add the zero-based index of the alternative held by the variant

Useful when distinguishing repeated alternative types, e.g. std::variant<int, int>.
google · May 29, 2020 · 70d7f04 · 70d7f04
1 parent 8bd8aea
commit 70d7f04
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diff --git a/googletest/include/gtest/gtest-printers.h b/googletest/include/gtest/gtest-printers.h
@@ -736,9 +736,9 @@ class UniversalPrinter<Variant<T...>> {
   static void Print(const Variant<T...>& value, ::std::ostream* os) {
     *os << '(';
 #if __cplusplus >= 201703L
-    std::visit(Visitor{os}, value);
+    std::visit(Visitor{os, value.index()}, value);
 #else
-    absl::visit(Visitor{os}, value);
+    absl::visit(Visitor{os, value.index()}, value);
 #endif  // __cplusplus >= 201703L
     *os << ')';
   }
@@ -747,10 +747,11 @@ class UniversalPrinter<Variant<T...>> {
   struct Visitor {
     template <typename U>
     void operator()(const U& u) const {
-      *os << "'" << GetTypeName<U>() << "' with value ";
+      *os << "'" << GetTypeName<U>() << "(" << index << ")' with value ";
       UniversalPrint(u, os);
     }
     ::std::ostream* os;
+    std::size_t index;
   };
 };
 

diff --git a/googletest/test/googletest-printers-test.cc b/googletest/test/googletest-printers-test.cc
@@ -1582,11 +1582,11 @@ struct NonPrintable {
 
 TEST(PrintOneofTest, Basic) {
   using Type = internal::Variant<int, StreamableInGlobal, NonPrintable>;
-  EXPECT_EQ("('int' with value 7)", PrintToString(Type(7)));
-  EXPECT_EQ("('StreamableInGlobal' with value StreamableInGlobal)",
+  EXPECT_EQ("('int(0)' with value 7)", PrintToString(Type(7)));
+  EXPECT_EQ("('StreamableInGlobal(1)' with value StreamableInGlobal)",
             PrintToString(Type(StreamableInGlobal{})));
   EXPECT_EQ(
-      "('testing::gtest_printers_test::NonPrintable' with value 1-byte object "
+      "('testing::gtest_printers_test::NonPrintable(2)' with value 1-byte object "
       "<11>)",
       PrintToString(Type(NonPrintable{})));
 }