Remove drush-aliases SSH calls to find the absolute app root

This was done for dedicated (Enterprise) environments (whose absolute app root
was not /app). Drush now supports relative paths (since 9.6.2) so this is
unnecessary.

Users whose dedicated (Enterprise) sites are on old versions of Drush 9 (i.e.
between 9.0.0 and 9.6.2) are advised to upgrade Drush to at least 9.6.2. 9.7.1
is the latest version at the time of writing.

See the Drush fix in drush-ops/drush#4019

src/Command/Local/LocalDrushAliasesCommand.php

@@ -118,31 +118,6 @@ protected function execute(InputInterface $input, OutputInterface $output)
                     $this->debug('Fetching deployment information for environment: ' . $environment->id);
                     $this->api()->getCurrentDeployment($environment);
                 }
-
-                if ($environment->deployment_target === 'local') {
-                    continue;
-                }
-                foreach ($apps as $app) {
-                    $sshUrl = $environment->getSshUrl($app->getName());
-                    if (empty($sshUrl)) {
-                        continue;
-                    }
-                    try {
-                        $appRoot = $envVarsService->getEnvVar('APP_DIR', new RemoteHost($sshUrl, $ssh, $shell));
-                    } catch (\Symfony\Component\Process\Exception\RuntimeException $e) {
-                        $this->stdErr->writeln(sprintf(
-                            'Unable to find app root for environment %s, app %s',
-                            $this->api()->getEnvironmentLabel($environment, 'comment'),
-                            '<comment>' . $app->getName() . '</comment>'
-                        ));
-                        $this->stdErr->writeln($e->getMessage());
-                        continue;
-                    }
-                    if (!empty($appRoot)) {
-                        $this->debug(sprintf('App root for %s: %s', $sshUrl, $appRoot));
-                        $drush->setCachedAppRoot($sshUrl, $appRoot);
-                    }
-                }
             }
 
             $drush->createAliases($project, $projectRoot, $environments, $current_group);

src/Service/Drush.php

@@ -39,9 +39,6 @@ class Drush
     /** @var string|null */
     protected $executable;
 
-    /** @var string[] */
-    protected $cachedAppRoots = [];
-
     /**
      * @param Config|null $config
      * @param Shell|null $shellHelper
@@ -70,25 +67,6 @@ public function getHomeDir()
         return $this->homeDir ?: Filesystem::getHomeDirectory();
     }
 
-    /**
-     * @param string $sshUrl
-     * @param string $enterpriseAppRoot
-     */
-    public function setCachedAppRoot($sshUrl, $enterpriseAppRoot)
-    {
-        $this->cachedAppRoots[$sshUrl] = $enterpriseAppRoot;
-    }
-
-    /**
-     * @param string $sshUrl
-     *
-     * @return string
-     */
-    public function getCachedAppRoot($sshUrl)
-    {
-        return isset($this->cachedAppRoots[$sshUrl]) ? $this->cachedAppRoots[$sshUrl] : false;
-    }
-
     /**
      * Find the global Drush configuration directory.
      *

src/SiteAlias/DrushAlias.php

@@ -246,19 +246,9 @@ protected function generateRemoteAlias(Environment $environment, LocalApplicatio
             'options' => [
                 $this->getAutoRemoveKey() => true,
             ],
+            'root' => $app->getDocumentRoot(),
         ];
 
-        // For most environments, we know the application root directory is
-        // '/app'. It's different in Enterprise environments.
-        if ($environment->deployment_target !== 'local') {
-            $appRoot = $this->drush->getCachedAppRoot($sshUrl);
-            if ($appRoot) {
-                $alias['root'] = rtrim($appRoot, '/') . '/' . $app->getDocumentRoot();
-            }
-        } else {
-            $alias['root'] = '/app/' . $app->getDocumentRoot();
-        }
-
         list($alias['user'], $alias['host']) = explode('@', $sshUrl, 2);
 
         if ($url = $this->drush->getSiteUrl($environment, $app)) {