fix: item-batch validation

backend/database/bespoke.ts

@@ -132,6 +132,26 @@ export class BespokeQueries {
     `);
   }
 
+  static async itemHasTransactions(
+    db: DatabaseCore,
+    item: string
+  ): Promise<boolean> {
+  /*
+    * to check if an item of given name is present in the SLE
+    * taking the count of items from SLE which has the given item name
+    * if the count is greater than 0 considers item exists in SLE, returns true 
+    * if the count is lesser than 0 considers item does not exist in SLE, returns false
+  */
+    const query = db.knex!(ModelNameEnum.StockLedgerEntry)
+      .select('item')
+      .where('item', item);
+
+    const value = (await query) as Record<string, string | null>[];
+
+    if (!value) return false;
+    return true;
+  }
+
   static async getStockQuantity(
     db: DatabaseCore,
     item: string,
@@ -168,5 +188,3 @@ export class BespokeQueries {
     return value[0][Object.keys(value[0])[0]];
   }
 }
-
-// 

fyo/core/dbHandler.ts

@@ -325,6 +325,12 @@ export class DatabaseHandler extends DatabaseBase {
     )) as number | null;
   }
 
+  async itemHasTransactions(item: string): Promise<boolean | null> {
+    return (await this.#demux.callBespoke('itemHasTransactions', item)) as
+      | boolean
+      | null;
+  }
+
   /**
    * Internal methods
    */

models/baseModels/Item/Item.ts

@@ -20,6 +20,31 @@ export class Item extends Doc {
   for?: 'Purchases' | 'Sales' | 'Both';
   hasBatchNumber?: boolean;
 
+  async beforeSync() {
+    /*
+      * This code block is to prevent users from changing the value of Has Batch No Checkbox
+        of the items which already did transactions
+      * allowing users to change the value of Has Batch No of the items which already did
+        transactions will result in incorect SLEs 
+    */
+    const ifItemHasBatchNumber = await Boolean(
+      this.fyo.db.get('Item', this.name! || '', 'hasBatchNumber')
+    );
+
+    if (this.hasBatchNumber == ifItemHasBatchNumber) {
+      return;
+    }
+
+    const isItemExistsInSLE = await this.fyo.db.itemHasTransactions(this.name!);
+
+    if (ifItemHasBatchNumber && isItemExistsInSLE) {
+      throw new ValidationError(
+        this.fyo.t`Cannot change value of Has Batch No as ${this
+          .name!} already has transactions against it. `
+      );
+    }
+  }
+
   formulas: FormulaMap = {
     incomeAccount: {
       formula: async () => {
@@ -121,6 +146,7 @@ export class Item extends Doc {
       !this.fyo.singles.AccountingSettings?.enableInventory ||
       this.itemType !== 'Product' ||
       (this.inserted && !this.trackItem),
+    hasBatchNumber: () => !this.trackItem || false,
   };
 
   readOnly: ReadOnlyMap = {