Settings deserialization fails if FilterParams.CurrentColumnizer can't be deserialized

[AndisGrossteins]

This is the issue I already mentioned in #468.

Settings deserialization fails to instantiate FilterParams.CurrentColumnizer property from JSON path FilterParams.CurrentColumnizer.Text which is "Default (single line)" in the settings.json file.

Exception text from log file (version 1.20.0):

LogExpert.Config.ConfigManager|Error while deserializing config data: Newtonsoft.Json.JsonSerializationException: Could not create an instance of type LogExpert.ILogLineColumnizer. Type is an interface or abstract class and cannot be instantiated. Path 'FilterParams.CurrentColumnizer.Text', line 1, position 9424.
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateNewObject(JsonReader reader, JsonObjectContract objectContract, JsonProperty containerMember, JsonProperty containerProperty, String id, Boolean& createdFromNonDefaultCreator)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.SetPropertyValue(JsonProperty property, JsonConverter propertyConverter, JsonContainerContract containerContract, JsonProperty containerProperty, JsonReader reader, Object target)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateObject(Object newObject, JsonReader reader, JsonObjectContract contract, JsonProperty member, String id)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.SetPropertyValue(JsonProperty property, JsonConverter propertyConverter, JsonContainerContract containerContract, JsonProperty containerProperty, JsonReader reader, Object target)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateObject(Object newObject, JsonReader reader, JsonObjectContract contract, JsonProperty member, String id)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader reader, Type objectType, Boolean checkAdditionalContent)
   at Newtonsoft.Json.JsonSerializer.DeserializeInternal(JsonReader reader, Type objectType)
   at Newtonsoft.Json.JsonSerializer.Deserialize(JsonReader reader, Type objectType)
   at Newtonsoft.Json.JsonConvert.DeserializeObject(String value, Type type, JsonSerializerSettings settings)
   at Newtonsoft.Json.JsonConvert.DeserializeObject[T](String value, JsonSerializerSettings settings)
   at Newtonsoft.Json.JsonConvert.DeserializeObject[T](String value)
   at LogExpert.Config.ConfigManager.LoadOrCreateNew(FileInfo fileInfo)

The cause of the issue is [JsonIgnore] attribute on FilterParams.CurrentColumnizer which is from System.Text.Json.Serialization but settings serialization is done with Newtonsoft.Json so the attribute is ignored when serializing. Changing the using statement in FilterParams.cs from System.Text.Json.Serialization to Newtonsoft.Json fixes the issue but the CurrentColumnizer setting is lost.

There are multiple other settings object properties with [field: NonSerialized] attribute set which must be a leftover from when settings were serialized into binary format. These might be replaced by [JsonIgnore] but I'd like some input regarding this from current project maintainers.

[Hirogen]

I'll have a look seems to be a bug.

This will be part of the rework that the persister now uses json instead of xml.

if you want, you can get the latest version from the branch persister_in_json but it currently does not build, because the implementation is not finished yet

[AndisGrossteins]

Yes, I'm already looking at the branch. Introducing a custom attribute and converter for serializing columnizers seems smart and more robust.

I was pondering a simpler approach using Json.NET error handling event in ConfigManager just to avoid losing all the settings in case one entry can't be deserialized.

Also, don't know why the [field: NonSerialized] property is ignored by Json.NET because documentation on newtonsoft.com says the System.NonSerializedAttribute is supported.

[Hirogen]

JSON.net and newtonsoft json are 2 different implementations of the json format. JSON.net does not support everything that newtonsoft does. thats why I use the newtonsoft one

I would like to use the .net one, because it's a native implementation, but it's just not there yet

[AndisGrossteins]

JSON.net and newtonsoft json are 2 different implementations of the json format. JSON.net does not support everything that newtonsoft does. thats why I use the newtonsoft one

Wait, isn't Newtonsoft.Json on GitHub and Json.NET project the same thing? It certainly looks like it is one projet because the website links to the GitHub repo and repo links back to documentation. I guess the only confusion is that project is called Json.NET but repo and namespace is Newtonsoft.Json.

[Hirogen]

could be that I'm confusing this now with System.Text.Json 😅

[Hirogen]

this should now work, the snap shot can be downloaded here as artifact https://github.com/LogExperts/LogExpert/actions/runs/18108950348

[AndisGrossteins]

I'm getting an unhandled exception (in a message box) when loading a file with existing XML persistence file and after clicking on "Column restrict" checkbox:

NullReferenceException
   at LogExpert.UI.Controls.LogWindow.LogWindow.IsFilterSearchDirty(FilterParams filterParams) in D:\a\LogExpert\LogExpert\src\LogExpert.UI\Controls\LogWindow\LogWindow.cs:line 4633
   at LogExpert.UI.Controls.LogWindow.LogWindow.CheckForFilterDirty() in D:\a\LogExpert\LogExpert\src\LogExpert.UI\Controls\LogWindow\LogWindow.cs:line 4618
   at LogExpert.UI.Controls.LogWindow.LogWindow.OnColumnRestrictCheckBoxCheckedChanged(Object sender, EventArgs e) in D:\a\LogExpert\LogExpert\src\LogExpert.UI\Controls\LogWindow\LogWindow.cs:line 1485
   at System.Windows.Forms.CheckBox.set_CheckState(CheckState value)
   at System.Windows.Forms.CheckBox.OnClick(EventArgs e)
   at System.Windows.Forms.CheckBox.OnMouseUp(MouseEventArgs mevent)
   at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ButtonBase.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.Callback(HWND hWnd, MessageId msg, WPARAM wparam, LPARAM lparam)

The stack trace is not logged by NLog but just this line:

2025-09-30 22:08:33.9658|FATAL|Program|System.Threading.ThreadExceptionEventArgs

And another unhandled exception when trying to interact with filter search text comboBox because filterParams.SearchText is null:

Object reference not set to an instance of an object.\n\n
NullReferenceException
   at LogExpert.UI.Controls.LogWindow.LogWindow.IsFilterSearchDirty(FilterParams filterParams) in D:\a\LogExpert\LogExpert\src\LogExpert.UI\Controls\LogWindow\LogWindow.cs:line 4633
   at LogExpert.UI.Controls.LogWindow.LogWindow.CheckForFilterDirty() in D:\a\LogExpert\LogExpert\src\LogExpert.UI\Controls\LogWindow\LogWindow.cs:line 4618
   at LogExpert.UI.Controls.LogWindow.LogWindow.OnFilterComboBoxTextChanged(Object sender, EventArgs e) in D:\a\LogExpert\LogExpert\src\LogExpert.UI\Controls\LogWindow\LogWindow.cs:line 2042
   at System.Windows.Forms.ComboBox.OnTextChanged(EventArgs e)
   at System.Windows.Forms.ComboBox.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.Callback(HWND hWnd, MessageId msg, WPARAM wparam, LPARAM lparam)

This must be related to what I wrote about broken UI when persistence loading fails in PR #472 comment.

[Hirogen]

I'll have a look tonight