rocksdanister/lively · error · ArgumentNullException

json null/corrupt

Error message

json null/corrupt

What it means

Thrown by the generic JsonStorage<T>.LoadData when Newtonsoft.Json deserialises the file to null. This loader backs most on-disk config/metadata in Lively, so the message is generic. Note the exception TYPE is ArgumentNullException with a message string as paramName — the type does not match the failure (corruption, not a null argument).

Source

Thrown at src/Lively/Lively.Common/Helpers/Storage/JsonStorage.cs:20

using System.IO;
using Newtonsoft.Json;

namespace Lively.Common.Helpers.Storage
{
    public static class JsonStorage<T>
    {
        public static T LoadData(string filePath)
        {
            // deserialize JSON directly from a file
            using StreamReader file = File.OpenText(filePath);
            var serializer = new JsonSerializer
            {
                //TypeNameHandling = TypeNameHandling.Auto
            };
            var tmp = (T)serializer.Deserialize(file, typeof(T));

            //if file is corrupted, json can return null.
            return (tmp != null ? tmp : throw new ArgumentNullException("json null/corrupt"));
        }

        public static void StoreData(string filePath, T data)
        {
            JsonSerializer serializer = new JsonSerializer
            {
                Formatting = Formatting.Indented,
                //serializer.Converters.Add(new JavaScriptDateTimeConverter());
                NullValueHandling = NullValueHandling.Include,
                //TypeNameHandling = TypeNameHandling.Auto,
            };

            using StreamWriter sw = new StreamWriter(filePath);
            using JsonWriter writer = new JsonTextWriter(sw);
            serializer.Serialize(writer, data, typeof(T));
        }
    }
}

View on GitHub (pinned to c1036feb66)

Solutions

1. Open the file and confirm it is non-empty, valid JSON matching T's schema.
2. Delete or back up the offending file so the app regenerates defaults on next start.
3. Wrap LoadData in try/catch and fall back to default(T) / a fresh settings instance, logging the corruption.
4. If maintaining the lib, replace the throw with a typed JsonException/InvalidDataException and pass the file path for diagnostics.

Example fix

// before
return (tmp != null ? tmp : throw new ArgumentNullException("json null/corrupt"));

// after
return tmp ?? throw new JsonException($"{filePath} deserialised to null (empty or wrong schema for {typeof(T).Name})");

if (!File.Exists(filePath) || new FileInfo(filePath).Length == 0)
    return default(T); // or regenerate defaults
var json = File.ReadAllText(filePath);
if (string.IsNullOrWhiteSpace(json) || json.Trim() == "null") return default(T);

static bool TryLoad<T>(string path, out T value)
{
    value = default;
    try { value = JsonStorage<T>.LoadData(path); return value != null; }
    catch { return false; }
}

T cfg;
try { cfg = JsonStorage<T>.LoadData(path); }
catch (ArgumentNullException ex) when (ex.ParamName?.Contains("json null") == true)
{ cfg = DefaultT(); /* reset to defaults and persist */ }

When it happens

Trigger: Any JsonStorage<T>.LoadData(filePath) where the file is empty, contains JSON that deserialises to null (e.g. literal "null", or an empty object for a non-nullable reference type that the converter leaves null), or the type T cannot be bound from the content.

Common situations: Empty settings file left by a failed write or reset; hand-edited config that became invalid; upgrade/downgrade where T's shape changed; files with content "null" from a previous bug; encoding/BOM issues.

Related errors

• Corrupted wallpaper metadata
• libmpv depreciated player selected.
• libmpvExt depreciated player selected.
• libvlc depreciated player selected.
• xaml island gif player not available.

AI-assisted analysis of rocksdanister/lively@c1036feb66 (2026-08-13). Data as JSON: /api/errors/a2e8e2526bf04d51. Report an issue: GitHub.