Add additional proto validation to descriptor builds.

These would normally be caught by the parser, but would be bypassed by dynamic descriptor builds.

PiperOrigin-RevId: 572010482

src/google/protobuf/descriptor.cc

@@ -7920,6 +7920,19 @@ void DescriptorBuilder::ValidateFieldFeatures(
   // Rely on our legacy validation for proto2/proto3 files.
   if (IsLegacyFeatureSet(field->features())) return;
 
+  // Double check proto descriptors in editions.  These would usually be caught
+  // by the parser, but may not be for dynamically built descriptors.
+  if (proto.label() == FieldDescriptorProto::LABEL_REQUIRED) {
+    AddError(field->full_name(), proto, DescriptorPool::ErrorCollector::NAME,
+             "Required label is not allowed under editions.  Use the feature "
+             "field_presence = LEGACY_REQUIRED to control this behavior.");
+  }
+  if (proto.type() == FieldDescriptorProto::TYPE_GROUP) {
+    AddError(field->full_name(), proto, DescriptorPool::ErrorCollector::NAME,
+             "Group types are not allowed under editions.  Use the feature "
+             "message_encoding = DELIMITED to control this behavior.");
+  }
+
   // Validate legacy options that have been migrated to features.
   if (field->options().has_packed()) {
     AddError(field->full_name(), proto, DescriptorPool::ErrorCollector::NAME,

src/google/protobuf/descriptor_unittest.cc

@@ -9983,6 +9983,51 @@ TEST_F(FeaturesTest, InvalidJsonUniquenessCustomError) {
       "conflicts with the custom JSON name of field \"bar\".\n");
 }
 
+TEST_F(FeaturesTest, InvalidRequiredLabel) {
+  BuildDescriptorMessagesInTestPool();
+  BuildFileWithErrors(
+      R"pb(
+        name: "foo.proto"
+        syntax: "editions"
+        edition: EDITION_2023
+        message_type {
+          name: "Foo"
+          field {
+            name: "bar"
+            number: 1
+            label: LABEL_REQUIRED
+            type: TYPE_STRING
+          }
+        }
+      )pb",
+      "foo.proto: Foo.bar: NAME: Required label is not allowed under editions. "
+      " Use the feature field_presence = LEGACY_REQUIRED to control this "
+      "behavior.\n");
+}
+
+TEST_F(FeaturesTest, InvalidGroupLabel) {
+  BuildDescriptorMessagesInTestPool();
+  BuildFileWithErrors(
+      R"pb(
+        name: "foo.proto"
+        syntax: "editions"
+        edition: EDITION_2023
+        message_type {
+          name: "Foo"
+          field {
+            name: "bar"
+            number: 1
+            type_name: ".Foo"
+            label: LABEL_OPTIONAL
+            type: TYPE_GROUP
+          }
+        }
+      )pb",
+      "foo.proto: Foo.bar: NAME: Group types are not allowed under editions.  "
+      "Use the feature message_encoding = DELIMITED to control this "
+      "behavior.\n");
+}
+
 // Test that the result of FileDescriptor::DebugString() can be used to create
 // the original descriptors.
 class FeaturesDebugStringTest