From 4ea8f4a5ccf07c2548be1ffc2e0885fae9537196 Mon Sep 17 00:00:00 2001
From: TJ Yin <ytj@meta.com>
Date: Thu, 30 Jan 2025 10:15:40 -0800
Subject: [PATCH] diff(src,dst) should generate empty patch if src == dst

Reviewed By: pranavtbhat

Differential Revision: D68864929

fbshipit-source-id: d2dfee5952e65c84c1ce6be852a249f0a416d484
---
 thrift/lib/cpp2/patch/test/DynamicPatchTest.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/thrift/lib/cpp2/patch/test/DynamicPatchTest.cpp b/thrift/lib/cpp2/patch/test/DynamicPatchTest.cpp
index 4cc04c148ff..4c58f964990 100644
--- a/thrift/lib/cpp2/patch/test/DynamicPatchTest.cpp
+++ b/thrift/lib/cpp2/patch/test/DynamicPatchTest.cpp
@@ -100,6 +100,7 @@ void testOneWay(T src, T dst) {
   auto other =
       detail::createPatchFromObject<PatchType>(badge, patch.toObject());
   EXPECT_EQ(other.toObject(), patch.toObject());
+  EXPECT_EQ(patch.empty(), src == dst);
 }
 
 TEST(DynamicPatchTest, Binary) {
@@ -162,6 +163,7 @@ void testMapAndObject(
   auto patch = DiffVisitorBase{}.diff(objSrc, objDst);
   applyPatch(patch.toObject(), objSrc);
   EXPECT_EQ(objSrc, objDst);
+  EXPECT_EQ(patch.empty(), src == dst);
 
   if (mightBeUnion) {
     EXPECT_TRUE(patch.holds_alternative<DynamicUnknownPatch>(badge));