Use newly split feature defaults in plugins and runtimes.

The new fields fixed_features and overridable_features can be simply merged to recover the old aggregate defaults.  By splitting them though, plugins and runtimes get some extra information about lifetimes for enforcement.

PiperOrigin-RevId: 625527117

editions/defaults_test.cc

@@ -50,11 +50,13 @@ TEST(DefaultsTest, Check2023) {
   EXPECT_EQ(defaults->defaults()[0].edition(), EDITION_PROTO2);
   EXPECT_EQ(defaults->defaults()[1].edition(), EDITION_PROTO3);
   EXPECT_EQ(defaults->defaults()[2].edition(), EDITION_2023);
-  EXPECT_EQ(defaults->defaults()[2].features().field_presence(),
+  EXPECT_EQ(defaults->defaults()[2].overridable_features().field_presence(),
             FeatureSet::EXPLICIT);
-  EXPECT_EQ(
-      defaults->defaults()[2].features().GetExtension(pb::test).file_feature(),
-      pb::VALUE3);
+  EXPECT_EQ(defaults->defaults()[2]
+                .overridable_features()
+                .GetExtension(pb::test)
+                .file_feature(),
+            pb::VALUE3);
 }
 
 TEST(DefaultsTest, CheckFuture) {
@@ -67,23 +69,29 @@ TEST(DefaultsTest, CheckFuture) {
   EXPECT_EQ(defaults->defaults()[0].edition(), EDITION_PROTO2);
   EXPECT_EQ(defaults->defaults()[1].edition(), EDITION_PROTO3);
   EXPECT_EQ(defaults->defaults()[2].edition(), EDITION_2023);
-  EXPECT_EQ(defaults->defaults()[2].features().field_presence(),
+  EXPECT_EQ(defaults->defaults()[2].overridable_features().field_presence(),
             FeatureSet::EXPLICIT);
-  EXPECT_EQ(
-      defaults->defaults()[2].features().GetExtension(pb::test).file_feature(),
-      pb::VALUE3);
+  EXPECT_EQ(defaults->defaults()[2]
+                .overridable_features()
+                .GetExtension(pb::test)
+                .file_feature(),
+            pb::VALUE3);
   EXPECT_EQ(defaults->defaults()[3].edition(), EDITION_2024);
-  EXPECT_EQ(defaults->defaults()[3].features().field_presence(),
+  EXPECT_EQ(defaults->defaults()[3].overridable_features().field_presence(),
             FeatureSet::EXPLICIT);
-  EXPECT_EQ(
-      defaults->defaults()[3].features().GetExtension(pb::test).file_feature(),
-      pb::VALUE3);
+  EXPECT_EQ(defaults->defaults()[3]
+                .overridable_features()
+                .GetExtension(pb::test)
+                .file_feature(),
+            pb::VALUE3);
   EXPECT_EQ(defaults->defaults()[4].edition(), EDITION_99997_TEST_ONLY);
-  EXPECT_EQ(defaults->defaults()[4].features().field_presence(),
+  EXPECT_EQ(defaults->defaults()[4].overridable_features().field_presence(),
             FeatureSet::EXPLICIT);
-  EXPECT_EQ(
-      defaults->defaults()[4].features().GetExtension(pb::test).file_feature(),
-      pb::VALUE4);
+  EXPECT_EQ(defaults->defaults()[4]
+                .overridable_features()
+                .GetExtension(pb::test)
+                .file_feature(),
+            pb::VALUE4);
 }
 
 TEST(DefaultsTest, CheckFarFuture) {
@@ -96,29 +104,37 @@ TEST(DefaultsTest, CheckFarFuture) {
   EXPECT_EQ(defaults->defaults()[0].edition(), EDITION_PROTO2);
   EXPECT_EQ(defaults->defaults()[1].edition(), EDITION_PROTO3);
   EXPECT_EQ(defaults->defaults()[2].edition(), EDITION_2023);
-  EXPECT_EQ(defaults->defaults()[2].features().field_presence(),
+  EXPECT_EQ(defaults->defaults()[2].overridable_features().field_presence(),
             FeatureSet::EXPLICIT);
-  EXPECT_EQ(
-      defaults->defaults()[2].features().GetExtension(pb::test).file_feature(),
-      pb::VALUE3);
+  EXPECT_EQ(defaults->defaults()[2]
+                .overridable_features()
+                .GetExtension(pb::test)
+                .file_feature(),
+            pb::VALUE3);
   EXPECT_EQ(defaults->defaults()[3].edition(), EDITION_2024);
-  EXPECT_EQ(defaults->defaults()[3].features().field_presence(),
+  EXPECT_EQ(defaults->defaults()[3].overridable_features().field_presence(),
             FeatureSet::EXPLICIT);
-  EXPECT_EQ(
-      defaults->defaults()[3].features().GetExtension(pb::test).file_feature(),
-      pb::VALUE3);
+  EXPECT_EQ(defaults->defaults()[3]
+                .overridable_features()
+                .GetExtension(pb::test)
+                .file_feature(),
+            pb::VALUE3);
   EXPECT_EQ(defaults->defaults()[4].edition(), EDITION_99997_TEST_ONLY);
-  EXPECT_EQ(defaults->defaults()[4].features().field_presence(),
+  EXPECT_EQ(defaults->defaults()[4].overridable_features().field_presence(),
             FeatureSet::EXPLICIT);
-  EXPECT_EQ(
-      defaults->defaults()[4].features().GetExtension(pb::test).file_feature(),
-      pb::VALUE4);
+  EXPECT_EQ(defaults->defaults()[4]
+                .overridable_features()
+                .GetExtension(pb::test)
+                .file_feature(),
+            pb::VALUE4);
   EXPECT_EQ(defaults->defaults()[5].edition(), EDITION_99998_TEST_ONLY);
-  EXPECT_EQ(defaults->defaults()[5].features().field_presence(),
+  EXPECT_EQ(defaults->defaults()[5].overridable_features().field_presence(),
             FeatureSet::EXPLICIT);
-  EXPECT_EQ(
-      defaults->defaults()[5].features().GetExtension(pb::test).file_feature(),
-      pb::VALUE5);
+  EXPECT_EQ(defaults->defaults()[5]
+                .overridable_features()
+                .GetExtension(pb::test)
+                .file_feature(),
+            pb::VALUE5);
 }
 
 TEST(DefaultsTest, Embedded) {
@@ -133,11 +149,13 @@ TEST(DefaultsTest, Embedded) {
   EXPECT_EQ(defaults.defaults()[0].edition(), EDITION_PROTO2);
   EXPECT_EQ(defaults.defaults()[1].edition(), EDITION_PROTO3);
   EXPECT_EQ(defaults.defaults()[2].edition(), EDITION_2023);
-  EXPECT_EQ(defaults.defaults()[2].features().field_presence(),
+  EXPECT_EQ(defaults.defaults()[2].overridable_features().field_presence(),
             FeatureSet::EXPLICIT);
-  EXPECT_EQ(
-      defaults.defaults()[2].features().GetExtension(pb::test).file_feature(),
-      pb::VALUE3);
+  EXPECT_EQ(defaults.defaults()[2]
+                .overridable_features()
+                .GetExtension(pb::test)
+                .file_feature(),
+            pb::VALUE3);
 }
 
 TEST(DefaultsTest, EmbeddedBase64) {
@@ -155,11 +173,13 @@ TEST(DefaultsTest, EmbeddedBase64) {
   EXPECT_EQ(defaults.defaults()[0].edition(), EDITION_PROTO2);
   EXPECT_EQ(defaults.defaults()[1].edition(), EDITION_PROTO3);
   EXPECT_EQ(defaults.defaults()[2].edition(), EDITION_2023);
-  EXPECT_EQ(defaults.defaults()[2].features().field_presence(),
+  EXPECT_EQ(defaults.defaults()[2].overridable_features().field_presence(),
             FeatureSet::EXPLICIT);
-  EXPECT_EQ(
-      defaults.defaults()[2].features().GetExtension(pb::test).file_feature(),
-      pb::VALUE3);
+  EXPECT_EQ(defaults.defaults()[2]
+                .overridable_features()
+                .GetExtension(pb::test)
+                .file_feature(),
+            pb::VALUE3);
 }
 
 }  // namespace

java/core/src/main/java/com/google/protobuf/Descriptors.java

@@ -127,18 +127,18 @@ public final class Descriptors {
               + javaEditionDefaults.getMaximumEdition()
               + "!");
     }
-    FeatureSet found = null;
+    FeatureSetEditionDefault found = null;
     for (FeatureSetEditionDefault editionDefault : javaEditionDefaults.getDefaultsList()) {
       if (editionDefault.getEdition().getNumber() > edition.getNumber()) {
         break;
       }
-      found = editionDefault.getFeatures();
+      found = editionDefault;
     }
     if (found == null) {
       throw new IllegalArgumentException(
           "Edition " + edition + " does not have a valid default FeatureSet!");
     }
-    return found;
+    return found.getFixedFeatures().toBuilder().mergeFrom(found.getOverridableFeatures()).build();
   }
 
   private static FeatureSet internFeatures(FeatureSet features) {

java/core/src/test/java/com/google/protobuf/DescriptorsTest.java

@@ -1242,7 +1242,7 @@ public class DescriptorsTest {
     public void setUp() {
       FeatureSetDefaults.Builder defaults = Descriptors.getJavaEditionDefaults().toBuilder();
       for (FeatureSetEditionDefault.Builder editionDefaults : defaults.getDefaultsBuilderList()) {
-        setTestFeature(editionDefaults.getFeaturesBuilder(), 1);
+        setTestFeature(editionDefaults.getOverridableFeaturesBuilder(), 1);
       }
       Descriptors.setTestJavaEditionDefaults(defaults.build());
 

python/google/protobuf/descriptor_pool.py

@@ -737,7 +737,7 @@ class DescriptorPool(object):
     for d in self._edition_defaults.defaults:
       if d.edition > edition:
         break
-      found = d.features
+      found = d
     if found is None:
       raise TypeError(
           'No valid default found for edition %s!'
@@ -745,7 +745,8 @@ class DescriptorPool(object):
       )
 
     defaults = descriptor_pb2.FeatureSet()
-    defaults.CopyFrom(found)
+    defaults.CopyFrom(found.fixed_features)
+    defaults.MergeFrom(found.overridable_features)
     return defaults
 
   def _InternFeatures(self, features):

python/google/protobuf/internal/descriptor_pool_test.py

@@ -1131,19 +1131,49 @@ class FeatureSetDefaults(unittest.TestCase):
         file._GetFeatures().HasExtension(unittest_features_pb2.test)
     )
 
+  def testMergedDefaults(self):
+    pool = descriptor_pool.DescriptorPool()
+    fixed = descriptor_pb2.FeatureSet()
+    fixed.CopyFrom(unittest_features_pb2.DESCRIPTOR._GetFeatures())
+    fixed.field_presence = descriptor_pb2.FeatureSet.IMPLICIT
+    fixed.ClearField('message_encoding')
+    defaults = descriptor_pb2.FeatureSetDefaults(
+        defaults=[
+            descriptor_pb2.FeatureSetDefaults.FeatureSetEditionDefault(
+                edition=descriptor_pb2.Edition.EDITION_PROTO2,
+                fixed_features=fixed,
+                overridable_features=descriptor_pb2.FeatureSet(
+                    message_encoding=descriptor_pb2.FeatureSet.DELIMITED
+                ),
+            )
+        ],
+        minimum_edition=descriptor_pb2.Edition.EDITION_PROTO2,
+        maximum_edition=descriptor_pb2.Edition.EDITION_2023,
+    )
+    pool.SetFeatureSetDefaults(defaults)
+    file_desc = descriptor_pb2.FileDescriptorProto(name='some/file.proto')
+    file = pool.AddSerializedFile(file_desc.SerializeToString())
+    self.assertEqual(
+        file._GetFeatures().message_encoding,
+        descriptor_pb2.FeatureSet.DELIMITED,
+    )
+    self.assertEqual(
+        file._GetFeatures().field_presence, descriptor_pb2.FeatureSet.IMPLICIT
+    )
+
   def testOverride(self):
     pool = descriptor_pool.DescriptorPool()
     defaults = descriptor_pb2.FeatureSetDefaults(
         defaults=[
             descriptor_pb2.FeatureSetDefaults.FeatureSetEditionDefault(
                 edition=descriptor_pb2.Edition.EDITION_PROTO2,
-                features=unittest_features_pb2.DESCRIPTOR._GetFeatures(),
+                overridable_features=unittest_features_pb2.DESCRIPTOR._GetFeatures(),
             )
         ],
         minimum_edition=descriptor_pb2.Edition.EDITION_PROTO2,
         maximum_edition=descriptor_pb2.Edition.EDITION_2023,
     )
-    defaults.defaults[0].features.Extensions[
+    defaults.defaults[0].overridable_features.Extensions[
         unittest_features_pb2.test
     ].file_feature = unittest_features_pb2.VALUE9
     pool.SetFeatureSetDefaults(defaults)
@@ -1177,7 +1207,7 @@ class FeatureSetDefaults(unittest.TestCase):
               defaults=[
                   descriptor_pb2.FeatureSetDefaults.FeatureSetEditionDefault(
                       edition=descriptor_pb2.Edition.EDITION_PROTO2,
-                      features=unittest_features_pb2.DESCRIPTOR._GetFeatures(),
+                      overridable_features=unittest_features_pb2.DESCRIPTOR._GetFeatures(),
                   )
               ],
               minimum_edition=descriptor_pb2.Edition.EDITION_2023,
@@ -1197,11 +1227,11 @@ class FeatureSetDefaults(unittest.TestCase):
               defaults=[
                   descriptor_pb2.FeatureSetDefaults.FeatureSetEditionDefault(
                       edition=descriptor_pb2.Edition.EDITION_PROTO3,
-                      features=unittest_features_pb2.DESCRIPTOR._GetFeatures(),
+                      overridable_features=unittest_features_pb2.DESCRIPTOR._GetFeatures(),
                   ),
                   descriptor_pb2.FeatureSetDefaults.FeatureSetEditionDefault(
                       edition=descriptor_pb2.Edition.EDITION_PROTO2,
-                      features=unittest_features_pb2.DESCRIPTOR._GetFeatures(),
+                      overridable_features=unittest_features_pb2.DESCRIPTOR._GetFeatures(),
                   ),
               ],
               minimum_edition=descriptor_pb2.Edition.EDITION_PROTO2,
@@ -1217,11 +1247,11 @@ class FeatureSetDefaults(unittest.TestCase):
               defaults=[
                   descriptor_pb2.FeatureSetDefaults.FeatureSetEditionDefault(
                       edition=descriptor_pb2.Edition.EDITION_UNKNOWN,
-                      features=unittest_features_pb2.DESCRIPTOR._GetFeatures(),
+                      overridable_features=unittest_features_pb2.DESCRIPTOR._GetFeatures(),
                   ),
                   descriptor_pb2.FeatureSetDefaults.FeatureSetEditionDefault(
                       edition=descriptor_pb2.Edition.EDITION_PROTO2,
-                      features=unittest_features_pb2.DESCRIPTOR._GetFeatures(),
+                      overridable_features=unittest_features_pb2.DESCRIPTOR._GetFeatures(),
                   ),
               ],
               minimum_edition=descriptor_pb2.Edition.EDITION_PROTO2,
@@ -1238,7 +1268,7 @@ class FeatureSetDefaults(unittest.TestCase):
         defaults=[
             descriptor_pb2.FeatureSetDefaults.FeatureSetEditionDefault(
                 edition=descriptor_pb2.Edition.EDITION_PROTO2,
-                features=unittest_features_pb2.DESCRIPTOR._GetFeatures(),
+                overridable_features=unittest_features_pb2.DESCRIPTOR._GetFeatures(),
             )
         ],
         minimum_edition=descriptor_pb2.Edition.EDITION_PROTO2,
@@ -1252,7 +1282,7 @@ class FeatureSetDefaults(unittest.TestCase):
         defaults=[
             descriptor_pb2.FeatureSetDefaults.FeatureSetEditionDefault(
                 edition=descriptor_pb2.Edition.EDITION_PROTO2,
-                features=unittest_features_pb2.DESCRIPTOR._GetFeatures(),
+                overridable_features=unittest_features_pb2.DESCRIPTOR._GetFeatures(),
             )
         ],
         minimum_edition=descriptor_pb2.Edition.EDITION_PROTO2,
@@ -1267,7 +1297,7 @@ class FeatureSetDefaults(unittest.TestCase):
         defaults=[
             descriptor_pb2.FeatureSetDefaults.FeatureSetEditionDefault(
                 edition=descriptor_pb2.Edition.EDITION_2023,
-                features=unittest_features_pb2.DESCRIPTOR._GetFeatures(),
+                overridable_features=unittest_features_pb2.DESCRIPTOR._GetFeatures(),
             )
         ],
         minimum_edition=descriptor_pb2.Edition.EDITION_PROTO2,
@@ -1285,7 +1315,7 @@ class FeatureSetDefaults(unittest.TestCase):
         defaults=[
             descriptor_pb2.FeatureSetDefaults.FeatureSetEditionDefault(
                 edition=descriptor_pb2.Edition.EDITION_PROTO3,
-                features=unittest_features_pb2.DESCRIPTOR._GetFeatures(),
+                overridable_features=unittest_features_pb2.DESCRIPTOR._GetFeatures(),
             )
         ],
         minimum_edition=descriptor_pb2.Edition.EDITION_PROTO3,
@@ -1305,7 +1335,7 @@ class FeatureSetDefaults(unittest.TestCase):
         defaults=[
             descriptor_pb2.FeatureSetDefaults.FeatureSetEditionDefault(
                 edition=descriptor_pb2.Edition.EDITION_PROTO2,
-                features=unittest_features_pb2.DESCRIPTOR._GetFeatures(),
+                overridable_features=unittest_features_pb2.DESCRIPTOR._GetFeatures(),
             )
         ],
         minimum_edition=descriptor_pb2.Edition.EDITION_PROTO2,

python/google/protobuf/internal/descriptor_test.py

@@ -1455,13 +1455,13 @@ class FeatureInheritanceTest(unittest.TestCase):
         defaults=[
             descriptor_pb2.FeatureSetDefaults.FeatureSetEditionDefault(
                 edition=descriptor_pb2.Edition.EDITION_PROTO2,
-                features=unittest_pb2.TestAllTypes.DESCRIPTOR._GetFeatures(),
+                overridable_features=unittest_pb2.TestAllTypes.DESCRIPTOR._GetFeatures(),
             )
         ],
         minimum_edition=descriptor_pb2.Edition.EDITION_PROTO2,
         maximum_edition=descriptor_pb2.Edition.EDITION_2023,
     )
-    defaults.defaults[0].features.Extensions[
+    defaults.defaults[0].overridable_features.Extensions[
         unittest_features_pb2.test
     ].multiple_feature = 1
     ret.pool.SetFeatureSetDefaults(defaults)

src/google/protobuf/compiler/command_line_interface_unittest.cc

@@ -2102,21 +2102,31 @@ TEST_F(CommandLineInterfaceTest, EditionDefaultsWithExtension) {
   EXPECT_EQ(defaults.defaults(3).edition(), EDITION_2024);
   EXPECT_EQ(defaults.defaults(4).edition(), EDITION_99997_TEST_ONLY);
   EXPECT_EQ(defaults.defaults(5).edition(), EDITION_99998_TEST_ONLY);
-  EXPECT_EQ(
-      defaults.defaults(0).features().GetExtension(pb::test).file_feature(),
-      pb::EnumFeature::VALUE1);
-  EXPECT_EQ(
-      defaults.defaults(2).features().GetExtension(pb::test).file_feature(),
-      pb::EnumFeature::VALUE3);
-  EXPECT_EQ(
-      defaults.defaults(3).features().GetExtension(pb::test).file_feature(),
-      pb::EnumFeature::VALUE3);
-  EXPECT_EQ(
-      defaults.defaults(4).features().GetExtension(pb::test).file_feature(),
-      pb::EnumFeature::VALUE4);
-  EXPECT_EQ(
-      defaults.defaults(5).features().GetExtension(pb::test).file_feature(),
-      pb::EnumFeature::VALUE5);
+  EXPECT_EQ(defaults.defaults(0)
+                .fixed_features()
+                .GetExtension(pb::test)
+                .file_feature(),
+            pb::EnumFeature::VALUE1);
+  EXPECT_EQ(defaults.defaults(2)
+                .overridable_features()
+                .GetExtension(pb::test)
+                .file_feature(),
+            pb::EnumFeature::VALUE3);
+  EXPECT_EQ(defaults.defaults(3)
+                .overridable_features()
+                .GetExtension(pb::test)
+                .file_feature(),
+            pb::EnumFeature::VALUE3);
+  EXPECT_EQ(defaults.defaults(4)
+                .overridable_features()
+                .GetExtension(pb::test)
+                .file_feature(),
+            pb::EnumFeature::VALUE4);
+  EXPECT_EQ(defaults.defaults(5)
+                .overridable_features()
+                .GetExtension(pb::test)
+                .file_feature(),
+            pb::EnumFeature::VALUE5);
 }
 
 #ifndef _WIN32

src/google/protobuf/descriptor_unittest.cc

@@ -10730,7 +10730,7 @@ TEST_F(DescriptorPoolFeaturesTest, UnknownDefaults) {
   FeatureSetDefaults defaults = ParseTextOrDie(R"pb(
     defaults {
       edition: EDITION_UNKNOWN
-      features {}
+      overridable_features {}
     }
     minimum_edition: EDITION_PROTO2
     maximum_edition: EDITION_2023
@@ -10744,11 +10744,11 @@ TEST_F(DescriptorPoolFeaturesTest, NotStrictlyIncreasing) {
   FeatureSetDefaults defaults = ParseTextOrDie(R"pb(
     defaults {
       edition: EDITION_PROTO3
-      features {}
+      overridable_features {}
     }
     defaults {
       edition: EDITION_PROTO2
-      features {}
+      overridable_features {}
     }
     minimum_edition: EDITION_PROTO2
     maximum_edition: EDITION_2023
@@ -10766,7 +10766,7 @@ TEST_F(DescriptorPoolFeaturesTest, OverrideDefaults) {
   FeatureSetDefaults defaults = ParseTextOrDie(R"pb(
     defaults {
       edition: EDITION_PROTO2
-      features {
+      overridable_features {
         field_presence: EXPLICIT
         enum_type: CLOSED
         repeated_field_encoding: EXPANDED

src/google/protobuf/feature_resolver.cc

@@ -418,7 +418,9 @@ absl::StatusOr<FeatureResolver> FeatureResolver::Create(
             edition_default.edition(), ".");
       }
     }
-    RETURN_IF_ERROR(ValidateMergedFeatures(edition_default.features()));
+    FeatureSet features = edition_default.fixed_features();
+    features.MergeFrom(edition_default.overridable_features());
+    RETURN_IF_ERROR(ValidateMergedFeatures(features));
 
     prev_edition = edition_default.edition();
   }
@@ -435,7 +437,9 @@ absl::StatusOr<FeatureResolver> FeatureResolver::Create(
     return Error("No valid default found for edition ", edition);
   }
 
-  return FeatureResolver(std::prev(first_nonmatch)->features());
+  FeatureSet features = std::prev(first_nonmatch)->fixed_features();
+  features.MergeFrom(std::prev(first_nonmatch)->overridable_features());
+  return FeatureResolver(std::move(features));
 }
 
 absl::StatusOr<FeatureSet> FeatureResolver::MergeFeatures(

src/google/protobuf/feature_resolver_test.cc

@@ -215,6 +215,39 @@ TEST(FeatureResolverTest, DefaultsGeneratedPoolCustom) {
   EXPECT_FALSE(merged.HasExtension(pb::cpp));
 }
 
+TEST(FeatureResolverTest, DefaultsMergedFeatures) {
+  absl::StatusOr<FeatureSetDefaults> defaults =
+      FeatureResolver::CompileDefaults(FeatureSet::descriptor(),
+                                       {GetExtension(pb::test)}, EDITION_2023,
+                                       EDITION_2023);
+  ASSERT_OK(defaults);
+  ASSERT_EQ(defaults->defaults_size(), 3);
+
+  defaults->mutable_defaults(2)
+      ->mutable_fixed_features()
+      ->MutableExtension(pb::test)
+      ->set_file_feature(pb::VALUE7);
+  defaults->mutable_defaults(2)
+      ->mutable_fixed_features()
+      ->MutableExtension(pb::test)
+      ->set_multiple_feature(pb::VALUE6);
+  defaults->mutable_defaults(2)
+      ->mutable_overridable_features()
+      ->MutableExtension(pb::test)
+      ->clear_file_feature();
+  defaults->mutable_defaults(2)
+      ->mutable_overridable_features()
+      ->MutableExtension(pb::test)
+      ->set_multiple_feature(pb::VALUE8);
+
+  absl::StatusOr<FeatureSet> features = GetDefaults(EDITION_2023, *defaults);
+  ASSERT_OK(features);
+
+  const pb::TestFeatures& ext = features->GetExtension(pb::test);
+  EXPECT_EQ(ext.file_feature(), pb::VALUE7);
+  EXPECT_EQ(ext.multiple_feature(), pb::VALUE8);
+}
+
 TEST(FeatureResolverTest, DefaultsTooEarly) {
   absl::StatusOr<FeatureSetDefaults> defaults =
       FeatureResolver::CompileDefaults(FeatureSet::descriptor(),
@@ -437,13 +470,15 @@ TEST(FeatureResolverTest, CreateUnknownEnumFeature) {
   for (int i = 0; i < descriptor.field_count(); ++i) {
     const FieldDescriptor& field = *descriptor.field(i);
 
+    // Clear the feature, which should be invalid.
     FeatureSetDefaults defaults = *valid_defaults;
     FeatureSet* features =
-        defaults.mutable_defaults()->Mutable(0)->mutable_features();
-    const Reflection& reflection = *features->GetReflection();
+        defaults.mutable_defaults()->Mutable(0)->mutable_overridable_features();
+    features->GetReflection()->ClearField(features, &field);
+    features =
+        defaults.mutable_defaults()->Mutable(0)->mutable_fixed_features();
+    features->GetReflection()->ClearField(features, &field);
 
-    // Clear the feature, which should be invalid.
-    reflection.ClearField(features, &field);
     EXPECT_THAT(FeatureResolver::Create(EDITION_2023, defaults),
                 HasError(AllOf(HasSubstr(field.name()),
                                HasSubstr("must resolve to a known value"))));

upb/reflection/file_def.c

@@ -232,20 +232,35 @@ const UPB_DESC(FeatureSet*)
   size_t n;
   const UPB_DESC(FeatureSetDefaults_FeatureSetEditionDefault)* const* d =
       UPB_DESC(FeatureSetDefaults_defaults)(defaults, &n);
-  const UPB_DESC(FeatureSet)* ret = NULL;
+  const UPB_DESC(FeatureSetDefaults_FeatureSetEditionDefault)* result = NULL;
   for (size_t i = 0; i < n; i++) {
     if (UPB_DESC(FeatureSetDefaults_FeatureSetEditionDefault_edition)(d[i]) >
         edition) {
       break;
     }
-    ret = UPB_DESC(FeatureSetDefaults_FeatureSetEditionDefault_features)(d[i]);
+    result = d[i];
   }
-  if (ret == NULL) {
+  if (result == NULL) {
     _upb_DefBuilder_Errf(ctx, "No valid default found for edition %s",
                          upb_FileDef_EditionName(edition));
     return NULL;
   }
-  return ret;
+
+  // Merge the fixed and overridable features to get the edition's default
+  // feature set.
+  const UPB_DESC(FeatureSet)* fixed = UPB_DESC(
+      FeatureSetDefaults_FeatureSetEditionDefault_fixed_features)(result);
+  const UPB_DESC(FeatureSet)* overridable = UPB_DESC(
+      FeatureSetDefaults_FeatureSetEditionDefault_overridable_features)(result);
+  if (!fixed && !overridable) {
+    _upb_DefBuilder_Errf(ctx, "No valid default found for edition %s",
+                         upb_FileDef_EditionName(edition));
+    return NULL;
+  } else if (!fixed) {
+    return overridable;
+  }
+  return _upb_DefBuilder_DoResolveFeatures(ctx, fixed, overridable,
+                                           /*is_implicit=*/true);
 }
 
 // Allocate and initialize one file def, and add it to the context object.