From 13dae9f90e7b77bb606bb622f7ee9bdca36d5344 Mon Sep 17 00:00:00 2001
From: Pranav C <pranavxc@gmail.com>
Date: Wed, 15 Feb 2023 15:20:32 +0530
Subject: [PATCH] fix: block circular lookup creation

Signed-off-by: Pranav C <pranavxc@gmail.com>
---
 .../smartsheet/column/LookupOptions.vue       |  2 +-
 .../nocodb/src/lib/meta/api/columnApis.ts     |  9 +++++---
 .../src/lib/meta/api/helpers/columnHelpers.ts | 23 ++++++++++++++++++-
 3 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/packages/nc-gui/components/smartsheet/column/LookupOptions.vue b/packages/nc-gui/components/smartsheet/column/LookupOptions.vue
index b205d4f06c..582108fb37 100644
--- a/packages/nc-gui/components/smartsheet/column/LookupOptions.vue
+++ b/packages/nc-gui/components/smartsheet/column/LookupOptions.vue
@@ -50,7 +50,7 @@ const columns = $computed<ColumnType[]>(() => {
   if (!selectedTable?.id) {
     return []
   }
-  return metas[selectedTable.id].columns.filter((c: ColumnType) => !isSystemColumn(c))
+  return metas[selectedTable.id].columns.filter((c: ColumnType) => !isSystemColumn(c) && c.id !== vModel.value.id)
 })
 
 onMounted(() => {
diff --git a/packages/nocodb/src/lib/meta/api/columnApis.ts b/packages/nocodb/src/lib/meta/api/columnApis.ts
index dcc04d7bf5..f039144f72 100644
--- a/packages/nocodb/src/lib/meta/api/columnApis.ts
+++ b/packages/nocodb/src/lib/meta/api/columnApis.ts
@@ -40,8 +40,8 @@ import { MetaTable } from '../../utils/globals';
 import formulaQueryBuilderv2 from '../../db/sql-data-mapper/lib/sql/formulav2/formulaQueryBuilderv2';
 import {
   createHmAndBtColumn,
-  validateRequiredField,
   validateLookupPayload,
+  validateRequiredField,
   validateRollupPayload,
 } from './helpers';
 
@@ -626,9 +626,12 @@ export async function columnSetAsPrimary(req: Request, res: Response) {
 async function updateRollupOrLookup(colBody: any, column: Column<any>) {
   if (
     UITypes.Lookup === column.uidt &&
-    validateRequiredField(colBody, ['fk_lookup_column_id', 'fk_relation_column_id'])
+    validateRequiredField(colBody, [
+      'fk_lookup_column_id',
+      'fk_relation_column_id',
+    ])
   ) {
-    await validateLookupPayload(colBody);
+    await validateLookupPayload(colBody, column.id);
     await Column.update(column.id, colBody);
   } else if (
     UITypes.Rollup === column.uidt &&
diff --git a/packages/nocodb/src/lib/meta/api/helpers/columnHelpers.ts b/packages/nocodb/src/lib/meta/api/helpers/columnHelpers.ts
index ae9e6b00dd..b9847b0627 100644
--- a/packages/nocodb/src/lib/meta/api/helpers/columnHelpers.ts
+++ b/packages/nocodb/src/lib/meta/api/helpers/columnHelpers.ts
@@ -8,6 +8,7 @@ import {
 } from 'nocodb-sdk';
 import Column from '../../../models/Column';
 import LinkToAnotherRecordColumn from '../../../models/LinkToAnotherRecordColumn';
+import LookupColumn from '../../../models/LookupColumn';
 import Model from '../../../models/Model';
 import { getUniqueColumnAliasName } from '../../helpers/getUniqueName';
 import validateParams from '../../helpers/validateParams';
@@ -111,13 +112,33 @@ export async function validateRollupPayload(
 }
 
 export async function validateLookupPayload(
-  payload: ColumnReqType & { uidt: UITypes }
+  payload: ColumnReqType & { uidt: UITypes },
+  columnId?: string
 ) {
   validateParams(
     ['title', 'fk_relation_column_id', 'fk_lookup_column_id'],
     payload
   );
 
+  // check for circular reference
+  if (columnId) {
+    let lkCol: LookupColumn | LookupColumnReqType =
+      payload as LookupColumnReqType;
+    while (lkCol) {
+      // check if lookup column is same as column itself
+      if (columnId === lkCol.fk_lookup_column_id)
+        throw new Error('Circular lookup reference not allowed');
+      lkCol = await Column.get({ colId: lkCol.fk_lookup_column_id }).then(
+        (c: Column) => {
+          if (c.uidt === 'Lookup') {
+            return c.getColOptions<LookupColumn>();
+          }
+          return null;
+        }
+      );
+    }
+  }
+
   const relation = await (
     await Column.get({
       colId: (payload as LookupColumnReqType).fk_relation_column_id,