chg: [metaTemplate:update] Gracefully handle case when template on disk is not readable

src/Controller/MetaTemplatesController.php

@@ -404,8 +404,18 @@ class MetaTemplatesController extends AppController
         $metaTemplate = $this->MetaTemplates->get($template_id, [
             'contain' => ['MetaTemplateFields']
         ]);
-        $templateOnDisk = $this->MetaTemplates->readTemplateFromDisk($metaTemplate->uuid);
+        $error = '';
+        $errorMessage = '';
+        $templateOnDisk = $this->MetaTemplates->readTemplateFromDisk($metaTemplate->uuid, $error);
+        if (is_null($templateOnDisk)) {
+            $errorMessage = __('Could not retreive template\'s status. Reason: {0}', $error);
+            $this->Flash->error($errorMessage);
+            $templateOnDisk = [];
+        }
         $templateStatus = $this->MetaTemplates->getStatusForMetaTemplate($templateOnDisk, $metaTemplate);
+        if (!empty($errorMessage)) {
+            $templateStatus['error'] = $errorMessage;
+        }
         $this->set('templateOnDisk', $templateOnDisk);
         $this->set('templateStatus', $templateStatus);
         return [

src/Model/Table/MetaTemplatesTable.php

@@ -555,6 +555,10 @@ class MetaTemplatesTable extends AppTable
                     if (substr($file, -5) === '.json') {
                         $errorMessage = '';
                         $template = $this->decodeTemplateFromDisk($path . $file, $errorMessage);
+                        if (!empty($errorMessage)) {
+                            $error = $errorMessage;
+                            return null;
+                        }
                         if (!empty($template) && $template['uuid'] == $uuid) {
                             return $template;
                         }
@@ -1318,6 +1322,13 @@ class MetaTemplatesTable extends AppTable
         $updateStatus['next_version'] = $template['version'];
         $updateStatus['new'] = false;
         $updateStatus['automatically-updateable'] = false;
+        $updateStatus['conflicts'] = [];
+        if (empty($template)) {
+            $updateStatus['up-to-date'] = false;
+            $updateStatus['automatically-updateable'] = false;
+            $updateStatus['can-be-removed'] = false;
+            return $updateStatus;
+        }
         if (intval($metaTemplate->version) >= intval($template['version'])) {
             $updateStatus['up-to-date'] = true;
             $updateStatus['conflicts'][] = __('Could not update the template. Local version is equal or newer.');

templates/MetaTemplates/update.php

@@ -11,6 +11,14 @@ if ($updateStatus['up-to-date']) {
         'dismissible' => false,
     ]);
     $modalType = 'ok-only';
+} else if (empty($updateStatus['templateOnDisk'])) {
+    $diskTemplateError = $templateStatus['error'] ?? __('Unknown');
+    $bodyHtml .= $this->Bootstrap->alert([
+        'variant' => 'danger',
+        'html' => sprintf('<strong>%s</strong> %s<p>%s</p>', __('Could not get template on disk.'), __('Reason:'), h($diskTemplateError)),
+        'dismissible' => false,
+    ]);
+    $modalType = 'ok-only';
 } else {
     if ($updateStatus['automatically-updateable']) {
         $bodyHtml .= $this->Bootstrap->alert([