%s " #__INV_CMP " %s:%s.\n%s", \
-                   #__VAL1, #__VAL2, #__VAL1,                           \
-                   ::paddle::string::to_string(__val1), #__VAL2,        \
-                   ::paddle::string::to_string(__val2),                 \
+                   " %s, but received %s " #__INV_CMP " %s.\n%s",              \
+                   #__VAL1, #__VAL2,                                           \
+                   ::paddle::platform::details::BinaryCompareMessageConverter< \
+                       __kCanToString__>::Convert(#__VAL1, __val1),            \
+                   ::paddle::platform::details::BinaryCompareMessageConverter< \
+                       __kCanToString__>::Convert(#__VAL2, __val2),            \
                    ::paddle::string::Sprintf(__VA_ARGS__));                    \
     }                                                                          \
   } while (0)

paddle/fluid/platform/enforce_test.cc

@@ -11,7 +11,9 @@ limitations under the License. */
 
 #include <array>
 #include <iostream>
+#include <list>
 #include <memory>
+#include <set>
 
 #include "gtest/gtest.h"
 #include "paddle/fluid/platform/enforce.h"
@@ -296,3 +298,64 @@ TEST(enforce, cuda_success) {
 #endif
 }
 #endif
+
+struct CannotToStringType {
+  explicit CannotToStringType(int num) : num_(num) {}
+
+  bool operator==(const CannotToStringType& other) const {
+    return num_ == other.num_;
+  }
+
+  bool operator!=(const CannotToStringType& other) const {
+    return num_ != other.num_;
+  }
+
+ private:
+  int num_;
+};
+
+TEST(enforce, cannot_to_string_type) {
+  static_assert(
+      !paddle::platform::details::CanToString<CannotToStringType>::kValue,
+      "CannotToStringType must not be converted to string");
+  static_assert(paddle::platform::details::CanToString<int>::kValue,
+                "int can be converted to string");
+  CannotToStringType obj1(3), obj2(4), obj3(3);
+
+  PADDLE_ENFORCE_NE(obj1, obj2, "Object 1 is not equal to Object 2");
+  PADDLE_ENFORCE_EQ(obj1, obj3, "Object 1 is equal to Object 3");
+
+  std::string msg = "Compare obj1 with obj2";
+  try {
+    PADDLE_ENFORCE_EQ(obj1, obj2, msg);
+  } catch (paddle::platform::EnforceNotMet& error) {
+    std::string ex_msg = error.what();
+    LOG(INFO) << ex_msg;
+    EXPECT_TRUE(ex_msg.find(msg) != std::string::npos);
+    EXPECT_TRUE(
+        ex_msg.find("Expected obj1 == obj2, but received obj1 != obj2") !=
+        std::string::npos);
+  }
+
+  msg = "Compare x with y";
+  try {
+    int x = 3, y = 2;
+    PADDLE_ENFORCE_EQ(x, y, msg);
+  } catch (paddle::platform::EnforceNotMet& error) {
+    std::string ex_msg = error.what();
+    LOG(INFO) << ex_msg;
+    EXPECT_TRUE(ex_msg.find(msg) != std::string::npos);
+    EXPECT_TRUE(ex_msg.find("Expected x == y, but received x:3 != y:2") !=
+                std::string::npos);
+  }
+
+  std::set<int> set;
+  PADDLE_ENFORCE_EQ(set.begin(), set.end());
+  set.insert(3);
+  PADDLE_ENFORCE_NE(set.begin(), set.end());
+
+  std::list<float> list;
+  PADDLE_ENFORCE_EQ(list.begin(), list.end());
+  list.push_back(4);
+  PADDLE_ENFORCE_NE(list.begin(), list.end());
+}