util: add deep comparison helpers for shared_ptr

Author: kwvg

src/Makefile.am

@@ -365,6 +365,7 @@ BITCOIN_CORE_H = \
   util/moneystr.h \
   util/overflow.h \
   util/overloaded.h \
+  util/pointer.h \
   util/ranges.h \
   util/readwritefile.h \
   util/underlying.h \

src/evo/deterministicmns.h

@@ -180,7 +180,7 @@ class CDeterministicMNList
         }
     }
 
-    template<typename Stream>
+    template <typename Stream>
     void Unserialize(Stream& s)
     {
         Clear();

src/util/pointer.h

@@ -0,0 +1,38 @@
+// Copyright (c) 2025 The Dash Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_UTIL_POINTER_H
+#define BITCOIN_UTIL_POINTER_H
+
+#include <memory>
+
+namespace util {
+/* Deep equality comparison helper for std::shared_ptr<T> */
+template <typename T>
+bool shared_ptr_equal(const std::shared_ptr<T>& lhs, const std::shared_ptr<T>& rhs)
+    requires requires { *lhs == *rhs; }
+{
+    /* Same object or both blank */
+    if (lhs == rhs) return true;
+    /* Inequal initialization state */
+    if (!lhs || !rhs) return false;
+    /* Deep comparison */
+    return *lhs == *rhs;
+}
+
+/* Deep inequality comparison helper for std::shared_ptr<T> */
+template <typename T>
+bool shared_ptr_not_equal(const std::shared_ptr<T>& lhs, const std::shared_ptr<T>& rhs)
+    requires requires { *lhs != *rhs; }
+{
+    /* Same object or both blank */
+    if (lhs == rhs) return false;
+    /* Inequal initialization state */
+    if (!lhs || !rhs) return true;
+    /* Deep comparison */
+    return *lhs != *rhs;
+}
+} // namespace util
+
+#endif // BITCOIN_UTIL_POINTER_H

test/util/data/non-backported.txt

@@ -42,6 +42,7 @@ src/unordered_lru_cache.h
 src/util/edge.*
 src/util/enumerate.h
 src/util/irange.h
+src/util/pointer.h
 src/util/ranges.h
 src/util/ranges_set.*
 src/util/wpipe.*