NEW NullDatabase (#10016)

* NEW DatabaselessKernel to support operation without DB

This is required for GraphQL code generation in CI (without a working runtime database/webserver environment).
Context: https://github.com/silverstripe/silverstripe-graphql/issues/388

* New --no-database option for sake

* Refactor to abstract class

* Apply feedback peer review

Co-authored-by: Aaron Carlino <unclecheese@leftandmain.com>
Co-authored-by: Maxime Rainville <maxime@silverstripe.com>

cli-script.php

@@ -4,6 +4,9 @@
 use SilverStripe\Control\CLIRequestBuilder;
 use SilverStripe\Control\HTTPApplication;
 use SilverStripe\Core\CoreKernel;
+use SilverStripe\ORM\DB;
+use SilverStripe\ORM\Connect\NullDatabase;
+use SilverStripe\Core\DatabaselessKernel;
 
 require __DIR__ . '/src/includes/autoload.php';
 
@@ -16,8 +19,17 @@ if (!in_array(PHP_SAPI, ["cli", "cgi", "cgi-fcgi"])) {
 // Build request and detect flush
 $request = CLIRequestBuilder::createFromEnvironment();
 
+
+$skipDatabase = in_array('--no-database', $argv);
+if ($skipDatabase) {
+    DB::set_conn(new NullDatabase());
+}
 // Default application
-$kernel = new CoreKernel(BASE_PATH);
+$kernel = $skipDatabase
+    ? new DatabaselessKernel(BASE_PATH)
+    : new CoreKernel(BASE_PATH);
+
 $app = new HTTPApplication($kernel);
 $response = $app->handle($request);
+
 $response->output();

src/Core/BaseKernel.php

@@ -0,0 +1,507 @@
+<?php
+
+namespace SilverStripe\Core;
+
+use InvalidArgumentException;
+use Monolog\Handler\StreamHandler;
+use Monolog\Logger;
+use Psr\Log\LoggerInterface;
+use SilverStripe\Config\Collections\CachedConfigCollection;
+use SilverStripe\Control\Director;
+use SilverStripe\Control\HTTPResponse;
+use SilverStripe\Control\HTTPResponse_Exception;
+use SilverStripe\Core\Cache\ManifestCacheFactory;
+use SilverStripe\Core\Config\ConfigLoader;
+use SilverStripe\Core\Config\CoreConfigFactory;
+use SilverStripe\Core\Injector\Injector;
+use SilverStripe\Core\Injector\InjectorLoader;
+use SilverStripe\Core\Injector\SilverStripeServiceConfigurationLocator;
+use SilverStripe\Core\Manifest\ClassLoader;
+use SilverStripe\Core\Manifest\ClassManifest;
+use SilverStripe\Core\Manifest\ModuleLoader;
+use SilverStripe\Core\Manifest\ModuleManifest;
+use SilverStripe\Dev\DebugView;
+use SilverStripe\Dev\Deprecation;
+use SilverStripe\Logging\ErrorHandler;
+use SilverStripe\View\PublicThemes;
+use SilverStripe\View\SSViewer;
+use SilverStripe\View\ThemeManifest;
+use SilverStripe\View\ThemeResourceLoader;
+use Exception;
+
+/**
+ * Simple Kernel container
+ */
+abstract class BaseKernel implements Kernel
+{
+    /**
+     * @var Kernel
+     */
+    protected $nestedFrom = null;
+
+    /**
+     * @var Injector
+     */
+    protected $container = null;
+
+    /**
+     * @var string
+     */
+    protected $enviroment = null;
+
+    /**
+     * @var ClassLoader
+     */
+    protected $classLoader = null;
+
+    /**
+     * @var ModuleLoader
+     */
+    protected $moduleLoader = null;
+
+    /**
+     * @var ConfigLoader
+     */
+    protected $configLoader = null;
+
+    /**
+     * @var InjectorLoader
+     */
+    protected $injectorLoader = null;
+
+    /**
+     * @var ThemeResourceLoader
+     */
+    protected $themeResourceLoader = null;
+
+    protected $basePath = null;
+
+    /**
+     * Indicates whether the Kernel has been booted already
+     *
+     * @var bool
+     */
+    private $booted = false;
+
+
+    /**
+     * Create a new kernel for this application
+     *
+     * @param string $basePath Path to base dir for this application
+     */
+    public function __construct($basePath)
+    {
+        $this->basePath = $basePath;
+
+        // Initialise the dependency injector as soon as possible, as it is
+        // subsequently used by some of the following code
+        $injectorLoader = InjectorLoader::inst();
+        $injector = new Injector(['locator' => SilverStripeServiceConfigurationLocator::class]);
+        $injectorLoader->pushManifest($injector);
+        $this->setInjectorLoader($injectorLoader);
+
+        // Manifest cache factory
+        $manifestCacheFactory = $this->buildManifestCacheFactory();
+
+        // Class loader
+        $classLoader = ClassLoader::inst();
+        $classLoader->pushManifest(new ClassManifest($basePath, $manifestCacheFactory));
+        $this->setClassLoader($classLoader);
+
+        // Module loader
+        $moduleLoader = ModuleLoader::inst();
+        $moduleManifest = new ModuleManifest($basePath, $manifestCacheFactory);
+        $moduleLoader->pushManifest($moduleManifest);
+        $this->setModuleLoader($moduleLoader);
+
+        // Config loader
+        // @todo refactor CoreConfigFactory
+        $configFactory = new CoreConfigFactory($manifestCacheFactory);
+        $configManifest = $configFactory->createRoot();
+        $configLoader = ConfigLoader::inst();
+        $configLoader->pushManifest($configManifest);
+        $this->setConfigLoader($configLoader);
+
+        // Load template manifest
+        $themeResourceLoader = ThemeResourceLoader::inst();
+        $themeResourceLoader->addSet(SSViewer::PUBLIC_THEME, new PublicThemes());
+        $themeResourceLoader->addSet(SSViewer::DEFAULT_THEME, new ThemeManifest(
+            $basePath,
+            null, // project is defined in config, and this argument is deprecated
+            $manifestCacheFactory
+        ));
+        $this->setThemeResourceLoader($themeResourceLoader);
+    }
+
+    /**
+     * Initialise PHP with default variables
+     */
+    protected function bootPHP()
+    {
+        if ($this->getEnvironment() === self::LIVE) {
+            // limited to fatal errors and warnings in live mode
+            error_reporting(E_ALL & ~(E_DEPRECATED | E_STRICT | E_NOTICE));
+        } else {
+            // Report all errors in dev / test mode
+            error_reporting(E_ALL | E_STRICT);
+        }
+
+        /**
+         * Ensure we have enough memory
+         */
+        Environment::increaseMemoryLimitTo('64M');
+
+        // Ensure we don't run into xdebug's fairly conservative infinite recursion protection limit
+        if (function_exists('xdebug_enable')) {
+            $current = ini_get('xdebug.max_nesting_level');
+            if ((int)$current < 200) {
+                ini_set('xdebug.max_nesting_level', 200);
+            }
+        }
+
+        /**
+         * Set default encoding
+         */
+        mb_http_output('UTF-8');
+        mb_internal_encoding('UTF-8');
+        mb_regex_encoding('UTF-8');
+
+        /**
+         * Enable better garbage collection
+         */
+        gc_enable();
+    }
+
+    /**
+     * Boot all manifests
+     *
+     * @param bool $flush
+     */
+    protected function bootManifests($flush)
+    {
+        // Setup autoloader
+        $this->getClassLoader()->init(
+            $this->getIncludeTests(),
+            $flush,
+            $this->getIgnoredCIConfigs()
+        );
+
+        // Find modules
+        $this->getModuleLoader()->init(
+            $this->getIncludeTests(),
+            $flush,
+            $this->getIgnoredCIConfigs()
+        );
+
+        // Flush config
+        if ($flush) {
+            $config = $this->getConfigLoader()->getManifest();
+            if ($config instanceof CachedConfigCollection) {
+                $config->setFlush(true);
+            }
+        }
+        // tell modules to sort, now that config is available
+        $this->getModuleLoader()->getManifest()->sort();
+
+        // Find default templates
+        $defaultSet = $this->getThemeResourceLoader()->getSet('$default');
+        if ($defaultSet instanceof ThemeManifest) {
+            $defaultSet->setProject(
+                ModuleManifest::config()->get('project')
+            );
+            $defaultSet->init(
+                $this->getIncludeTests(),
+                $flush,
+                $this->getIgnoredCIConfigs()
+            );
+        }
+    }
+
+    /**
+     * Include all _config.php files
+     */
+    protected function bootConfigs()
+    {
+        global $project;
+        $projectBefore = $project;
+        $config = ModuleManifest::config();
+        // After loading all other app manifests, include _config.php files
+        $this->getModuleLoader()->getManifest()->activateConfig();
+        if ($project && $project !== $projectBefore) {
+            Deprecation::notice('5.0', '$project global is deprecated');
+            $config->set('project', $project);
+        }
+    }
+
+    /**
+     * Turn on error handling
+     * @throws Exception
+     */
+    protected function bootErrorHandling()
+    {
+        // Register error handler
+        $errorHandler = Injector::inst()->get(ErrorHandler::class);
+        $errorHandler->start();
+
+        // Register error log file
+        $errorLog = Environment::getEnv('SS_ERROR_LOG');
+        if ($errorLog) {
+            $logger = Injector::inst()->get(LoggerInterface::class);
+            if ($logger instanceof Logger) {
+                $logger->pushHandler(new StreamHandler($this->basePath . '/' . $errorLog, Logger::WARNING));
+            } else {
+                user_error("SS_ERROR_LOG setting only works with Monolog, you are using another logger", E_USER_WARNING);
+            }
+        }
+    }
+
+    /**
+     * Get the environment type
+     *
+     * @return string
+     *
+     * @deprecated 5.0 use Director::get_environment_type() instead. Since 5.0 it should return only if kernel overrides. No checking SESSION or Environment.
+     */
+    public function getEnvironment()
+    {
+        // Check set
+        if ($this->enviroment) {
+            return $this->enviroment;
+        }
+
+        // Check saved session
+        $env = $this->sessionEnvironment();
+        if ($env) {
+            return $env;
+        }
+
+        // Check getenv
+        if ($env = Environment::getEnv('SS_ENVIRONMENT_TYPE')) {
+            return $env;
+        }
+
+        return self::LIVE;
+    }
+
+    /**
+     * Check or update any temporary environment specified in the session.
+     *
+     * @return null|string
+     *
+     * @deprecated 5.0 Use Director::get_session_environment_type() instead
+     */
+    protected function sessionEnvironment()
+    {
+        if (!$this->booted) {
+            // session is not initialyzed yet, neither is manifest
+            return null;
+        }
+
+        return Director::get_session_environment_type();
+    }
+
+    abstract public function boot($flush = false);
+
+    abstract public function isFlushed();
+
+    /**
+     * Check if there's a legacy _ss_environment.php file
+     *
+     * @throws HTTPResponse_Exception
+     */
+    protected function detectLegacyEnvironment()
+    {
+        // Is there an _ss_environment.php file?
+        if (!file_exists($this->basePath . '/_ss_environment.php') &&
+            !file_exists(dirname($this->basePath) . '/_ss_environment.php')
+        ) {
+            return;
+        }
+
+        // Build error response
+        $dv = new DebugView();
+        $body = implode([
+            $dv->renderHeader(),
+            $dv->renderInfo(
+                "Configuration Error",
+                Director::absoluteBaseURL()
+            ),
+            $dv->renderParagraph(
+                'You need to replace your _ss_environment.php file with a .env file, or with environment variables.<br><br>'
+                . 'See the <a href="https://docs.silverstripe.org/en/4/getting_started/environment_management/">'
+                . 'Environment Management</a> docs for more information.'
+            ),
+            $dv->renderFooter()
+        ]);
+
+        // Raise error
+        $response = new HTTPResponse($body, 500);
+        throw new HTTPResponse_Exception($response);
+    }
+
+    /**
+     * If missing configuration, redirect to install.php if it exists.
+     * Otherwise show a server error to the user.
+     *
+     * @param string $msg Optional message to show to the user on an installed project (install.php missing).
+     */
+    protected function redirectToInstaller($msg = '')
+    {
+        // Error if installer not available
+        if (!file_exists(Director::publicFolder() . '/install.php')) {
+            throw new HTTPResponse_Exception(
+                $msg,
+                500
+            );
+        }
+
+        // Redirect to installer
+        $response = new HTTPResponse();
+        $response->redirect(Director::absoluteURL('install.php'));
+        throw new HTTPResponse_Exception($response);
+    }
+
+    /**
+     * @return ManifestCacheFactory
+     */
+    protected function buildManifestCacheFactory()
+    {
+        return new ManifestCacheFactory([
+            'namespace' => 'manifestcache',
+            'directory' => TEMP_PATH,
+        ]);
+    }
+
+    /**
+     * When manifests are discovering files, tests files in modules using the following CI library type will be ignored.
+     *
+     * The purpose of this method is to avoid loading PHPUnit test files with incompatible definitions.
+     *
+     * @return string[] List of CI types to ignore as defined by `Module`.
+     */
+    protected function getIgnoredCIConfigs(): array
+    {
+        return [];
+    }
+
+    /**
+     * @return bool
+     */
+    protected function getIncludeTests()
+    {
+        return false;
+    }
+
+    /**
+     * @param bool $bool
+     */
+    protected function setBooted(bool $bool): void
+    {
+        $this->booted = $bool;
+    }
+
+    public function shutdown()
+    {
+    }
+
+    public function nest()
+    {
+        // Clone this kernel, nesting config / injector manifest containers
+        $kernel = clone $this;
+        $kernel->setConfigLoader($this->configLoader->nest());
+        $kernel->setInjectorLoader($this->injectorLoader->nest());
+        $kernel->nestedFrom = $this;
+        return $kernel;
+    }
+
+    public function activate()
+    {
+        $this->configLoader->activate();
+        $this->injectorLoader->activate();
+
+        // Self register
+        $this->getInjectorLoader()
+            ->getManifest()
+            ->registerService($this, Kernel::class);
+        return $this;
+    }
+
+    public function getNestedFrom()
+    {
+        return $this->nestedFrom;
+    }
+
+    public function getContainer()
+    {
+        return $this->getInjectorLoader()->getManifest();
+    }
+
+    public function setInjectorLoader(InjectorLoader $injectorLoader)
+    {
+        $this->injectorLoader = $injectorLoader;
+        $injectorLoader
+            ->getManifest()
+            ->registerService($this, Kernel::class);
+        return $this;
+    }
+
+    public function getInjectorLoader()
+    {
+        return $this->injectorLoader;
+    }
+
+    public function getClassLoader()
+    {
+        return $this->classLoader;
+    }
+
+    public function setClassLoader(ClassLoader $classLoader)
+    {
+        $this->classLoader = $classLoader;
+        return $this;
+    }
+
+    public function getModuleLoader()
+    {
+        return $this->moduleLoader;
+    }
+
+    public function setModuleLoader(ModuleLoader $moduleLoader)
+    {
+        $this->moduleLoader = $moduleLoader;
+        return $this;
+    }
+
+    public function setEnvironment($environment)
+    {
+        if (!in_array($environment, [self::DEV, self::TEST, self::LIVE, null])) {
+            throw new InvalidArgumentException(
+                "Director::set_environment_type passed '$environment'.  It should be passed dev, test, or live"
+            );
+        }
+        $this->enviroment = $environment;
+        return $this;
+    }
+
+    public function getConfigLoader()
+    {
+        return $this->configLoader;
+    }
+
+    public function setConfigLoader($configLoader)
+    {
+        $this->configLoader = $configLoader;
+        return $this;
+    }
+
+    public function getThemeResourceLoader()
+    {
+        return $this->themeResourceLoader;
+    }
+
+    public function setThemeResourceLoader($themeResourceLoader)
+    {
+        $this->themeResourceLoader = $themeResourceLoader;
+        return $this;
+    }
+}

src/Core/CoreKernel.php

@@ -2,190 +2,30 @@
 
 namespace SilverStripe\Core;
 
-use InvalidArgumentException;
-use Monolog\Handler\StreamHandler;
-use Monolog\Logger;
-use Psr\Log\LoggerInterface;
-use SilverStripe\Config\Collections\CachedConfigCollection;
-use SilverStripe\Control\Director;
-use SilverStripe\Control\HTTPResponse;
 use SilverStripe\Control\HTTPResponse_Exception;
-use SilverStripe\Core\Cache\ManifestCacheFactory;
-use SilverStripe\Core\Config\ConfigLoader;
-use SilverStripe\Core\Config\CoreConfigFactory;
-use SilverStripe\Core\Injector\Injector;
-use SilverStripe\Core\Injector\InjectorLoader;
-use SilverStripe\Core\Injector\SilverStripeServiceConfigurationLocator;
-use SilverStripe\Core\Manifest\ClassLoader;
-use SilverStripe\Core\Manifest\ClassManifest;
-use SilverStripe\Core\Manifest\ModuleLoader;
-use SilverStripe\Core\Manifest\ModuleManifest;
-use SilverStripe\Dev\DebugView;
 use SilverStripe\Dev\Install\DatabaseAdapterRegistry;
-use SilverStripe\Logging\ErrorHandler;
 use SilverStripe\ORM\DB;
-use SilverStripe\View\PublicThemes;
+use Exception;
-use SilverStripe\View\SSViewer;
-use SilverStripe\View\ThemeManifest;
-use SilverStripe\View\ThemeResourceLoader;
-use SilverStripe\Dev\Deprecation;
 
 /**
  * Simple Kernel container
  */
-class CoreKernel implements Kernel
+class CoreKernel extends BaseKernel
 {
-    /**
-     * @var Kernel
-     */
-    protected $nestedFrom = null;
-
-    /**
-     * @var Injector
-     */
-    protected $container = null;
-
-    /**
-     * @var string
-     */
-    protected $environment = null;
-
-    /**
-     * @var ClassLoader
-     */
-    protected $classLoader = null;
-
-    /**
-     * @var ModuleLoader
-     */
-    protected $moduleLoader = null;
-
-    /**
-     * @var ConfigLoader
-     */
-    protected $configLoader = null;
-
-    /**
-     * @var InjectorLoader
-     */
-    protected $injectorLoader = null;
-
-    /**
-     * @var ThemeResourceLoader
-     */
-    protected $themeResourceLoader = null;
-
-    protected $basePath = null;
-
-    /**
-     * Indicates whether the Kernel has been booted already
-     *
-     * @var bool
-     */
-    private $booted = false;
 
     /**
      * Indicates whether the Kernel has been flushed on boot
-     * Uninitialized before boot
+     * Uninitialised before boot
      *
      * @var bool
      */
     private $flush;
 
     /**
-     * Create a new kernel for this application
+     * @param false $flush
-     *
+     * @throws HTTPResponse_Exception
-     * @param string $basePath Path to base dir for this application
+     * @throws Exception
      */
-    public function __construct($basePath)
-    {
-        $this->basePath = $basePath;
-
-        // Initialise the dependency injector as soon as possible, as it is
-        // subsequently used by some of the following code
-        $injectorLoader = InjectorLoader::inst();
-        $injector = new Injector(['locator' => SilverStripeServiceConfigurationLocator::class]);
-        $injectorLoader->pushManifest($injector);
-        $this->setInjectorLoader($injectorLoader);
-
-        // Manifest cache factory
-        $manifestCacheFactory = $this->buildManifestCacheFactory();
-
-        // Class loader
-        $classLoader = ClassLoader::inst();
-        $classLoader->pushManifest(new ClassManifest($basePath, $manifestCacheFactory));
-        $this->setClassLoader($classLoader);
-
-        // Module loader
-        $moduleLoader = ModuleLoader::inst();
-        $moduleManifest = new ModuleManifest($basePath, $manifestCacheFactory);
-        $moduleLoader->pushManifest($moduleManifest);
-        $this->setModuleLoader($moduleLoader);
-
-        // Config loader
-        // @todo refactor CoreConfigFactory
-        $configFactory = new CoreConfigFactory($manifestCacheFactory);
-        $configManifest = $configFactory->createRoot();
-        $configLoader = ConfigLoader::inst();
-        $configLoader->pushManifest($configManifest);
-        $this->setConfigLoader($configLoader);
-
-        // Load template manifest
-        $themeResourceLoader = ThemeResourceLoader::inst();
-        $themeResourceLoader->addSet(SSViewer::PUBLIC_THEME, new PublicThemes());
-        $themeResourceLoader->addSet(SSViewer::DEFAULT_THEME, new ThemeManifest(
-            $basePath,
-            null, // project is defined in config, and this argument is deprecated
-            $manifestCacheFactory
-        ));
-        $this->setThemeResourceLoader($themeResourceLoader);
-    }
-
-    /**
-     * Get the environment type
-     *
-     * @return string
-     *
-     * @deprecated 5.0 use Director::get_environment_type() instead. Since 5.0 it should return only if kernel overrides. No checking SESSION or Environment.
-     */
-    public function getEnvironment()
-    {
-        // Check set
-        if ($this->environment) {
-            return $this->environment;
-        }
-
-        // Check saved session
-        $env = $this->sessionEnvironment();
-        if ($env) {
-            return $env;
-        }
-
-        // Check getenv
-        if ($env = Environment::getEnv('SS_ENVIRONMENT_TYPE')) {
-            return $env;
-        }
-
-        return self::LIVE;
-    }
-
-    /**
-     * Check or update any temporary environment specified in the session.
-     *
-     * @return null|string
-     *
-     * @deprecated 5.0 Use Director::get_session_environment_type() instead
-     */
-    protected function sessionEnvironment()
-    {
-        if (!$this->booted) {
-            // session is not initialized yet, neither is manifest
-            return null;
-        }
-
-        return Director::get_session_environment_type();
-    }
-
     public function boot($flush = false)
     {
         $this->flush = $flush;
@@ -198,22 +38,23 @@ class CoreKernel implements Kernel
         $this->bootDatabaseGlobals();
         $this->validateDatabase();
 
-        $this->booted = true;
+        $this->setBooted(true);
     }
 
     /**
-     * Include all _config.php files
+     * Check that the database configuration is valid, throwing an HTTPResponse_Exception if it's not
+     *
+     * @throws HTTPResponse_Exception
      */
-    protected function bootConfigs()
+    protected function validateDatabase()
     {
-        global $project;
+        $databaseConfig = DB::getConfig();
-        $projectBefore = $project;
+        // Gracefully fail if no DB is configured
-        $config = ModuleManifest::config();
+        if (empty($databaseConfig['database'])) {
-        // After loading all other app manifests, include _config.php files
+            $msg = 'Silverstripe Framework requires a "database" key in DB::getConfig(). ' .
-        $this->getModuleLoader()->getManifest()->activateConfig();
+                'Did you forget to set SS_DATABASE_NAME or SS_DATABASE_CHOOSE_NAME in your environment?';
-        if ($project && $project !== $projectBefore) {
+            $this->detectLegacyEnvironment();
-            Deprecation::notice('5.0', '$project global is deprecated');
+            $this->redirectToInstaller($msg);
-            $config->set('project', $project);
         }
     }
 
@@ -260,80 +101,6 @@ class CoreKernel implements Kernel
         DB::setConfig($databaseConfig);
     }
 
-    /**
-     * Check that the database configuration is valid, throwing an HTTPResponse_Exception if it's not
-     *
-     * @throws HTTPResponse_Exception
-     */
-    protected function validateDatabase()
-    {
-        $databaseConfig = DB::getConfig();
-        // Gracefully fail if no DB is configured
-        if (empty($databaseConfig['database'])) {
-            $msg = 'Silverstripe Framework requires a "database" key in DB::getConfig(). ' .
-                'Did you forget to set SS_DATABASE_NAME or SS_DATABASE_CHOOSE_NAME in your environment?';
-            $this->detectLegacyEnvironment();
-            $this->redirectToInstaller($msg);
-        }
-    }
-
-    /**
-     * Check if there's a legacy _ss_environment.php file
-     *
-     * @throws HTTPResponse_Exception
-     */
-    protected function detectLegacyEnvironment()
-    {
-        // Is there an _ss_environment.php file?
-        if (!file_exists($this->basePath . '/_ss_environment.php') &&
-            !file_exists(dirname($this->basePath) . '/_ss_environment.php')
-        ) {
-            return;
-        }
-
-        // Build error response
-        $dv = new DebugView();
-        $body = implode([
-            $dv->renderHeader(),
-            $dv->renderInfo(
-                "Configuration Error",
-                Director::absoluteBaseURL()
-            ),
-            $dv->renderParagraph(
-                'You need to replace your _ss_environment.php file with a .env file, or with environment variables.<br><br>'
-                . 'See the <a href="https://docs.silverstripe.org/en/4/getting_started/environment_management/">'
-                . 'Environment Management</a> docs for more information.'
-            ),
-            $dv->renderFooter()
-        ]);
-
-        // Raise error
-        $response = new HTTPResponse($body, 500);
-        throw new HTTPResponse_Exception($response);
-    }
-
-    /**
-     * If missing configuration, redirect to install.php if it exists.
-     * Otherwise show a server error to the user.
-     *
-     * @param string $msg Optional message to show to the user on an installed project (install.php missing).
-     */
-    protected function redirectToInstaller($msg = '')
-    {
-        // Error if installer not available
-        if (!file_exists(Director::publicFolder() . '/install.php')) {
-            throw new HTTPResponse_Exception(
-                $msg,
-                500
-            );
-        }
-
-        // Redirect to installer
-        $response = new HTTPResponse();
-        $response->redirect(Director::absoluteURL('install.php'));
-        throw new HTTPResponse_Exception($response);
-    }
-
     /**
      * Load database config from environment
      *
@@ -451,247 +218,6 @@ class CoreKernel implements Kernel
         return null;
     }
 
-    /**
-     * Initialise PHP with default variables
-     */
-    protected function bootPHP()
-    {
-        if ($this->getEnvironment() === self::LIVE) {
-            // limited to fatal errors and warnings in live mode
-            error_reporting(E_ALL & ~(E_DEPRECATED | E_STRICT | E_NOTICE));
-        } else {
-            // Report all errors in dev / test mode
-            error_reporting(E_ALL | E_STRICT);
-        }
-
-        /**
-         * Ensure we have enough memory
-         */
-        Environment::increaseMemoryLimitTo('64M');
-
-        // Ensure we don't run into xdebug's fairly conservative infinite recursion protection limit
-        if (function_exists('xdebug_enable')) {
-            $current = ini_get('xdebug.max_nesting_level');
-            if ((int)$current < 200) {
-                ini_set('xdebug.max_nesting_level', 200);
-            }
-        }
-
-        /**
-         * Set default encoding
-         */
-        mb_http_output('UTF-8');
-        mb_internal_encoding('UTF-8');
-        mb_regex_encoding('UTF-8');
-
-        /**
-         * Enable better garbage collection
-         */
-        gc_enable();
-    }
-
-    /**
-     * @return ManifestCacheFactory
-     */
-    protected function buildManifestCacheFactory()
-    {
-        return new ManifestCacheFactory([
-            'namespace' => 'manifestcache',
-            'directory' => TEMP_PATH,
-        ]);
-    }
-
-    /**
-     * @return bool
-     */
-    protected function getIncludeTests()
-    {
-        return false;
-    }
-
-    /**
-     * When manifests are discovering files, tests files in modules using the following CI library type will be ignored.
-     *
-     * The purpose of this method is to avoid loading PHPUnit test files with incompatible definitions.
-     *
-     * @return string[] List of CI types to ignore as defined by `Module`.
-     */
-    protected function getIgnoredCIConfigs(): array
-    {
-        return [];
-    }
-
-    /**
-     * Boot all manifests
-     *
-     * @param bool $flush
-     */
-    protected function bootManifests($flush)
-    {
-        // Setup autoloader
-        $this->getClassLoader()->init(
-            $this->getIncludeTests(),
-            $flush,
-            $this->getIgnoredCIConfigs()
-        );
-
-        // Find modules
-        $this->getModuleLoader()->init(
-            $this->getIncludeTests(),
-            $flush,
-            $this->getIgnoredCIConfigs()
-        );
-
-        // Flush config
-        if ($flush) {
-            $config = $this->getConfigLoader()->getManifest();
-            if ($config instanceof CachedConfigCollection) {
-                $config->setFlush(true);
-            }
-        }
-        // tell modules to sort, now that config is available
-        $this->getModuleLoader()->getManifest()->sort();
-
-        // Find default templates
-        $defaultSet = $this->getThemeResourceLoader()->getSet('$default');
-        if ($defaultSet instanceof ThemeManifest) {
-            $defaultSet->setProject(
-                ModuleManifest::config()->get('project')
-            );
-            $defaultSet->init(
-                $this->getIncludeTests(),
-                $flush,
-                $this->getIgnoredCIConfigs()
-            );
-        }
-    }
-
-    /**
-     * Turn on error handling
-     */
-    protected function bootErrorHandling()
-    {
-        // Register error handler
-        $errorHandler = Injector::inst()->get(ErrorHandler::class);
-        $errorHandler->start();
-
-        // Register error log file
-        $errorLog = Environment::getEnv('SS_ERROR_LOG');
-        if ($errorLog) {
-            $logger = Injector::inst()->get(LoggerInterface::class);
-            if ($logger instanceof Logger) {
-                $logger->pushHandler(new StreamHandler($this->basePath . '/' . $errorLog, Logger::WARNING));
-            } else {
-                user_error("SS_ERROR_LOG setting only works with Monolog, you are using another logger", E_USER_WARNING);
-            }
-        }
-    }
-
-    public function shutdown()
-    {
-    }
-
-    public function nest()
-    {
-        // Clone this kernel, nesting config / injector manifest containers
-        $kernel = clone $this;
-        $kernel->setConfigLoader($this->configLoader->nest());
-        $kernel->setInjectorLoader($this->injectorLoader->nest());
-        $kernel->nestedFrom = $this;
-        return $kernel;
-    }
-
-    public function activate()
-    {
-        $this->configLoader->activate();
-        $this->injectorLoader->activate();
-
-        // Self register
-        $this->getInjectorLoader()
-            ->getManifest()
-            ->registerService($this, Kernel::class);
-        return $this;
-    }
-
-    public function getNestedFrom()
-    {
-        return $this->nestedFrom;
-    }
-
-    public function getContainer()
-    {
-        return $this->getInjectorLoader()->getManifest();
-    }
-
-    public function setInjectorLoader(InjectorLoader $injectorLoader)
-    {
-        $this->injectorLoader = $injectorLoader;
-        $injectorLoader
-            ->getManifest()
-            ->registerService($this, Kernel::class);
-        return $this;
-    }
-
-    public function getInjectorLoader()
-    {
-        return $this->injectorLoader;
-    }
-
-    public function getClassLoader()
-    {
-        return $this->classLoader;
-    }
-
-    public function setClassLoader(ClassLoader $classLoader)
-    {
-        $this->classLoader = $classLoader;
-        return $this;
-    }
-
-    public function getModuleLoader()
-    {
-        return $this->moduleLoader;
-    }
-
-    public function setModuleLoader(ModuleLoader $moduleLoader)
-    {
-        $this->moduleLoader = $moduleLoader;
-        return $this;
-    }
-
-    public function setEnvironment($environment)
-    {
-        if (!in_array($environment, [self::DEV, self::TEST, self::LIVE, null])) {
-            throw new InvalidArgumentException(
-                "Director::set_environment_type passed '$environment'.  It should be passed dev, test, or live"
-            );
-        }
-        $this->environment = $environment;
-        return $this;
-    }
-
-    public function getConfigLoader()
-    {
-        return $this->configLoader;
-    }
-
-    public function setConfigLoader($configLoader)
-    {
-        $this->configLoader = $configLoader;
-        return $this;
-    }
-
-    public function getThemeResourceLoader()
-    {
-        return $this->themeResourceLoader;
-    }
-
-    public function setThemeResourceLoader($themeResourceLoader)
-    {
-        $this->themeResourceLoader = $themeResourceLoader;
-        return $this;
-    }
-
     /**
      * Returns whether the Kernel has been flushed on boot
      *

src/Core/DatabaselessKernel.php

@@ -0,0 +1,63 @@
+<?php
+
+namespace SilverStripe\Core;
+
+use Exception;
+
+/**
+ * Boot a kernel without requiring a database connection.
+ * This is a workaround for the lack of composition in the boot stages
+ * of CoreKernel, as well as for the framework's misguided assumptions
+ * around the availability of a database for every execution path.
+ *
+ * @internal
+ */
+class DatabaselessKernel extends BaseKernel
+{
+    /**
+     * Indicates whether the Kernel has been flushed on boot
+     * Uninitialised before boot
+     *
+     * @var bool
+     */
+    private $flush;
+
+    /**
+     * Allows disabling of the configured error handling.
+     * This can be useful to ensure the execution context (e.g. composer)
+     * can consistently use its own error handling.
+     *
+     * @var boolean
+     */
+    protected $bootErrorHandling = true;
+
+    public function setBootErrorHandling(bool $bool)
+    {
+        $this->bootErrorHandling = $bool;
+        return $this;
+    }
+
+    /**
+     * @param false $flush
+     * @throws Exception
+     */
+    public function boot($flush = false)
+    {
+        $this->flush = $flush;
+
+        $this->bootPHP();
+        $this->bootManifests($flush);
+        $this->bootErrorHandling();
+        $this->bootConfigs();
+
+        $this->setBooted(true);
+    }
+
+    /**
+     * @return bool
+     */
+    public function isFlushed()
+    {
+        return $this->flush;
+    }
+}

src/ORM/Connect/NullDatabase.php

@@ -0,0 +1,336 @@
+<?php
+
+namespace SilverStripe\ORM\Connect;
+
+use BadMethodCallException;
+use Exception;
+
+/**
+ * Utility class required due to bad coupling in framework.
+ * Not every framework execution should require a working database connection.
+ * For example, when generating class and config manifests for deployment bundles,
+ * or when generating code in a silverstripe/graphql schema build.
+ *
+ * This class creates the required no-ops to fulfill the contract,
+ * and create exceptions as required.
+ *
+ * It also avoids introducing new third party core dependencies that
+ * would be required with https://github.com/tractorcow/silverstripe-proxy-db.
+ *
+ * @internal
+ */
+class NullDatabase extends Database
+{
+    /**
+     * @var string
+     */
+    private $errorMessage = 'Using NullDatabase, cannot interact with database';
+
+    /**
+     * @var string
+     */
+    private $queryErrorMessage = 'Using NullDatabase, cannot execute query: %s';
+
+    /**
+     * @param string $msg
+     */
+    public function setErrorMessage(string $msg): self
+    {
+        $this->errorMessage = $msg;
+        return $this;
+    }
+
+    /**
+     * @param string $msg
+     */
+    public function setQueryErrorMessage(string $msg): self
+    {
+        $this->queryErrorMessage = $msg;
+        return $this;
+    }
+
+    /**
+     * @throws NullDatabaseException
+     */
+    public function query($sql, $errorLevel = E_USER_ERROR)
+    {
+        throw new NullDatabaseException(sprintf($this->queryErrorMessage, $sql));
+    }
+
+    /**
+     * @throws NullDatabaseException
+     */
+    public function preparedQuery($sql, $parameters, $errorLevel = E_USER_ERROR)
+    {
+        throw new NullDatabaseException(sprintf($this->queryErrorMessage, $sql));
+    }
+
+    /**
+     * @throws NullDatabaseException
+     */
+    public function getConnector()
+    {
+        throw new NullDatabaseException($this->errorMessage);
+    }
+
+    /**
+     * @throws NullDatabaseException
+     */
+    public function getSchemaManager()
+    {
+        throw new NullDatabaseException($this->errorMessage);
+    }
+
+    /**
+     * @throws NullDatabaseException
+     */
+    public function getQueryBuilder()
+    {
+        throw new NullDatabaseException($this->errorMessage);
+    }
+
+
+    public function getGeneratedID($table)
+    {
+        // no-op
+    }
+
+    public function isActive()
+    {
+        return true;
+    }
+
+    public function escapeString($value)
+    {
+        return $value;
+    }
+
+    public function quoteString($value)
+    {
+        return $value;
+    }
+
+    public function escapeIdentifier($value, $separator = '.')
+    {
+        return $value;
+    }
+
+    protected function escapeColumnKeys($fieldValues)
+    {
+        return $fieldValues;
+    }
+
+    /**
+     * @throws NullDatabaseException
+     */
+    public function manipulate($manipulation)
+    {
+        throw new NullDatabaseException($this->errorMessage);
+    }
+
+    /**
+     * @throws NullDatabaseException
+     */
+    public function clearAllData()
+    {
+        throw new NullDatabaseException($this->errorMessage);
+    }
+
+    /**
+     * @throws NullDatabaseException
+     */
+    public function clearTable($table)
+    {
+        throw new NullDatabaseException($this->errorMessage);
+    }
+
+    public function nullCheckClause($field, $isNull)
+    {
+        return '';
+    }
+
+    public function comparisonClause(
+        $field,
+        $value,
+        $exact = false,
+        $negate = false,
+        $caseSensitive = null,
+        $parameterised = false
+    ) {
+        return '';
+    }
+
+    public function formattedDatetimeClause($date, $format)
+    {
+        return '';
+    }
+
+    public function datetimeIntervalClause($date, $interval)
+    {
+        return '';
+    }
+
+    public function datetimeDifferenceClause($date1, $date2)
+    {
+        return '';
+    }
+
+    public function concatOperator()
+    {
+        return '';
+    }
+
+    public function supportsCollations()
+    {
+        return false;
+    }
+
+    public function supportsTimezoneOverride()
+    {
+        return false;
+    }
+
+    public function getVersion()
+    {
+        return '';
+    }
+
+    public function getDatabaseServer()
+    {
+        return '';
+    }
+
+    public function affectedRows()
+    {
+        return 0;
+    }
+
+    public function searchEngine(
+        $classesToSearch,
+        $keywords,
+        $start,
+        $pageLength,
+        $sortBy = "Relevance DESC",
+        $extraFilter = "",
+        $booleanSearch = false,
+        $alternativeFileFilter = "",
+        $invertedMatch = false
+    ) {
+        // no-op
+    }
+
+    public function supportsTransactions()
+    {
+        return false;
+    }
+
+    public function supportsSavepoints()
+    {
+        return false;
+    }
+
+
+    public function supportsTransactionMode(string $mode): bool
+    {
+        return false;
+    }
+
+    public function withTransaction(
+        $callback,
+        $errorCallback = null,
+        $transactionMode = false,
+        $errorIfTransactionsUnsupported = false
+    ) {
+        // no-op
+    }
+
+    public function supportsExtensions($extensions)
+    {
+        return false;
+    }
+
+    public function transactionStart($transactionMode = false, $sessionCharacteristics = false)
+    {
+        // no-op
+    }
+
+    public function transactionSavepoint($savepoint)
+    {
+        // no-op
+    }
+
+    public function transactionRollback($savepoint = false)
+    {
+        // no-op
+    }
+
+    public function transactionEnd($chain = false)
+    {
+        // no-op
+    }
+
+    public function transactionDepth()
+    {
+        return 0;
+    }
+
+    public function supportsLocks()
+    {
+        return false;
+    }
+
+    public function canLock($name)
+    {
+        return false;
+    }
+
+    public function getLock($name, $timeout = 5)
+    {
+        return false;
+    }
+
+    public function releaseLock($name)
+    {
+        return false;
+    }
+
+    public function connect($parameters)
+    {
+        // no-op
+    }
+
+    public function databaseExists($name)
+    {
+        return false;
+    }
+
+    public function databaseList()
+    {
+        return [];
+    }
+
+    public function selectDatabase($name, $create = false, $errorLevel = E_USER_ERROR)
+    {
+        // no-op
+    }
+
+    public function dropSelectedDatabase()
+    {
+        // no-op
+    }
+
+    public function getSelectedDatabase()
+    {
+        // no-op
+    }
+
+    public function now()
+    {
+        return '';
+    }
+
+    public function random()
+    {
+        return '';
+    }
+}

src/ORM/Connect/NullDatabaseException.php

@@ -0,0 +1,12 @@
+<?php
+namespace SilverStripe\ORM\Connect;
+
+use LogicException;
+
+/**
+ * Exception thrown when a database operation is attempted on a `NullDatabase`.
+ * @internal
+ */
+class NullDatabaseException extends LogicException
+{
+}