Fixes #1590: blt doctor only returns error output.

Author: grasmash

scripts/drupal-vm/config.yml

@@ -25,7 +25,7 @@ drupal_build_composer_project: false
 drupal_build_composer: false
 drupal_composer_path: false
 drupal_composer_install_dir: "/var/www/${project.machine_name}"
-drupal_core_path: "{{ drupal_composer_install_dir }}/docroot"
+drupal_core_path: "/var/www/${project.machine_name}/docroot"
 ssh_home: /var/www/${project.machine_name}
 
 drupal_db_user: drupal

src/Robo/Commands/Blt/DoctorCommand.php

@@ -60,8 +60,13 @@ public function doctor() {
    *   The command result.
    */
   protected function executeDoctorInsideVm() {
-    $drupal_vm_config = Yaml::parse(file_get_contents($this->getConfigValue('repo.root') . '/box/config.yml'));
-    $repo_root = $drupal_vm_config['vagrant_synced_folders'][0]['destination'];
+    $drupal_vm_config_filepath = $this->getConfigValue('repo.root') . '/box/config.yml';
+    $drupal_vm_config = Yaml::parse(file_get_contents($drupal_vm_config_filepath));
+    $repo_root = $drupal_vm_config['drupal_core_path'];
+    if (strstr($repo_root, '{{')) {
+      throw new \Exception("The value of drupal_core_path in $drupal_vm_config_filepath contains an unresolved Ansible variable. Please do not use variable placeholders for drupal_core_path. BLT cannot resolve them.");
+    }
+
     $this->say("Drupal VM was detected. Running blt doctor inside of VM...");
     $command = "cd $repo_root && $repo_root/vendor/bin/drush cc drush && $repo_root/vendor/bin/drush --include=$repo_root/vendor/acquia/blt/drush blt-doctor -r $repo_root/docroot";