FieldValidator for Godot (C#)

A strict, pre-run dependency checker for Godot C#.

FieldValidator ensures that all your critical [Export] fields are assigned before the game starts. It scans your Resources and Scenes, enforcing assignments via attributes, and prevents the project from running if dependencies are missing.

Why use this?

Godot's built-in _GetConfigurationWarnings is powerful but often overkill for simple null checks:

1. Boilerplate: Writing a unique validation method for every single field is tedious.
2. The [Tool] Virus: To see warnings in the editor, your scripts must use [Tool]. This forces every dependency (other Nodes/Resources) to also be [Tool], which can break complex logic or cause instantiation issues (see Godot Issue #80298).

FieldValidator solves this. It runs purely as an Editor Plugin. Your runtime scripts remain clean, standard C# classes—no [Tool] required.

Key Features

• Zero Runtime Overhead: Validation happens only when you click "Build/Play".
• Decoupled Logic: Works on any Node or Resource, regardless of whether it uses [Tool].
• Build Blocking: If a required field is null, the build is cancelled immediately, preventing runtime crashes.
• Recursive Scanning: Checks Scenes, Nodes, and even Resources nested inside other Resources.
• Collection Support: Validates that arrays/lists are not only assigned but that their contents are not null.

Installation

1. Copy the FieldValidator folder into your project's addons/ directory.
2. Go to Project -> Project Settings -> Plugins and enable FieldValidator.

Usage

Simply add the namespace and tag your exported fields with the provided attributes.

1. Enforce Single Assignments ([MustSet])

Use [MustSet] to ensure a field is not null.

using Godot;
using FieldValidator;

public partial class MyPlayer : Node
{
    // If this is null in the Inspector, the game will refuse to start.
    [Export] [MustSet] 
    public required PackedScene BulletPrefab { get; set; } = null!;

    [Export] [MustSet] 
    public required NodePath EnemyPath = null!; 
}

2. Enforce Collection Integrity ([MemberMustSet])

Use [MemberMustSet] to ensure a collection is not null AND that none of its elements are null.

public partial class Inventory : Resource
{
    // Fails if the array is null OR if any item inside calls IsInstanceValid() == false
    [Export] [MustSet] [MemberMustSet]
    public Godot.Collections.Array<ItemResource> StartingItems { get; set; }
}

Workflow

1. Automatic Check: Whenever you build the project (Play), the plugin scans all .tscn and .tres files.

• Pass: The game starts normally.
• Fail: The build is aborted. The Output panel lists exactly which file, node, and property caused the error.

2. Manual Check: Open addons/FieldValidator/FieldValidatorScript.cs in the Script Editor and go to File > Run. This performs a validation scan without trying to launch the game.

Example Output

When a field is missing, the Godot console will output the following and block the game from starting:

[❌ Error] [Resource: res://resources/Actions/AnyActionDef.tres]->_transitions[4] :: _conditions -> Array element at [2] is null (MemberMustSet)
[❌ Error] [Scene: res://scenes/Characters/Player/Player.tscn] :: [Node: MotorComponent] :: TimeContext -> Assignment required (MustSet)
[❌ Error] [Scene: res://scenes/Test/Playground.tscn] :: [Node: MotorComponent] :: TimeContext -> Assignment required (MustSet)

❌ Validation Failed! Found 3 null reference errors. Execution blocked.
Duration: 6.04ms

Configuration (.fieldignore)

To prevent the validator from scanning specific folders (e.g., third-party addons), create a file named .fieldignore in your project root (res://).

Format:

# Ignore specific folders
addons/
test_assets/

# Ignore specific files
res://Scenes/Draft/WipLevel.tscn

Note: .godot/, .vs/, and .vscode/ are ignored by default.

License

MIT License.