Merge pull request #16159 from markdroth/ref_counted_ptr_polymorphism_fix

Fix RefCountedPtr to handle polymorphism.

2 files changed, 67 insertions, 6 deletions

diff --git a/test/core/channel/channel_trace_test.cc b/test/core/channel/channel_trace_test.cc
index 99d9a4847f..f224457a55 100644
--- a/test/core/channel/channel_trace_test.cc
+++ b/test/core/channel/channel_trace_test.cc
@@ -187,8 +187,8 @@ TEST_P(ChannelTracerTest, ComplexTest) {
   AddSimpleTrace(&tracer);
   AddSimpleTrace(&tracer);
   AddSimpleTrace(&tracer);
-  sc1.reset(nullptr);
-  sc2.reset(nullptr);
+  sc1.reset();
+  sc2.reset();
 }
 
 // Test a case in which the parent channel has subchannels and the subchannels
@@ -234,9 +234,9 @@ TEST_P(ChannelTracerTest, TestNesting) {
       grpc_slice_from_static_string("subchannel one inactive"), sc1);
   AddSimpleTrace(&tracer);
   ValidateChannelTrace(&tracer, 8, GetParam());
-  sc1.reset(nullptr);
-  sc2.reset(nullptr);
-  conn1.reset(nullptr);
+  sc1.reset();
+  sc2.reset();
+  conn1.reset();
 }
 
 INSTANTIATE_TEST_CASE_P(ChannelTracerTestSweep, ChannelTracerTest,
diff --git a/test/core/gprpp/ref_counted_ptr_test.cc b/test/core/gprpp/ref_counted_ptr_test.cc
index aa30b72282..463b5e8966 100644
--- a/test/core/gprpp/ref_counted_ptr_test.cc
+++ b/test/core/gprpp/ref_counted_ptr_test.cc
@@ -127,7 +127,7 @@ TEST(RefCountedPtr, ResetFromNonNullToNull) {
 TEST(RefCountedPtr, ResetFromNullToNull) {
   RefCountedPtr<Foo> foo;
   EXPECT_EQ(nullptr, foo.get());
-  foo.reset(nullptr);
+  foo.reset();
   EXPECT_EQ(nullptr, foo.get());
 }
 
@@ -175,6 +175,67 @@ TEST(RefCountedPtr, RefCountedWithTracing) {
   foo->Unref(DEBUG_LOCATION, "foo");
 }
 
+class BaseClass : public RefCounted<BaseClass> {
+ public:
+  BaseClass() {}
+};
+
+class Subclass : public BaseClass {
+ public:
+  Subclass() {}
+};
+
+TEST(RefCountedPtr, ConstructFromSubclass) {
+  RefCountedPtr<BaseClass> p(New<Subclass>());
+}
+
+TEST(RefCountedPtr, CopyAssignFromSubclass) {
+  RefCountedPtr<BaseClass> b;
+  EXPECT_EQ(nullptr, b.get());
+  RefCountedPtr<Subclass> s = MakeRefCounted<Subclass>();
+  b = s;
+  EXPECT_NE(nullptr, b.get());
+}
+
+TEST(RefCountedPtr, MoveAssignFromSubclass) {
+  RefCountedPtr<BaseClass> b;
+  EXPECT_EQ(nullptr, b.get());
+  RefCountedPtr<Subclass> s = MakeRefCounted<Subclass>();
+  b = std::move(s);
+  EXPECT_NE(nullptr, b.get());
+}
+
+TEST(RefCountedPtr, ResetFromSubclass) {
+  RefCountedPtr<BaseClass> b;
+  EXPECT_EQ(nullptr, b.get());
+  b.reset(New<Subclass>());
+  EXPECT_NE(nullptr, b.get());
+}
+
+TEST(RefCountedPtr, EqualityWithSubclass) {
+  Subclass* s = New<Subclass>();
+  RefCountedPtr<BaseClass> b(s);
+  EXPECT_EQ(b, s);
+}
+
+void FunctionTakingBaseClass(RefCountedPtr<BaseClass> p) {
+  p.reset();  // To appease clang-tidy.
+}
+
+TEST(RefCountedPtr, CanPassSubclassToFunctionExpectingBaseClass) {
+  RefCountedPtr<Subclass> p = MakeRefCounted<Subclass>();
+  FunctionTakingBaseClass(p);
+}
+
+void FunctionTakingSubclass(RefCountedPtr<Subclass> p) {
+  p.reset();  // To appease clang-tidy.
+}
+
+TEST(RefCountedPtr, CanPassSubclassToFunctionExpectingSubclass) {
+  RefCountedPtr<Subclass> p = MakeRefCounted<Subclass>();
+  FunctionTakingSubclass(p);
+}
+
 }  // namespace
 }  // namespace testing
 }  // namespace grpc_core