1250: added plugin to prevent disabling default source

app/code/Magento/InventoryAdminUi/Ui/DataProvider/SourceDataProvider.php

@@ -22,6 +22,8 @@
  */
 class SourceDataProvider extends DataProvider
 {
+    const SOURCE_FORM_NAME = 'inventory_source_form_data_source';
+
     /**
      * @var SourceRepositoryInterface
      */
@@ -88,25 +90,23 @@ public function __construct(
     public function getData()
     {
         $data = parent::getData();
-        if ('inventory_source_form_data_source' === $this->name) {
+        if (self::SOURCE_FORM_NAME === $this->name) {
             // It is need for support of several fieldsets.
             // For details see \Magento\Ui\Component\Form::getDataSourceData
             if ($data['totalRecords'] > 0) {
                 $sourceCode = $data['items'][0][SourceInterface::SOURCE_CODE];
                 $sourceGeneralData = $data['items'][0];
-                $sourceGeneralData['disable_source_code'] = !empty($sourceGeneralData['source_code']);
                 $dataForSingle[$sourceCode] = [
                     'general' => $sourceGeneralData,
                 ];
-                $data = $dataForSingle;
-            } else {
-                $sessionData = $this->session->getSourceFormData(true);
-                if (null !== $sessionData) {
-                    // For details see \Magento\Ui\Component\Form::getDataSourceData
-                    $data = [
-                        '' => $sessionData,
-                    ];
-                }
+                return $dataForSingle;
+            }
+            $sessionData = $this->session->getSourceFormData(true);
+            if (null !== $sessionData) {
+                // For details see \Magento\Ui\Component\Form::getDataSourceData
+                $data = [
+                    '' => $sessionData,
+                ];
             }
         }
         return $data;

app/code/Magento/InventoryAdminUi/view/adminhtml/ui_component/inventory_source_form.xml

@@ -58,9 +58,6 @@
                 </validation>
                 <dataType>text</dataType>
                 <label translate="true">Code</label>
-                <imports>
-                    <link name="disabled">${ $.provider }:data.general.disable_source_code</link>
-                </imports>
             </settings>
         </field>
         <field name="name" formElement="input" sortOrder="20">

app/code/Magento/InventoryCatalogAdminUi/Plugin/InventoryAdminUi/DataProvider/PreventDisablingDefaultSourcePlugin.php

@@ -0,0 +1,79 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\InventoryCatalogAdminUi\Plugin\InventoryAdminUi\DataProvider;
+
+use Magento\Framework\App\RequestInterface;
+use Magento\InventoryApi\Api\Data\SourceItemInterface;
+use Magento\InventoryCatalogApi\Api\DefaultSourceProviderInterface;
+use Magento\InventoryAdminUi\Ui\DataProvider\SourceDataProvider;
+
+class PreventDisablingDefaultSourcePlugin
+{
+    /**
+     * @var DefaultSourceProviderInterface
+     */
+    private $defaultSourceProvider;
+
+    /**
+     * @var RequestInterface
+     */
+    private $request;
+
+    /**
+     * @param DefaultSourceProviderInterface $defaultSourceProvider
+     * @param RequestInterface $request
+     */
+    public function __construct(
+        DefaultSourceProviderInterface $defaultSourceProvider,
+        RequestInterface $request
+    ) {
+        $this->defaultSourceProvider = $defaultSourceProvider;
+        $this->request = $request;
+    }
+
+    /**
+     * @param SourceDataProvider $subject
+     * @param $meta
+     * @return array
+     */
+    public function afterGetMeta(
+        SourceDataProvider $subject,
+        $meta
+    ): array {
+        $isFormComponent = SourceDataProvider::SOURCE_FORM_NAME === $subject->getName();
+        if (!$isFormComponent || !$this->isDefaultSource()) {
+            return $meta;
+        }
+
+        $meta['general'] = [
+            'children' => [
+                'enabled' => [
+                    'arguments' => [
+                        'data' => [
+                            'config' => [
+                                'disabled' => true,
+                            ]
+                        ]
+                    ]
+                ]
+            ]
+        ];
+
+        return $meta;
+    }
+
+    /**
+     * @return bool
+     */
+    private function isDefaultSource(): bool
+    {
+        $defaultSourceCode = $this->defaultSourceProvider->getCode();
+        $currentSourceCode = $this->request->getParam(SourceItemInterface::SOURCE_CODE);
+        return $defaultSourceCode === $currentSourceCode;
+    }
+}

app/code/Magento/InventoryCatalogAdminUi/etc/adminhtml/di.xml

@@ -45,4 +45,7 @@
     <type name="Magento\InventoryAdminUi\Model\Stock\StockSourceLinkProcessor">
         <plugin name="prevent_process_for_default_stock" type="Magento\InventoryCatalogAdminUi\Plugin\InventoryAdminUi\Stock\StockSaveProcessor\PreventProcessDefaultStockLinksPlugin"/>
     </type>
+    <type name="Magento\InventoryAdminUi\Ui\DataProvider\SourceDataProvider">
+        <plugin name="prevent_disabling_default_source" type="Magento\InventoryCatalogAdminUi\Plugin\InventoryAdminUi\DataProvider\PreventDisablingDefaultSourcePlugin"/>
+    </type>
 </config>

app/code/Magento/InventoryCatalogAdminUi/view/adminhtml/ui_component/inventory_source_form.xml

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+-->
+<form xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Ui:etc/ui_configuration.xsd">
+    <fieldset name="general">
+        <field name="enabled">
+            <settings>
+                <notice translate="true">The Default Source must be enabled. A default source is required for single source merchants and product migration.</notice>
+            </settings>
+        </field>
+    </fieldset>
+</form>