stride3d/stride · error · ArgumentNullException

stream

Error message

stream

What it means

Serializer.Deserialize(Stream, Type, ...) guards its input with a null check and throws ArgumentNullException when the stream parameter is null. It is a plain validation guard: the caller passed a null Stream, so there is nothing to deserialize.

Solutions

1. Pass a valid opened Stream (e.g. File.OpenRead(path)) to Deserialize
2. Check stream for null before calling and raise a file-specific error with the path
3. Use the string/TextReader overloads when the content is already in memory
4. Ensure asset-loading helpers throw on failure instead of returning null streams

Example fix

// before
var obj = serializer.Deserialize(stream, typeof(Config)); // stream == null
// after
using var stream = File.OpenRead(path);
var obj = serializer.Deserialize(stream, typeof(Config));

if (stream is null) throw new FileNotFoundException("Input stream for deserialization is missing");

static bool IsReadable(Stream s) => s != null && s.CanRead;

try { return serializer.Deserialize(stream, expectedType); }
catch (ArgumentNullException ex) when (ex.ParamName == "stream") { throw new InvalidOperationException("Stream was not opened before deserialization", ex); }

When it happens

Trigger: Calling Deserialize(null, expectedType) — a stream returned null from config lookup, a File.OpenRead failure swallowed upstream, or a lazily-initialized field never assigned.

Common situations: Reading assets/config where an optional file is absent and the stream variable stays null; factory methods returning null stream on error instead of throwing.

Related errors

• ArgumentNullException: data
• ArgumentNullException: heightmap
• ArgumentNullException: paramName
• bytecode
• Can't resize VirtualFileStream if endPosition is not -1.

AI-assisted analysis of stride3d/stride@96fad776d2 (2026-09-14). Data as JSON: /api/errors/868258fd06a5b750. Report an issue: GitHub.

Appendix: source

Thrown at sources/core/Stride.Core.Yaml/Serialization/Serializer.cs:255

        /// </summary>
        /// <param name="reader">The reader.</param>
        /// <returns>A deserialized object.</returns>
        public object Deserialize(TextReader reader)
        {
            return Deserialize(reader, null);
        }

        /// <summary>
        /// Deserializes an object from the specified <see cref="Stream" /> with an expected specific type.
        /// </summary>
        /// <param name="stream">The stream.</param>
        /// <param name="expectedType">The expected type.</param>
        /// <param name="contextSettings">The context settings.</param>
        /// <returns>A deserialized object.</returns>
        /// <exception cref="System.ArgumentNullException">stream</exception>
        public object Deserialize(Stream stream, Type expectedType, SerializerContextSettings contextSettings = null)
        {
            if (stream == null) throw new ArgumentNullException(nameof(stream));

            return Deserialize(new StreamReader(stream), expectedType, null, contextSettings);
        }

        /// <summary>
        /// Deserializes an object from the specified <see cref="Stream" /> with an expected specific type.
        /// </summary>
        /// <param name="stream">The stream.</param>
        /// <param name="expectedType">The expected type.</param>
        /// <param name="contextSettings">The context settings.</param>
        /// <param name="context">The context used to deserialize this object.</param>
        /// <returns>A deserialized object.</returns>
        /// <exception cref="System.ArgumentNullException">stream</exception>
        public object Deserialize(Stream stream, Type expectedType, SerializerContextSettings contextSettings, out SerializerContext context)
        {
            if (stream == null) throw new ArgumentNullException(nameof(stream));

            return Deserialize(new StreamReader(stream), expectedType, null, contextSettings, out context);

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