JamesNK/Newtonsoft.Json · error · ArgumentException

Value must be positive.

Error message

Value must be positive.

What it means

Thrown by the JsonReader.MaxDepth setter when assigning a value less than or equal to zero. MaxDepth caps nesting depth to defend against deeply nested or malicious JSON (stack overflow / denial of service); a non-positive cap is meaningless, so the setter rejects it with ArgumentException. Null is permitted and means no limit.

Source

Thrown at Src/Newtonsoft.Json/JsonReader.cs:240

        public string? DateFormatString
        {
            get => _dateFormatString;
            set => _dateFormatString = value;
        }

        /// <summary>
        /// Gets or sets the maximum depth allowed when reading JSON. Reading past this depth will throw a <see cref="JsonReaderException"/>.
        /// A null value means there is no maximum. 
        /// The default value is <c>64</c>.
        /// </summary>
        public int? MaxDepth
        {
            get => _maxDepth;
            set
            {
                if (value <= 0)
                {
                    throw new ArgumentException("Value must be positive.", nameof(value));
                }

                _maxDepth = value;
            }
        }

        /// <summary>
        /// Gets the type of the current JSON token. 
        /// </summary>
        public virtual JsonToken TokenType => _tokenType;

        /// <summary>
        /// Gets the text value of the current JSON token.
        /// </summary>
        public virtual object? Value => _value;

        /// <summary>
        /// Gets the .NET type for the current JSON token.

View on GitHub (pinned to 4f73e74372)

Solutions

1. Use a positive integer (e.g. 64, the library default) for MaxDepth.
2. Pass null to explicitly disable the depth cap rather than 0.
3. Validate config-driven values before assignment: if (depth is > 0 int d) reader.MaxDepth = d;.

Example fix

// before
reader.MaxDepth = 0;

// after
reader.MaxDepth = 64; // or leave null for no limit

if (configuredDepth is int d && d > 0)
{
    reader.MaxDepth = d;
}

static bool IsValidMaxDepth(int? v) => v is null or > 0;

When it happens

Trigger: Setting reader.MaxDepth = 0, reader.MaxDepth = -1, or computing MaxDepth from user/config input that can be zero or negative.

Common situations: Loading MaxDepth from configuration/environment without validating; passing 0 intending 'use default'; arithmetic that subtracts and yields a negative.

Related errors

• Value must be positive.
• Value must be positive.
• Indentation value must be greater than 0.
• value
• value

AI-assisted analysis of JamesNK/Newtonsoft.Json@4f73e74372 (2026-08-07). Data as JSON: /api/errors/32235dab29dab8c0. Report an issue: GitHub.