Make CliInstaller control the processing logic of the error

Previously, if there was an error during CLI installation,
CliInstaller::showStatusMessage() exited the script directly. The exit
timing of the script should be given to the caller, not the callee.
So, I coding:
[1] Remove `exit()` from CliInstaller::showStatusMessage()
[2] Make the callee to return Status, the caller determine how to handle these Status
[3] Strictly check the key database type instead of just outputting message

Bug: T46511
Change-Id: I72ffd33fe5c592b9ea78f37bae5a9c081295c624

autoload.php

@@ -884,6 +884,7 @@ $wgAutoloadLocalClasses = [
 	'MediaWiki\\Diff\\WordAccumulator' => __DIR__ . '/includes/diff/WordAccumulator.php',
 	'MediaWiki\\HeaderCallback' => __DIR__ . '/includes/HeaderCallback.php',
 	'MediaWiki\\Http\\HttpRequestFactory' => __DIR__ . '/includes/http/HttpRequestFactory.php',
+	'MediaWiki\\Installer\\InstallException' => __DIR__ . '/includes/installer/InstallException.php',
 	'MediaWiki\\Interwiki\\ClassicInterwikiLookup' => __DIR__ . '/includes/interwiki/ClassicInterwikiLookup.php',
 	'MediaWiki\\Interwiki\\InterwikiLookup' => __DIR__ . '/includes/interwiki/InterwikiLookup.php',
 	'MediaWiki\\Interwiki\\InterwikiLookupAdapter' => __DIR__ . '/includes/interwiki/InterwikiLookupAdapter.php',

includes/installer/CliInstaller.php

@@ -21,6 +21,7 @@
  * @ingroup Deployment
  */
 
+use MediaWiki\Installer\InstallException;
 use MediaWiki\MediaWikiServices;
 
 /**
@@ -51,6 +52,7 @@ class CliInstaller extends Installer {
 	 * @param string $siteName
 	 * @param string|null $admin
 	 * @param array $options
+	 * @throws InstallException
 	 */
 	function __construct( $siteName, $admin = null, array $options = [] ) {
 		global $wgContLang;
@@ -114,7 +116,7 @@ class CliInstaller extends Installer {
 			$status = $this->validateExtensions(
 				'extension', 'extensions', $options['extensions'] );
 			if ( !$status->isOK() ) {
-				$this->showStatusMessage( $status );
+				throw new InstallException( $status );
 			}
 			$this->setVar( '_Extensions', $status->value );
 		} elseif ( isset( $options['with-extensions'] ) ) {
@@ -125,7 +127,7 @@ class CliInstaller extends Installer {
 		if ( isset( $options['skins'] ) ) {
 			$status = $this->validateExtensions( 'skin', 'skins', $options['skins'] );
 			if ( !$status->isOK() ) {
-				$this->showStatusMessage( $status );
+				throw new InstallException( $status );
 			}
 			$skins = $status->value;
 		} else {
@@ -176,15 +178,23 @@ class CliInstaller extends Installer {
 
 		$vars = Installer::getExistingLocalSettings();
 		if ( $vars ) {
-			$this->showStatusMessage(
-				Status::newFatal( "config-localsettings-cli-upgrade" )
-			);
+			$status = Status::newFatal( "config-localsettings-cli-upgrade" );
+			$this->showStatusMessage( $status );
+			return $status;
 		}
 
-		$this->performInstallation(
+		$result = $this->performInstallation(
 			[ $this, 'startStage' ],
 			[ $this, 'endStage' ]
 		);
+		// PerformInstallation bails on a fatal, so make sure the last item
+		// completed before giving 'next.' Likewise, only provide back on failure
+		$lastStepStatus = end( $result );
+		if ( $lastStepStatus->isOk() ) {
+			return Status::newGood();
+		} else {
+			return $lastStepStatus;
+		}
 	}
 
 	/**
@@ -248,11 +258,6 @@ class CliInstaller extends Installer {
 				$this->showMessage( ...$w );
 			}
 		}
-
-		if ( !$status->isOK() ) {
-			echo "\n";
-			exit( 1 );
-		}
 	}
 
 	public function envCheckPath() {

includes/installer/InstallException.php

@@ -0,0 +1,51 @@
+<?php
+/**
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+namespace MediaWiki\Installer;
+
+use Throwable;
+
+/**
+ * Exception thrown if an error occur which installation
+ * @ingroup Exception
+ */
+class InstallException extends \MWException {
+	/**
+	 * @var \Status State when an exception occurs
+	 */
+	private $status;
+
+	/**
+	 * InstallException constructor.
+	 * @param \Status $status State when an exception occurs
+	 * @param string $message The Exception message to throw
+	 * @param int $code The Exception code
+	 * @param Throwable|null $previous The previous throwable used for the exception chaining
+	 */
+	public function __construct( \Status $status, $message = '', $code = 0,
+		Throwable $previous = null ) {
+		parent::__construct( $message, $code, $previous );
+		$this->status = $status;
+	}
+
+	public function getStatus() : \Status {
+		return $this->status;
+	}
+}

includes/installer/Installer.php

@@ -756,6 +756,8 @@ abstract class Installer {
 	 */
 	protected function envCheckDB() {
 		global $wgLang;
+		/** @var string|null $dbType The user-specified database type */
+		$dbType = $this->getVar( 'wgDBtype' );
 
 		$allNames = [];
 
@@ -768,25 +770,27 @@ abstract class Installer {
 		$databases = $this->getCompiledDBs();
 
 		$databases = array_flip( $databases );
+		$ok = true;
 		foreach ( array_keys( $databases ) as $db ) {
 			$installer = $this->getDBInstaller( $db );
 			$status = $installer->checkPrerequisites();
 			if ( !$status->isGood() ) {
+				if ( !$this instanceof WebInstaller && $db === $dbType ) {
+					// Strictly check the key database type instead of just outputting message
+					// Note: No perform this check run from the web installer, since this method always called by
+					// the welcome page under web installation, so $dbType will always be 'mysql'
+					$ok = false;
+				}
 				$this->showStatusMessage( $status );
-			}
-			if ( !$status->isOK() ) {
 				unset( $databases[$db] );
 			}
 		}
 		$databases = array_flip( $databases );
 		if ( !$databases ) {
 			$this->showError( 'config-no-db', $wgLang->commaList( $allNames ), count( $allNames ) );
-
-			// @todo FIXME: This only works for the web installer!
 			return false;
 		}
-
-		return true;
+		return $ok;
 	}
 
 	/**
@@ -1586,7 +1590,7 @@ abstract class Installer {
 	 * @param callable $startCB A callback array for the beginning of each step
 	 * @param callable $endCB A callback array for the end of each step
 	 *
-	 * @return array Array of Status objects
+	 * @return Status[] Array of Status objects
 	 */
 	public function performInstallation( $startCB, $endCB ) {
 		$installResults = [];

maintenance/install.php

@@ -115,7 +115,12 @@ class CommandLineInstaller extends Maintenance {
 			$this->setPassOption();
 		}
 
-		$installer = InstallerOverrides::getCliInstaller( $siteName, $adminName, $this->mOptions );
+		try {
+			$installer = InstallerOverrides::getCliInstaller( $siteName, $adminName, $this->mOptions );
+		} catch ( \MediaWiki\Installer\InstallException $e ) {
+			$this->output( $e->getStatus()->getMessage()->parse() . "\n" );
+			return false;
+		}
 
 		$status = $installer->doEnvironmentChecks();
 		if ( $status->isGood() ) {
@@ -123,17 +128,21 @@ class CommandLineInstaller extends Maintenance {
 		} else {
 			$installer->showStatusMessage( $status );
 
-			return;
+			return false;
 		}
 		if ( !$envChecksOnly ) {
-			$installer->execute();
+			$status = $installer->execute();
+			if ( !$status->isGood() ) {
+				return false;
+			}
 			$installer->writeConfigurationFile( $this->getOption( 'confpath', $IP ) );
+			$installer->showMessage(
+				'config-install-success',
+				$installer->getVar( 'wgServer' ),
+				$installer->getVar( 'wgScriptPath' )
+			);
 		}
-		$installer->showMessage(
-			'config-install-success',
-			$installer->getVar( 'wgServer' ),
-			$installer->getVar( 'wgScriptPath' )
-		);
+		return true;
 	}
 
 	private function setDbPassOption() {