XINCGer/Unity3DTraining · error · DescriptorValidationException

Missing name.

Error message

Missing name.

What it means

DescriptorPool.ValidateSymbolName throws DescriptorValidationException when a descriptor being registered (message, field, enum, etc.) has an empty Name. Every proto declaration must have a non-empty identifier name, so an empty name is rejected during descriptor construction.

Solutions

1. Set the Name property on every proto descriptor before building (e.g. new DescriptorProto { Name = "MyMessage" }).
2. Inspect the serialized FileDescriptorSet (protoc --descriptor_set_out) for declarations missing name fields.
3. Regenerate descriptors with protoc rather than hand-crafting or editing serialized descriptor bytes.
4. Add a pre-build check that iterates your FileDescriptorProto tree and asserts every declaration has a non-empty Name.

Example fix

// before
var msg = new DescriptorProto(); // Name unset -> "Missing name."
fileProto.MessageTypes.Add(msg);
// after
var msg = new DescriptorProto { Name = "MyMessage" };
fileProto.MessageTypes.Add(msg);

static void AssertNamesSet(FileDescriptorProto file)
{
    foreach (var m in file.MessageTypes)
        if (string.IsNullOrEmpty(m.Name)) throw new InvalidOperationException("Descriptor missing name");
}

bool HasName(IDescriptor d) => !string.IsNullOrEmpty(d.Name);

try
{
    var fd = FileDescriptor.BuildFromByteString(bytes, dependencies);
}
catch (DescriptorValidationException ex) when (ex.Message == "Missing name.")
{
    // reject/deserialize the descriptor set at source
}

When it happens

Trigger: Constructing descriptors (directly via DescriptorProtos or via FileDescriptor.BuildFromByteString) where a FieldDescriptorProto/DescriptorProto/EnumDescriptorProto has an unset or empty 'name' — typically a hand-constructed DescriptorProto or a corrupted/missing 'name' field in a serialized FileDescriptorSet.

Common situations: Programmatically building FileDescriptorProto/DescriptorProto and forgetting to set Name before building; a descriptor set produced by a broken codegen or tooling pipeline dropping name fields; manual edits to serialized descriptors.

Understand the failure class

Background: "must not be empty", "cannot be empty" — required-field validation errors across open-source libraries — this error's family across 41 libraries.

Related errors

• " " is not a valid identifier.
• Field numbers must be positive integers.
• " " is already defined (as something other than a package)…
• " " is already defined in file " ".
• Field number has already been used in " " by field " ".

AI-assisted analysis of XINCGer/Unity3DTraining@016f98412e (2026-09-12). Data as JSON: /api/errors/e01085eba5c54789. Report an issue: GitHub.

Appendix: source

Thrown at NetWorkAndResources/Socket_Protobuff/Assets/Plugins/Google.Protobuf/Reflection/DescriptorPool.cs:196

                }
                throw new DescriptorValidationException(descriptor, message);
            }
            descriptorsByName[fullName] = descriptor;
        }

        private static readonly Regex ValidationRegex = new Regex("^[_A-Za-z][_A-Za-z0-9]*$",
                                                                  FrameworkPortability.CompiledRegexWhereAvailable);

        /// <summary>
        /// Verifies that the descriptor's name is valid (i.e. it contains
        /// only letters, digits and underscores, and does not start with a digit).
        /// </summary>
        /// <param name="descriptor"></param>
        private static void ValidateSymbolName(IDescriptor descriptor)
        {
            if (descriptor.Name == "")
            {
                throw new DescriptorValidationException(descriptor, "Missing name.");
            }
            if (!ValidationRegex.IsMatch(descriptor.Name))
            {
                throw new DescriptorValidationException(descriptor,
                                                        "\"" + descriptor.Name + "\" is not a valid identifier.");
            }
        }

        /// <summary>
        /// Returns the field with the given number in the given descriptor,
        /// or null if it can't be found.
        /// </summary>
        internal FieldDescriptor FindFieldByNumber(MessageDescriptor messageDescriptor, int number)
        {
            FieldDescriptor ret;
            fieldsByNumber.TryGetValue(new DescriptorIntPair(messageDescriptor, number), out ret);
            return ret;
        }

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