From f36e0c2513f02dc7ef012ae0f0437ac305fc11f5 Mon Sep 17 00:00:00 2001
From: Laurent Cozic <laurent@cozic.net>
Date: Sun, 7 Jun 2020 12:47:43 +0100
Subject: [PATCH] All: Fixes #3334: Prevent notebook to be the parent of itself

---
 CliClient/tests/models_Folder.js       | 7 ++++++-
 ReactNativeClient/lib/models/Folder.js | 9 +++++++++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/CliClient/tests/models_Folder.js b/CliClient/tests/models_Folder.js
index 17ec6a4bb7b..bba7db40050 100644
--- a/CliClient/tests/models_Folder.js
+++ b/CliClient/tests/models_Folder.js
@@ -185,7 +185,6 @@ describe('models_Folder', function() {
 	}));
 
 	it('should recursively find folder path', asyncTest(async () => {
-
 		const f1 = await Folder.save({ title: 'folder1' });
 		const f2 = await Folder.save({ title: 'folder2', parent_id: f1.id });
 		const f3 = await Folder.save({ title: 'folder3', parent_id: f2.id });
@@ -218,4 +217,10 @@ describe('models_Folder', function() {
 		expect(sortedFolderTree[1].children[0].id).toBe(f5.id);
 		expect(sortedFolderTree[2].id).toBe(f6.id);
 	}));
+
+	it('should not allow setting a notebook parent as itself', asyncTest(async () => {
+		const f1 = await Folder.save({ title: 'folder1' });
+		const hasThrown = await checkThrowAsync(() => Folder.save({ id: f1.id, parent_id: f1.id }, { userSideValidation: true }));
+		expect(hasThrown).toBe(true);
+	}));
 });
diff --git a/ReactNativeClient/lib/models/Folder.js b/ReactNativeClient/lib/models/Folder.js
index 25a79aee846..b445d2a41e9 100644
--- a/ReactNativeClient/lib/models/Folder.js
+++ b/ReactNativeClient/lib/models/Folder.js
@@ -125,6 +125,11 @@ class Folder extends BaseItem {
 				const folder = foldersById[parentId];
 				if (!folder) break; // https://github.com/laurent22/joplin/issues/2079
 				folder.note_count = (folder.note_count || 0) + noteCount.note_count;
+
+				// Should not happen anymore but just to be safe, add the check below
+				// https://github.com/laurent22/joplin/issues/3334
+				if (folder.id === folder.parent_id) break;
+
 				parentId = folder.parent_id;
 			} while (parentId);
 		});
@@ -403,6 +408,10 @@ class Folder extends BaseItem {
 			if (!('duplicateCheck' in options)) options.duplicateCheck = true;
 			if (!('reservedTitleCheck' in options)) options.reservedTitleCheck = true;
 			if (!('stripLeftSlashes' in options)) options.stripLeftSlashes = true;
+
+			if (o.id && o.parent_id && o.id === o.parent_id) {
+				throw new Error('Parent ID cannot be the same as ID');
+			}
 		}
 
 		if (options.stripLeftSlashes === true && o.title) {