MC-36410: [Chrome] Loader stacks during import when the same file is checked after update

Author: tsviklinskyi

app/code/Magento/ImportExport/Block/Adminhtml/Import/Edit/Form.php

@@ -226,6 +226,7 @@ protected function _prepareForm()
                 'title' => __('Select File to Import'),
                 'required' => true,
                 'class' => 'input-file',
+                'onchange' => 'varienImport.refreshLoadedFileLastModified(this);',
                 'note' => __(
                     'File must be saved in UTF-8 encoding for proper import'
                 ),
@@ -282,7 +283,7 @@ protected function getDownloadSampleFileHtml()
     private function getImportBehaviorTooltip()
     {
         $html = '<div class="admin__field-tooltip tooltip">
-            <a class="admin__field-tooltip-action action-help" target="_blank" title="What is this?" 
+            <a class="admin__field-tooltip-action action-help" target="_blank" title="What is this?"
                 href="https://docs.magento.com/m2/ce/user_guide/system/data-import.html"><span>'
             . __('What is this?')
             . '</span></a></div>';

app/code/Magento/ImportExport/i18n/en_US.csv

@@ -127,3 +127,4 @@ Summary,Summary
 "File %1 deleted","File %1 deleted"
 "Please provide valid export file name","Please provide valid export file name"
 "%1 is not a valid file","%1 is not a valid file"
+"Something went wrong while getting data from a file, please re-upload file","Something went wrong while getting data from a file, please re-upload file"

app/code/Magento/ImportExport/view/adminhtml/templates/import/form/before.phtml

@@ -7,6 +7,10 @@
 <?php
 /** @var $block \Magento\ImportExport\Block\Adminhtml\Import\Edit\Before */
 /** @var \Magento\Framework\View\Helper\SecureHtmlRenderer $secureRenderer */
+$fieldNameSourceFile = \Magento\ImportExport\Model\Import::FIELD_NAME_SOURCE_FILE;
+$uploaderErrorMessage = $block->escapeHtml(
+    __('Something went wrong while getting data from a file, please re-upload file')
+);
 ?>
 
 <?php $scriptString = <<<script
@@ -49,6 +53,12 @@ require([
          */
         sampleFilesBaseUrl: '{$block->escapeJs($block->getUrl('*/*/download/', ['filename' => 'entity-name']))}',
 
+        /**
+        * Loaded file last modified
+        * @type {int|null}
+        */
+        loadedFileLastModified: null,
+
         /**
          * Reset selected index
          * @param {string} elementId
@@ -162,11 +172,36 @@ require([
             }
         },
 
+        /**
+         * Refresh loaded file last modified
+         */
+        refreshLoadedFileLastModified: function(e) {
+            if (jQuery(e)[0].files.length > 0) {
+                this.loadedFileLastModified = jQuery(e)[0].files[0].lastModified;
+            } else {
+                this.loadedFileLastModified = null;
+            }
+        },
+
         /**
          * Post form data to dynamic iframe.
          * @param {string} newActionUrl OPTIONAL Change form action to this if specified
          */
         postToFrame: function(newActionUrl) {
+            var fileUploader = document.getElementById('{$fieldNameSourceFile}');
+
+            for (var i = 0; i < fileUploader.files.length; i++) {
+                const file = fileUploader.files[i];
+
+                if (this.loadedFileLastModified !== file.lastModified) {
+                    alert({
+                        content: '{$uploaderErrorMessage}'
+                    });
+                    fileUploader.value = null;
+                    return;
+                }
+            }
+
             if (!jQuery('[name="' + this.ifrElemName + '"]').length) {
                 jQuery('body').append('<iframe name="' + this.ifrElemName + '" id="' + this.ifrElemName + '"/>');
                 jQuery('iframe#' + this.ifrElemName).attr('display', 'none');