Assign/remove source from a product triggers cache clearance request for all grouped prdoucts

Preconditions (*)

magento/module-inventory-cache
Magento 2.4.7-p2

What is happening?

MSI has this function in place as around method. Which gets the product IDs from inventory_stock_ID table before and after. Pay attention to around method here. https://github.com/magento/inventory/blob/790c7ff267be04be6cc57f4502e005bec560a2b3/InventoryCache/Plugin/InventoryIndexer/Indexer/Stock/Strategy/Sync/CacheFlush.php#L51

Then, it also has this function as after method to index grouped products, which happens after the above function (around) runs, meaning at this time, the system has already sent all the grouped product IDs to clear the cache. https://github.com/magento/inventory/blob/790c7ff267be04be6cc57f4502e005bec560a2b3/InventoryGroupedProductIndexer/Plugin/InventoryIndexer/Indexer/Stock/Strategy/Sync/ReindexFullPlugin.php#L43

Explanation

    public function aroundExecuteList(Sync $subject, callable $proceed, array $stockIds)
    {
        $beforeReindexProductIds = $this->getProductIdsByStockIds->execute($stockIds); 
        //finds 500 products, at this point there are grouped products because after plugin would have run earlier and had added grouped products

        $proceed($stockIds);

        $afterReindexProductIds = $this->getProductIdsByStockIds->execute($stockIds); 
        //finds 299 products, at this stage after plugin hasn't run yet, as it is around method

        $productIdsForCacheClean = array_diff($beforeReindexProductIds, $afterReindexProductIds); 
        //diff is 201 -- grouped products (200) and 1 product that actually being reindexed for

        if ($productIdsForCacheClean) {
            $this->flushCacheByProductIds->execute($productIdsForCacheClean); 
            //201 grouped products (200) are sent to clear the cache
        }
    }

What this means?

If I have 200 grouped products in my system, every time a single product's (not related to grouped whatsoever) sources deleted/added, then it will send the cache clear request for this product PLUS that 200 grouped products.

Steps to reproduce (*)

Make sure you have some grouped products
Run bin/magento indexer:reindex inventory

Expected result (*)

The system should only send impacted products to clear the cache

Actual result (*)

The system sends all the grouped products to clear the cache every time it is indexing.

Proposed solution:

https://github.com/magento/inventory/pull/3402

magento / inventory

Assign/remove source from a product triggers cache clearance request for all grouped prdoucts #3403