Fix IPv6 encoding in protobuf

src/Formats/ProtobufSerializer.cpp

@@ -1852,25 +1852,26 @@ namespace
 
             write_function = [this](IPv6 value)
             {
-                ipToString(value, text_buffer);
+                text_buffer = String(IPV6_BINARY_LENGTH, '\0');
+                memcpy(text_buffer.data(), &value.toUnderType(), IPV6_BINARY_LENGTH);
                 writeStr(text_buffer);
             };
 
             read_function = [this]() -> IPv6
             {
                 readStr(text_buffer);
-                return parse<IPv6>(text_buffer);
+                if (text_buffer.size() != IPV6_BINARY_LENGTH)
+                    throw Exception(ErrorCodes::PROTOBUF_BAD_CAST,
+                                    "Could not convert bytes field {} to IPv6 for inserting into column {} - field size {} is not equal to IPv6 size {}",
+                                    field_descriptor.full_name(), column_name, text_buffer.size(), IPV6_BINARY_LENGTH);
+                IPv6 value;
+                memcpy(&value.toUnderType(), text_buffer.data(), IPV6_BINARY_LENGTH);
+                return value;
             };
 
             default_function = [this]() -> IPv6 { return parse<IPv6>(field_descriptor.default_value_string()); };
         }
 
-        static void ipToString(const IPv6 & ip, String & str)
-        {
-            WriteBufferFromString buf{str};
-            writeText(ip, buf);
-        }
-
         std::function<void(IPv6)> write_function;
         std::function<IPv6()> read_function;
         std::function<IPv6()> default_function;

tests/queries/0_stateless/02751_protobuf_ipv6.reference

@@ -0,0 +1,2 @@
+::ffff:1.2.3.4
+::ffff:1.2.3.4

tests/queries/0_stateless/02751_protobuf_ipv6.sh

@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+# Tags: no-fasttest
+
+CURDIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
+# shellcheck source=../shell_config.sh
+. "$CURDIR"/../shell_config.sh
+
+SCHEMADIR=$CURDIR/format_schemas
+
+
+echo -ne '\x12\x1a\x10\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xff\xff\x01\x02\x03\x04' | $CLICKHOUSE_LOCAL --input-format Protobuf --format_schema="$SCHEMADIR/02751_protobuf_ipv6:Message" --structure="ipv6_bytes IPv6" -q "select * from table"
+
+$CLICKHOUSE_LOCAL -q "select '::ffff:1.2.3.4'::IPv6 as ipv6_bytes format Protobuf settings format_schema = '$SCHEMADIR/02751_protobuf_ipv6:Message'" | $CLICKHOUSE_LOCAL --input-format Protobuf --format_schema="$SCHEMADIR/02751_protobuf_ipv6:Message" --structure="ipv6_bytes IPv6"  -q "select * from table"
+

tests/queries/0_stateless/format_schemas/02751_protobuf_ipv6.proto

@@ -0,0 +1,6 @@
+syntax = "proto3";
+
+message Message
+{
+    bytes ipv6_bytes = 3;
+}