libbitcoin · echennells · Jul 1, 2026
diff --git a/builds/gnu/Makefile.am b/builds/gnu/Makefile.am
@@ -238,6 +238,7 @@ test_libbitcoin_node_test_SOURCES = \
     ${srcdir}/../../test/chasers/chaser_template.cpp \
     ${srcdir}/../../test/chasers/chaser_transaction.cpp \
     ${srcdir}/../../test/chasers/chaser_validate.cpp \
+    ${srcdir}/../../test/messages/block.cpp \
     ${srcdir}/../../test/protocols/protocol.cpp \
     ${srcdir}/../../test/sessions/session.cpp
 

diff --git a/builds/msvc/vs2022/libbitcoin-node-test/libbitcoin-node-test.vcxproj b/builds/msvc/vs2022/libbitcoin-node-test/libbitcoin-node-test.vcxproj
@@ -135,6 +135,7 @@
     <ClCompile Include="..\..\..\..\test\estimator.cpp" />
     <ClCompile Include="..\..\..\..\test\full_node.cpp" />
     <ClCompile Include="..\..\..\..\test\main.cpp" />
+    <ClCompile Include="..\..\..\..\test\messages\block.cpp" />
     <ClCompile Include="..\..\..\..\test\protocols\protocol.cpp" />
     <ClCompile Include="..\..\..\..\test\sessions\session.cpp" />
     <ClCompile Include="..\..\..\..\test\settings.cpp" />

diff --git a/builds/msvc/vs2022/libbitcoin-node-test/libbitcoin-node-test.vcxproj.filters b/builds/msvc/vs2022/libbitcoin-node-test/libbitcoin-node-test.vcxproj.filters
@@ -13,12 +13,15 @@
     <Filter Include="src\chasers">
       <UniqueIdentifier>{4BD50864-D3BC-4F64-0000-000000000001}</UniqueIdentifier>
     </Filter>
-    <Filter Include="src\protocols">
+    <Filter Include="src\messages">
       <UniqueIdentifier>{4BD50864-D3BC-4F64-0000-000000000002}</UniqueIdentifier>
     </Filter>
-    <Filter Include="src\sessions">
+    <Filter Include="src\protocols">
       <UniqueIdentifier>{4BD50864-D3BC-4F64-0000-000000000003}</UniqueIdentifier>
     </Filter>
+    <Filter Include="src\sessions">
+      <UniqueIdentifier>{4BD50864-D3BC-4F64-0000-000000000004}</UniqueIdentifier>
+    </Filter>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="..\..\..\..\test\block_arena.cpp">
@@ -72,6 +75,9 @@
     <ClCompile Include="..\..\..\..\test\main.cpp">
       <Filter>src</Filter>
     </ClCompile>
+    <ClCompile Include="..\..\..\..\test\messages\block.cpp">
+      <Filter>src\messages</Filter>
+    </ClCompile>
     <ClCompile Include="..\..\..\..\test\protocols\protocol.cpp">
       <Filter>src\protocols</Filter>
     </ClCompile>

diff --git a/builds/msvc/vs2026/libbitcoin-node-test/libbitcoin-node-test.vcxproj b/builds/msvc/vs2026/libbitcoin-node-test/libbitcoin-node-test.vcxproj
@@ -135,6 +135,7 @@
     <ClCompile Include="..\..\..\..\test\estimator.cpp" />
     <ClCompile Include="..\..\..\..\test\full_node.cpp" />
     <ClCompile Include="..\..\..\..\test\main.cpp" />
+    <ClCompile Include="..\..\..\..\test\messages\block.cpp" />
     <ClCompile Include="..\..\..\..\test\protocols\protocol.cpp" />
     <ClCompile Include="..\..\..\..\test\sessions\session.cpp" />
     <ClCompile Include="..\..\..\..\test\settings.cpp" />

diff --git a/builds/msvc/vs2026/libbitcoin-node-test/libbitcoin-node-test.vcxproj.filters b/builds/msvc/vs2026/libbitcoin-node-test/libbitcoin-node-test.vcxproj.filters
@@ -13,12 +13,15 @@
     <Filter Include="src\chasers">
       <UniqueIdentifier>{4BD50864-D3BC-4F64-0000-000000000001}</UniqueIdentifier>
     </Filter>
-    <Filter Include="src\protocols">
+    <Filter Include="src\messages">
       <UniqueIdentifier>{4BD50864-D3BC-4F64-0000-000000000002}</UniqueIdentifier>
     </Filter>
-    <Filter Include="src\sessions">
+    <Filter Include="src\protocols">
       <UniqueIdentifier>{4BD50864-D3BC-4F64-0000-000000000003}</UniqueIdentifier>
     </Filter>
+    <Filter Include="src\sessions">
+      <UniqueIdentifier>{4BD50864-D3BC-4F64-0000-000000000004}</UniqueIdentifier>
+    </Filter>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="..\..\..\..\test\block_arena.cpp">
@@ -72,6 +75,9 @@
     <ClCompile Include="..\..\..\..\test\main.cpp">
       <Filter>src</Filter>
     </ClCompile>
+    <ClCompile Include="..\..\..\..\test\messages\block.cpp">
+      <Filter>src\messages</Filter>
+    </ClCompile>
     <ClCompile Include="..\..\..\..\test\protocols\protocol.cpp">
       <Filter>src\protocols</Filter>
     </ClCompile>

diff --git a/include/bitcoin/node/messages/block.hpp b/include/bitcoin/node/messages/block.hpp
@@ -41,18 +41,17 @@ struct BCN_API block
     ////static block deserialize(uint32_t version, system::reader& source,
     ////    bool witness=true) NOEXCEPT;
 
-    /// These return false if witness or version is inconsistent with block data.
+    /// The held block is serialized in the requested form; a witnessed view
+    /// is stripped when serialized without witness.
+    /// The bool overload returns false only on a short output buffer.
     bool serialize(uint32_t version, const system::data_slab& data,
         bool witness=true) const NOEXCEPT;
     void serialize(uint32_t version, system::writer& sink,
         bool witness=true) const NOEXCEPT;
     size_t size(uint32_t version, bool witness=true) const NOEXCEPT;
 
-    /// Wire serialized block.
-    system::data_chunk block_data{};
-
-    /// Block contains witness data (if applicable).
-    const bool witnessed_{};
+    /// The block, serialized on demand as witnessed or stripped.
+    system::chain::block_view block;
 };
 
 } // namespace messages

diff --git a/src/messages/block.cpp b/src/messages/block.cpp
@@ -36,28 +36,20 @@ const uint32_t block::version_maximum = level::maximum_protocol;
 bool block::serialize(uint32_t version, const data_slab& data,
     bool witness) const NOEXCEPT
 {
-    if (witness != witnessed_)
-        return false;
-
     system::stream::out::fast out{ data };
     system::write::bytes::fast writer{ out };
     serialize(version, writer, witness);
     return writer;
 }
 
-// Sender must ensure that version/witness are consistent with channel.
-void block::serialize(uint32_t, writer& sink,
-    bool BC_DEBUG_ONLY(witness)) const NOEXCEPT
+void block::serialize(uint32_t, writer& sink, bool witness) const NOEXCEPT
 {
-    BC_ASSERT(witness == witnessed_);
-    sink.write_bytes(block_data);
+    block.to_data(sink, witness);
 }
 
-// Sender must ensure that version/witness are consistent with channel.
-size_t block::size(uint32_t, bool BC_DEBUG_ONLY(witness)) const NOEXCEPT
+size_t block::size(uint32_t, bool witness) const NOEXCEPT
 {
-    BC_ASSERT(witness == witnessed_);
-    return block_data.size();
+    return block.is_valid() ? block.serialized_size(witness) : zero;
 }
 
 } // namespace messages

diff --git a/src/protocols/protocol_block_out_106.cpp b/src/protocols/protocol_block_out_106.cpp
@@ -229,8 +229,11 @@ void protocol_block_out_106::send_block(const code& ec) NOEXCEPT
     }
 
     const auto start = logger::now();
-    node::messages::block out{ query.get_wire_block(link, witness), witness };
-    if (out.block_data.empty())
+    node::messages::block out
+    {
+        { query.get_wire_block(link, witness), witness }
+    };
+    if (!out.block.is_valid())
     {
         LOGR("Requested block " << encode_hash(item.hash) << " from ["
             << opposite() << "] not found.");

diff --git a/test/messages/block.cpp b/test/messages/block.cpp
@@ -0,0 +1,64 @@
+/**
+ * Copyright (c) 2011-2026 libbitcoin developers (see AUTHORS)
+ *
+ * This file is part of libbitcoin.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include "../test.hpp"
+
+BOOST_AUTO_TEST_SUITE(block_tests)
+
+using namespace network::messages;
+
+// The message holds a block_view and serializes in the requested form. Genesis
+// is non-witness (witnessed and stripped forms are identical); the witnessed
+// strip is covered by the libbitcoin-system block_view to_data tests.
+
+BOOST_AUTO_TEST_CASE(block__serialize__witness__expected)
+{
+    const system::settings settings{ system::chain::selection::mainnet };
+    const node::messages::block instance
+    {
+        { settings.genesis_block.to_data(true), true }
+    };
+    system::data_chunk buffer(instance.size(peer::level::canonical, true));
+    BOOST_REQUIRE(instance.serialize(peer::level::canonical, { buffer }, true));
+    BOOST_REQUIRE_EQUAL(buffer, settings.genesis_block.to_data(true));
+}
+
+BOOST_AUTO_TEST_CASE(block__serialize__non_witness__expected)
+{
+    const system::settings settings{ system::chain::selection::mainnet };
+    const node::messages::block instance
+    {
+        { settings.genesis_block.to_data(true), false }
+    };
+    system::data_chunk buffer(instance.size(peer::level::canonical, false));
+    BOOST_REQUIRE(instance.serialize(peer::level::canonical, { buffer }, false));
+    BOOST_REQUIRE_EQUAL(buffer, settings.genesis_block.to_data(false));
+}
+
+BOOST_AUTO_TEST_CASE(block__serialize__short_buffer__false)
+{
+    const system::settings settings{ system::chain::selection::mainnet };
+    const node::messages::block instance
+    {
+        { settings.genesis_block.to_data(true), true }
+    };
+    system::data_chunk buffer(sub1(instance.size(peer::level::canonical, true)));
+    BOOST_REQUIRE(!instance.serialize(peer::level::canonical, { buffer }, true));
+}
+
+BOOST_AUTO_TEST_SUITE_END()