stride3d/stride · error · InvalidOperationException

Unexpected type [ ] to add while serializable types are…

Error message

Unexpected type [{0}] to add while serializable types are frozen

What it means

ProfileInfo.Add enforces that once the serializable-type set is frozen (after initial scanning), no new non-generic types can be added. This is an internal ordering invariant: late additions would not be part of the generated serializer set.

Solutions

Register all serializers before the freeze point (during attribute scanning, not code generation)
Pre-resolve the serializer earlier so the type is added before IsFrozen is set
If writing a processor extension, hook into the scanning phase rather than the generation phase
In Stride source, unfreeze only with care or extend the frozen set explicitly

Example fix

// before
// custom processor step run after serialization codegen started
context.ResolveSerializer(myType); // frozen
// after
// run resolution during ProcessSerializers attribute-scan phase, before code generation
ScanSerializers(context, myType);

Defensive patterns

Strategy: validation

Validate before calling

// Resolve all serializers during the scan phase; assert none are pending at codegen time:
if (profile.IsFrozen && pendingTypes.Count > 0)
    throw new InvalidOperationException("Late serializer registrations: " + string.Join(",", pendingTypes));

Try / catch

try { context.AddSerializableType(type, info); }
catch (InvalidOperationException ex) when (ex.Message.Contains("frozen"))
{
    logger.Warn($"Type {type} registered too late; move registration before codegen");
}

Prevention

Register all serializers during attribute scanning, before code generation
Order custom processor steps before the freeze point
Never trigger new serializer resolution from code-generation hooks

When it happens

Trigger: AddSerializableType (via any serializer resolution path) tries to register a new non-generic SerializableTypeInfo after the processor froze the profile's type list.

Common situations: Custom assembly-processing extensions that resolve serializers too late in the pipeline; a serializer whose resolution triggers discovery of new types after freeze; Stride source modifications changing processing order.

Understand the failure class

Background: "Invalid state transition" errors: "status must be X, actually Y", "already rejected/charging/uninstalled", "cannot ... while running" — what they mean when a library rejects your call — this error's family across 31 libraries.

Related errors

AI-assisted analysis of stride3d/stride@96fad776d2 (2026-09-14). Data as JSON: /api/errors/0bbca590b25dafbf. Report an issue: GitHub.

Appendix: source

Thrown at sources/core/Stride.Core.AssemblyProcessor/Serializers/CecilSerializerContext.cs:608

        public bool TryGetSerializableTypeInfo(TypeReference type, bool generic, out SerializableTypeInfo result)
        {
            return generic
                ? GenericSerializableTypes.TryGetValue(type, out result)
                : SerializableTypes.TryGetValue(type, out result);
        }

        public void AddSerializableTypeInfo(TypeReference typeReference, SerializableTypeInfo serializableTypeInfo)
        {
            if (serializableTypeInfo.Mode != DataSerializerGenericMode.None)
            {
                GenericSerializableTypes.Add(typeReference, serializableTypeInfo);
            }
            else
            {
                if (IsFrozen)
                {
                    throw new InvalidOperationException(string.Format("Unexpected type [{0}] to add while serializable types are frozen", typeReference));
                }
                SerializableTypes.Add(typeReference, serializableTypeInfo);
            }
        }
    }
}

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