Find localization entries that are not used

FindUsedKeys.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using UnityEditor;
using UnityEditor.Localization;
using UnityEditor.SceneManagement;
using UnityEngine;
using UnityEngine.Localization.Tables;
using Object = UnityEngine.Object;

public class FindUnusedLocalizationKeys : EditorWindow {
	HashSet<(string collectionName, long entryId)> m_FoundEntries;

	[MenuItem("Window/Asset Management/Localization unused key finder")]
	static void CreateWizard() {
		EditorWindow.GetWindow<FindUnusedLocalizationKeys>();
	}


	void OnGUI() {
		if (GUILayout.Button("Search")) {
			Search();
		}
	}

	void Search() {
		EditorUtility.DisplayProgressBar("Localization unused key finder", "Searching", 0);

		m_FoundEntries = new HashSet<(string collectionName, long entryId)>();

		var sceneGUIDs = AssetDatabase.FindAssets("t:Scene");
		string[] guids = new string[] { "t:Prefab", "t:ScriptableObject" }.SelectMany(e => AssetDatabase.FindAssets(e)).ToArray();

		var i = 0;
		bool cancelled = false;

		try {
			for (int j = 0; j < sceneGUIDs.Length; j++) {
				var sceneGUID = sceneGUIDs[j];
				var path = AssetDatabase.GUIDToAssetPath(sceneGUID);
				try {
					var scene = EditorSceneManager.OpenScene(path, OpenSceneMode.Single);
					if (EditorUtility.DisplayCancelableProgressBar("Localization unused key finder", $"Checking scene [{j}/{sceneGUIDs.Length}]. {path}", j / (float) sceneGUIDs.Length)) {
						cancelled = true;
						break;
					}
					var components = FindObjectsOfType<GameObject>().SelectMany(t => t.GetComponents<Component>()).ToArray();
					for (int k = 0; k < components.Length; k++) {
						if (i % 200 == 0 && EditorUtility.DisplayCancelableProgressBar("Localization unused key finder", $"(Pass 1/2) Checking scene [{j}/{sceneGUIDs.Length}], object [{k}/{components.Length}]. {path}", j / (float) sceneGUIDs.Length + k / (float) components.Length / sceneGUIDs.Length)) {
							cancelled = true;
							break;
						}
						ExtractTableReferences(components[k]);
					}
					if (cancelled) break;
				}
				catch (ArgumentException a) {
					// Scene may be read only. NEXT!
				}
			}

			for (int j = 0; j < guids.Length; j++) {
				if (cancelled) break;
				var guid = guids[j];
				var path = AssetDatabase.GUIDToAssetPath(guid);
				var objs = AssetDatabase.LoadAllAssetsAtPath(path);
				for (int k = 0; k < objs.Length; k++) {
					if (i % 200 == 0 && EditorUtility.DisplayCancelableProgressBar("Localization unused key finder", $"(Pass 2/2) Checking rest of assets [{j}/{guids.Length}], component [{k}/{objs.Length}]. {path}", i / (float) sceneGUIDs.Length + j / (float) guids.Length / sceneGUIDs.Length + k / (float) guids.Length / sceneGUIDs.Length / objs.Length)) {
						cancelled = true;
						break;
					}
					var obj = objs[k];
					ExtractTableReferences(obj);
				}
			}
		}
		finally {
			EditorUtility.ClearProgressBar();
		}

		FindMissingEntries();
	}

	void FindMissingEntries() {
		var sb = new StringBuilder();
		foreach (var collection in LocalizationEditorSettings.GetStringTableCollections()) {
			foreach (var entry in collection.SharedData.Entries) {
				if (m_FoundEntries.Contains((collection.TableCollectionName, entry.Id))) {
					// Entry is used
					sb.AppendLine($"[X] YES USED - {collection.TableCollectionName} / {entry.Key}");
				}
				else {
					// Entry is not used.
					sb.AppendLine($"[ ] NOT USED - {collection.TableCollectionName} / {entry.Key}");
				}
			}
		}

		Debug.Log(sb.ToString());
	}

	void ExtractTableReferences(Object unityObject) {
		if (unityObject == null)
			return;

		var so = new SerializedObject(unityObject);
		var itr = so.GetIterator();
		// This is ultra slow
		while (itr.Next(true)) {
			if (itr.type == "LocalizedString") {
				if (itr.isArray) {
					for (int i = 0; i < itr.arraySize; i++) {
						Process(itr.GetArrayElementAtIndex(i));
					}
				}
				else Process(itr);
				void Process(SerializedProperty itr) {
					var collectionNameProperty = itr.FindPropertyRelative("m_TableReference.m_TableCollectionName");
					//if (collectionNameProperty == null) return;
					var collectionName = collectionNameProperty.stringValue;

					TableReference tableReference;
					if (collectionName.StartsWith("GUID:"))
						tableReference = Guid.Parse(collectionName.Substring("GUID:".Length, collectionName.Length - "GUID:".Length));
					else
						tableReference = collectionName;

					var key = itr.FindPropertyRelative("m_TableEntryReference.m_Key");
					var keyId = itr.FindPropertyRelative("m_TableEntryReference.m_KeyId");
					TableEntryReference tableEntryReference;
					if (keyId.longValue == 0)
						tableEntryReference = key.stringValue;
					else
						tableEntryReference = keyId.longValue;

					var collection = LocalizationEditorSettings.GetStringTableCollection(tableReference);
					var stringTableEntry = collection?.SharedData.GetEntryFromReference(tableEntryReference);
					if (stringTableEntry != null) {
						m_FoundEntries.Add((collection.TableCollectionName, stringTableEntry.Id));
					}
				}
			}
		}
	}
}