Add nodiscard to has_*/*_size accessors.

PiperOrigin-RevId: 828685303

Author: ckennelly

editions/golden/compare_cpp_codegen_failure.txt

@@ -42,9 +42,9 @@
    };
 -  // optional int32 int32_field = 1;
 +  // int32 int32_field = 1;
-   bool has_int32_field() const;
+   [[nodiscard]] bool has_int32_field()
+       const;
    void clear_int32_field() ;
-   ::int32_t int32_field() const;
 @@ @@
 
  // SimpleProto3

editions/golden/compare_cpp_codegen_failure.xml

@@ -5,7 +5,7 @@
 <failure message="Value of: third_party/protobuf/editions/golden/simple_proto3.pb.cc&#x0A;Expected: &#x0A;// Generated by the protocol buffer compiler.  DO NOT EDIT!&#x0A;// NO CHECKED-IN PROTOBUF GENCODE&#x0A;// source: third_party/protobuf/editions/golden/simple_proto3.proto&#x0A;&#x0A;#include &quot;third_party/protobuf/editions/golden/simple_proto3.pb.h&quot;&#x0A;&#x0A;#include &lt;algorithm&gt;&#x0A;#include &lt;type_traits&gt;&#x0A;#include &quot;third_party/protobuf/io/coded_stream.h&quot;&#x0A;#include &quot;third_party/protobuf/generated_message_tctable_impl.h&quot;&#x0A;#include &quot;third_party/protobuf/internal_visibility.h&quot;&#x0A;#include &quot;third_party/protobuf/extension_set.h&quot;&#x0A;#include &quot;third_party/protobuf/generated_message_util.h&quot;&#x0A;#include &quot;third_party/protobuf/wire_format_lite.h&quot;&#x0A;#include &quot;third_party/protobuf/io/zero_copy_stream_impl_lite.h&quot;&#x0A;#include &quot;third_party/protobuf/v2/generated_message_table_impl.h&quot;&#x0A;// @@protoc_insertion_point(includes)&#x0A;&#x0A;// Must be included last.&#x0A;, with the difference:&#x0A;@@ @@&#x0A;     ::_pbi::TcParser::GetTable&lt;::protobuf_editions_test::golden::SimpleProto3&gt;(),  // to_prefetch&#x0A;     #endif  // PROTOBUF_PREFETCH_PARSE_TABLE&#x0A;   }, {{&#x0A;-    // optional int32 int32_field = 1;&#x0A;+    // int32 int32_field = 1;&#x0A;     {::_pbi::TcParser::FastV32S1,&#x0A;      {8, 0, 0,&#x0A;       PROTOBUF_FIELD_OFFSET(SimpleProto3, _impl_.int32_field_)}},&#x0A;   }}, {{&#x0A;     65535, 65535&#x0A;   }}, {{&#x0A;-    // optional int32 int32_field = 1;&#x0A;+    // int32 int32_field = 1;&#x0A;     {PROTOBUF_FIELD_OFFSET(SimpleProto3, _impl_.int32_field_), _Internal::kHasBitsOffset + 0, 0, (0 | ::_fl::kFcOptional | ::_fl::kInt32)},&#x0A;   }},&#x0A;   // no aux_entries&#x0A;@@ @@&#x0A;   (void)cached_has_bits;&#x0A; &#x0A;   cached_has_bits = this_._impl_._has_bits_[0];&#x0A;-  // optional int32 int32_field = 1;&#x0A;+  // int32 int32_field = 1;&#x0A;   if (CheckHasBit(cached_has_bits, 0x00000001U)) {&#x0A;     target =&#x0A;         ::proto2::internal::WireFormatLite::WriteInt32ToArrayWithField&lt;1&gt;(&#x0A;@@ @@&#x0A;   (void)cached_has_bits;&#x0A; &#x0A;    {&#x0A;-    // optional int32 int32_field = 1;&#x0A;+    // int32 int32_field = 1;&#x0A;     cached_has_bits = this_._impl_._has_bits_[0];&#x0A;     if (CheckHasBit(cached_has_bits, 0x00000001U)) {&#x0A;       total_size += ::_pbi::WireFormatLite::Int32SizePlusOne(" type=""></failure>
 </testcase>
 <testcase name="third_party/protobuf/editions/golden/simple_proto3.pb.h" status="run" result="completed" classname="DiffTest">
-<failure message="Value of: third_party/protobuf/editions/golden/simple_proto3.pb.h&#x0A;Expected: &#x0A;// Generated by the protocol buffer compiler.  DO NOT EDIT!&#x0A;// NO CHECKED-IN PROTOBUF GENCODE&#x0A;// source: third_party/protobuf/editions/golden/simple_proto3.proto&#x0A;&#x0A;#ifndef third_5fparty_2fprotobuf_2feditions_2fgolden_2fsimple_5fproto3_2eproto_2epb_2eh&#x0A;#define third_5fparty_2fprotobuf_2feditions_2fgolden_2fsimple_5fproto3_2eproto_2epb_2eh&#x0A;&#x0A;#include &lt;limits&gt;&#x0A;#include &lt;string&gt;&#x0A;#include &lt;type_traits&gt;&#x0A;#include &lt;utility&gt;&#x0A;&#x0A;#include &quot;third_party/protobuf/runtime_version.h&quot;&#x0A;#include &quot;third_party/protobuf/io/coded_stream.h&quot;&#x0A;#include &quot;third_party/protobuf/arena.h&quot;&#x0A;#include &quot;third_party/protobuf/arenastring.h&quot;&#x0A;#include &quot;third_party/protobuf/generated_message_tctable_decl.h&quot;&#x0A;#include &quot;third_party/protobuf/v2/generated_message_table.h&quot;&#x0A;#include &quot;third_party/protobuf/v2/generated_message_table_impl.h&quot;&#x0A;#include &quot;third_party/protobuf/v2/batch_builder.h&quot;&#x0A;#include &quot;third_party/protobuf/v2/batch_wire_format.h&quot;&#x0A;#include &quot;third_party/protobuf/generated_message_util.h&quot;&#x0A;#include &quot;third_party/protobuf/metadata_lite.h&quot;&#x0A;#include &quot;third_party/protobuf/message_lite.h&quot;&#x0A;// @@protoc_insertion_point(includes)&#x0A;&#x0A;// Must be included last.&#x0A;&#x0A;#endif  // third_5fparty_2fprotobuf_2feditions_2fgolden_2fsimple_5fproto3_2eproto_2epb_2eh&#x0A;, with the difference:&#x0A;@@ @@&#x0A;   enum : int {&#x0A;     kInt32FieldFieldNumber = 1,&#x0A;   };&#x0A;-  // optional int32 int32_field = 1;&#x0A;+  // int32 int32_field = 1;&#x0A;   bool has_int32_field() const;&#x0A;   void clear_int32_field() ;&#x0A;   ::int32_t int32_field() const;&#x0A;@@ @@&#x0A; &#x0A; // SimpleProto3&#x0A; &#x0A;-// optional int32 int32_field = 1;&#x0A;+// int32 int32_field = 1;&#x0A; inline bool SimpleProto3::has_int32_field() const {&#x0A;   bool value = CheckHasBit(_impl_._has_bits_[0], 0x00000001U);&#x0A;   return value;" type=""></failure>
+<failure message="Value of: third_party/protobuf/editions/golden/simple_proto3.pb.h&#x0A;Expected: &#x0A;// Generated by the protocol buffer compiler.  DO NOT EDIT!&#x0A;// NO CHECKED-IN PROTOBUF GENCODE&#x0A;// source: third_party/protobuf/editions/golden/simple_proto3.proto&#x0A;&#x0A;#ifndef third_5fparty_2fprotobuf_2feditions_2fgolden_2fsimple_5fproto3_2eproto_2epb_2eh&#x0A;#define third_5fparty_2fprotobuf_2feditions_2fgolden_2fsimple_5fproto3_2eproto_2epb_2eh&#x0A;&#x0A;#include &lt;limits&gt;&#x0A;#include &lt;string&gt;&#x0A;#include &lt;type_traits&gt;&#x0A;#include &lt;utility&gt;&#x0A;&#x0A;#include &quot;third_party/protobuf/runtime_version.h&quot;&#x0A;#include &quot;third_party/protobuf/io/coded_stream.h&quot;&#x0A;#include &quot;third_party/protobuf/arena.h&quot;&#x0A;#include &quot;third_party/protobuf/arenastring.h&quot;&#x0A;#include &quot;third_party/protobuf/generated_message_tctable_decl.h&quot;&#x0A;#include &quot;third_party/protobuf/v2/generated_message_table.h&quot;&#x0A;#include &quot;third_party/protobuf/v2/generated_message_table_impl.h&quot;&#x0A;#include &quot;third_party/protobuf/v2/batch_builder.h&quot;&#x0A;#include &quot;third_party/protobuf/v2/batch_wire_format.h&quot;&#x0A;#include &quot;third_party/protobuf/generated_message_util.h&quot;&#x0A;#include &quot;third_party/protobuf/metadata_lite.h&quot;&#x0A;#include &quot;third_party/protobuf/message_lite.h&quot;&#x0A;// @@protoc_insertion_point(includes)&#x0A;&#x0A;// Must be included last.&#x0A;&#x0A;#endif  // third_5fparty_2fprotobuf_2feditions_2fgolden_2fsimple_5fproto3_2eproto_2epb_2eh&#x0A;, with the difference:&#x0A;@@ @@&#x0A;   enum : int {&#x0A;     kInt32FieldFieldNumber = 1,&#x0A;   };&#x0A;-  // optional int32 int32_field = 1;&#x0A;+  // int32 int32_field = 1;&#x0A;   [[nodiscard]] bool has_int32_field()&#x0A;       const;&#x0A;   void clear_int32_field() ;&#x0A;@@ @@&#x0A; &#x0A; // SimpleProto3&#x0A; &#x0A;-// optional int32 int32_field = 1;&#x0A;+// int32 int32_field = 1;&#x0A; inline bool SimpleProto3::has_int32_field() const {&#x0A;   bool value = CheckHasBit(_impl_._has_bits_[0], 0x00000001U);&#x0A;   return value;" type=""></failure>
 </testcase>
 <testcase name="third_party/protobuf/editions/golden/simple_proto3.proto.static_reflection.h" status="run" result="completed" classname="DiffTest">
 </testcase>

src/google/protobuf/compiler/cpp/message.cc

@@ -835,7 +835,8 @@ void MessageGenerator::GenerateFieldAccessorDeclarations(io::Printer* p) {
                 p->Emit({Sub("name_size", absl::StrCat(name, "_size"))
                              .AnnotatedAs(field)},
                         R"cc(
-                          $deprecated_attr $int $name_size$() $const_impl$;
+                          [[nodiscard]] $deprecated_attr $int $name_size$()
+                              $const_impl$;
                         )cc");
 
                 p->Emit({Sub("_internal_name_size",
@@ -854,7 +855,8 @@ void MessageGenerator::GenerateFieldAccessorDeclarations(io::Printer* p) {
                 p->Emit({Sub("has_name", absl::StrCat("has_", name))
                              .AnnotatedAs(field)},
                         R"cc(
-                          $deprecated_attr $bool $has_name$() $const_impl$;
+                          [[nodiscard]] $deprecated_attr $bool $has_name$()
+                              $const_impl$;
                         )cc");
               }},
              {"internal_hazzer",
@@ -2224,7 +2226,7 @@ void MessageGenerator::GenerateClassDefinition(io::Printer* p) {
           // Generate oneof function declarations
           for (auto oneof : OneOfRange(descriptor_)) {
             p->Emit({{"oneof_name", oneof->name()}}, R"cc(
-              inline bool has_$oneof_name$() const;
+              [[nodiscard]] inline bool has_$oneof_name$() const;
               inline void clear_has_$oneof_name$();
             )cc");
           }