Introduce IterableConfig

Bug: T301544
Change-Id: I0a93ebb5305f95cf1b12df276f25a44195fedafa

5 files changed, 113 insertions, 4 deletions

diff --git a/includes/Settings/Config/ArrayConfigBuilder.php b/includes/Settings/Config/ArrayConfigBuilder.php
index 300590278680..61790eba7b83 100644
--- a/includes/Settings/Config/ArrayConfigBuilder.php
+++ b/includes/Settings/Config/ArrayConfigBuilder.php
@@ -4,6 +4,7 @@ namespace MediaWiki\Settings\Config;
 
 use Config;
 use HashConfig;
+use MediaWiki\Config\IterableConfig;
 
 class ArrayConfigBuilder implements ConfigBuilder {
 
@@ -30,7 +31,8 @@ class ArrayConfigBuilder implements ConfigBuilder {
 	/**
 	 * Build the configuration.
 	 *
-	 * @return Config
+	 * @todo Once we can use PHP 7.4, change the return type declaration to IterableConfig.
+	 * @return IterableConfig
 	 */
 	public function build(): Config {
 		return new HashConfig( $this->config );
diff --git a/includes/config/HashConfig.php b/includes/config/HashConfig.php
index d020d20fe01c..36311b4490fe 100644
--- a/includes/config/HashConfig.php
+++ b/includes/config/HashConfig.php
@@ -20,12 +20,14 @@
  * @file
  */
 
+use MediaWiki\Config\IterableConfig;
+
 /**
  * A Config instance which stores all settings as a member variable
  *
  * @since 1.24
  */
-class HashConfig implements Config, MutableConfig {
+class HashConfig implements Config, MutableConfig, IterableConfig {
 
 	/**
 	 * Array of config settings
@@ -75,4 +77,22 @@ class HashConfig implements Config, MutableConfig {
 	public function set( $name, $value ) {
 		$this->settings[$name] = $value;
 	}
+
+	/**
+	 * @inheritDoc
+	 * @since 1.38
+	 * @return Traversable
+	 */
+	public function getIterator(): Traversable {
+		return new ArrayIterator( $this->settings );
+	}
+
+	/**
+	 * @inheritDoc
+	 * @since 1.38
+	 * @return string[]
+	 */
+	public function getNames(): array {
+		return array_keys( $this->settings );
+	}
 }
diff --git a/includes/config/IterableConfig.php b/includes/config/IterableConfig.php
new file mode 100644
index 000000000000..7584cc518078
--- /dev/null
+++ b/includes/config/IterableConfig.php
@@ -0,0 +1,52 @@
+<?php
+/**
+ * Interface for iterable configuration instances.
+ *
+ * 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\Config;
+
+use Config;
+use IteratorAggregate;
+use Traversable;
+
+/**
+ * Interface for iterable configuration instances.
+ *
+ * @stable to implement
+ *
+ * @since 1.38
+ */
+interface IterableConfig extends Config, IteratorAggregate {
+
+	/**
+	 * Returns a traversable view of the configuration variables in this Config object.
+	 *
+	 * @return Traversable<string,mixed>
+	 */
+	public function getIterator(): Traversable;
+
+	/**
+	 * Returns the names of configuration variables in this Config object.
+	 *
+	 * @return string[]
+	 */
+	public function getNames(): array;
+
+}
diff --git a/tests/phpunit/unit/includes/Settings/Config/ArrayConfigBuilderTest.php b/tests/phpunit/unit/includes/Settings/Config/ArrayConfigBuilderTest.php
index e67904bbc7df..fa1bed069917 100644
--- a/tests/phpunit/unit/includes/Settings/Config/ArrayConfigBuilderTest.php
+++ b/tests/phpunit/unit/includes/Settings/Config/ArrayConfigBuilderTest.php
@@ -2,6 +2,7 @@
 
 namespace MediaWiki\Tests\Unit\Settings\Config;
 
+use MediaWiki\Config\IterableConfig;
 use MediaWiki\Settings\Config\ArrayConfigBuilder;
 use MediaWiki\Settings\Config\ConfigBuilder;
 use PHPUnit\Framework\TestCase;
@@ -32,7 +33,12 @@ class ArrayConfigBuilderTest extends TestCase {
 		$this->builder
 			->set( 'foo',  'bar' )
 			->set( 'baz', 'quu' );
-		$this->assertSame( 'bar', $this->builder->build()->get( 'foo' ) );
-		$this->assertSame( 'quu', $this->builder->build()->get( 'baz' ) );
+
+		$config = $this->builder->build();
+
+		$this->assertInstanceOf( IterableConfig::class, $config );
+		$this->assertSame( 'bar', $config->get( 'foo' ) );
+		$this->assertSame( 'quu', $config->get( 'baz' ) );
+		$this->assertSame( [ 'foo', 'baz' ], $config->getNames() );
 	}
 }
diff --git a/tests/phpunit/unit/includes/config/HashConfigTest.php b/tests/phpunit/unit/includes/config/HashConfigTest.php
index 97815ef27e1a..17d176ae8757 100644
--- a/tests/phpunit/unit/includes/config/HashConfigTest.php
+++ b/tests/phpunit/unit/includes/config/HashConfigTest.php
@@ -61,4 +61,33 @@ class HashConfigTest extends \MediaWikiUnitTestCase {
 		$conf->set( 'one', '3' );
 		$this->assertSame( '3', $conf->get( 'one' ) );
 	}
+
+	/**
+	 * @covers HashConfig::getNames
+	 */
+	public function testGetNames() {
+		$conf = new HashConfig( [
+			'one' => '1',
+		] );
+		$conf->set( 'two', '2' );
+
+		$this->assertSame( [ 'one', 'two' ], $conf->getNames() );
+	}
+
+	/**
+	 * @covers HashConfig::getIterator
+	 */
+	public function testTraversable() {
+		$conf = new HashConfig( [
+			'one' => '1',
+		] );
+		$conf->set( 'two', '2' );
+
+		$actual = [];
+		foreach ( $conf as $name => $value ) {
+			$actual[$name] = $value;
+		}
+
+		$this->assertSame( [ 'one' => '1', 'two' => '2' ], $actual );
+	}
 }