Get concrete error message of CouldNotSaveException

Question

We need to get concrete error message when Magento\Catalog\Model\ProductRepository throws CouldNotSaveException during saveProduct()

private function saveProduct($product): void
{
    try {
        $this->removeProductFromLocalCacheBySku($product->getSku());
        $this->removeProductFromLocalCacheById($product->getId());
        $this->resourceModel->save($product);
    } catch (ConnectionException $exception) {
...
    } catch (\Exception $e) {
        throw new CouldNotSaveException(
            __('The product was unable to be saved. Please try again.'),
            $e
        );
    }
}

An easy way would be just adding the message in that code

__('The product was unable to be saved. Please try again.' . $e->getMessage())

But we can't edit that file, as this is a project hosted in Adobe Cloud. So, how can we get that message instead of application default message?

Answer 1

1. Create Plugin for ProductRepositoryInterface

In example also creates additional logger to write exception to separate file

app/code/Acme/StackExchange/etc/di.xml

<?xml version="1.0" encoding="UTF-8"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <!-- Create Virtual Logger -->
    <virtualType name="Acme\StackExchange\Model\VirtualLoggerHandler" type="Magento\Framework\Logger\Handler\Base">
        <arguments>
            <argument name="fileName" xsi:type="string">/var/log/acme_stackexchange.log</argument>
        </arguments>
    </virtualType>
    <virtualType name="Acme\StackExchange\Model\VirtualLogger" type="Magento\Framework\Logger\Monolog">
        <arguments>
            <argument name="handlers" xsi:type="array">
                <item name="system" xsi:type="object">Acme\StackExchange\Model\VirtualLoggerHandler</item>
            </argument>
        </arguments>
    </virtualType>
    <!-- Register Plugin -->
    <type name="Magento\Catalog\Api\ProductRepositoryInterface">
        <plugin name="Acme_StackExchange_Plugin_Catalog_Model_ProductRepositoryPlugin"
                type="Acme\StackExchange\Plugin\Catalog\Model\ProductRepositoryPlugin" sortOrder="10"/>
    </type>
    <!-- Pass Virtual Logger to Plugin -->
    <type name="Acme\StackExchange\Plugin\Catalog\Model\ProductRepositoryPlugin">
        <arguments>
            <argument name="logger" xsi:type="object">Acme\StackExchange\Model\VirtualLogger</argument>
        </arguments>
    </type>
</config>

2. Create a Plugin

app/code/Acme/StackExchange/Plugin/Catalog/Model/ProductRepositoryPlugin.php

<?php
declare(strict_types=1);

namespace Acme\StackExchange\Plugin\Catalog\Model;

use Magento\Catalog\Api\Data\ProductInterface;
use Magento\Catalog\Api\ProductRepositoryInterface;
use Magento\Framework\Exception\CouldNotSaveException;
use Psr\Log\LoggerInterface;

class ProductRepositoryPlugin
{
    protected LoggerInterface $logger;

    public function __construct(
        LoggerInterface $logger
    ) {
        $this->logger = $logger;
    }

    public function aroundSave(
        ProductRepositoryInterface $subject,
        callable $proceed,
        ProductInterface $product,
        $saveOptions = false
    ): ProductInterface {
        try {
            return $proceed($product, $saveOptions);
        } catch (CouldNotSaveException $e) {
            if ($e->getPrevious()) {
                $this->logger->critical($e->getPrevious());
            }
            throw $e;
        }
    }
}

Answer 2

Patch is the way to go, we use https://github.com/cweagans/composer-patches.

composer require cweagans/composer-patches

General flow is this:

1. Create a copy of original file, edit the file, create a patch file using diff command. Patches are relative to package folder:

   cd vendor/magento/module-catalog
   cp Model/ProductRepository.php Model/ProductRepository.orig.php
   # Edit Model/ProductRepository.php with your changes...
   mkdir ../../../patches
   diff -u Model/ProductRepository.orig.php Model/ProductRepository.php > ../../../patches/Magento_Catalog-save-product-original-exception.patch
   

   In my example it looks like this:

   --- Model/ProductRepository.orig.php    2022-07-18 10:35:56.200056524 +0300
   +++ Model/ProductRepository.php 2022-07-18 10:37:34.022779326 +0300
   @@ -909,7 +909,7 @@
                throw $e;
            } catch (\Exception $e) {
                throw new CouldNotSaveException(
   -                __('The product was unable to be saved. Please try again.'),
   +                __('The product was unable to be saved. Please try again. ' . $e->getMessage()),
                    $e
                );
            }
   
   

2. Place your patch in project folder or to public URL. patches/ local folder in this example.

3. Register patch in composer.json

   {
       "extra": {
           "magento-force": "override",
           "composer-exit-on-patch-failure": true,
           "patches": {
               "magento/module-catalog": {
                   "Original exception message in product save": "patches/Magento_Catalog-save-product-original-exception.patch"
               }
           },
       }
   }
   

4. Do composer install

Our collection of patches - https://github.com/ConvertGroupsAS/magento2-patches