Issue #3063129 by heddn, tatarbj: Backport DiskSpace

ReadinessCheckers/DiskSpace.php

+<?php
+
+/**
+ * Disk space checker.
+ */
+class DiskSpace implements ReadinessCheckerInterface {
+
+  /**
+   * Minimum disk space (in bytes) is 10mb.
+   */
+  const MINIMUM_DISK_SPACE = 10000000;
+
+  /**
+   * Megabyte divisor.
+   */
+  const MEGABYTE_DIVISOR = 1000000;
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function run() {
+    return static::diskSpaceCheck();
+  }
+
+  /**
+   * Check if the filesystem has sufficient disk space.
+   *
+   * @return array
+   *   An array of translatable strings if there is not sufficient space.
+   */
+  protected static function diskSpaceCheck() {
+    $messages = [];
+    if (disk_free_space(DRUPAL_ROOT) < static::MINIMUM_DISK_SPACE) {
+      $messages[] = t('Logical disk "@root" has insufficient space. There must be at least @space megabytes free.', [
+        '@root' => DRUPAL_ROOT,
+        '@space' => static::MINIMUM_DISK_SPACE / static::MEGABYTE_DIVISOR,
+      ]);
+    }
+    return $messages;
+  }
+
+}

ReadinessCheckers/ReadinessCheckerManager.php

@@ -27,7 +27,7 @@ class ReadinessCheckerManager {
     static::$checkers['warning'][0][] = 'MissingProjectInfo';
     static::$checkers['warning'][0][] = 'ModifiedFiles';
     static::$checkers['warning'][0][] = 'PhpSapi';
-    static::$checkers['error'][0][] = 'PhpSapi';
+    static::$checkers['error'][0][] = 'DiskSpace';
     static::$checkers['error'][0][] = 'ReadOnlyFilesystem';
 
     return static::$checkers;

automatic_updates.info

@@ -11,6 +11,7 @@ files[] = ModifiedFilesService.php
 files[] = ReadinessCheckers/ReadinessCheckerManager.php
 files[] = ReadinessCheckers/ReadinessCheckerInterface.php
 files[] = ReadinessCheckers/BlacklistPhp72Versions.php
+files[] = ReadinessCheckers/DiskSpace.php
 files[] = ReadinessCheckers/FileOwnership.php
 files[] = ReadinessCheckers/MissingProjectInfo.php
 files[] = ReadinessCheckers/ModifiedFiles.php