What causes "ObjectSerializerBackend can not be null" in stride3d/stride?

Assign an instance such as new DefaultObjectSerializerBackend() or your custom subclass

stride3d/stride · error · ArgumentNullException

ObjectSerializerBackend can not be null

Error message

ObjectSerializerBackend can not be null

What it means

SerializerSettings.ObjectSerializerBackend supplies low-level object (de)serialization behavior and is mandatory. Assigning null throws ArgumentNullException to fail fast rather than crashing later mid-serialization with a NullReferenceException.

Solutions

Assign an instance such as new DefaultObjectSerializerBackend() or your custom subclass
Fix the DI registration/factory so it returns a non-null backend

Example fix

// before
settings.ObjectSerializerBackend = ResolveBackend(); // null
// after
settings.ObjectSerializerBackend = ResolveBackend() ?? new DefaultObjectSerializerBackend();

Defensive patterns

Strategy: validation

Validate before calling

settings.ObjectSerializerBackend = backend ?? new DefaultObjectSerializerBackend();

Try / catch

try { settings.ObjectSerializerBackend = backend; } catch (ArgumentNullException) { settings.ObjectSerializerBackend = new DefaultObjectSerializerBackend(); }

Prevention

Fall back to DefaultObjectSerializerBackend when custom backends fail to resolve
Verify DI registrations for custom backends in startup tests

When it happens

Trigger: `settings.ObjectSerializerBackend = null` or a factory method returning null for the backend.

Common situations: Overriding the backend via DI/config where the override resolution fails; typos in registration causing an unbound resolution.

Related errors

AI-assisted analysis of stride3d/stride@96fad776d2 (2026-09-14). Data as JSON: /api/errors/e29cc051b92adb24. Report an issue: GitHub.

Appendix: source

Thrown at sources/core/Stride.Core.Yaml/Serialization/SerializerSettings.cs:289

            set
            {
                if (value == null)
                    throw new ArgumentNullException("value", $"{nameof(Attributes)} can not be null");
                attributeRegistry = value;
            }
        }

        /// <summary>
        /// Gets or sets the ObjectSerializerBackend. Default implementation is <see cref="DefaultObjectSerializerBackend"/>
        /// </summary>
        /// <value>The ObjectSerializerBackend.</value>
        public IObjectSerializerBackend ObjectSerializerBackend
        {
            get { return objectSerializerBackend; }
            set
            {
                if (value == null)
                    throw new ArgumentNullException("value", $"{nameof(ObjectSerializerBackend)} can not be null");
                objectSerializerBackend = value;
            }
        }

        /// <summary>
        /// Gets or sets the default factory to instantiate a type. Default is <see cref="DefaultObjectFactory" />.
        /// </summary>
        /// <value>The default factory to instantiate a type.</value>
        /// <exception cref="System.ArgumentNullException">value</exception>
        public IObjectFactory ObjectFactory
        {
            get { return objectFactory; }
            set
            {
                if (value == null)
                    throw new ArgumentNullException("value", $"{nameof(ObjectFactory)} can not be null");
                objectFactory = value;
            }

View on GitHub (pinned to 96fad776d2)