Issue #3117465: Fix exception when a project does not have a release with usage

usage/project_usage.module

@@ -238,25 +238,27 @@ function project_usage_restws_response_alter(&$response, $function, $formatName,
         $usage[$row->project_nid][$row->nid] = $row->count;
         $release_nids[] = $row->nid;
       }
-      $result = (new EntityFieldQuery())->entityCondition('entity_type', 'node')
-        ->propertyCondition('status', NODE_PUBLISHED)
-        ->propertyCondition('nid', $release_nids)
-        ->execute();
-      if (!empty($result['node'])) {
-        field_attach_load('node', $result['node'], FIELD_LOAD_CURRENT, [
-          'field_id' => field_info_field('field_release_version')['id'],
-        ]);
-        $release_branches = [];
-        foreach ($result['node'] as $release) {
-          $release_branches[$release->nid] = project_release_get_branch($release->field_release_version[LANGUAGE_NONE][0]['value']) . 'x';
-        }
-        foreach ($usage as $project_nid => $releases) {
-          foreach ($releases as $nid => $count) {
-            if (isset($response['list'][$nid_map[$project_nid]]['project_usage'][$release_branches[$nid]])) {
-              $response['list'][$nid_map[$project_nid]]['project_usage'][$release_branches[$nid]] += $count;
-            }
-            else {
-              $response['list'][$nid_map[$project_nid]]['project_usage'][$release_branches[$nid]] = $count;
+      if (!empty($release_nids)) {
+        $result = (new EntityFieldQuery())->entityCondition('entity_type', 'node')
+          ->propertyCondition('status', NODE_PUBLISHED)
+          ->propertyCondition('nid', $release_nids)
+          ->execute();
+        if (!empty($result['node'])) {
+          field_attach_load('node', $result['node'], FIELD_LOAD_CURRENT, [
+            'field_id' => field_info_field('field_release_version')['id'],
+          ]);
+          $release_branches = [];
+          foreach ($result['node'] as $release) {
+            $release_branches[$release->nid] = project_release_get_branch($release->field_release_version[LANGUAGE_NONE][0]['value']) . 'x';
+          }
+          foreach ($usage as $project_nid => $releases) {
+            foreach ($releases as $nid => $count) {
+              if (isset($response['list'][$nid_map[$project_nid]]['project_usage'][$release_branches[$nid]])) {
+                $response['list'][$nid_map[$project_nid]]['project_usage'][$release_branches[$nid]] += $count;
+              }
+              else {
+                $response['list'][$nid_map[$project_nid]]['project_usage'][$release_branches[$nid]] = $count;
+              }
             }
           }
         }